[Elecraft] [Moon-Net] Using K3 for 2m EME

[Lance Collister, W7GJ]

Hi Ed,

TNX for your thoughts.  Yes, an external transverter would have been more flexible, 
but I was hoping for something self contained.  Oh well....

I wired up a pair of BNC coaxial relays to my 2m relay switch box, and that seems to 
safely terminate the output of my 2m preamp during XMIT, as well as redirect the 2m 
output from the K3's new #3 coaxial connector to the input of my solid state driver 
amp. It all seems to work now, so I am anxious to see how the stability looks  on 
JT65 tmrw when I give it an actual workout on 2m EME.

Sure am glad to have the K3 home again!  GL with the 5W0M group - hopefully they will 
start hearing some stations soon ;-)   VY 73, Lance

On 4/9/2013 12:53 AM, Edward R Cole wrote:
> Lance ,
>
> As you know I run the K3 for eme, as well.  I chose the new L-series DEMI 
> transverter so it was built to my spec as perfect interface with K3.  It seems most 
> of the ham world is unfamiliar with separated Rx and Tx (though Elecraft did a 
> super job on the KVX3 option...but then forgot it when they designed the K144XV). 
> Well, probably assumed most users would be working FM repeaters or using brick amps 
> with internal switching for CW/SSB.  EME is just too niche.
>
> Only suggestion is modifying the K144XV to eliminate TR switching; not sure how 
> easy that would be.  keeping the K144XV inside the K3 cabinet is problematic with 
> running extra cables...or add an external coax relay (maybe the simplest solution).
>
> I will be incorporating the 2M module in the KX3 when it is available.  It will be 
> a standard common ANT connection so will require external TR relay to separate Rx 
> and Tx for preamps and PA.  I will likely only use it as 28-MHz IF for mw 
> transverters and built the required ckts into the mw transverters (my 3400-144 and 
> 10368-144 transverters have common IF).
>
> BTW my DEMI L144-28HP DRX is a dream for working adaptive pol on 2m-eme.  
> Unfortunately, DEMI made only one.  With the IQ+ as competition, its doubtful it 
> would be an item that DEMI will manufacture.  I hear a Tx is coming out for the IQ+.
>
> 73, Ed - KL7UW
>
> At 03:37 PM 4/8/2013, Lance Collister, W7GJ wrote:
>> I wonder if anybody has any ideas about this.  Prior to my trip to TX5K, I used my K3
>> for receive on 2m EME by setting up the transverter port for a 28 to 144 MHz
>> transverter, and I just plugged my 28 MHz converter into that nicely isolated receive
>> port.   The receiver worked great, but I was eventually interested in getting the
>> internal 2m transmitter module so I could use the more stable K3 on XMIT too.   I was
>> using my old IC746 as a separate transmitter on 2m EME, and - as most of you know -
>> it drifts quite noticeably every sequence.  And besides, I thought for traveling it
>> would be convenient to have both 2m and 6m capability in one lightweight box.
>>
>> So, now I have the 2m module installed in my K3 ;-)  The problem is that I can no
>> longer use the transverter port....it is hard wired to the 2m module.   And
>> apparently, the only 2m connector is the new one (a BNC called antenna jack #3) that
>> is used for box receive and transmit.   So there seems to be no way to use the K3
>> with a separate protected receive line anymore!
>>
>> For 6m EME, there is no problem - I just bring my 6m preamp line into the separate RX
>> ANT jack, and the 6m transmit power goes out through the UHF antenna jack #2.   For
>> 2m EME, though, I can't figure out how to bring in a separate receive line (either on
>> 2m from my tower mounted preamp or after my receive converter at 28 MHz) and still be
>> able to transmit on 2m.  The K3 does not support cross band operation, so I cannot
>> use the RX ANT jack to safely receive my converter output on 28 MHz and still
>> transmit using the internal 10w 2m module.
>>
>> Has anybody figured out a way to modify the circuitry or software to provide a
>> separate receive line for 2m operation?  It seems like I just made a very expensive
>> mistake, and should have just bought an external transverter so I could retain use of
>> the separate transverter receive jack on the rear of the K3. If not, I guess I will
>> just have to go back to using the IC746 for my transmitter on 2m, and defining a
>> second transverter setting for the K3 that will allow me to bring in my 28 MHz
>> converter output into that receive only jack.  This latter option DOES seem to work,
>> but of course, the internal transmit capability of the K3 on 2m is thrown out the 
>> window.
>>
>> Of course, there is always the solution of adding more sequenced external coaxial
>> relays to switch the K3's solitary new BNC antenna jack #3, between my driver amp
>> input and my 2m preamp output. However, the whole point of this expensive exercise
>> was to try to take advantage of the great separate receiver antenna capabilities
>> offered by the K3 on all other bands, apparently EXCEPT if you add the built-in 2m
>> option :-(
>>
>> Any suggestions would be greatly appreciated.    Elecraft Tech Support suggested that
>> I ask users for ideas, since they also are baffled on how to make this work, and I
>> guess are surprised at my application.   MNI TNX and VY 73, Lance
>>
>> -- 
>> Lance Collister, W7GJ
>> (ex WA3GPL, WA1JXN, WA1JXN/C6A, ZF2OC/ZF8, E51SIX, 3D2LR, 5W0GJ, E6M)
>> P.O. Box 73
>> Frenchtown, MT   59834-0073
>> USA
>> TEL: (406) 626-5728
>> QTH: DN27ub
>> URL: http://www.bigskyspaces.com/w7gj
>> Windows Messenger: W7GJ at hotmail.com
>> Skype: lanceW7GJ
>> 2m DXCC #11/6m DXCC #815
>>
>> Interested in 6m EME?  Ask me about subscribing to the Magic Band EME
>> email group, or just fill in the request box at the bottom of my web
>> page (above)!
>>
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>
>


-- 
Lance Collister, W7GJ
(ex WA3GPL, WA1JXN, WA1JXN/C6A, ZF2OC/ZF8, E51SIX, 3D2LR, 5W0GJ, E6M)
P.O. Box 73
Frenchtown, MT   59834-0073
USA
TEL: (406) 626-5728
QTH: DN27ub
URL: http://www.bigskyspaces.com/w7gj
Windows Messenger: W7GJ at hotmail.com
Skype: lanceW7GJ
2m DXCC #11/6m DXCC #815

Interested in 6m EME?  Ask me about subscribing to the Magic Band EME
email group, or just fill in the request box at the bottom of my web
page (above)!