At 10:06 AM 9/25/2012, Bill W1PA wrote:
Based on the economics, those of us with aspirations of having a HEO
in the near future might be better off
upgrading our set-ups for the high-reliability _passive_ HEO that is
available (aka EME).
With absolutely no intent at sarcasm, any pointers to articles on
how to take a HEO-class station up to EME-capable?
Are "small station-small station" QSO's possible on EME, or does at
least one station have to look like W5UN or Arecibo? (ok, maybe a
little sarcasm)
Bill W1PA (sitting on some collapsible C-band dishes)
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Bill,
I will break my current policy of not contributing info to amsat-bb
and answer this one -- as I am one former HEO user that migrated to
eme. In truth that began before the launch of AO-40. I copied my
first eme signal in the fall of 1997 from a large eme station running
CW. I used half of my 20T cushcraft 2m satellite antenna (the
vertical half) and my ARR preamp. In 1998-99 I began building my eme station:
http://www.kl7uw.com/eme144.htm
I started with two M2 XP20 (ten-element yagi), an ARR P144VDG preamp
and a 120w motorola repeater PA to work W5UN and KB8RQ on CW. This
grew to my current four XP20 with polarity switching and better
preamps plus 1300w PA (8877).
Any one that still has an AO-40 class 2m antenna (at least 10-element
and 13 dBi gain) with a good 2m preamp and at least 150w amplifier
can become an entry-level 2m-eme station. You still probably will
not be able to contact a similar equipped station but there are many
stations like mine that you can work. Az-el tracking helps but not
absolutely necessary.
This is possible with smaller stations due to the digital sw called
JT65. JT65 enables detection of signals 10-dB weaker than CW can be
copied. The old standard station for CW eme was four ten-element
yagis and 600w output (typ what one got from a pair of 4CX250's under
the old 1000w maximum dc input regulation).
One yagi is 6-dB less than four and 150w is 6-dB less than 600w,
totaling a drop of 12-dB.
With two 13-dBi yagis and 400-600w one can work stations of the same
size (though it may be difficult at times).
JT65 is available FREE and downloaded from:
http://physics.princeton.edu/pulsar/K1JT/
click the link to WSJT and download WSJT9.3
Those that are serious about trying eme should consider subscribing
to the MoonNet e-mail reflector where one can find plenty of help
getting started:
http://www.nlsa.com/nets/moon-net-help.html
The above suggestion is provided to those stations that miss HEO sats
and desire more technical challenge than they experience with FM LEO
(orbiting repeaters).
I will reply directly to inquiries or questions but will not post
further on amsat-bb.
73, Ed - KL7UW
600m - 3cm
EME: 50/144/432/1296/3400
http://www.kl7uw.com/
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