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Timebomb
Junior Member
Username: Timebomb
Post Number: 35
Registered: 2-2005
| | Posted on Friday, April 15, 2005 - 1:18 pm: | 
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I've got a few mic adapters that have really come in handy. One converts a 4 pin mic(Cobra) to a 5 pin mic plug. Is there a model that converts a 5 pin mic(Cobra) to a 4 pin mic plug? My Silver Eagle is a 5 pin, and I'd like to try it on some of my 4 pin radios, without having to rewire. Thanks! |
Tech808
Moderator
Username: Tech808
Post Number: 5542
Registered: 8-2002
| | Posted on Friday, April 15, 2005 - 1:32 pm: |
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You mean like the ones that Copper carries below that i did the Review on?
Microphone Adapters
They are very handy for everyone to have. 
Lon
Tech808
CEF808
N9OSN  |
Timebomb
Junior Member
Username: Timebomb
Post Number: 36
Registered: 2-2005
| | Posted on Friday, April 15, 2005 - 3:53 pm: |
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Yup, I bought all mine from Copper, and I see the 4 pin to 5 pin, but what about a 5 pin to 4 pin? Are these made? |
Timebomb
Junior Member
Username: Timebomb
Post Number: 37
Registered: 2-2005
| | Posted on Friday, April 15, 2005 - 4:33 pm: |
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Weird, my last post didn't show up.
Tech808, I'm aware of the mic adapters listed, I bought them here! I'm wondering if there is a 5 pin to 4 pin Cobra style. Opposite of the 4 to 5. Just curious why there wouldn't be one. |
Tech808
Moderator
Username: Tech808
Post Number: 5549
Registered: 8-2002
| | Posted on Friday, April 15, 2005 - 4:42 pm: |
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Timebomb,
You need to remember this is a Moderated Forum and your posts will not appear until a Moderator sees it, reads it and approves it.
Sorry but at this time there are no 5 to 4 pin mic adapters being made that I know of.
But Copper should have the C4P6MAG adapter soon to add to your collection which will allow you to use Cobra/Uniden 4 Pin mics with the 6 Pin Magnum Radios.
As soon as they are in stock I will make a post.
Hope this helps,
Lon
Tech808
CEF808
N9OSN
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2600
Advanced Member
Username: 2600
Post Number: 545
Registered: 7-2002
| | Posted on Saturday, April 16, 2005 - 12:22 am: |
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Hey Timebomb,
If I'm reading all this right, they sell an adapter to put a 5-pin MIKE onto a 4-pin RADIO,
but NOT to put a 4-pin mike onto a 5-pin radio.
I have seen folks try to use a 4-pin mike, with only one ground wire, on a 5-pin radio that has TWO separate ground pins. One ground (pin 1) is for audio alone, and the other ground on pin 4 is for transmit/receive switching alone.
Most attempts to put the 4-pin mike onto the 5-pin radio result in feedback noises of some kind, on transmit or receive, or both. The reason is that the mike has only one ground connection, and the radio has TWO. This leaves you three choices.
1)Tie the two grounds together.
2) ONLY hook to the audio ground on pin 2.
3) ONLY hook to the T/R ground on pin 4.
In real life, some folks will get away with one of these "lashups" by keeping the mike gain, volume, or both turned down far enough.
I never recommend it precisely because it's hard to predict what kind of result you'll get. Just because one guy got it to work "in spite of itself" is no guarantee that you will.
The one strategy that DOES work is to change the 5-pin socket on the radio to a 4-pin. The separate T/R switching ground is no longer hooked to the mike socket, but to a relay added inside the radio. The relay has its own, separate ground connection to the "pin 4" wire. A small transistor isolates the transmit pin (3) on the new 4-pin jack from the sensitive audio ground wire, hooked to pin 1 on the new 4-pin socket.
This cures the random "squeal" problems that result (usually) from the first 3 choices above.
Trouble is, it's expensive, complex and also requires capacitors and chokes to be installed on the new 4-pin socket. The factory mike socket is filtered, and the new one needs to be as well.
Another way involves using a commercial "roger beep" board that has a small relay on it. The beep board gets modified by cutting the foil trace on the relay's common pin. The now-separate relay pin now goes to the pin-4 T/R-circuit ground wire without creating a "ground loop" connection to the audio ground. The sensing circuit on the beep board's green wire keeps the audio circuit isolated from the T/R switch circuit.
Too bad nobody has posted a "how to" for that on the web.
73
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2600
Advanced Member
Username: 2600
Post Number: 547
Registered: 7-2002
| | Posted on Saturday, April 16, 2005 - 1:01 am: |
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Hmm. Open mouth, insert foot. Checked Copper's listing for the adapter cords. They ALL take a 4-pin mike. Duh...
Normally I have a policy NOT to criticize stuff Copper sells, no matter what I may (personally) think of it. Just good manners, that's all.
Thought I had killed that post, once I looked at the catalog description and figured out I had gotten Timebomb's question backwards.
Looks like I didn't accomplish that. Appears the moderator approved it right away.
My technical analysis of the "two grounds on one wire" problem still stands, but now I gotta ask. Just which of the first 3 choices do they use in the "4-pin mike to 5-pin radio" adapter?
It has to be # 1, 2, or 3.
Or they thought of something I didn't. Happens all the time.
73
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