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

John Lawson jpl15 at panix.com
Wed Aug 16 12:13:35 EDT 2006



   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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