UHF antenna for Sat ops
 

Hello everyone,

I would greatly appreciate any advice in subject of choosing a vertical
antenna for satellite operations. I can hear VO-52 / FO-29 5-7 / 5-9
using my mobile antenna NR 770 H fix on a mast 9ft above the ground.

I am cosidering builing a Super J-Pole antenna.
http://www.n7qvc.com/amateur_radio/copper.html

Do you think that this vertical will be sufficient to bounce 50W of
signal back to Earth of the satellite ? If not , what other homebrew
antenna will be fine for this purpose ?

Thank you for your helpful response .

Phil

"philnyc" wrote in message
oups.com...
Hello everyone,

I would greatly appreciate any advice in subject of choosing a vertical
antenna for satellite operations. I can hear VO-52 / FO-29 5-7 / 5-9
using my mobile antenna NR 770 H fix on a mast 9ft above the ground.

I am cosidering builing a Super J-Pole antenna.
http://www.n7qvc.com/amateur_radio/copper.html

Do you think that this vertical will be sufficient to bounce 50W of
signal back to Earth of the satellite ? If not , what other homebrew
antenna will be fine for this purpose ?

Thank you for your helpful response .

Phil

Phil

I've been trying to figure out how to build an antenna for receiving polar
orbiting weather satellite signals. The satellites send down RHCP on 137
MHz.
A turnstile antenna works pretty well for satellite monitoring, and is
pretty easy to build.
There are helical configurations that are commonly considered to be the
ultimate weather satellite receiving antenna, but can be tricky to make work
properly..
I submit that I know a way to build an antenna with 4 dipoles that perform
as well as (or better than) a helix for satellite reception. I refer to
the hemispherical patterned antenna concept as the "Cross". It is simple
and wouldnt qualify as an invention, its a concept, and it works. It is
alot easier for me to build one than it is to describe it. But, the cross
antenna is two pairs of crossed dipoles. Each pair is two crossed dipoles
spaced apart and fed in phase. One pair is fed 90 degrees later than the
other.

I'd be "only too pleased" to E-mail notes and performance data on the
concept if you have interest.
I can produce good images from NOAA 17 whenever it is above 1 degree ( 2
degrees would be a safer number) above the horizon, viewing it from horizon
to horizon with that stationary, 4 dipole array.

Jerry

You would be better served with a "Potato Masher" for your purpose. You may
view the info at http://members.aol.com/k5oe/

"philnyc" wrote in message
oups.com...
Hello everyone,

I would greatly appreciate any advice in subject of choosing a vertical
antenna for satellite operations. I can hear VO-52 / FO-29 5-7 / 5-9
using my mobile antenna NR 770 H fix on a mast 9ft above the ground.

I am cosidering builing a Super J-Pole antenna.
http://www.n7qvc.com/amateur_radio/copper.html

Do you think that this vertical will be sufficient to bounce 50W of
signal back to Earth of the satellite ? If not , what other homebrew
antenna will be fine for this purpose ?

Thank you for your helpful response .

Phil

Jerry, thank you for your replay, kindly please forward the
instructions on how to build a turnstile antenna for 145 and 435 . Are
the arms 1/2 wave or 1/4 ?

Thanx again.
Phil

Jerry, thank you for your replay, kindly please forward the
instructions on how to build a turnstile antenna for 145 and 435 . Are
the arms 1/2 wave or 1/4 ?



Thanx again.
Phil

Phil wrote:
"If not, what other homebrew antenna will be fine for this purpose?"

A turnstile with reflector?

High gain comes from narrow beamwidth. A lower gain antenna is easier to
use as it is a larger window on the sky.

Unless the vertical antenna is an axial helix or something similar, it
likely has a null in the direction of its open-circuited end. There are
better choices.

There are many antenna options. Most are covered in the ARRL Antenna
Book. It has a complete chapter on "Antennas hor Space Communications"
In my 19th edition, this is Chapter 19. Construction details are given
too.

Best regards, Richard Harrison, KB5WZI

I'm trying to show my email , it should be shown this way:

philnyc22 at hotmail.com

On 24 Jul 2005 12:26:03 -0700, "philnyc"
wrote:

From: "philnyc"
Newsgroups: rec.radio.amateur.antenna
Subject: UHF antenna for Sat ops
Date: 24 Jul 2005 12:26:03 -0700

....


I'm trying to show my email , it should be shown this way:

philnyc22 at hotmail.com

Hi OM,

You are trying to be too coy about your address. I suspect you think
it will cut down on spam. Truth of the matter is your address is
quite obvious in the headers (shown above your post and in the
salutory line introducing this response) where the spambots look -
they could care less how you munge it up in the body.

By the way, Jerry has spent a lot of effort in working on his design.
Consider it closely.

73's
Richard Clark, KB7QHC

"philnyc" wrote in message
oups.com...
Jerry, thank you for your replay, kindly please forward the
instructions on how to build a turnstile antenna for 145 and 435 . Are
the arms 1/2 wave or 1/4 ?

Thanx again.
Phil

Phil

I havent persued this Cross concept with the intention of identifying
"just one way" of building an antenna. I dont mean to imply that my choice
was a good one. Maybe I should be more specific. I just havent yet
learned enough about how this "hemispherical pattern shaped" works. So far,
I've seen that 4 lambda over 2 dipoles can be nested into a slanted vertical
array to provide highly elyptical polarization thruout the hemisphere. It
is two pairs of crossed dipoles, each pair fed in phase and one pair fed 90
degrees later than the other.
I think the turnstile (with reflectors) has been described in many wer
sites. I could send you an accurate sketch of one, but you can surely get
better instructions from the Internet. Turnstiles are decent antennas for
hemispherical CP coverage and pretty easy to understand and build.
If you are definitely going to build an antenna from which you would
appreciate hemispherical elyptically polarized coverage, E-mail me. i
can/will help you understand either/both the turnstile and the Cross. I
wish I could help you understand the QHA or QFH helix antennas, they work
very well. But, I just dont have them figured out.

Jerry

hi,

http://www.cebik.com/wire/turns.html

http://www.cebik.com/vhf/ms2.html