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Re: Transystem problems



>From: "Don Woodward" <dbwoodw@abraxis.com>
>I haven't been able to hear anything from AO-40 yesterday or today (first
>time I've tried).
>
>I've changed the crystal to 8.125 mHz from JAN to make the output come out
>at 144 mHz.
>
>As a test, on my Yaesu 726 with 2m/70cm/6m modules (and satellite module) I
>put the RX on 144.0 mHz and TX on 50.1 mHz and could not hear or see any
>signal - I did put my frequency counter antenna near the crystal with the
>side cover removed from the trans system and counter read 8.125 mHz.
>
>Any ideas?

Yes Don,

Apparently your 726 is nice and linear on 50.1 MHz and not producing any
harmonics.  The way to get the harmonics is to make a simple diode
generator..and I mean simple.  

Go to Radio Shack  and buy an 1N1005 diode [276-1104], a panel coax
connector [278-152], and five 47K-1/2w resistors [276-whatever]...about
five bucks!  Solder the diode and resistors in parallel across the center
pin to ground.  It is good for up to 2.5w of RF at 50 MHz.  You will get
50x48=2400 MHz out.  How much?...I dunno!  Theory says Po = Pin/N  where N
= the multiplier.  So maybe you get 1/48 watts...that should be loud.
Place a small probe antenna [one inch piece of wire] on the Drake and hold
the diode/resistor/connector "deal" near but NOT touching the probe.  Start
tuning around where you think it should be.  I found my Drake was 433.832
for a xtal that should have produced 433.9.  Not bad! 

If you have a VHF signal generator try, 400 or 600 or 800 MHz instead.  At
800 MHz I had a booming signal with this little critter using -20 dBm into
it.  The S2 beacon freq. of 2401.318 translates to 600.2395 x 4.  That's
the frequency you want to know on your IF receiver.

Definitely nice to have one of these in case you have doubts about your
equipment.

Ed

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