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Author Topic: L-Tronics L-per  (Read 5960 times)

K5CQB

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L-Tronics L-per
« on: June 21, 2008, 03:10:53 PM »

I have a couple of L-Tronics Little L-per's, model LH-60-S.  They have crystals for 243 MHZ in them.  I am interested in DF'ing on 2 meters.  Will these work if I stick the appropriate crystals in them and change the antennas?  Or will more be needed?    

Thanks,
Jim  
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WB6BYU

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L-Tronics L-per
« Reply #1 on: June 21, 2008, 10:06:38 PM »

While L-Tronics has a very good service and upgrade policy, I know that
they won't convert those units to other frequency bands.  That doesn't
mean that it can't be done, but it may not be simple.

The L-Pers use a crystal controlled front end, so you would need to
change the input tuned circuits and modify the oscillator chain to get
the right injection frequency.  I don't have the schematic for these
units to know how the multiplier chain works, but that may be one of
the major differences between that circuit and the dual-band 121/243
MHz units.  I suspect that the oscillator chain will be the most difficult
part of the conversion:  once you get past the mixer the rest of the
circuit doesn't have to change.

It may be simpler to build an up-converter with a tunable oscillator
around 100 MHz to convert the 2m band up to 243 MHz.  (But you may
lose some of the excellent gain control range.)   This probably could be
combined with the antenna switchbox.  You'll have to arrange for the
switched DC on the coax to be passed through to the antennas.

You'll also need a set of antennas for 2m.  You can order them from
L-Tronics or build your own.  They aren't simply a pair of switched
whips, though - it actually is a 2-element yagi that switches back and
forth between pointing left and pointing right.  There are a number of
ways this can be done.

If you are alway hunting on the same frequency then it may be worthwhile
to modify the units to 2m.  You can ask Lou at L-Tronics if she can sell
you a manual for the LH-60, but since it was a military product they
may not be available.

Good luck!

- Dale WB6BYU
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