I'm new to satellite stuff. I got an Arrow-II antenna to get started. It works pretty well. I live in San Francisco and I can go on the deck or hang out the window and hear the easy satellites.
I would like to graduate to sitting in a chair, inside, with two free hands, while working a satellite. What is a good choice for the next step up for an antenna that I can install on a flat roof for mode-J operation?
Do I need an az-el rotator for the next step up or is there some cheaper/simpler solution? It will be about a 75-foot cable run from a roof antenna to my radio, will I need a mast-head type preamp for the receiver?
thanks, jeff
I'm new to satellite stuff. Do I need an az-el rotator
Not at all for any of the present satellites. Just a $75 TV rotator from radio shack. Tilt your Arrow up a fixed 15 degrees and you can work the satellites from horizon to horizon.
LEO satellites are below 30 degrees 75% of the time. When they are above 30, they are 6 to 10 dB closer and so pointing is not an issue. They are below 45 degrees 94% of the time. Above 60 degrees only 2% of the time and it just isnt worth chasing that 2%.
See the plot on: http://www.ew.usna.edu/~bruninga/rotator1.html
Bob, Wb4APR
Does that apply to the ISS as well?
Thanks,
Ken Owen, N6KTH
-----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of Robert Bruninga Sent: Friday, January 04, 2008 3:56 PM To: 'Jeff Mock'; 'Amsat-Bb@Amsat. Org' Subject: [amsat-bb] Re: Antenna advice
I'm new to satellite stuff. Do I need an az-el rotator
Not at all for any of the present satellites. Just a $75 TV rotator from radio shack. Tilt your Arrow up a fixed 15 degrees and you can work the satellites from horizon to horizon.
LEO satellites are below 30 degrees 75% of the time. When they are above 30, they are 6 to 10 dB closer and so pointing is not an issue. They are below 45 degrees 94% of the time. Above 60 degrees only 2% of the time and it just isnt worth chasing that 2%.
See the plot on: http://www.ew.usna.edu/~bruninga/rotator1.html
Bob, Wb4APR
_______________________________________________ Sent via [email protected]. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
At 06:01 PM 1/4/2008, Jeff Mock wrote:
I'm new to satellite stuff. I got an Arrow-II antenna to get started. It works pretty well. I live in San Francisco and I can go on the deck or hang out the window and hear the easy satellites.
I would like to graduate to sitting in a chair, inside, with two free hands, while working a satellite. What is a good choice for the next step up for an antenna that I can install on a flat roof for mode-J operation?
Do I need an az-el rotator for the next step up or is there some cheaper/simpler solution? It will be about a 75-foot cable run from a roof antenna to my radio, will I need a mast-head type preamp for the receiver?
thanks, jeff
Hi Jeff,
You can work all of the SSB and FM LEO satellites with just omni-directional antennas. I personally managed to get VUCC-satellite (#58,) 49 states, and about 40 countries on LEO satellites using just omni antennas.
I think I may have one of the longest distance qsos on a LEO sat at 7084 Km using only omni antennas (but Bruce VE9QRP and his "International Panel of Judges" may have a comment on that! :)
For mode B (VO-52 and AO-07) you do not need a preamp as long as you use low loss coax. Shoot for 1 dB total loss to the antennas. I use LMR-400 and LMR-600 depending on the length and band.
For mode J, a preamp at the antenna is essential for all cases, even with a beam.
In any case, I can highly recommend the "EZ-Lindenblad" for a 2m antenna in the August 2007 QST:
http://www.arrl.org/qst/2007/08/monteiro.pdf
So, to more directly answer your question, you can certainly make lots of satellite qsos without needing an AzEl rotor system It is more difficult using omni's but once you get the hang of it it is not that difficult.
welcome to satellites and 73, Tony AA2TX
Hi folks:
So, I understand those that say it's not worth "chasing the last 2 percent" with an elevation rotor. Is there ANY advantage to having EL capability for satellite purposes? What about for working the ISS?
Thanks,
Ken, N6KTH
Hi Ken...
Of course there are advantages to az/el tracking. With "spot on" TRACKING you will have better signal levels to work with on receive and be able to use less power on transmit.
The disadvantages of az/el are that you do need ACCURATE TRACKING or you can possibly worsen your received signal strength from the Sats. ISS is especially a challenge as it is so close to the Earth's surface (~200) miles that it's passes can move across your visible sky really quickly.
Your initial inquiry included a "hands off" requirement. That means tracking software that controls the rotors automatically. While you are at it you might as well adjust for doppler. Not much on 2 meters but enough, and a requirement on 435.
