Astatic Echo Board troubles

[NightRanger3151]

Hello all,
New member here. I've got a problem I am having a hard time figuring out with my Cobra 29 LTD. Please take a look at the video and see if you may have a suggestion as to why my radio is acting up as a mobile unit. It only started this after I added an Astatic Echo board to it. What's weird is the echo works great in the house when I use the radio as a base unit but acts up in the car. I would really appreciate any feedback. I can tell you this, the car has a trucker 2000 antenna mounted onto the truck lid (solid mount) with the swr's down to 1.0 to 1.1 on all channels and seems to work great. I tried another radio in the car and everything was fine. I don't know what the ohms are on the antenna, I don't have an antenna analyzer to check that. I have tried wiring the radio straight to battery instead of fuse box, I've added more ground to radio and antenna and nothing changes. I've tried 3 different mics. It seems like it is getting some really bad RF but I can't seem to find from where. Maybe I've just got a bad echo board ... but if so why does it work when I move the radio to the house?

http://www.youtube.com/watch?v=Uvgz7ml7bpM

[ramblingman]

tell me how youve got your echo board wired up...

[NightRanger3151]

Here is some pics. I had the ground hooked up but have disconnected it so it wouldn't loop and am just using the ground from the mic connector that the black wires hook to as the ground.

[ramblingman]

to start with your echo board should be run on 8 volts dc not 13.8,,,and a good place to run all of your grounds are one of the metal tuning cans in radio,,should be easy to reach one of these with all your grounds..your mic ground will work...but ive found the metal if cans work better and are easier to get too.if you cant find a 8 volt source,,you can put a 1.5k ohm resistor in line with the 13.8 volt source and this should pull it down between 8-10 volts..i think if you get it down closer to 8 volts dc it will work better for you........but if youve got a v.o.m..id find a 8 volt source in the tx mode.

[NightRanger3151]

ok, will try again. I tried it on a spot that was 10v but will try to find or create an 8v and let you know. Thanks.

[NightRanger3151]

I got the echo board hooked up at 8.1 volts and there was still no difference. I really am beginng to think it has something to do with my antenna. Especially since it works so well when i hook it as a base radio. But if it, is it isn't showing up on a swr check.

[ramblingman]

what excually is it doing,when you say acting up...is the echo cutting in and out or the radio cutting in and out,,is in in tx or rx mode..try to tell us all you can about what it is doing...

[NightRanger3151]

hard to explain so I took a video of it. You can watch the video here http://www.youtube.com/watch?v=Uvgz7ml7bpM the last few seconds of the video is the problem with the radio in the car with echo board installed.

[sonoma]

not sure what echo board you have but most of them have a ground wire also along with the 2 black wires at the mic socket.does this board have a ground in conjunction with the power wire.if so ground it to one of the cans on the circuit board.I had a cobra 29 that was doing the same thing and I had to play with the location of the ground wire.I also had to put the mic grounds t the cans also to get this to stop.hope this might help.

[sonoma]

forgot that mine was fine on the base also.it only did this in a peterbuilt truck.moved it to a kenworth and it did not do this.

[NightRanger3151]

forgot that mine was fine on the base also.it only did this in a peterbuilt truck.moved it to a kenworth and it did not do this.

Thanks will try moving the ground. After grounding to the cans did it work in the Peterbuilt?

[NightRanger3151]

I hooked the ground wire back up to the echo board and grounded it and both grounding mic wires to a tuning can and it still does the same noise. grrrrrrrrrrrrr.

[Rick]

Sounds like a Ground loop problem.

Make sure the power to the Echo board power is taken from the Emitter of TR23 (8 VDC) and board is grounded to a tuning can or good known ground.

Hear a trick to try first, make sure the radio is not touching the vehicle chassis and remove the antenna and connect the radio to dummy load, and then try it, if the problem as gone then it is ground loop problem.

If it is ground loop problem, try unhooking one on ground leads from the Echo board at a time.

Also, turn the Echo right down to see if this has any affect. Let us know how you get on.

[NightRanger3151]

Sounds like a Ground loop problem.

Make sure the power to the Echo board power is taken from the Emitter of TR23 (8 VDC) and board is grounded to a tuning can or good known ground.

Hear a trick to try first, make sure the radio is not touching the vehicle chassis and remove the antenna and connect the radio to dummy load, and then try it, if the problem as gone then it is ground loop problem.

