[R-390] break-in question, 390A and 390

[David C. Hallam]

A T-R switch is a more elegant solution than two relays.  At the time I 
set up the R-390, I did not have one.  I do now but am a little hesitant 
about putting the output of my Invader 2000 into the T-R switch.

David
KW4DH

On 7/24/2011 11:42 AM, rbethman wrote:
> Amen!  It took a bit to figure that one out.
>
> What was very startling, was to have the R-390A off the antenna switch 
> with only about a 3 ft jumper of coax attached.  Somone across town 
> lit up on the frequency and I swear the R-390A darn near jumped up!
>
> Yes - they ARE that sensitive!
>
> I've managed to eliminate the extra relay by using a Johnson T-R 
> Switch, and using the break-in.
>
> I monitor MY signal AND the one I am listening to by picking the 455Kc 
> off the rear and feeding it into a Kenwood SM-220 w/BP-8.
>
> Bob - N0DGN
>
> On 7/24/2011 11:33 AM, David C. Hallam wrote:
>> The break in relay on the R-390 only grounds the antenna input and does
>> not mute the receiver.  What you have to do is open the RF gain
>> connection on the back panel strip.  I did it with a relay.  On transmit
>> you ground the R-390 break in relay and open the relay in the RF gain
>> circuit.
>>
>> David
>> KW4DH
>>
>> On 7/24/2011 10:42 AM, frankshughes at aim.com wrote:
>>> Hi,
>>> I am seeking advice on break-in function and troubleshooting audio.
>>>
>>>
>>> I have a Collins 32S-3 transmitter, and am trying to use either a 
>>> 390A or 390
>>> to receive.
>>>
>>>
>>> I have deduced that the relay logic for the 32S-3 (Open w/ PTT) had 
>>> to be reversed
>>> to work with the "break in" contact on the 390A and 390 terminal 
>>> strip (N.O.)
>>>
>>>
>>> So I put a relay in the circuit between the 32S-3 and 390, works great.
>>>
>>>
>>> The ohm meter shows that when I PTT the 32S-3, the 390A and the 390
>>> antenna input center pin goes to ground, and the audio also 
>>> squelches to full quiet.
>>>
>>>
>>> However, I get lots of audio output from the 390A and the 390 when I 
>>> speak into the mic!!!
>>>
>>>
>>> So even though the antenna input is grounded, both the 390A and the 
>>> 390 are still getting
>>> signal input.
>>>
>>>
>>> The audio is also present from the 390 and 390A if I disconnect the 
>>> antenna and activate break in
>>> while keying the 32S-3.
>>>
>>>
>>> Is the 32S-3 bleeding RF into the shack the 390 and 390A can pick up 
>>> even with the antenna disconnected?
>>> (How can these things be so sensitive to tiny RF levels...oh, wait....)
>>>
>>>
>>> If so, building a Faraday cage around my transmitting position would 
>>> be ....crazy.....OK, plan "B" is to
>>> put a relay into the audio circuit to open the input to the speaker 
>>> at the same time PTT is activating
>>> break-in.
>>>
>>>
>>> Or what else can I do????
>>>
>>>
>>> Thanks,
>>> Frank
>>> KJ4OLL
>>>
>

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