[R-390] R-390A Break-in question

[David C. Hallam]

What I have done is to add a relay contact to open the RF gain circuit.
There are terminals on the rear terminal strip to do this.  At least there
are on my R-390.  The relay contacts need to be isolated from chassis
ground.

David
KC2JD

-----Original Message-----
From: r-390-bounces at mailman.qth.net
[mailto:r-390-bounces at mailman.qth.net]On Behalf Of John Lawson
Sent: Wednesday, August 16, 2006 12:14 PM
To: r-390 at mailman.qth.net
Subject: [R-390] R-390A Break-in question




   After completing some repairs to my Venerable Valiant, I also took the
opportunity to finish wiring up the 'PTT' circuits - previously I'd been
using the OldSkool method of switching the reciever to Standby, switching
the antenna manually from RCV to XMT, and switching on the Transmitter -
pretty clumsy and disaster-prone (tho I somehow managed never to actually
put power into the front end of the 390A) and very difficult to carry on a
rapid conversation....


   Anyway, I wired in a DowKey and used the contacts on it to ground the
break-in point on the 390A, as per the manual.  Both relays are working, and
the antenna input shows 'ground' when it's energized....  (I'm using the
Unbal
side).  The problem is that when transmitting, I still have "leakage" into
the
radio - the carrier meter reads up to about 40, and enough audio gets out of
the speakers to cause feedback, unless I manually rotate the Local Gain
control
full down.  The Line Gain and meter show nothing, BTW.

  The radio has the top cover in place, the chassis is grounded solidly to
earth, the transmitter is likewise grounded, the antenna tuner is grounded
(I'm
using ladder-line from tuner to my loop antenna feedpoint) and a small
'field
strength' meter that I keep on the shelf to watch such things shows no
unusual
amount of RF in the shack. All wiring is shielded/grounded, etc. The antenna
easily and repeatably tunes up to a 1.1:1 on the AM Fone portions of 80M
(generally 3870 Khtz). Power into the tuner is about 150 Watts from the
Valiant.


   Someone has mentioned to me that this is fairly normal R-390A behavior,
but
since I've just now started using the rig this way, I thought to ask the
Assembled Experts here if there might actually be a problem with the radio,
or
at least some mitigation of the syptoms that can be done.


   More/better details of station and wiring upon request....


   Thanks Y'all!


Cheers

John  KB6SCO
Valiant, Ranger, ELMAC AF-67
R-390, R-390A, R-388

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