If it is ground loop problem, try unhooking one on ground leads from the Echo board at a time.

Also, turn the Echo right down to see if this has any affect. Let us know how you get on.

Ok, I did the trick you suggested and yes the problem disappears when I use a dummy load.
I then hooked back up to the car's antenna and noise was back. I also moved the power to TR23 (8 VDC) and played with the ground wires unhooking one and then another and nothing helped when I did that.
And when I turn the echo knob it doesn't make any difference at all. In fact I can turn the echo off and it's still there.

Now I did try something today that may or may not be of any help ... But I was thinking since the problem is only there when the antenna on the car is being used (with base antenna it works fine) I would try this test ... I added a 20 ft section of rg-58u to the car antenna's coax and then moved the radio away from the antenna and then powered the radio with a power supply plugged into an outside outlet that had a 12 foot lead. This way I was able to move the radio around somewhat. When I first keyed the mic standing away from the car the problem was gone. But when I would walk around the problem would appear and then disappear. But I would have to be in just the right spot for it to totally disappear. In other words the noise was there most of the time. ... Like I said, don't know if that means anything or not.

[NightRanger3151]

Found this on the internet ... This is exactly what mine is doing.

'Trouble Shooting CB Echo Reverb Audio'

One of the most frustrating problems that often occur when adding power microphones or external Echo Repeater effects boxes or boards to existing radio installations is RF feedback or looping (Squealing). RF feedback is caused when some of the transmitted radio energy from the antenna is able to find it?s way back to the microphone input of the CB. Even if your radio didn?t have any problems before, adding a audio Echo Repeater can start an RF feedback problem if your radio and antenna system are not installed properly or in good condition. Make sure that you have good, solid ground connections on your radio and antenna, that are free from corrosion. Also make sure that your antenna coax is in good condition and not pinched or shorted. Have the SWR (Standing Wave Ratio) of your system checked. Preferable, it should be 1.5:1 or better. Also there is less chance of RF feedback problems if the Echo box chassis or Echo board is not connected to the metal chassis of your CB radio or vehicle. Mount to a non-metal panel or use double-sided foam tape (I have mine mounted with industrial strength Velcro).

[ramblingman]

it is going into self oscellation...do you have the echo board secured to the side rail of the radio..or did you do like some do,,just tape it up and leave it loose inside radio..

[NightRanger3151]

I mounted it to the chassis of the radio. but I've also tried it not mounted. With it not mounted the noise is not as bad.

[NightRanger3151]

Here's more info ... I removed the mic and connected pins 1 and 3 and the noise was gone. I have an old cobra mic that has had the mic removed from it and I hooked it up and keyed and no buzzing either. A soon as I hooked the mic back though the noise was back.

[Rick]

Try soldering a 1n to 10n disc cap from Pin1 and 2 and from Pin2 to chassis on the mic socket.

[NightRanger3151]

Try soldering a 1n to 10n disc cap from Pin1 and 3 and from Pin1 to ground on the mic socket.

mmmmm, ok thanks. Not sure I will get to it tonight but I will try.

[NightRanger3151]

ok after reading this again I'm not sure what you mean by 'Pin1 to ground on the mic socket'. I thought Pin1 was the ground on the mic socket?

[Rick]

Sorry my error. I have edited my last post.

[Pioneer621]

Hello! Just thought I would give an idea of what I have done to eliminate the RF feed back type problem with the echo boards.

I have installed a couple dozen or more of the ASTATIC echo boards in Cobra 29 LTD's (most versions of the 29) & have encountered that very same problem, MANY times! The easiest way to stop the feed back problem (at least for me it works), is to install a 1k ohm resistor in line with the input of the echo board (maybe slightly higher than 1k in some cases, but 1k usually does the trick), so un-solder the echo input wire from the MIC socket (pin-2), then solder one end of the 1k ohm resistor to PIN-2 of the MIC socket, then solder the input wire from the echo board to the free end of the resistor, that usually always removes that problem. Though you will loose a little bit of audio from the resistor being in series with its input, it never hurts mine enough to worry about & it is a quick way to stop the problem. I have never had any bad reports about my audio, so never drops it that bad. Probably not the best method out there, but it has worked well for me. Experimenting with the grounding points may help as well.

