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Old May 8th 05, 06:21 AM
Bill Meara
 
Posts: n/a
Default HB projects in London

In the interest of stirring up more discussion, I thought I'd give an
update on projects here at M0HBR (HomeBrewRadio).

-- Yesterday I put a new (old) 17 meter receiver into operation. It is
a Doug Demaw "Barbados" single conversion superhet. I built one from
scratch for 20 meters many years ago (see my web site for details).
Somewhere along the line Dale, W4OP, sold me his version. I used that
one briefly on 20 meters, but then it spent a lot of time on the shelf.
Lately I've been looking for a dedicated RX for my HB 17 meter SSB TX
(sharing the Drake 2-B with other transmitters involves too much cable
plugging and unplugging at bandswitch time!). So Dale's RX was pressed
into service. I widened the 5 Mhz ladder filter for SSB service by
changing the caps. And I got some 23 Mhz crystals from JAN to make a
VXO that would cover 17 meter phone. I use 2 crystals and can switch
betwen them from the front panel. I worked Estonnia with yesterday.

-- It may be that I'm getting lazy, but continuing with the "let's make
band switching easier" theme... I was getting tired of having to retune
my balanced antenna tuner each time I went from 40 to 17. The circuit
was so simple, I just decided to build another one, and make it a
dedicated tuner for 17. It is the classic balanced tuner circuit -- I
think it dates from the thirties: tank circuit link coupled to the TX,
with the parallel feeders connected to the coil via small alligator
clips. Now I can just go from band to band with the push of a button.

Upcoming projects:

-- I need to put my HW-30 on 2 meter AM. There is a very active VHF-am
group here in the UK and I need to get on the air. I plan on using the
lunchbox with a converter-to- Drake 2B for receive.

-- I need to match up my old Mate for the Mighty Midget RX with my 40
meter DSB transmitter. I have a 455 khz SSB filter for it, but I
haven't figured out yet how to match the impedances and get it into the
RX. Filtering currently being done -- poorly -- by one 455 khz IF can.

73 from London
Bill M0HBR N2CQR CU2JL
http://planeta.clix.pt/n2cqr