[VHFcontesting] What's your favorite IF radio?

[Bill Schwantes]

Hi Dan,

I use a pair of Elecraft K2 radios as IFs on 28 Mhz. I like the IF
performance and the ability to use DSP, bandwidth filters and noise
blanking to manage noise and interference.  I use one dedicated to 50 MHz
and the second K2 as an IF for 144, 222, 432, 902 and 1296 in concert with
the KRC2 band decoder.  The KRC2 drives a homebrewed band switch that
manages the IF paths, mic audio, CW keying assignment, amplifier sequencing
and TR sequencing. The band switch box also has SO2R type audio controls so
I can listen to either IF radio or both radios at once with one in each
ear. That allows me to listen to 6 and 2 meters while in motion.

The K2 has a very useful 0 dB drive level, they package well in limited
rover space, K2s draw very little current and despite being kit built
radios, they're reliable and rugged.

Unfortunately they're not perfect. The three drawbacks to the K2 as an IF
are:

   1. There's no FM  --  Recent rules changes make it much more likely that
   FM will become a bigger portion of a rove station's score. There's no easy
   workaround for this drawback and I'm still trying to figure out how to
   overcome this deficiency for my rove station.
   2. There's no "transmit" button on the K2. For CW my station uses a
   manual TR control which puts the transverters, amps and TR relays in
   transmit through a sequencer.  CW keying the K2 can then take place without
   clacking the relays and asking for hot-switching trouble. QSK isn't
   possible using the sequencers. That's no fault of the K2 but it would be
   handy to have an "xmit" button on the K2 to initiate the sequence. An easy
   workaround by installing a "transmit" switch for transverters, amps and TR
   relays.
   3. Low audio from the internal speaker. After several roves with the K2s
   audio maxed, I finally added external audio amps for the external speakers
   I use.  Headphone audio is barely adequate unless your rove vehicle is
   quiet as a Bentley or Rolls Royce.  Mine is a diesel pickup so the K2 audio
   is too low for operation in motion. External amplification is another easy
   workaround but it adds complexity to the station.

I'm in the process of Integrating the Elecraft KX3 as an IF for 2.3, 3.4,
5.7 and 10 Ghz bands.  It looks like that will be straightforward but I
have not completed that so I'll hold comments until that work is finished.

73, Bill
W7QQ DM65sb



3 drawbacks  --  no FM, no transmit button, low audio