I run my ASTATIC echo boards at 13.8 vDC, according to the manual of the ASTATIC board it will operate from 8 to 18 volts DC, I have also tried mine at 8 volts to see if that would eliminate the problem, but only made it worse on some of my radios, so all ASTATIC echo boards I use are soldered DIRECTLY to the ON / OFF volume switch in the Cobra 29's, on the switched side. Though MANY / MOST other echo boards need 8 volts, but the new astatic boards or all of the ones I have used operate on 13.8 v without any trouble (at least for me it did not make a difference from 8 to 13.8 volts).

Ok, just wanted to give you an idea of what I have done to eliminate the problem easily, though your in great hands with the guys helping you already, but again, just thought I would chime in with an idea! I hope the info helps! Hope you get the problem figured out! Hello everybody & Take Care! Best Regards, Pioneer621

[NightRanger3151]

Hello! Just thought I would give an idea of what I have done to eliminate the RF feed back type problem with the echo boards.

I have installed a couple dozen or more of the ASTATIC echo boards in Cobra 29 LTD's (most versions of the 29) & have encountered that very same problem, MANY times! The easiest way to stop the feed back problem (at least for me it works), is to install a 1k ohm resistor in line with the input of the echo board (maybe slightly higher than 1k in some cases, but 1k usually does the trick), so un-solder the echo input wire from the MIC socket (pin-2), then solder one end of the 1k ohm resistor to PIN-2 of the MIC socket, then solder the input wire from the echo board to the free end of the resistor, that usually always removes that problem. Though you will loose a little bit of audio from the resistor being in series with its input, it never hurts mine enough to worry about & it is a quick way to stop the problem. I have never had any bad reports about my audio, so never drops it that bad. Probably not the best method out there, but it has worked well for me. Experimenting with the grounding points may help as well.

I run my ASTATIC echo boards at 13.8 vDC, according to the manual of the ASTATIC board it will operate from 8 to 18 volts DC, I have also tried mine at 8 volts to see if that would eliminate the problem, but only made it worse on some of my radios, so all ASTATIC echo boards I use are soldered DIRECTLY to the ON / OFF volume switch in the Cobra 29's, on the switched side. Though MANY / MOST other echo boards need 8 volts, but the new astatic boards or all of the ones I have used operate on 13.8 v without any trouble (at least for me it did not make a difference from 8 to 13.8 volts).

Ok, just wanted to give you an idea of what I have done to eliminate the problem easily, though your in great hands with the guys helping you already, but again, just thought I would chime in with an idea! I hope the info helps! Hope you get the problem figured out! Hello everybody & Take Care! Best Regards, Pioneer621

Thank you for your post Pioneer621! At least I know I'm not alone with this problem. Thought maybe I had some strange alien radio or something.

[NightRanger3151]

Pioneer621,
I tried the 1k resistor idea on the Astatic echo board and the cobra 29 LTD is talking loud and proud! I can set it to full echo and reverb if I want (not that I would use it like that) and with the dynamike set at full even with a power mic and this thing won't do the feedback anymore! I am so glad you posted your experiance with this problem. Thanks so much.

Thanks to all for the help.

[Pioneer621]

NightRanger3151,
I am very happy to hear you got it working & the info I supplied helped you out! As I said before, it is probably not the best method out there, but it does usually always work & is easy & quick to do. The guys that were helping you are VERY knowledgeable & would have got you fixed up as well, but since I did not see any one mention adding a resistor in line with the MIC input I thought I would add the note incase you wanted to try it. I am glad your radio is talking Loud & Proud! I love CB radio work & I am glad I could help out; I do try to help when I can or at least give ideas of what one can try. Take Care my Friend! Pioneer621

[Rick]

The best way is with a choke, 5uH to about 15uH should do the job.

[Pioneer621]

Thanks for the info Rick, I will keep that in mind next time I have that problem with one of my radios, I did not even think of using a choke in series with its input, I appreciate the info! NightRanger3151, you may want try the choke in your radio as Rick suggested as that may be a better solution to your problem. Take Care my Friends! Pioneer621

[zeppfrog]

good tip... not sure, since i keep my sound off on the pc... and too lazy to crawl under and hook it up , if my own board makes the same noise you are talking about, an odd farting sound... lol... but sounds like the trick to me. I have tried the astatic in several radios myself and came up with this one prob a few times. thought I had fried the echo board first time, but put it over in another rig and it was fine.
I imagine a ferrite bead on the same wire would also kill the RF interference . will test that one out and see if it gets it done.