[Elecraft] Question about KRX3 install

[Don Wilhelm]

Tom,

Perhaps I can state things in a different way to help you along.
First, the SubRX can always use the main antenna, but if you do that, 
there is a 3 dB coupler in the path, so your receive signal strength 
goes down by 3 dB both in the main RX and the SubRX.

The way to avoid the 3 dB loss is to set the subRX to use the AUX 
input.  If you select AUX on the subRX, then the input will come from 
one of two places depending on how you have connected the TMP cable.  If 
you connect it to the KAT3, the AUX antenna will be the non-transmit 
antenna - in other words, if you have 2 antennas (necessary for 
Diversity reception) - but both antennas are transmit capable, you can 
connect one antenna to the ANT1 jack and the other to the ANT2 jack.  
You will transmit on the one selected by the ANT1/2 button, and  the 
subRX will receive on the other one.

If you have a separate receive only antenna, you would want to connect 
the subRX AUX input to the BNC jack - in that case install the BNC and 
its cable.

I have set up a couple K3s with both cables installed, but only one 
connected to the subRX AUX jack - the other it taped to the top of the 
subRX enclosure.  If you want to change which one is connected to the 
subRX AUX jack, it is a simple matter of removing the top cover and 
unplugging one TMP cable and plugging the other one in. If you install 
both, I suggest that you get out your label machine and mark which cable 
is which.

73,
Don W3FPR


On 6/13/2015 1:11 PM, Thomas Schaefer wrote:
> I don't mean to be obtuse, but I don’t follow.
>
> The way the book is written is it sounds like I can choose an option. There was a downside described ion the manual to having the AUX though non-used antenna port. I also do not need to use a separate antenna. All I ever want to do is have the Sub RX on the main antenna. I use the sub rx strictly to hear the other side of a pile up.
>
> I am going to check out my other K3 that I received that had the sub RX in it. Let me see what it did.
>
>