Topband: Nostalgic "openings"

Bruce k1fz at
Sun Jan 19 01:17:21 EST 2014

Hi Charlie,

The HT-32 project took place at  a TV station where I worked. They had a 
well equipped  work shop at the transmitter site.
I had some idle time each work day to build and test.

Great on building your double lattice filter. Opening up the HC-6 crystals 
is a delicate
operation. A friend tried it and too much heat and bye, bye crystal.  I had 
ground many of the larger FT-243 type chrystals
but never tried the loading process. Think one of the other guys tried it 
with pencil lead. He was trying to build a double lattice filter with a 
flat bandpass with steep sides.  Was looking for perfection and never gave 
up trying.

I have a BC-696 up attic.  I used another one mobile with a PE-103 dynamotor 
in the 1950's.     I could zero beat a station with only 6 volts on the 
oscillator tube plate.
It probably was 3/4 KCS off when transmitting. but the old wide band AM it 
did not matter.  But that oscillator just wanted to go !


> Hi, Bruce
> Yes, I remember "The IMP - A 3 Tube Filter Rig" by Joe Galeski, W4IMP!
> Wanted to build one, but by then I was designing and building my own rigs,
> and home-brewing my own back-to-back double half-lattice crystal filters,
> while working my way through college as a technician/junior engineer in a
> radio plant. I built one crystal filter from 2105 KHz crystals that were
> used as the 2nd L.O in a citizens-band transceiver that we manufactured.
> They wre  used to convert the 1650 KHz first IF to 455 KHz. I opened up 
> the
> HC-6 crystal cans and very carefully loaded and matched a couple of the 
> 2105
> crystal a bit lower in frequency wth with tiny bits of solder to pruduce 
> an
> SSB- width double 1/2 lattice filter that I built an SSB rig  aound that I
> used for a while with my NC-109 receiver.
> Wow, home-brewing an HT-32 must have been quite a project!!
> 73,
> Charlie, K4OTV

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