FM02 help sound is horrible [Archive] - Do It Yourself Christmas Forums

harrison0550

11-22-2011, 03:45 PM

After reading all the reviews here I thought this was going to be a good fm transmitter but currently it sounds 10 times worse than my moded tune cast. I really hope I'm doing something wrong.

Here is my setup:
Fm02 in metal enclosure
Dipole antenna built out of romex ground wire according to the wikki specs.
Pc power supply out of old computer
12' rg58 pre made with bnc fitting from radio shack

Station I'm using is 107.3 so I cut each side of the dipole to 26 1/8 inches.
Have replaced the audio cable twice now with no success.
Have tried 3 different audio devices. iPod, iPad, laptop.
Have turned the volume way do and up and everywhere in between to see if maybe I was just over diving the audio.

The sound is hollow and static both directly in front of my house and stays that way for close to a 1/4 mile away. Progressively getting worse the further I drive of course. Even my denon surrond sound receiver has trouble staying locked onto the signal and it's 25 ft away from the dipole antenna.

I don't know if it's a signal problem or sound problem as it won't stay clear long enough for me to tell. So stressed over this thing I want to trash it and go buy another belkin but with all the success you guys have had it makes me think I'm doing something wrong. Does anyone have any other suggestions?

a158946

11-22-2011, 04:00 PM

how is your dipole connected to the coax?

a158946

11-22-2011, 04:03 PM

I will also say, I'm having some issues myself as well, but not from multiple devices. I try an ipod, and it works flawlessly with much better range than my old tunecast. My issues are sound quality coming from PC I think. getting ready to try an add-in sound card instead of my onboard. also, I feel like i've got ferrite beads out the wazoo with my FM02. Not sure which ones I need / don't need at this point, with all the various steps I took to get the nice clean sound coming out of my iPod, but "if it works, don't fix it", right?

Materdaddy

11-22-2011, 04:03 PM

Try checking for continuity between legs of the antenna. Maybe it's shorted and therefore not radiating properly?

dirknerkle

11-22-2011, 04:09 PM

The problem is likely two-fold. For one, keep the volumne level down. The FM02 is pretty sensitive to that. Secondly, lose the PC power supply. It's a switching power supply and as such, is probably very, very noisy. Try the radio with a battery only and see if that makes a difference. If it's still noisy with a battery, then it's a transmitter problem. If it works fine with the battery, then the ps is the problem.

I've tried it with a PC power supply -- horribly noisy. I use a wall wart with some extra caps just before the power goes to the radio. Nice and quiet.

harrison0550

11-22-2011, 04:12 PM

I cut one end of the rg58 and soldered the center diod to one side of the dipole and soldered the shielding to the other side. I could be wrong here but I don't think it's a antenna problem because the rubber ducky test antenna does the same thing but in much shorter distances of course. Should I run to radio shack and grab ferrit beads for everything? I mean with the dipole it picks up further than I need it too but sounds like crap. It just seems there is no sweet spot in the volume. If I turn the pc volume down real low it gets more static in the truck and if I turn it up I get the shhhhhhhh at the end of every word.

jboyles7

11-22-2011, 04:14 PM

@ a158946:

If your iPod is good, then I highly recommend this external sound card:

http://us.store.creative.com/Creative-Sound-Blaster-XFi-Go-Pro/M/B0044DEDC0.htm

a158946

11-22-2011, 04:19 PM

If your iPod is good, then I highly recommend this external sound card:

http://us.store.creative.com/Creative-Sound-Blaster-XFi-Go-Pro/M/B0044DEDC0.htm

thanks, and sorry ( wasn't trying to hijack the thread)

ChiefWarrant

11-22-2011, 04:21 PM

Try Dirks battery test first, it could be getting noise from the PS. A ferrite bead will help a little, but not enough to make a big difference. If the battery test eliminates the problem then use a different power supply. I was able to get fairly decent results using a WallWart/Ferrite Beads/and a voltage regulator. It sounds 1000% better than my tunecast mod sounded.

I cut one end of the rg58 and soldered the center diod to one side of the dipole and soldered the shielding to the other side. I could be wrong here but I don't think it's a antenna problem because the rubber ducky test antenna does the same thing but in much shorter distances of course. Should I run to radio shack and grab ferrit beads for everything? I mean with the dipole it picks up further than I need it too but sounds like crap. It just seems there is no sweet spot in the volume. If I turn the pc volume down real low it gets more static in the truck and if I turn it up I get the shhhhhhhh at the end of every word.

harrison0550

11-22-2011, 05:11 PM

Alright sorry it took a min, I had to run to my storage unit and get a battery but phewww that seemed to clean the sound up nicely so now I need to figure out what all I need to get for the wall wart. I work for comcast so I have a bunch of different wall warts. Can I use the one I used to have on my belkin? It was crystal clear with it but is only 8V 500 mA. I also have one that says +12V 1.833A 22W. Any suggestions?

Oh I'm also still getting the shhhhhhhh at the end of some words but if I turn it down anymore then it would almost be muted.

Aurbo99

11-22-2011, 05:23 PM

Make sure your PC system sound volume is set to less than 50%, most of my hissing problems occurred with the sound above 50%

Dirk is right get it off the PC power supply and turn the system sound volume down.

Can you post a picture of your dipole?

harrison0550

11-22-2011, 05:38 PM

Unfortunately my wife has my digital camera in her car but it looks exactly like the one in the wikki. I used white 1" PVC and followed the directions to a "T".

I went ahead and hooked up the 8V power supply after reading another thread that said people have successfully got it working all the way down to 6V and since I knew the 8V supply was clean in the past I went ahead and hooked it up. It's sounding better and better but still seems like it's not great. Maybe I'm expecting to much here.

Oh and the volume is all the way down to 33.

harrison0550

11-22-2011, 11:42 PM

Sorry so late on the pics but turns out the wife didn't have my digital camera so I will have to use the camera phone until I can find it. I brought it inside and put it in an upstairs window because it started raining and became a pain to work outside anymore. Crazy thing is that between the power supply swap and moving it upstairs my sound quality has improved considerably. I think I may just leave it in the window.

Pics:
http://img573.imageshack.us/img573/2511/imagemsn.jpg
By harrison0550 (http://profile.imageshack.us/user/harrison0550) at 2011-11-22

http://img214.imageshack.us/img214/3440/imageuxp.jpg
By harrison0550 (http://profile.imageshack.us/user/harrison0550) at 2011-11-22

Pwmcguire

11-23-2011, 06:41 AM

This is what I use, get it all at radio shack, use a perf board, bend the component leads to each other and solder them to complete the circuit. Here is the website I pulled it from. http://www.dxing.info/equipment/wall_warts_bryant.dx

12333
I use a wall wart with some extra caps just before the power goes to the radio. Nice and quiet.

Aurbo99

11-23-2011, 08:16 AM

when you tested your reception quality.. did you remain "line of sight" with the antenna? ( is it mounted above your roof line?)

ukewarrior

11-23-2011, 09:00 AM

Folks may have 'tested' it at 8v, but the unit is designed to perform at stated specifications at 12V.
Noise is almost always due to issues external to the FM02.
These can be many. You need to try different cables and you need to have a ferrite bead on your cables.
Did you check out the wiki for guidance?
http://www.doityourselfchristmas.com/wiki/index.php?title=Vastelec_FM02

Unfortunately my wife has my digital camera in her car but it looks exactly like the one in the wikki. I used white 1" PVC and followed the directions to a "T".

