[Elecraft] K3 Phones / Diversity Question

Fri Aug 3 17:37:30 EDT 2012

Not necessarily so. The DRA can be either an antenna connected to the Aux jack OR it can be ANT1 or ANT2, whichever is not being used by the Main receiver. In my case, I'm set up for the latter. I can switch the SubRX between ANT1 and ANT2 by going this way. It affords me the ability to transmit on my Hustler 5BTV if I so choose, while using the doublet for receive. I don't think I'd normally do it like that, but I can if I want. Had I opted to put my other antenna on the Aux (Rx Ant) jack, it would only be useable as a receive antenna.

Anyway, I've solved the problem. Shortly after installing my SubRX, I also installed the K144XV 2 meter module. Had a small user problem with filter installation on the main receiver, and in my haste to get things put back together, I managed to connect the TMP cable from the 2 meter antenna to the SubRX input port. No wonder I had such extremely weak signals when I went to diversity mode - a 2 meter ground plane antenna mounted just above roof level makes a horrible 20 meter receiving antenna!!! 

Interestingly, having done that, it also meant that the cable from the KAT3 that should have gone to the SubRX was connected into the 2 Meter module. This had the unusual result of the K3 outputting it's 10 watts of 144 MHz RF into a ground-mounted 40-10 meter HF vertical. And it worked! I had a local simplex QSO and was able to hit (with nearly full quieting) a repeater close to 90 miles away.

Thanks for everyone's input in tracking down this very strange problem!!

Jim / W6JHB

On   Friday, Aug 3, 2012, at  Friday, 11:32 AM, N5GE wrote:

> The diversity receive antenna (DRA) must be connected to the AUX antenna on the
> back of the K3.  Unless your DRA has the same gain as the transmit antenna you
> will need to use a Preamp on the DRA.
> 
> I use a DRA that is a 38 inch diameter loop of aluminum tubing that I can rotate
> to peak up the signal of the far off station.  That loop has a 35 dB LNA
> attached.
> 
> Most of us don't have the space to erect a large receive only, so we use smaller
> antennae for the DRA.  If you are one who has the property to make a full size
> DRA, then you can probably get by without a Preamp unless you locate the DRA as
> far away from the TX antenna as possible.  The old ship to shore stations used
> to locate the DRA and RX antennas miles from the transmitter, so since most of
> us can't do that, here are some links to specialized RX antennas.
> 
> http://www.pixelsatradio.com/product/shortwave-magnetic-loop-antenna/
> 
> http://www.dxengineering.com/search/department/antennas/brand/dx-engineering/part-type/hf-receive-antennas
> 
> Don't let this discourage you.  The antenna I use is the one from PixelSat
> Radio, but you can make one just like it yourself if you like to build things.
> 
> Amateur Radio Operator N5GE
> ARRL Lifetime Member
> QCWA Lifetime Member
> 
> On Fri, 03 Aug 2012 10:16:18 -0700, Jim Bennett <w6jhb at mac.com> wrote:
> 
>> Still have issues with this. Here are the settings in Config that I'm assuming are relevant:
>> 
>> L-Mix-R = A  b
>> SPKRS = 1
>> SPKR + Ph = no
>> SQ Main = Sub Pot
>> SQ Sub = Sub Pot
>> Sub AF = Nor
>> 
>> With these Config settings, the K3 works fine with the SubRX turned off; equal Main audio in both headphones. When I turn on the SubRX, it is still OK; I get Main audio in the left ear and Sub audio in the right ear. I know I'm getting the Sub audio in the right ear, as I can turn the sub VFO and hear the frequency change in my right ear. BUT, as soon as I turn on Diversity, I get almost no signal in the right ear. It isn't silent - it's just that the signal that is pounding in on the Main is nearly inaudible on the Sub. If the signal being received on the Main is less than S7, I can't even hear it on the Sub with Diversity turned on. If it is an S9 or greater signal, then I can just barely hear it on the Sub when Diversity is turned on.
>> 
>> Very strange. The SubRX works fine until Diversity mode is enabled.
>> 
>> Any ideas? Does this need to be escalated to Elecraft Tech Support?
>> 
>> 
>> On   Friday, Aug 3, 2012, at  Friday, 6:02 AM, Mike K2MK wrote:
>> 
>>> Hi Jim,
>>> 
>>> One of the following might be helpful.
>>> 
>>> If you have CONFIG:SPKRS set to 1 and CONFIG:SPKR+PH set to YES it will turn
>>> off the right channel of your headphones. Avoid the problem by turning
>>> CONFIG:SPKR+PH to no when using diversity.
>>> 
>>> You also need to consider the setting of two other parameters which can be
>>> confusing with respect to SUB RX use. The first is CONFIG:SUB AF. Depending
>>> on whether you have chosen BALANCE or NOR it changes the way the concentric
>>> audio control operates. The second is CONFIG:L-MIX-R which controls which
>>> receiver's audio is in which ear. This control gets overridden when
>>> diversity is used and reverts to MAIN in left ear and SUB in right ear. So
>>> you might have one arrangement set for general SUB RX use and when you go to
>>> diversity it changes.
>>> 
>>> 73,
>>> Mike K2MK
>>> 
>>> 
>>> 
>>> Jim Bennett wrote
>>>> 
>>>> I just recently added the sub receiver to my K3. I've been using the Sub
>>>> receiver (without diversity turned on) and all was fine. I have the Yamaha
>>>> CM500 headset - one cable plugged into the Phones jack and the other going
>>>> to the Mic jack. I also have an Icom SP-20 external speaker, and it's
>>>> connected to the Spkrs jack. 
>>>> 
>>>> Well, I engaged Diversity mode and at first thought it was working
>>>> properly. But, when I turned the AF to zero on the Main receiver, I
>>>> realized that the audio on the Sub was almost nonexistent signals are
>>>> there, but really, really weak. OK, so looking at the Config parameters, I
>>>> noticed in the KRX3 manual that SPKRS should be set to 1. Mine was set to
>>>> 2. I changed it to one and now have zero audio coming from the Sub
>>>> receiver. Not exactly what I was hoping for.
>>>> 
>>>> What do I need to do to get my headphone audio in Diversity mode to act as
>>>> it does with the Sub turned on, but Diversity off? 
>>>> 
>>>> Confused, I am.
>>>> 
>>>> Jim / W6JHB
>>>> 
>>> 
>>> 
>>> 
>>> 
>>> --
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