How to Operate AO-27
(The Repeater in the Sky)



Requirements:
U.S. License Class:
Technician or higher.
Equipment:
2-Meter and 70 cm FM transceivers.
Antennas:
VHF/UHF yagis, verticals, eggbeaters, etc.

For the latest information on AO-27, browse Amrad Oscar 27 (AO-27) satellite 
page.

Unlike the other analog OSCARs, AO-27 (Eyesat) has only one uplink receive 
frequency, 145.850 MHz, and one downlink transmit frequency, 436.800 MHz. It 
operates in FM only, so all-mode equipment is not necessary for this one.

Even though you can talk to this satellite with your common FM equipment, the 
transmitter will whisper back at only .8 Watts, making it one of the toughest 
LEO (Low Earth Orbit) satellites to hear. This is the only sticky wicket with 
AO-27. If you can't hear the downlink with your present wicket (and most hams 
can't, since wickets don't make good antennas), the recommended hearing aid
is a 435 MHz beam. A beam alone will bring the signals up to acceptable
levels, but a preamplifier would really squeeze the maximum S-Units out of
the downlink.

Now you're probably thinking that this is going to require more equipment
than you were expecting. Well, not really. The satellite is capable of
hearing an HT, running 5 Watts through a 5/8-wavelength antenna. Full
quieting. Period. Your signal may get squashed by people running 25+ Watts
through their beams. Most hams forget the rule about only using the least
amount of power necessary to carry out the communication. This sensitive
receiver makes this a very enticing satellite to try. Many hams work AO-27
with HTs. But as you grab your HTs and go hunting for this bird, remember...

DON'T ATTEMPT TO TRANSMIT TO AO-27 UNLESS YOU CAN HEAR THE DOWNLINK!

On a typical pass, it is very common to hear at least one operator calling CQ 
throughout the duration, deaf to the many other stations answering the call. 
This is very disruptive to on-going communication and is very bad manners.
What would Emily Post say? 
And speaking of etiquette, since AO-27 has a single-frequency downlink, one 
should be mindful of others who may be waiting to use the satellite themselves. 
It is very easy to operate AO-27 like a repeater, but when this repeater times 
out, it stays out for up to 10 hours at a time. Always keep your QSOs short and 
sweet. Don't be a ham who's a satellite hog.



For more information on AO-27
Check out the spacecraft description on the AMSAT Web site.


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73's XE2EKY. Hector
GRID: DM22
E-MAIL: xe2eky@cinco.ampr.org
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