I went ahead and hooked up the 8V power supply after reading another thread that said people have successfully got it working all the way down to 6V and since I knew the 8V supply was clean in the past I went ahead and hooked it up. It's sounding better and better but still seems like it's not great. Maybe I'm expecting to much here.

Oh and the volume is all the way down to 33.

CaptKirk

11-23-2011, 02:25 PM

I also have one that says +12V 1.833A 22W. Any suggestions?

The specs are fine- remember that the amperage is the MAX the power supply can supply- the FM02 will only use the current it needs. My guess from the amperage is that is actually a small switching power supply which will be well regulated (check it unloaded with your Multimeter- if it is within a volt or so of 12V then you are good to go). I am using something similar with great results. The down side to switchers is that some can have output "ripple" because of the switching technology. That is solved with filter caps but in my case I did not need to filter as the output seems to be clean.

macebobo

11-23-2011, 03:22 PM

I had a similar issue and I found it was 2 different problems. One was that the antenna connector was touching the metal enclosure so I made that hole bigger and second was RFI/EMI which was solved by a few snap chokes and putting them on the wall wart tamer input, the 12V FM02 input and the sound cable input. After this was in place, the sound is nice and clear.

Also, before I began sequencing, I normalized all the songs in my show with Audacity to make sure the levels were nearly equal and set the sound level of my computer to ~50%

Good luck and Happy Thanksgiving. -- John

harrison0550

11-23-2011, 04:19 PM

Folks may have 'tested' it at 8v, but the unit is designed to perform at stated specifications at 12V.
Noise is almost always due to issues external to the FM02.
These can be many. You need to try different cables and you need to have a ferrite bead on your cables.
Did you check out the wiki for guidance?
http://www.doityourselfchristmas.com/wiki/index.php?title=Vastelec_FM02

Thanks I went and got ferrite beads for all the cables today and the sound is much better now. Is there a problem leaving the 8V power supply on it this season? I'm a little scared to try the +12 1.833A one at this point because it just says ac adapter on it were the 8V says AC/DC. I can't afford to burn this thing up right now. My show lights up tomorrow night. I don't have any testers here to see what the unloaded voltage reading is.

macebobo

11-23-2011, 04:26 PM

Can you take a picture of the 12V one you have and post it here? Failing that, here is what I would do if it were me. I would trek out to Goodwill or your favorite thrift store and get a 9-12V AC to DC adapter and use that. Though some think you shouldn't use the 8V one, I sometimes take the "if it is working, leave it alone" strategy myself.

P.S. If you put your location in your profile, maybe there is someone close to you that could help a fellow DIY'er out. -- John

Thanks I went and got ferrite beads for all the cables today and the sound is much better now. Is there a problem leaving the 8V power supply on it this season? I'm a little scared to try the +12 1.833A one at this point because it just says ac adapter on it were the 8V says AC/DC. I can't afford to burn this thing up right now. My show lights up tomorrow night. I don't have any testers here to see what the unloaded voltage reading is.

ukewarrior

11-23-2011, 05:32 PM

If you get the results you want with 8v, then go ahead and use it !

Thanks I went and got ferrite beads for all the cables today and the sound is much better now. Is there a problem leaving the 8V power supply on it this season? I'm a little scared to try the +12 1.833A one at this point because it just says ac adapter on it were the 8V says AC/DC. I can't afford to burn this thing up right now. My show lights up tomorrow night. I don't have any testers here to see what the unloaded voltage reading is.

harrison0550

11-23-2011, 07:42 PM

Well scratch that, I get decent enough sound when it's hooked up to my iPad but the min I hook it up to any computer in the house it sounds like crap again. Just static like crazy! I went ahead and switched it over to the 12v power supply as well with no change in sound quality. This thing makes me so mad I want to punch a puppy!

macebobo

11-23-2011, 07:53 PM

In order to save a puppy:

1) Did you put a choke on your audio cable near the input of the FM02?
2) It could be the jack of your laptop is corroded (Grasping at straws here) - What does it sound like with a pair of headphones?
3) Send all puppies to live with a friend until this is resolved. (It's all I got)

12338

-- John

harrison0550

11-23-2011, 08:00 PM

1: yes I put a ferrit on it.
2: it sounds fine with anything other than the fm02 hooked up to it.
3: no puppies will be harmed in the destruction of the FM02.

LabRat

11-23-2011, 08:01 PM

Is the volume on the PC's turned *all the way* down? (ie. with ZERO volume.. are you still getting static? ) This can immediately rule out the signal itself, and let you focus on ground loops and the like. If you don't, and the statis is related to the volume of the signal, that changes the focus.

macebobo

11-23-2011, 08:08 PM

harrison0550

11-23-2011, 08:26 PM

Yes with the volume all the way down I still have static when it's hooked up to one of my laptops. However if I unplug the 3.5mm jack the static is gone and is clear. Also if I leave it hooked up to my iPad and stop music playback there is no static.

I've got 3 laptops and all are having the same issue.

I'm now moving the big screen to hook it up to my home theater pc to see if it has static. If that works I will just have to install LOR on my HTPC. Grrrrr I will post back once I have an answer.

IdunBenhad

11-23-2011, 08:38 PM

HI:
After having read all the posts in this thread, one thing stands out: Some people are trying the blame the antenna. That is probably the last thing in the pile to look at. From the description, the antenna was constructed per instructions and there is probably no reason to spend any more time on that problem. The only thing that may affect it is the mounting and proximity to other objects. This can throw the resonant frequency off. Just make sure all the coax connections are good and especially the braid of the coax. This is the shielding/grounding part of the system.

Apparently Windows is being used, so bring up the Mixer in Windows by double clicking on the speaker icon in the tray. Make sure ALL levels are at zero except the one you are using. Start with this control at the bottom and slowly increase the level until the signal sounds noisy, distorted or raspy, and then turn it back down until the noise goes away.

As others have suggested, the PC power supply is not the best thing to use. If you have good range with the 8 volt supply, use it. The only thing that will happen to the FM02 is that its power output will be down from a 12.5 vdc supply. Don't worry about the current rating of your 12 volt supply. The FM02 draws around 75 ma., which is .075 amps. You have over 1.8 amps available, but will never use it in this application. Your 12 supply may be a switching supply, but you can tell if it is transformer or switching by the weight. If it is heavy for its size, it is a transformer. If it is relatively light, it is a switching supply. Switching supplies can be problems, but there are a good many of them that are OK. I would guess from the current rating, the supply is a switching type.