So...your decision becomes...do you stop operating as you collect this gear,software and fund this transition, or do you take the next step up and set up an AZ rotor while you are contemplating the rest. How much time do you have to accomplish this setup? How much money? What type of antennas are you considering? Circular polarization? Antenna gain vs required accuracy?
You have mentioned ISS several times...it can be worked with a HT and a rubber duck...at least on a clear pass. It has been shown many times that one of the best antennas for ISS is a 19" whip over a good groundplane. The same antenna works on 435 also.
Your available time and money should help set your goals for your antenna system and reap the rewards you are satisfied with.
Me...I'm a minimalist ;-)
Roger WA1KAT
----- Original Message ----- From: "Ken Owen" [email protected] To: [email protected] Sent: Saturday, January 05, 2008 11:20 AM Subject: [amsat-bb] Re: Antenna advice
Hi folks:
So, I understand those that say it's not worth "chasing the last 2
percent"
with an elevation rotor. Is there ANY advantage to having EL capability
for
satellite purposes? What about for working the ISS?
Thanks,
Ken, N6KTH
Sent via [email protected]. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
Roger what Roger said (sorry for the pun ;-)):
But if you are eventually thinking of operating MEO or HEO satellites then progressing to high(er) gain antennas, circular polarity, az-el tracking, auto-tracking or auto-tuning makes some sense. This is often a financial question so if you are wanting to maximize your satellite station for the future then it may make sense to upgrade to a larger antenna system. OTOH if you want to keep expenses low then use of omni antennas or a fixed-elevation small yagi with an azimuth rotator can be quite usable for the existing Leos and ISS. For P3E and Eagle one will need more (like AO-13/AO-40).
I worked ISS with 50w and a ARX-270 (9-dBd) vertical when ISS was 1500 km away on our southern horizon. This antenna is not optimum for higher elevation passes of satellites, and a 2m 1/4 WL ground plane is better, overall. I used one with a 432-MHz preamp to copy AO-51 Telemetry.
My "AO-40 Satellite Antenna" system is still in the process of set up on a new 10-foot tower. When done it will consist of KLM-22C, M2-436CP42, 33-inch offset-feed dish, and 2.4 GHz corner-reflector. 145 and 435 will have switchable CP. The B5400 az-el rotator will utilize a Unitrac-2000 for auto-tracking and I will add auto-tuning on the FT-847. A 1268 MHz 45-element loop-yagi will round out the satellite suite.
But I did not start out with these antennas in 1985. My station was a CC 10T (later a 20T) and a CC 416T with a manual rotation system (grab the mast and twist or grab the cord and pull to lift the array - cross-boom strapped to a door hinge with cord run thru a pulley. Elevation was established with a series of nails in the wall of the building that the mast was mounted on (pull the cord and hook it on lower nail for higher elevation). Station ran IC-211 (10w) and MM432 (4w) with Commodore-64 satellite predicts (Oscar locator before that). I worked a lot of AO-10 with that set up...oh and the station was set up in a tent in the Alaska bush with a battery for power!
Those were the days,my friend! 73 Ed - KL7UW (back then I was K8MWA/KL7)
At 10:12 AM 1/5/2008, Roger Kolakowski wrote:
Hi Ken...
Of course there are advantages to az/el tracking. With "spot on" TRACKING you will have better signal levels to work with on receive and be able to use less power on transmit.
The disadvantages of az/el are that you do need ACCURATE TRACKING or you can possibly worsen your received signal strength from the Sats. ISS is especially a challenge as it is so close to the Earth's surface (~200) miles that it's passes can move across your visible sky really quickly.
Your initial inquiry included a "hands off" requirement. That means tracking software that controls the rotors automatically. While you are at it you might as well adjust for doppler. Not much on 2 meters but enough, and a requirement on 435.
So...your decision becomes...do you stop operating as you collect this gear,software and fund this transition, or do you take the next step up and set up an AZ rotor while you are contemplating the rest. How much time do you have to accomplish this setup? How much money? What type of antennas are you considering? Circular polarization? Antenna gain vs required accuracy?
You have mentioned ISS several times...it can be worked with a HT and a rubber duck...at least on a clear pass. It has been shown many times that one of the best antennas for ISS is a 19" whip over a good groundplane. The same antenna works on 435 also.
Your available time and money should help set your goals for your antenna system and reap the rewards you are satisfied with.
Me...I'm a minimalist ;-)
Roger WA1KAT
----- Original Message ----- From: "Ken Owen" [email protected] To: [email protected] Sent: Saturday, January 05, 2008 11:20 AM Subject: [amsat-bb] Re: Antenna advice
Hi folks:
So, I understand those that say it's not worth "chasing the last 2
percent"
with an elevation rotor. