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

[rbethman]

David,

I put the output of the BC-610 into it.  That's 400W carrier.  I DO get 
100% modulation.  I actually have to dial things down to stay with the 
1500W PEP.

That T-R Switch is built like a tank!

Bob - N0DGN

On 7/24/2011 12:28 PM, David C. Hallam wrote:
> 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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