Don't be unhappy with your FM02. It is a very rugged, versatile unit. It appears to me your problems are in the audio feeding it and not the transmitter itself.

And, don't worry about the puppy. If you need one, my neighborhood sounds like a kennel, so there is a good supply. "JUST BEIN' KIDDIN' as my granddaughter used to say.

harrison0550

11-23-2011, 08:50 PM

Ok well I got it hooked up to the home theater pc and the sound quality was 1000x's better than I have heard yet. Drove all the way out of the neighborhood with clear audio. Unfortunately I can't use this pc as it also acts as a server sending HD tv signals to 6 tv's in my house. So I guess I'm heading to the storage unit to see if I still have a tower pc.

Well crap! I finally got good sound from a pc and was so clear I could here the real faint pulse of the power supply so I thought hey I got that other one. Hooked it up and it's about par for the corse now I hooked it up backwards and fried the whole thing. Won't even turn on now so I guess I'm done. Thanks for all the help anyway.

Pwmcguire

11-23-2011, 10:02 PM

Man, that sucks, It sounds like something I would do, :sad:

harrison0550

11-23-2011, 10:42 PM

Yup I'm a little screwed now. Does anyone have any idea what I just burnt up on this thing or how in the world I'm gonna replace it in 48 hours. Cause I'm really at a loss here.

dirknerkle

11-23-2011, 11:20 PM

On the day before a holiday, that's a tough order. You might have some luck with a tunecast, belkin or other short-range transmitter that's designed to transmit from an iPod (or similar mp3 player) to a car radio. Best Buy stores, Target, Radio Shack, etc. probably have these things. You may have to hack it a bit and solder in a longer antenna to get the signal out to the street with it. But I don't see a way of getting an FM02 on that short notice. You could also try office supply stores such as Office Max or Office Depot. They usually have gizmos like that too.

Or check on the Internet. Chattanooga's a pretty big city -- maybe there's a store that has electronic parts that might be able to help you out.

Mactayl

11-23-2011, 11:21 PM

Yup I'm a little screwed now. Does anyone have any idea what I just burnt up on this thing or how in the world I'm gonna replace it in 48 hours. Cause I'm really at a loss here.
I may be able to help you, my show is going to be a little different this year where I will not be using my FM02, and I would be willing to sell it to you if you really can't get yours working, I forgot what I paid for it but I would be willing to sell it to you for the same price i paid for it plus PayPal fees and shipping, if you are interested shoot me a PM

dirknerkle

11-23-2011, 11:43 PM

MAC! YOU DA MAN!!!! :thup:

harrison0550

11-24-2011, 12:22 AM

Oh Mac that would be awesome! I sent you a pm. At least I hope I did anyway, I'm on my iPads 3G headed down to Atlanta for thanksgiving right now so I hope the pm went through.

Thanks again guys.

Mactayl

11-24-2011, 12:53 AM

Oh Mac that would be awesome! I sent you a pm. At least I hope I did anyway, I'm on my iPads 3G headed down to Atlanta for thanksgiving right now so I hope the pm went through.

Thanks again guys.

PM went through, will talk at you tomorrow or when ever you are online, have a Happy Thanksgiving

Mac:biggrin:

Mactayl

11-24-2011, 01:11 AM

MAC! YOU DA MAN!!!! :thup:
Who is is this guy Dirk?????? sounds like someone from Minnesnowta :cool:

IdunBenhad

11-24-2011, 08:45 AM

Hi:
Mac, be sure and tell Harrison0550 about the Wall Wart Tamer PC board. As you know, I don't have a PC board for the W3 and the WWT might help him.

Mactayl

11-24-2011, 10:01 AM

Hi:
Mac, be sure and tell Harrison0550 about the Wall Wart Tamer PC board. As you know, I don't have a PC board for the W3 and the WWT might help him.

Will do,, thanks Idun,

harrison0550

11-25-2011, 12:30 AM

I read briefly about the wall wart tamer but just realized it was designed by you Mac. Thats pretty cool.

Mactayl

11-25-2011, 03:10 PM

I may be able to help you, my show is going to be a little different this year where I will not be using my FM02, and I would be willing to sell it to you if you really can't get yours working, I forgot what I paid for it but I would be willing to sell it to you for the same price i paid for it plus PayPal fees and shipping, if you are interested shoot me a PM

Oh Mac that would be awesome! I sent you a pm. At least I hope I did anyway, I'm on my iPads 3G headed down to Atlanta for thanksgiving right now so I hope the pm went through.

Thanks again guys.

The FM02 is one the way, check your email for shipping info, it will arrive on Monday, just make sure you connect it up correctly and double check the wiring first before you power it up :biggrin:

harrison0550

11-25-2011, 08:01 PM

The FM02 is one the way, check your email for shipping info, it will arrive on Monday, just make sure you connect it up correctly and double check the wiring first before you power it up :biggrin:

Thank you so much Mac! I got the shipping info and look forward to getting up and running next week. Sorry I didn't get back to you sooner, I got called into work this afternoon.

You are the man!

theatretch85

11-28-2011, 02:24 AM

I bought a 1/2 watt transmitter on eBay a couple years ago and tossed the power supply it came with (it was garbage) had another one which surprisingly works a lot better (same voltage, better current rating). Also, I found out this year that the adjustable fm antenna it comes with it crap too (think your standard boombox antenna. Funny enough an old CB cb antenna I modified when I bought the transmitter (I cut the end off and crimped on a BNC end) works extremely well. I had a ton of 60hz buzz in my transmitter with anything plugged into it (even a battery powered MP3 player) using the supplied antenna, the minute I hooked up my CB antenna all the buzzing went away and it sounds great again!

RFBurns

11-28-2011, 07:35 AM

Howdy folks!

The "shhhhh" issue is not a power supply problem, or audio source problem. The problem is the 19Khz pilot level on the BH1415 chip.

I recommend everyone download the BH1415 data sheet and look at the chip's block diagram and pin layout in order to follow along in solving this "shhhhh" problem.

Pin 19 is the 19Khz pilot tone level. By default, this pin is at a high capacitance state when left open. This pin adjusts the 19Khz pilot level. When it is left unconnected, the pilot level is 30+ percent above the standard 10 percent of modulating the carrier. If the pin is connected to a surface chip cap, this cap may be open or has changed value thus the 19Khz level is still too high.

In order to correct this, a proper modulation monitor or O-scope capable of 100Mhz or more will be needed to adjust properly.

The best capacitor value I have found that brings the 19Khz pilot level down to its standard 10 percent level is a 220pF. The pilot rides at around 11.3 percent. A far cry from the 30+ percent.

Connect the capacitor between Pin 19 of the BH1415 chip and ground.

Analysis of previous "fixes":

These previous "fixes" noted within this thread by operating the unit at a reduced voltage only drops the mean voltage feeding the chip and thus drops the chips ability to function correctly. By turning down the operating voltage, that is one way to reduce that hissing pilot level, but your also reducing the correct operating voltage for not just the FM chip, but the microprocessor, the PLL, the display, the final RF amp, the whole thing, not to mention reduced range and added distortions in the audio paths within the TX and FM chip itself.

A good example of this is taking a portable battery operated radio and put a weak battery in it and hear how distorted and low volume the audio is compared to a fresh correct voltage battery. The same happens to the FM02 when power is reduced to try to solve the hissing. It is not solving it at all, it is merely "covering it up" but it is still there and will always be there until the pilot level is correctly adjusted.

The reason why some transmitters using the BH1415 chip have the hissing is because the pilot is left to run wild so that at further distances the stereo transmission will still be received at those greater distances than it would be when the pilot is adjusted to standard. So moral here is either hassy hissy stereo at a distance, or excellent clean smooth sounding stereo audio within the intended range of these low power devices. I would go with the latter because all that hissing over driven pilot level is also decreasing your carrier power and reducing your range anyway.

Happy Holidays!!

RFB

ags0000

11-28-2011, 11:51 AM

Great information. For the FM02 specifically (among perhaps many implementations using the BH1415), how would this be done? I don't have my board available at the moment, but did pull up a picture from the Vast site. How/where did you add the 220pF cap to the board?

Thanks.

harrison0550

11-28-2011, 01:32 PM

Just wanted to chime back in and say thank you again Mac. The board arrived today safe and sound. I just hooked it up and I can honestly say now that something was wrong with my original board. The one you sent me sounds 100X's better and it's hooked up exactly the same way my original one was. Guess we can chalk the original horrible sound up to a faulty board. To bad I fried it or I would send it back.

ErnieHorning

11-28-2011, 02:28 PM

How/where did you add the 220pF cap to the board?
It’s all right there in his post.

Pin 19 is the 19Khz pilot tone level.

]The best capacitor value [/B]I have found that brings the 19Khz pilot level down to its standard 10 percent level is a 220pF.

Connect the capacitor between Pin 19 of the BH1415 chip and ground.

Mactayl

11-28-2011, 02:45 PM

ags0000

11-28-2011, 03:41 PM

It’s all right there in his post.

I did read the entire post, and understand the concept. My question may be very basic, so much so that it seems obvious. How do I physically connect a 220uF cap between pin 19 and ground? I see (in the picture I found, I still don't have the board in front of me) three vias (or that's what they appear to be) in that area. Is one electrically connected to pin 19 (if a capacitor is present in some derivative design using the same board, for example) and to be used for this purpose? Was a cap just soldered directly to the IC lead itself? Where was ground available? Does it matter if the cap is ceramic, tantalum, or something else?

Like I said, probably very basic, but if it's already been (successfully) done before, I'm happy to borrow from that experience.

Thanks.

RFBurns

11-29-2011, 12:51 AM

I used a plain ol ceramic disc cap, clipped the leads so they would be short but long enough to allow folding of the capacitor on its side so it rests on the board.

Now on some designs and board layouts, Pin 19 has solder on it, it is soldered to the foil pad on the board, and nothing else. Others have a chip capacitor from Pin 19 to ground, and a few of those have too high a value of capacitor for the proper pilot level.

Solder one lead of the cap to Pin 19 at it's very end to avoid over-heating the pin. Then solder the other end of the capacitor to a nearby ground on the board. If necessary you can run a short wire for the ground connection to the 220pf capacitor.

Use an iron no greater than a 15 watt or over-heating of the pin will result and possibly damage the FM chip.

Also note that the lead of the capacitor that connects to Pin 19 MUST be short as possible. If this lead is too long, it will pick up and inject clock pulse noise onto the pilot carrier. Secure the capacitor with a dab of silicone or putty.

Happy Holidays!!

RFB

IdunBenhad

11-29-2011, 08:46 AM

HI:
Many thanks to RFBurns for finding an answer to a problem with the FM02 and better still, supplying a fix for it. As RFB said, care must taken when soldering in the cap, but if most DIYCers can handle soldering a Renard board, then they can handle this.

One more thing to add to the list of possible problems and their fixes.

THANKS RFB.

ukewarrior

11-29-2011, 11:56 AM

I have incorporated this very good information into the FM02 wiki !
http://www.doityourselfchristmas.com/wiki/index.php?title=Vastelec_FM02

Here's the block diagram that RFBurns noted. Notice that pin 19 is specifically for adjusting the pilot tone !
http://www.doityourselfchristmas.com/wiki/images/e/e6/BH1415_block_diagram.jpg

ukewarrior

11-29-2011, 12:19 PM

RFB,
If you have done this, can you post a picture?
If not, let me know and I'll modify one of my units.
Thanks again for the info!!

I used a plain ol ceramic disc cap, clipped the leads so they would be short but long enough to allow folding of the capacitor on its side so it rests on the board.

Now on some designs and board layouts, Pin 19 has solder on it, it is soldered to the foil pad on the board, and nothing else. Others have a chip capacitor from Pin 19 to ground, and a few of those have too high a value of capacitor for the proper pilot level.

Solder one lead of the cap to Pin 19 at it's very end to avoid over-heating the pin. Then solder the other end of the capacitor to a nearby ground on the board. If necessary you can run a short wire for the ground connection to the 220pf capacitor.

Use an iron no greater than a 15 watt or over-heating of the pin will result and possibly damage the FM chip.

Also note that the lead of the capacitor that connects to Pin 19 MUST be short as possible. If this lead is too long, it will pick up and inject clock pulse noise onto the pilot carrier. Secure the capacitor with a dab of silicone or putty.

Happy Holidays!!

RFB

ags0000

11-29-2011, 12:30 PM

Has anyone been able to look at the FM02 and determine if what I've wondered from the online pictures are vias are actually viable connection points to pin 19, rather than having to solder directly to the IC lead? I still haven't been in the same room as mine so can't check for myself. Soldering to the lead is acceptable if necessary, of course.

Thanks.

RFBurns

11-30-2011, 07:59 AM

RFB,
If you have done this, can you post a picture?
If not, let me know and I'll modify one of my units.
Thanks again for the info!!

Here is a close up pic of the FM02 at the BH1415 IC location. Note the row of surface chip components above the IC. Also note that there is one slot that has nothing soldered in its slot. (far left of the row)

Probe for continuity between Pin 19 and the solder pad of the unused slot on the left closest to the FM chip. (marked with yellow in the picture) The other end of that slot would be ground. If you measure continuity between Pin 19 and the solder pad on the unused slot next to the IC itself, this would be where to install the 220pf capacitor.

The unit I have where this modification was done is not an FM02 unit, but a unit that uses the very same BH1415 FM chip. It too produced the "shhh/hissing" noise due to the over driven pilot level. After installing the 220pf capacitor, that brought down the pilot level and resolved the noise issue.

I have found this issue common on many different makes of transmitters using the BH1415 FM chip and no capacitor used to adjust the pilot level at Pin 19. And on others, there is a capacitor between Pin 19 and ground and those units do not have any noise issue.

Regardless of what unit type or make you may have, if it is using the BH1415 FM chip and there is no capacitor installed at Pin 19 and ground, the unit will have noise. The problem is with the lack of adjustment of the pilot level itself and that is done at Pin 19 of the BH1415 chip.

http://krocksradioone.com/imageweb/fm02pin19detail.jpg

Feel free to add this to the Wiki information.

Later I will put up a picture of the unit I have where the modification was done for the pilot level.

Happy Holidays!!

RFB

RFBurns

11-30-2011, 09:00 AM

Here is a pic of my unit and the installation of the capacitor on Pin 19 to ground. As can be seen, the pad where Pin 19 solders goes nowhere, it is merely a pad for the Pin 19 lead to solder to. Some models are exactly like this, while others may have a foil trace leading away to la la land and goes no where or connects to anything else.

One end of the adjustment capacitor is soldered to a nearby ground point and the other lead directly to Pin 19 on the FM chip.

http://krocksradioone.com/imageweb/BH1415PIN19MOD.jpg

I am not 100 percent positive if the vacant slot in the row of surface components above the IC in the FM02 actually goes to Pin 19, but is highly possible and would be the best place to put the adjustment capacitor. This will prevent from having to solder directly to the Pin 19 like I had to do in my unit.

Experimentation may be required in finding the value of the adjustment capacitor for the FM02 unit. I found 220pf to be the best for my particular unit, but that should also work in the FM02 since the FM chip is the same BH1415 IC.

Another thing to keep in mind is that these BH1415 chips have internal limiter circuits set up by the time constant components external to the chip for both the left and right audio channels. Sort of an on-board compressor/limiter. If your using an external audio processor you might have to adjust it so that it does not fight with the IC's internal processor or the internal IC processor fighting the external one. This internal processor of the chip was put there because the design concept of the BH1415 chip was intended for wireless link between car radios and mp3 or iPod devices...which was the same intent for the old BA1404 except that chip did not include an on-board audio processor.

The BH1415 was never really intended to be fed with audio going through an external audio processor.

Happy Holidays!

RFB

ags0000

12-01-2011, 03:22 AM

Well I finally was able to put my hands on my FM02. With a simple DMM I found that the "empty slot" for the SMD capacitor is not connected to pin 19 of the IC. However, the pad that is closest to the board edge is connected to ground. Looks like it's necessary to solder the capacitor directly to pin 19 and the far pad.

RFBurns

12-01-2011, 07:03 AM

Too bad there isn't a schematic around, would make things a whole lot easier.

Use caution and as little heat as possible when soldering the cap to the pin. Pre tin the cap leads so the solder will take faster and require less heat to do so. Should be fine.

Happy Holidays!!

RFB

Blackbeard

12-01-2011, 07:22 AM

I've had very good luck with my FM02. No hissing so far (knock on wood). My only problem was the two piece antenna connector that is press-fit together that might "unfit" itself if a lot of antenna cable movement was present. Soldering the two pieces would fix this but so far, I've not done that yet.

This thread has become a wealth of knowledge for the FM02, but without having to take apart my enclosure to verify, I'm wondering if any of the FM02 units had this capacitor. The discussion mentions transmitters with the BH1415 in general, and not directly mentions the FM02. There have been a few changes over the years to the FM02 so I'm curious if any of them ever had the capacitor. Maybe if they did, I might be able to explain my good fortune. If not, perhaps I should think about breaking the "If it ain't broke" rule.

RFBurns

12-01-2011, 07:50 AM

Its possible you may have one that has the adjustment capacitor on Pin 19 from the factory. SMD components, particularly resistors and capacitors can easily crack and open under light stresses. I was never a fan of SMD electronics not because they are so tiny and hard to work with, but they are incredibly vulnerable to even light stresses of the PC board such as handling or minor bumps and such.

If anyone does have a unit with the adjustment capacitor and are experiencing the noise issue suddenly, it is highly possible that SMD cap got stressed somehow and either cracked causing it to open, or the solder connections went bad.

Only way to really know is to have the schematic of your particular unit, or begin probing from Pin 19 to the nearby SMD components close to Pin 19 and check for continuity on one of the pads facing Pin 19.

Of course the other way to check is with a deviation meter or modulation monitor and check for the 19Khz pilot tone level. The standard modulation deviation for the 19Khz pilot tone is 10 percent, or 10 Khz deviation from center of carrier. It's ok to have it a little higher than 10 percent, but I would not go any higher than 15 percent. Both the 19Khz pilot and the 38Khz L-R sub carrier rob RF power by taking up bandwidth to be transmitted so if they are set too high, noise is just one problem encountered. The TPO, or Total Power Output of the unit will be reduced because the sub carrier and pilot carrier are occupying too much bandwidth at the high levels and forcing the amplifiers to "spread" out their workload to pass those as well as the main carrier. Too high of levels of sub carrier and pilot carrier can also over work the final and cause it to prematurely fail.

Happy Holidays!!

RFB

ukewarrior

12-01-2011, 10:23 AM

If there is interest, I can send whoever wants a couple of these capacitors for 10 cents.
You would simply send me a self addressed envelope with a dime and I would send you several 220pf caps.
PM me if you want to do this and I'll send you my snail mail address.

ags0000

12-01-2011, 01:56 PM

Is there any known instance of someone with the FM02 (not just a transmitter using the same BH1415 IC) that had the "sssshhh/hissss" symptom, added a 220pF cap to pin 19, and had the problem go away?

buymyemu

12-01-2011, 07:11 PM

My unit has developed an audible buzzzzz over the last week. My 12 v converter is over 40 years old and sits on my desk next to me. It has now, and always has had a very loud buzz.. Last week we did not notice the buzz on the car radio, we do now.

I think this is different than the Hiss that is being discussed here, yes?

My boat battery is around, I will try that shortly

RFBurns

12-01-2011, 11:00 PM

Is there any known instance of someone with the FM02 (not just a transmitter using the same BH1415 IC) that had the "sssshhh/hissss" symptom, added a 220pF cap to pin 19, and had the problem go away?

Good question. However where would the difference be between transmitters using the same IC chip producing the FM carrier, the pilot tone and L-R sub carrier???

The hissing is inherent to the FM chip if that pilot tone is left to run wild, wont matter what make or kind of TX the chip is sitting in...its the FM chip itself.

Ive been reading about various other issues with this FM02 unit all over this forum. Bad solder connections, flux residues left on brand new units, flaking out displays, and signal coverage reduction after a time.

I may just purchase one of these FM02 units and perform a little product review of my own...just for curiosity sake. :)

Happy Holidays!!

RFB

ukewarrior

12-01-2011, 11:10 PM

Given the fact over 400 of these units have been purchased and shipped by me,
I would say the 'problems' are non existent in any real numbers.

Not a single person has asked me to return their unit to VAST. (In another thread is the VAST warranty and in the wiki)

The 'shhhhhing' may indeed exist, but I contend it is a non-issue for our uses of these transmitters.
So, let's not stir up a pot of goo that doesn't really exist or matter in any material fashion.

I would also remind folks that before the FM01 & FM02, the prospects of a decent transmitter for under $100 was non-existent.
There was also no 'defacto-standard' for the DIY community and therefore, any type of common support and enhancements didn't exist.

I am absolutely thrilled with my VAST products for the price point !

Good question. However where would the difference be between transmitters using the same IC chip producing the FM carrier, the pilot tone and L-R sub carrier???

The hissing is inherent to the FM chip if that pilot tone is left to run wild, wont matter what make or kind of TX the chip is sitting in...its the FM chip itself.

Ive been reading about various other issues with this FM02 unit all over this forum. Bad solder connections, flux residues left on brand new units, flaking out displays, and signal coverage reduction after a time.

I may just purchase one of these FM02 units and perform a little product review of my own...just for curiosity sake. :)

Happy Holidays!!

RFB

ags0000

12-02-2011, 02:05 AM

Good question. However where would the difference be between transmitters using the same IC chip producing the FM carrier, the pilot tone and L-R sub carrier???
The hissing is inherent to the FM chip if that pilot tone is left to run wild, wont matter what make or kind of TX the chip is sitting in...its the FM chip itself.
...
RFB

I'm not doubting that. However, I'm not sure there isn't a cap somewhere on the board, tied to pin 19. I would presume it should be physically close to that pin to be effective, but I can only identify a very few traces on the top/bottom of the board (I also presume it is a 4 (or more) layer board). I may have made a mistake when probing the board with my (relatively) gigantic test leads/probes. It sure seems like that empty location where a SMD cap would fit would be wired up to pin 19.

ukewarrior

12-02-2011, 08:58 AM

Good News from VAST:

I asked VAST for the board layout and schematic for the FM02.
They said they will send it to me tomorrow.
So..... now we wait.

buymyemu

12-03-2011, 01:19 AM

RFBurns

12-03-2011, 09:11 AM

Good News from VAST:

I asked VAST for the board layout and schematic for the FM02.
They said they will send it to me tomorrow.
So..... now we wait.

Excellent! Could you post that once you receive it so we all can have a copy? That would be most appreciated.

Then we can take a look at how Vast has this BH1415 chip configured for both the 19Khz pilot level (if at all) and the time constant components in the audio section to see where they have the internal processor's attack and release times set at.

Though the time constant parts won't have anything to do with the 19Khz pilot level issue as they are separate circuits within the IC chip, it would be a good idea to know what component values are being used to calculate the time constants so that at the very least, there is an idea of what that part of the unit is doing.

Happy Holidays!!

RFB

RFBurns

12-03-2011, 09:16 AM

I spent a lot of time on this tonight. During the show I added ferrite beads to the audio input as well as the 12v input, made no difference. Did manage to pull the audio cable just out of the PC so only left(right?) channel made contact. For 1.5 hours I sent a very distorted signal out. Could not understand why people would stop, and leave after 1/2 song, got in my car and found out why (radio in house sounded fine)
After shutdown I tore into all of the wires. I have the transmitter in the middle of the desk, with a PC monitor to the right, a telephone/answering machine and a router to the left and antenna hanging vertically at the back left corner of the desk along the left side of the front window, right behind the telephone and router. Removed one wire at time. Finally determined it was the router and most specifically the enet cable from that to the show PC. The enet cable was within 1" of the antenna. They must have coupled? I did notice that when I touched the braided part of the antenna (Idunbenhad style), my buzz would go away.
All wires re-routed, router moved 5 feet away, and I have no more hum, buzz or hiss. Same transmit distance as before, just a nice clean signal.

This raises a point I was making about RF traveling onto audio and control wiring. Radio Shack has snap-on chokes you could add to your wiring to help remove inducted RF.

It's also good to keep those wires away from both the TX and its antenna! Even at the milliwatt ranges, that flea signal can cause all kinds of headaches....as you found out by that enet cable being within 1 inch of the antenna!!

Good thing the FM02 doesn't output in the watts range! Could have damaged your digital devices.

Glad you found the solution and resolved the problem. But it should also be a good message to all to keep them wires away from the TX module and its antenna.

For systems where wiring is already moved away but there is still hum issues or inductive interference issues onto other devices, use the Radio Shack snap-on chokes on all your wiring, both at the input and output points.

Happy Holidays!!

RFB

ukewarrior

12-03-2011, 11:38 PM

Ask and you shall receive.

The FM02 Schematic and PCB layout are now available in the FM02 wiki !

You will notice that pin 19 is NOT connected to anything on the board, including the nearby empty pad.

Wiki link:
http://www.doityourselfchristmas.com/wiki/index.php?title=Vastelec_FM02

RFBurns

12-04-2011, 12:03 AM

LabRat

12-04-2011, 08:15 AM

There should be a buffer stage before that final so that any impedance changes taking place at the antenna will not affect the loading of the RF output pin on the FM chip because loading effects can also affect how that FM chip performs and sounds.

There are days when I think I know what I'm doing with regards to blinky-flashy... .. and then I read something like this, and realize that I haven't a clue. Perhaps "radios" will become my research topic for 2012. To all the RadioHeads posting in these forums, *THANK YOU* for providing the debate/commentary/wisdom. It's makes for great reading, though at times I have to wonder if it was even English. :wacko:

ukewarrior

12-04-2011, 08:32 AM

Major Problems?

Not really. I've used one of these transmitters going on three seasons and it works great!

Now, can everything be improved? You bet !

Yep. Thanks for posting the schematic on the Wiki. Indeed, and there are several other things I noticed right off that will be major problems if not addressed.

RFB

RFBurns

12-04-2011, 08:40 AM

Materdaddy

12-04-2011, 12:21 PM

There are some users that are not experiencing any problems and a lot who are. Those that are having issues, they all seem to be pretty much the same kind of issues considering the differences in the local conditions, setups and antennas being used. But they also seem to point to the FM02 unit itself, particularly failing range and/or noise problems like the hum and white noise hash..aka pilot level.

Again I am a firm believer in "If it's not broke don't fix it". If its running let it run till it dies..if it dies. There is always that few out of the thousand units that just seem to work like they should, while the rest do nothing but give less than expected performance. You are one of the lucky ones.

Now that we have the schematic, everyone can see where even very simple modifications can help prolong the life cycle of the unit and improve performance in a few areas.

Happy Holidays!!

RFB

Uke as one of the lucky few? He has had a heck of a lot of FM02's pass through his hands for the sake of this community, with very few complaints about these units. I have a feeling your numbers are backwards as to the "good ones" and "bad ones" for the FM02.

I run one that works (mostly) perfectly, and from being on these forums for a little over a year, it seems like they are very popular here. Way more popular than the couple threads discussing issues. Not only that, they are probably people who have home-rolled antennae, no isolation between lines, ferrite beads, and are striving for perfection.

