[R-390] Balanced Antenna Connector

[Dan Martin]

Hmmm… I cannot quickly remember any cap/resistor antenna hookup Chuck recommended. Perhaps others will recall.

The arrangement I’ve successfully used is one described by Chuck:

The antenna connection is even more simple. The radio has been aligned using the "Balanced" antenna input located on the rear of the receiver. Turn the receiver around and face it. TB-102 will be on your left and TB-103 on the right. The "Balanced" antenna input is located in the upper middle. Examine the connector and notice it has two holes for pins located within the connector. Simply tin your antenna wire and insert it into the right hand pin hole. Insert a wire in the left hand hole and ground it using one of the screws which hold the antenna relay unit to the rear panel. The "Unbalanced" antenna input can also be used but with a decrease of performance unless it was aligned to that input.

 If you wish to use the proper connector, there are several approaches from which to choose. A combination of a UG-971/U and a UG-636A will adapt a BNC connector to the "balanced" antenna input. A UG-970/U will adapt a PL-259 to the "balanced" antenna input. A UG-636A/U will also adapt a BNC directly to the "unbalanced" antenna input.

I am aware of a cap/resistor combo Chuck recommended for outputting the diode load to an outboard preamp/amp combination. Perhaps that was what you’re thinking of?



Dan - WB4GRA




Sent from my iPhone

> On Oct 9, 2024, at 2:25 PM, 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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