[R-390] R-390A deaf below 600 KC?

[Jordan Arndt]

Paul...

In my experience, the unresponsive meter is likely to be due to a 
non-standard meter which doesn't have a 17-18ohm internal resistance. If 
that is not the case, then there are components in the meter circuit which 
need assessment.

As far as the antenna input is concerned, all 3 of my 390As exhibit 
mis-match effects from ~15 to 24MC with the 90ft wire antenna I use, when 
fed into the balanced input with the J207 side of the connection grounded. 
In fact, ungrounding that side eliminates that problem, so yes, impedance 
mis-matching can and does occur.

As far as a lack of sensitivity below 600khz, are you sure the cam and slug 
rack for that band is in alignment according to the manual. The cam for that 
band should be very near the peak of the cam when tuned to 00.999.99+, and 
continue past the peak of the cam as you pass 1.000.00+ on the bottom 
band...

I hope some of this helps....

73...Jordan VE6ZT

----- Original Message ----- 
From: "Paul Staupe" <staupe at gmail.com>
To: <r-390 at mailman.qth.net>
Sent: Sunday, November 28, 2021 6:40 AM
Subject: [R-390] R-390A deaf below 600 KC?


>I picked up an otherwise beautiful Amelco from a local yesterday but
> noticed three  things that were strange. First was that it didn’t like my
> Beverages on the twinax input but performed normally with a 160m
> vertical….  Can the impedance difference be that much of a issue?  My EAC
> doesn’t care between either antenna.
>
> Secondly, and more concerning is that below 600kc there literally is no
> signal.  I primarily use my EAC for BCB DXing and I need to figure this 
> out
> for sure.
>
> Thirdly, although the 10 turn pot is installed, the carrier level meter is
> very insensitive and only moves  1/8 of the scale between the loudest and
> lowest signals.
>
> So I’ve got a pretty looking radio but there is some work to be done. Any
> suggestions?
>
> Best regards,
>
> Paul
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