That being said, I do want to do a little more research into a couple minor issues with my FM02 (a high pitched whine that wasn't removed with the wall wart tamer). I'm not sure if it's a 19kHz tone or what, but I will be looking into this over the next couple weeks when I have free time.

budude

12-04-2011, 12:42 PM

Uke - can you get the schematic for the FM01 as well? My primary transmitter is the EDM-LCD which is great but my FM01 is my backup. If there are any enhancements that can be made as with the FM02 to make it a bit better from RF's suggestions that would be great. It seems to work fine but I'm willing to play with it for grins.

Keith R

12-04-2011, 12:58 PM

Yep. Thanks for posting the schematic on the Wiki. Indeed, and there are several other things I noticed right off that will be major problems if not addressed.

Such as the lack of a low pass filter, DC shunt path for static buildup on antennas, inadequate RF bypassing on the supply rails and not enough buffering between the IC RF output and the final stage. There should be a buffer stage before that final so that any impedance changes taking place at the antenna will not affect the loading of the RF output pin on the FM chip because loading effects can also affect how that FM chip performs and sounds.

Happy Holidays!!

RFB

Now that we have the schematic, everyone can see where even very simple modifications can help prolong the life cycle of the unit and improve performance in a few areas.
RFB

Now, can everything be improved? You bet !

ukewarrior

I have both a Vastelek FM01 and FM02 and both have static, especially between songs...and I can live with it. These transmitters are low cost effective ways of getting our signal out. I think the general tone is to follow some of the guidelines presented here to limit your noise, until lost cost effective solutions can be made to the current configuration, or a new design of our own build can be had and made available to the general DIYC community.
I appreciate all of the input from this forum as it makes my display better and better every year.
Keith

Mactayl

12-04-2011, 01:08 PM

Uke as one of the lucky few? He has had a heck of a lot of FM02's pass through his hands for the sake of this community, with very few complaints about these units. I have a feeling your numbers are backwards as to the "good ones" and "bad ones" for the FM02.I run one that works (mostly) perfectly, and from being on these forums for a little over a year, it seems like they are very popular here. Way more popular than the couple threads discussing issues. Not only that, they are probably people who have home-rolled antennae, no isolation between lines, ferrite beads, and are striving for perfection.That being said, I do want to do a little more research into a couple minor issues with my FM02 (a high pitched whine that wasn't removed with the wall wart tamer). I'm not sure if it's a 19kHz tone or what, but I will be looking into this over the next couple weeks when I have free time.I do not want anyone to get the wrong idea here,, the Wall Wart Tamer was not designed to get rid of a transmitter, coax or antenna problems, it was designed to cleanup any unwanted AC from a Wall Wart.. 60Hz.. a whine or other white/pink noise at a much higher in frequency is probably coming from something else after the Wall Wart Tamer. The Wall Wart Tamer provides a clean DC source that is it. The Wall Wart Tamer can also be used for other applications for a clean DC source.
I have owned 2 of the FM02's and for the cost you just can't beat it.......

RFBurns

12-04-2011, 03:00 PM

Uke as one of the lucky few? He has had a heck of a lot of FM02's pass through his hands for the sake of this community, with very few complaints about these units. I have a feeling your numbers are backwards as to the "good ones" and "bad ones" for the FM02.

Apparently the one he has now after the run of them is working good so far. Reading too much into my statement perhaps..or simply misunderstood or I was not clear in my statement.

I run one that works (mostly) perfectly, and from being on these forums for a little over a year, it seems like they are very popular here. Way more popular than the couple threads discussing issues. Not only that, they are probably people who have home-rolled antennae, no isolation between lines, ferrite beads, and are striving for perfection.

Why not strive for optimum performance...after all..how much time and investment has been expended on the light and controller and automation systems? Doesn't the RF part deserve the same attention and perfection as well?

That being said, I do want to do a little more research into a couple minor issues with my FM02 (a high pitched whine that wasn't removed with the wall wart tamer). I'm not sure if it's a 19kHz tone or what, but I will be looking into this over the next couple weeks when I have free time.

It's the 19Khz pilot level. In some receivers, cheap ones and so so mid grade ones, their filtering is not the greatest and will pass some of that pilot right through the audio chain and into the speakers. This is especially true when the transmitted 19Khz pilot level is 30+ percent higher than what it should be..10 percent +/- 1%.

Not only does the over driven pilot tone produce hiss and high pitch noise, it crunches the carrier level and causes the final to over-work itself by having to open its flood gates in bandwidth just to pass the main carrier, the L-R 38Khz sub carrier and the 19Khz pilot tone.

When adjusting the pilot tone level, do this with no modulation. The 220pf will get you in the ball park and the maximum capacitance you want in there would be a 5 nano farad.

Another thing to note about the time constants used in the FM02 (Pins 2/3 and 20/21) are the same values used in the Rohm test circuit! ICK!!! CHOKE N PUKE!!! Those values are not the best to be using for real application!

Power supply input filtering could use some attention too. As well as the final RF output section, which has NO low pass filter!! ACK!! It also does not have a buffer stage in between it and the RF output Pin 11. So when any loading changes take place on the final's output, that will also effect the output of the IC.

A little bit of basics of FM stereo transmission. If there is enough VSWR present along the RF chain, it can cause junky audio and cruddy stereo separation and harmonic distortions causing the sidebands of the modulation to spit and splatter far beyond the 200Khz deviation, just basically sounding like garbage.

Happy Holidays!!

RFB

Well despite all the little improvements that can be done to the FM02, its a good little unit for what is there.

Materdaddy

12-04-2011, 04:25 PM

I do not want anyone to get the wrong idea here,, the Wall Wart Tamer was not designed to get rid of a transmitter, coax or antenna problems, it was designed to cleanup any unwanted AC from a Wall Wart.. 60Hz.. a whine or other white/pink noise at a much higher in frequency is probably coming from something else after the Wall Wart Tamer. The Wall Wart Tamer provides a clean DC source that is it. The Wall Wart Tamer can also be used for other applications for a clean DC source.
I have owned 2 of the FM02's and for the cost you just can't beat it.......

I agree. I understand what the Wall Wart Tamer was designed to do. I just don't know what frequencies sound like what as for filtering, issues, etc. I am starting to look into that now. I have spent all of my time up until now dealing w/ the "electronics" side of my show, now that it's up and running, I am going to do a little more looking into the RF side of it. All of my friends/family who have come to see the show all say the transmitter sounds fine. I'm just a perfectionist.

Apparently the one he has now after the run of them is working good so far. Reading too much into my statement perhaps..or simply misunderstood or I was not clear in my statement.

Maybe I read into it too much, but the verbiage very much seemed like you were saying that the numbers were in favor of FM02s being bad and Uke was one of the few that had one work well.

Why not strive for optimum performance...after all..how much time and investment has been expended on the light and controller and automation systems? Doesn't the RF part deserve the same attention and perfection as well?

See my post above. I put this "last" as for the priority list of striving for perfection for multiple reasons. One, it's darn close to perfect (for my needs) already, and two, it's something I can tweak with the rest of the setup done. Had I gotten a perfect transmitter done, and nothing in the yard, what good would that have done me?

