[R-390] Filters

[Don Reaves]

I don't know of any easy way to search the QTH.net R-390A archives.  The
actual messages are stored in html format which makes it relatively easy to
browse them with a web browser, and they are organized so it is rather easy
to sequentially read or scan each message in each month's compilation.

As others have pointed out, using the Pearls of Wisdom collection will save
you some needless excursions off in the weeds of the archives.  Due to
software upgrades, glitches, QTH.net owner changes, most of the archives
prior to December 2001 are missing.

I don't know if they are still hosted online but the Hollow State News
newsletters in .pdf format are very useful. Issue 1 goes back to Sept.
1983.  There is a HSN reprint distilled with only R-390 information, which
mentions the AGC problems caused by a defective C-551 and some discussion
of the AGC time constants you may find relevant.  I've put this file and
its index up on my web page.

http://militaryradio.com/manuals/HSN/HSN-R390.pdf
http://militaryradio.com/manuals/HSN/HSN-R390Index.pdf

Don Reaves
R-390 List Manager



On Sun, Feb 3, 2013 at 9:55 AM, quartz55 <quartz55 at hughes.net> wrote:

> Hi.  New to this group.
>
> I have 2 R-390As.  Filters in one module seem fine, but the gain drifts,
> I'm working on that.  Other module has bad 2(weak) and 4(dead) but the 8
> and 16 seem good, but different gain through them.
>
> Was wondering if anyone has come up with a good cheap way to replace the
> filters?  Could it be possible to make an op-amp variable bandwidth 455
> filter to replace the mechanical ones?  Don't know the voltages involved in
> the filters, but maybe too much for op-amp filters?
>
> Is there any way to search the archives?
>
> N3DT
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Don Reaves  W5OR WD2XSH/15
8101 Barrett Rd. Roland AR 72135
VOIP landline:       501.420.3661