[Lowfer] LF converter, 10 meter radio, hear 600 meters

[Jim]

I have the Jackson Harbor converter and it's fine for what it does. I run mine 
with a 4 MHz crystal and it "up converts" the LF band.

But...

It's almost impossible to "perfectly" align. I can read within +/- better then 
5 Hz on the RX320 without it. If I connect the converter in, it's just about 
impossible to "tweak" it's crystal oscillator to where it will read exact.

For example, I have a local GPQ-278. If I tune to it's carrier, it's pretty 
much spot on 278 kHz. With the converter, I'll tune to 4.278 kHz and try to 
get the oscillator "on frequency". I've had difficulty getting it to better 
than within maybe 50 to 100 Hz of the desired frequency.

The second problem is stability. A crystal oscillator is fairly stable, but it 
will wander around a couple of Hz over time and you do have to give it a bit 
of time (maybe 10 minutes or so) to warm up.

The third thing is that I don't think you'll find any 28 MHz crystals that 
operate in "fundamental" mode. And even if you could, I'm not 100% sure 
they'd work in the circuit. Most crystals are "multiplied" to get much above 
10 to 15 MHz.

But, having said all of that...

With all the bragging about how accurate and stable the programable 
oscillators that are available are, that might well work. It wouldn't take a 
lot of modification to the converter circuit to feed it with an oscillator 
instead of it using its own oscillator.

One last thing I've found. I use the PA0RDT mini-whip. To get it to work well 
with the converter, I have to put around 20 dB of attenuation in line. 
Otherwise I seem to overdrive the converter. If I hook it to my vertical or 
longwire antenna, it actually does a respectable job of pulling them in.

Bottom line is that I think you could make it work if you used one of the 
programmed oscillator modules and a few mods.

73 de
Jim W4JBM

http://www.hamuniverse.com/w4jbm/

"With a soldering iron in one hand, a schematic in the other, and a puzzled 
look on his face..."