It's the 19Khz pilot level. In some receivers, cheap ones and so so mid grade ones, their filtering is not the greatest and will pass some of that pilot right through the audio chain and into the speakers. This is especially true when the transmitted 19Khz pilot level is 30+ percent higher than what it should be..10 percent +/- 1%.

Sounds about right. I notice it much more on an old A/V receiver in the garage and the wife's car. In my truck, there's probably better filtering in that head unit for the pilot tone, and it's barely noticeable. Most of the people I've talked to that have seen the show have newer cars which probably have fancier radios to filter the pilot tone better. Another reason I put off "perfecting" the radio transmission until last.

Not only does the over driven pilot tone produce hiss and high pitch noise, it crunches the carrier level and causes the final to over-work itself by having to open its flood gates in bandwidth just to pass the main carrier, the L-R 38Khz sub carrier and the 19Khz pilot tone.

I'll need to google about 13 things just to understand this statement. Thanks. :D

When adjusting the pilot tone level, do this with no modulation. The 220pf will get you in the ball park and the maximum capacitance you want in there would be a 5 nano farad.

I'll see what I have in the parts bin that is within those ranges if I get around to playing with the pilot tone. Thank you for the information.

Another thing to note about the time constants used in the FM02 (Pins 2/3 and 20/21) are the same values used in the Rohm test circuit! ICK!!! CHOKE N PUKE!!! Those values are not the best to be using for real application!

Power supply input filtering could use some attention too. As well as the final RF output section, which has NO low pass filter!! ACK!! It also does not have a buffer stage in between it and the RF output Pin 11. So when any loading changes take place on the final's output, that will also effect the output of the IC.

A little bit of basics of FM stereo transmission. If there is enough VSWR present along the RF chain, it can cause junky audio and cruddy stereo separation and harmonic distortions causing the sidebands of the modulation to spit and splatter far beyond the 200Khz deviation, just basically sounding like garbage.

Happy Holidays!!

RFB

Well despite all the little improvements that can be done to the FM02, its a good little unit for what is there.

The rest of this is greek to me as well. I'll be pulling out my "ARRL Extra Class" book, doing some google searches, etc.

Thank you for the great information on RF and the FM02. Also, thanks for the links (in a previous post) of other similar FM transmitters. At least one of them I clicked seemed to be a similar price point as the FM02 and might be a contender for the DIYC community's affections!

dirknerkle

12-04-2011, 04:53 PM

Materdaddy

12-04-2011, 06:18 PM

I'm confused. Are we trying to set up professional FM Stereo stations here with 100,000 watts of radiated power? Have we lost our perspective? Is the ARRL book necessary for a little station that on a good day goes 1/8 mile? :(

No, I'll be reading the ARRL book because I want to get my extra class soon as well, but in regards to this post, I want to understand more of what RFB is posting. On this entire forum, the posts in the last few days by him are the most confusing to me! :P

Just as another note... I also have the ARRL book on PIC programming that I need to spend some quality time with.

RFBurns

12-04-2011, 07:04 PM

I'm confused. Are we trying to set up professional FM Stereo stations here with 100,000 watts of radiated power? Have we lost our perspective? Is the ARRL book necessary for a little station that on a good day goes 1/8 mile? :(

LOL!!

The suggestions could seem like engineering a full blown 100KW station..but glad you said it first. That is recognizing good engineering practices and that is also helpful in 10 miliwatt setups for light shows.

Just trying to be helpful and provide some ideas to the issues being posted.

But if you would like to talk about engineering consulting for a 100KW blow torch or 50KW flame thrower just ask or shoot an email. :)

Happy Holidays!!

RFB

dirknerkle

12-04-2011, 07:53 PM

LOL!!

The suggestions could seem like engineering a full blown 100KW station..but glad you said it first. That is recognizing good engineering practices and that is also helpful in 10 miliwatt setups for light shows.

Just trying to be helpful and provide some ideas to the issues being posted.

But if you would like to talk about engineering consulting for a 100KW blow torch or 50KW flame thrower just ask or shoot an email. :)

Happy Holidays!!

RFB

I hear ya, RFB. And you are providing some valuable and technical information..... but at the risk of sounding like a moron (...like I haven't said THAT line before... :lol: ) in my opinion there has been so much time spent on this topic that I would most definitely deem it to be a GSW (Grand Spinning of the Wheels). Or gilding the lily. Or polishing the....

I'm wondering if sometimes too much information can become a sort of red herring that sends non-technical people in all directions other than perhaps what's important, which is to get the darned show going, and that has just 4 simple steps as it relates to an FM transmitter:

1. Connect a relatively short wire the darn transmitter's antenna output
2. Connect your PC's audio output to the transmitter's audio input terminals
3. Set the PC's audio output at about 20%
4. Power the transmitter with 12vdc.

I'm a bottom-line, results-oriented guy and I enjoy technology as much as the next person. But Christmas Eve is less than 3 weeks away and Adm. David Farragut's quote, "Damn the torpedoes, FULL SPEED AHEAD!" seems like a pretty good idea this late in the game.

And yes, Merry Christmas!!!

RFBurns

12-05-2011, 07:25 AM

I hear ya, RFB. And you are providing some valuable and technical information..... but at the risk of sounding like a moron (...like I haven't said THAT line before... :lol: ) in my opinion there has been so much time spent on this topic that I would most definitely deem it to be a GSW (Grand Spinning of the Wheels). Or gilding the lily. Or polishing the....

I'm wondering if sometimes too much information can become a sort of red herring that sends non-technical people in all directions other than perhaps what's important, which is to get the darned show going, and that has just 4 simple steps as it relates to an FM transmitter:

1. Connect a relatively short wire the darn transmitter's antenna output
2. Connect your PC's audio output to the transmitter's audio input terminals
3. Set the PC's audio output at about 20%
4. Power the transmitter with 12vdc.

I'm a bottom-line, results-oriented guy and I enjoy technology as much as the next person. But Christmas Eve is less than 3 weeks away and Adm. David Farragut's quote, "Damn the torpedoes, FULL SPEED AHEAD!" seems like a pretty good idea this late in the game.

And yes, Merry Christmas!!!

I agree. There are some obvious problems taking place that go far beyond the simple fixes. And it could be something not even related to the antenna itself or its mounting position or placement of cables and wires.

The thing I find interesting is much of the problems are so common across a large span of installations, that they all seem to end up with the same results.

Process of elimination is the best tool to finding out what's going on. And in no way am I suggesting anyone here has not done a thorough job in attempting to find the causes of the problems. However at some point one must say to themselves it's time to do something different in resolving these problems, and finding the causes so the problems do not happen again.

Perhaps all the problems won't be resolved in a 3 week time frame before the big day. But at least everyone has a head start on things for next year. Better late than never and no time like the present.

For now, being this close to the holiday, let's enjoy it and tackle the problems in more detail after the holidays. At least for those who are going through so much trouble. Congrats to those who are not experiencing these problems and hope their systems continue to work for them. For those going through the problems...eventually the solutions will be found...it's just a matter of finding them.

Happy Holidays!!

RFB