Galaxy DX99V Talkback Solutions

[Robb]

Problem scenario:
Black Eagle D104 on a Galaxy DX99V. Turn it on. SWR is OK; but how about a little echo to go with this great mic and radio? Turn it on and -WWWOWWW- feedback city! There is no getting rid of it - short of switching the echo off, and there is no adjustment of the volume on the talkback. The talkback and echo are both switched on/off with the same switch.

Solution(s):
*Cut the orange wire and disable the talkback alltogether, as per CBTricks here:
Galaxy Radios DX99V Service Manual

*Or - install a 470MK/ohm resistor as shown on the same page. But this may too much or too little; there is no definite way to know for sure - except with experimenting with the basic 470K/ohm value given.

Question:
*Is it possible to put a 250K/ohm pot in series with a 330K/ohm resistor and make it adjustable with this method?

Anybody ever do anything like this or solved it another way?
All opinion and experience welcome...
:headbang

 

[purenrg]

There is some information about this problem on cbtricks.com forum. I have a DX99v and I picked up a RF limited model UTB-1 board but have not installed it yet. Galaxy tech stated that this was best way to go with feedback/squeal problem for the 99s and others.

 

[mackmobile43]

try backing the mic gain down on the radio and or the microphonium, bad juju? who knows.

 

[Moleculo]

If you can put a resistor inline, you can surely put a variable resistor (pot) inline also to make it adjustable.

 

[Robb]

What did I finally do for this problem?
I tried one 470K ohm resistor; not enough.
Then I put two in series - still no dice. Then I put a 1M pot WITH 2 470K ohm resistors in series and it STILL didn't do what I wanted. Looking closer at this resistor mod; it is only good for reducing the distorting on the talk back circuit caused by a radio with more than 100% modulation = 'splatter'. NOT for adjusting the talk back volume.

SO - I put a SPST switch between the green wire at J15. If I want to adjust my echo level and depth, I have to flip the switch on the back so it turns the talk back circuit back on, turn the mic gain down enough (almost all of the way down - BTW), set echo/level, flip the switch back off, and turn up the mic gain.

Anyone have a better way? Fortunately, there was already a factory-made hole in the back of the radio that fit a mini SPST without any difficulty. But Galaxy really should have put an adjustable talk back volume on the radio. It is a pain in the butt to do it the way I did it - but at least I got it to work the way I need it to. I talked to the tech at Galaxy on the phone, and he suggested that I put a ferrite between the internal speaker and the board. I told him that it was audio feedback from too high a level out from the radio, and the sensitive D104/TUP9 just didn't allow me to get enough mic gain out of it to work on the air. He never did answer my email either, nor did his solution solve my dilemma. Mine works; and his didn't. Go figure - this guy must see this problem all of the time from people that have the DX99V and a D104 - and yet they offer no viable solution. I don't like the compromise I had to do to make it work the way it should. But I will keep the radio and keep my solution in place.

My Magnum OmegaForce has a feedback problem with my D104; but it also has a talk back volume to handle it the way that it should. Not knocking Galaxy; but why didn't they see that problem coming off of the drawing board?

 

[purenrg]

I will have to agree with you about Galaxy drooping the ball On the engineering of the talk back part!

If these radios are at 100% modulation are near they will do that head shaking feed back sequel.
But when running the stock Mic it's OK, but if your going to run a power Mic then your going to have too disconnect the factory talk back. First is your G99v have the new SMT type echo board or is your radio a older model 99v?

# 1 (old type echo board disconnect wire at tr35 this will disable the talk back without loosing echo.
# 2 (New SMT type echo board disconnect wire at j15, this is next r244 this also will give you echo without the talk back.


To have a variable talk back you need to install the UTB-1 talk back board, check out this model at rf limited for more details. This will give you the talk back that your looking for, while retaining the factory echo.

Also if your radio is new this mod may void you 2yr warranty

 

[9C1Driver]

If nothing else, sell the 99 and get a butt stomping Magnum S9 with variable talk back already there.

 

[Bionic Chicken]

The 99V should not need an amplified mike. This is what is generating the squeal. You can "dehorn" the mike (bypass the amp in it which works great) or pad the talkback down. Installing a relay talkback circuit will let you fine tune it to where you want.
If you want to use the amplified mike you need to make sure that the gain adjustment is just barely cracked open. You can add a 1K resistor in series with the audio wire of the mike (or experiment with the value) to pad the mike down also.

 

[hotrod]

If nothing else, sell the 99 and get a butt stomping Magnum S9 with variable talk back already there.

i agree.make sure your d104 is only just cracked opened.mine with the
mic pointing away turn it all way down then up just were the line is
straight up and down.then any futher adjustment use the mic gain
then if this fails just turn the tb off with the switch ya installed
guess this is why i love my magnum

 

[Robb]

Although I didn't mention it in my first post, I am using the DX99V for my mobile with a D104 handheld mic. It also has the same feedback problem - but not as bad as it is with the more sensitive D104 lollipop mic.

The solution works, as now that it is set - I can forget about it. Of course - the downside to this is that I don't have any talkback in the vehicle. That isn't really a problem for a mobile unit, but it would have better for Galaxy to not create a whole bunch of problems that they easily could have fixed before it got off of the drawing board.

This radio may very well work with a stock/unamplified mic. But how many people prefer to use a unamplified mic - unless you are a trucker that uses a noise-canceling mic? I should have kept my RoadKing that I sold last week. I never checked it out with that radio -anyway. My own fault for not checking it first!

 

[hotrod]

how far ya turning up the gain on the 104m6b.try it with the mic on#2or3 then
any futher adjustment do it with mic gain.id try 12oclock on mic gain.if that
fails and ya really want tb just buy a skythumper mic its supposed to be
a nc type mic but has audio like a power mic.

 

[7mmag]

skythumper mic

I run the skythumper on my 48T,works great and my gain is set at 10.5 position.Some people say I`m too loud,it`s nice to know your heard.I tried an astatic 636L first,switch broke in a couple of weeks and when it was working audio checks were not favorable.I`ll stick with the skythumper.

 

[crkfngr]

Get a Skythumper mike they are better than a RK56. I have tried D104 M6B and RK56, and ampified mikes give feedback I have tested all, feedback is gone with a nonamp mike and they sound clean and great. Check it out.

CB Microphones

73's
Crkfngr

 

[Robb]

I am very partial to the Astatic D104's; I don't leave home without them. I sold the Turner RK-56 that I had to a neighbor for only $30. I agree that either the RK-56 0r the SkyThumper would probably work out better - considering the feedback problem. But I have since put the talkback cut-out switch as per CBTricks suggested:
Galaxy Radios DX99V Service Manual

That mod works out fine for me, and I use the D104. I shut the talkback off from a switch that I put on the back. If I need/want to adjust the echo depth/delay, I flip the talkback switch to the 'on' position, turn the mic gain almost off, and then adjust the depth/delay parameters to my liking. I then turn the talkback off, and turn the mic gain back up to the 1-3 PM position. That is what I had to do to be able to use the preferred D104 mic. I get loads of flowers with that mic/radio combo in my vehicle. That is the only fault with the Galaxy DX 99V, other than the slight SSB drift when cold. But it has proved to be an excellent radio in my mobil, and I am thankful for having/finding/getting it...