[Elecraft] Any EME gurus with the XV-144 monitoring?

[Edward R Cole]

John,

I am no help regarding the XV-144 use with JT65 (I do not have the XV-144).

But JT65 does not require a linear amplifier.  It is FSK and will 
work with any amplifier that works with CW, including
Class-C and Class-E.  Of course it will work with linear's if that is 
what you have.  FSK generates a simple carrier (sine-wave) that is 
transmitted at different frequencies, but only one at a time.

JT65 does require at least frequency stability of 20-Hz to be easily 
decoded by the other station.  Also your computer time needs to be 
within 1-second accuracy.  JT65 is a synchronous code so time and 
frequency need to be the same at both stations.

I have no info on how well the XV-144 LO operates.  If you are using 
an IF of 28-MHz then the LO frequency is probably 116-MHz.  If the 
internal oscillator is not sufficiently stable, one solution would be 
using an external LO: either xtal or synthesized.  The synthesized LO 
would be phase-locked to a 10-MHz reference and give "perfect" 
frequency (perfect meaning < 1-Hz at 116-MHz).  GPS is not needed.  A 
cheap OCXO from e-bay will suffice (what I use):
http://www.kl7uw.com/Rubidium.htm

I have been installing ApolLO-VHF synthesizers made by Stephen Hicks, 
N5AC, who also makes the ApolLO A32 synth that is made for mw 
transverters (1296 and up).  Here is a link that describes the Apol LO-VHF:
http://www.downeastmicrowave.com/PDF/Manuals/VHFApolLO_Operation.PDF

Disclosure: I do install these for hams (small business).  I have 
this synth. installed in my 432-MHz transverter.  I have installed 
them in 144, 222, and 432 transverters.  Link is in my signature line.

But you can purchase direct from N5AC and install one 
yourself.  Minor cable attachments (soldering).  If you install the 
EXREF on your K3 then the synth makes sense to use with the 
transverter.  Only one OCXO is needed (spilt the output):
http://www.kl7uw.com/K3EXREF.htm

Often the big problem getting a xtal LO to be stable is isolating it 
from the heat of the transmit stages.  Contact me off list if you 
want me to expand on what I have written.

73, Ed - KL7UW
eme: 6m*/2m/23cm/9cm*
*under construction
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Subject: [Elecraft] Any EME gurus with the XV-144 monitoring?
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I'm laying out and gather up the parts needed to use of a XV-144 with 
my K3 for EME applications.


Since my aim is towards JT65, is there anyone on the Reflector who's done
it and found need to do a modification to the local oscillator in the 
XV-144 to enhance the
frequency stability?  The K3 has the TXCO option.  The 10 MHz 
reference using a GPS
reference seems necessary but I hope a GPS discipline is kill.


The output linearity on transmit should be ok but I'll be needing to
have an IPA plus PA chain without IMD growth as well and I'd like to
know how the EME boys are dealing with this side of their configurations.


Thanks,  John, W1QS




73, Ed - KL7UW
http://www.kl7uw.com
     "Kits made by KL7UW"
Dubus Mag business:
     dubususa at gmail.com