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Sunday, January 15, 2023

Working Walter KA4KXX from Hispaniola

 Walter KA4KXX in Orlando has been a prolific builder of rigs for many years, and has been a great friend of SolderSmoke:  Here are some of the SolderSmoke podcasts and blog posts in which Walter's solder melting was mentioned: https://soldersmoke.blogspot.com/search?q=KA4KXX

As we approach the end of our current stay in the Dominican Republic, I could not miss out on the chance to work Walter with his homebrew rigs.  Even though the space weather was stormy, and my dipole was droopy, we arranged to meet up on the high end of the 20 meter CW band this morning.   See the results in the video above.  A solid QSO with Walter.  He says it is HB2HB, but truth be told I was on a uBITX that was built more by Farhan than by me.  But this was a great contact.  Walter started with a 50W rig, then switched to his 3 watt rig with a DC receiver.  FB

Here is the e-mail I received from Walter after the QSO: 

Dear Bill:

Many thanks for the great video, and when
you return to Virginia look for your mailman
to bring a postcard from me!
Just after your phone call this morning I scanned
the band from 14.025 to 14.300 and heard only one
SSB QSO at 14.347, and even now I only hear
a half dozen SSB signals, so that makes what
we did even more amazing. 
The first photo below is my 3.5 watt NE602 direct conversion 
rig which is about 2 years old.  The transmit signal is created
by putting a 3 MHz VFO signal into an NE602 mixer with an 
11 MHz crystal, so the rig can receive CW and SSB from 
14.025 to 14.300 and can transmit CW anywhere in that range
with good frequency stability. 
The bottom photo is my new full break-in CW 50W rig which 
I just put on the air about a week ago and is still in the finalization stage.  
I am not yet happy with it, but then again I am more particular
now than I used to be.  It is really a trans-receiver with a single 
conversion superhet receiver at the bottom of the board using 
an NE602 pair with a 3-crystal 4 MHz 900 Hz bandwidth filter, 
and a single 10.080 crystal VFO which is tuned with a polyvaricon
for operating between 14.061 and 14.068 MHz.  
At the top is the VXO transmit section using a pair of 14.070 
crystals pulled down into the operating range.  This signal
is buffered and amplified to about 500 mW which is all that 
the MRF101 RF Power Amplifier needs.  Visible behind the
board is an AC-powered 24 VDC switching power supply which 
is connected in series with the 12 VDC battery to 
power the final stage with about 36 VDC.  The main 12 VDC is 
provided by a bench power supply which is not in the photo.
In both rigs the morse code key is the microswitch 
at the lower right corner.  (Way more handy and elegant 
than your key, I might say?)
This morning each of these rigs was connected to its own
end fed half wave antenna, one in my backyard 
and the other on the side of my house.  My antenna analyzer
shows them to be essentially equal, but my 50W rig does
not like one of them at all.
Making our international homebrew-to-homebrew contact 
today was a terrific ham radio experience, so thanks for all 
you do!
Orlando, FL



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