[R-390] Balanced Antenna Connector

[Barry Scott]

Hi Larry,

Okay - I see that connector now.  Thank you so much for the part
numbers for it.  The images for the connector in my R-390/URR look
exactly the ones I'm seeing now.

Looking at it from the back side, I think I can tell where the
original connector was removed and the twin-ax connector was installed
in the existing hold.

I had a need to open that relay box a couple of years ago when I first
started working on this radio.  I think it had something to do with
the antenna relay and I have a very vague memory of seeing some wiring
that had been disconnected and I _think_ I reconnected those.  I'll
have to check it.

Thanks!
Barry - N4BUQ

On Thu, Oct 10, 2024 at 5:20 AM Larry Haney <larry41gm2 at gmail.com> wrote:
>
> Hi again Barry,  You need a little more information about the twinax balanced ant connector mod.  Usually the antenna relay is disabled inside.  This is due to the construction of the original relay - some of the relay contacts are supported and connected directly to the contacts on the original female twinax connector that was removed.  This normally disables the relay from functioning, This may not be a problem for you, but you should know how it is working.  Repairing the relay once modified like this is nearly impossible.
>
> Regards, Larry
>
> On Wed, Oct 9, 2024 at 11:53 PM Larry Haney <larry41gm2 at gmail.com> wrote:
>>
>> Hi Barry,  The connector in your picture is the old original twinax connector.  Somebody modified your 390 and changed the new twinax to it.  It was used on the early sp-600s.  The male plug is available online and is known by the name ug-102, pl-284, Amphenol 83-22sp and 83-821.  Sorry I don't have any at the moment.
>>
>> Regards, Larry
>>
>> On Wed, Oct 9, 2024 at 2:00 PM Barry Scott <72volkswagon at gmail.com> wrote:
>>>
>>> Hi Larry,
>>>
>>> Those are the standard twin-ax connectors ("IBM"?).  I have one of
>>> those but this connector is different.  See the pictures below.  Those
>>> sockets appear to take a pin that's about 0.090" in diameter.  I just
>>> don't recognize it.
>>>
>>> Thanks,
>>> Barry - N4BUQ
>>>
>>> On Wed, Oct 9, 2024 at 3:04 PM Larry Haney <larry41gm2 at gmail.com> wrote:
>>> >
>>> > Hi Barry,  There are many manufacturers making the twinax male straight plug today for the balanced jack on the 390s.  There's Pasternack PE4104, PE-S330; ARC - 8-299, AMPHENOL - 82-5589-RFX, 162100; SPC Technology / SAMAR - SPC21084; Connex 162100; Pan Pacific TWX-3501; Aim Cambridge 27-9087, AIM 27-9080; AVA 403000 and others.
>>> >
>>> > If anyone would like one, I'll sell them an AVA 403000 for $3 + postage.
>>> >
>>> > Regards, Larry
>>> >
>>> > On Wed, Oct 9, 2024 at 11:21 AM Barry Scott <72volkswagon at gmail.com> wrote:
>>> >>
>>> >> What is the correct designation for the two-pin antenna connector
>>> >> (balanced) in the R-390/URR (likely the same for the R-390A/URR but I
>>> >> want to be specific just in case).
>>> >>
>>> >> Also, I think Chuck Rippel had a connection contraption that used a
>>> >> resistor (or two) so that 50-ohm unbalanced would match just a bit
>>> >> better using the balanced connection.  He had a website that depicted
>>> >> that but I don't know if that still exists.  Anyone know?
>>> >>
>>> >> Thanks,
>>> >> Barry - N4BUQ
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