[Elecraft] K4

[Edward R. Cole]

The FT-736R was well liked by satellite and weak-signal fans, 
alike.  The Mutek conversion of the receiver fixed all those issues 
making it a superb radio for its time.  In 1998 I bought its 
successor, the FT-847.  It added HF to 6m/2m/70cm making possible 
almost one radio ham shack (and this was copied by many other radios).

But one of the attractions of the 736 was the band module concept 
that permitted one to taylor-make their radio.  Actually, I see this 
approach with Elecraft and my K3 was built in that fashion.

Actually I am surprised at the introduction of the Icom-9100, since 
amateur satellite activity has taken a dive with the lack of 
high-orbiting linear-passband "birds".  Most of what is available 
today uses FM single channel technology so one need not invest in a 
radio like the 736 (with a few exceptions).  I guess Icom felt a need 
to compete in the HF-light market.

I have made a major decision to move over to using the K3 with adding 
VHF/UHF transverters starting two years ago.  I am looking to add 222 
and 432 to make the conversion complete (with the exception of 
900-MHz).  As soon as I receive info from DEMI on availability and 
delivery times, I will post my FT-847 for sale on e-bay.

It is too bad that cross-band full-duplex cannot be supported in the 
K3/KRX3 combo.  I do have an idea that might work.  It would entail 
adding a receiver on the 1st IF or the KRX3 and using the Aux antenna 
input connected to a transverter for receiving satellite downlinks. 
If the KRX3 1st IF is not defeated when the main K3 is transmitting 
it will work in duplex.  I propose to use my SDR-IQ this way.  For 
satellite uplink/downlink tuning, it will probably require a computer 
interface for tuning.  What firmware mods would be required for the 
K3 - is the question?  VFO-A and B need to be controlled separately 
and ideally VFO-A can be tuned while transmitting (but not entirely 
necessary).  Tracking sw exists to generate commands for dual Rx /Tx tuning.

A K4, Tayored after the 736 module concept covering 6m-23cm with all 
the bells of the K3 would find a large following in the weak-signal 
VHF+ crowd.  That crowd includes satellite, tropo-scatter Dxing, 
meteor scatter, and eme.  It could be based on a standard 28-32 MHz 
IF radio or a 50-54 MHz IF. The existing Elecraft transverters use 28-MHz.

So my K3/10 is becoming the K4 (in effect): 50/144/222*/432*/1296.


73, Ed - KL7UW, WD2XSH/45
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BP40IQ   500 KHz - 10-GHz   www.kl7uw.com
EME: 50-1.1kw?, 144-1.4kw, 432-100w, 1296-60w, 3400-?
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