Re: Is it possible to ask questions here?


"Ralph Mowery" <rmowery28146@xxxxxxxxxxxxx> wrote in message
news:13jcfvbr86cc72b@xxxxxxxxxxxxxxxxxxxxx

"Jerry Martes" <j.jmartes@xxxxxxxxxxx> wrote in message
news:m4qZi.419$763.177@xxxxxxxxxxx

I missed being able to be clear in my "other" post. If there is a
Beacon signal available from a POE satellite at 2meters there is an
Excellent 2Meter source of signal with which a person can use to Very
Accurately record the radiation pattern from horizon to horizon at all
azimuth angles. That radiation pattern will be the pattern of the Ground
antenna, not the satellite antenna. We have to assume the satellite
radiates equal in all directions.

The strength of the received signal is recorded into some program like
Excel as a function of time. The actual Az-El to the satellite is
published, or can be computed. So, it becomes fairly easy to record the
actual (ground based) antenna's radiation pattern which includes all the
environmental effects like trees and neighbors's houses.

Jerry KD6JDJ
Jerry you were clear to me. There are several things wrong trying to use
the sat to determine the patern of the antenna on the ground at other than
the specific pass. Low orbiting sats will start at a great distance as
they come over the horizon and get to with in a few hundred miles as they
go over head. The squnit angle of the sat antenna will change so the sat
antenna is not always pointing at the ground antenna. The apparent
polarity will change and that can make a big differance.

I have the KLM circular beam pair for 2 meters and 435 mhz on an az/el
setup and computer control. Also can switch from left to right circular
and have monitored the sats go over and sometimes have to switch left to
right as they pass for the best signal.

I have not tried it on a sat but for the Icoms ( it might work on others)
there is a program that will record the s-meter and draw a plot on the
screen . I have done it looking at repeaters and it does seem to work ok
for drawing paterns.

Hi Ralph

Although I disagree with your premise about "great distance and a few
hundred miles", I must admit that I lack knowledge of the satellites other
than the few NOAA satellites. The NOAA satellites are about 4 time more
distant at the horizon than overhead. That results about 12 dB less signal
at the low elevation angle. The 12 dB is fairly easy to put back in the
plot.
The guys at NASA/NOAA did an excellent job of tailoring the NOAA satellite
pattern shape so it is close to equal over the entire pass. I'd have
expected the "OSCAR" guys to have done the same and shaped their satellite
antenna beams to be essentially equal level over the angle at which the
Earth intercepts the satellite beam.
I'd like to know more about a 2Meter beacon satellite. Can you point me
to a site where I can learn about 2Meter beacon satellites? I have a
friend who will write me a program to plot signal strength as a function of
angle on a polar plot. He made me one for the NOAA (137 MHz) satellites.
I like modeling antennas at 2Meters and have an Icom PCR1000 that I'd like
to get some use out of.

Jerry KD6JDJ




.

Relevant Pages

  • Re: LEO receiving antennas was Re: Velocity Factor of Coax
    ... intends to build his own antenna to communicate with low earth orbiting ... Do you disagree that a DCA will perform better than a Lindenblad? ... satellite he's looking to listen to, or what kind of receiver he's using. ... I agree with you that a Turnstile is a good antenna for LEO satellite ...
    (rec.radio.amateur.antenna)
  • Re: Friends of Radio 3
    ... It may well be time for a 'new' tuner and/or a high-gain antenna on the ... a Freeview box or some form of satellite RX. ... Run a UHF antenna feed to the hifi room, and use a 'FreeView' box. ... We also seem to get more interference during the day than during the ...
    (uk.rec.audio)
  • Re: Antenna to cover AM broadcast to 999 mhz?
    ... antenna depending if I want to access a repeater or a satellite. ... myself a couple of turnstile types for the FM satellites. ... For vhf/uhf omnidirectional reception, your suggestion of a discone should ...
    (rec.radio.amateur.antenna)
  • Re: Is it possible to ask questions here?
    ... Accurately record the radiation pattern from horizon to horizon at all ... That radiation pattern will be the pattern of the Ground ... antenna, not the satellite antenna. ...
    (rec.radio.amateur.antenna)
  • Re: Is it possible to ask questions here?
    ... work well on signals from the ground. ... Ringo antenna sent most of its signal up at an angle. ... signal available from a POE satellite at 2meters there is an Excellent ... record the radiation pattern from horizon to horizon at all azimuth angles. ...
    (rec.radio.amateur.antenna)