[R-390] R-390 (non-A) - Low RF Gain or bad Antenna relay?

[Jordan Arndt]

My first instinct would be to try some different tubes and make sure you're 
making the measurement with sufficient decoupling...

73...Jordan VE6ZT

----- Original Message ----- 
From: "Barry Scott" <72volkswagon at gmail.com>
To: "Larry Haney" <larry41gm2 at gmail.com>
Cc: <r-390 at mailman.qth.net>
Sent: Saturday, November 09, 2024 3:13 PM
Subject: Re: [R-390] R-390 (non-A) - Low RF Gain or bad Antenna relay?


> Larry,
>
> Your document prompted me to check the three oscillators in my R390/URR.
>
> On page 46 of TM 11-5820-357-35, the expected voltages of the three
> oscillators is defined as being -3v to -11v.  I just checked those and
> the 1st oscillator is probably good enough (~ -4.8v) but the 2nd
> oscillator and the PTO are both quite under spec.
>
> I had scoped the outputs several months ago and I thought they were
> stronger than that (or, at least, good enough) but checking just now
> while in STANDBY with the VTVM tells a different story.  Looks like I
> have work to do.
>
> Thanks,
> Barry - N4BUQ
>
> On Thu, Nov 7, 2024 at 2:21 AM Larry Haney <larry41gm2 at gmail.com> wrote:
>>
>> Jerry,  Because I found many different 'specs' for the oscillator 
>> voltages
>> in the A, I wrote a doc about it.  The 390 voltages should be very
>> similar to the 390As in my doc: R390A Oscillator Output Level Affects
>> <https://www.r-390a.net/R390A%20Oscillator%20Output%20Level%20Affects.pdf>
>> .
>>
>> Regards, Larry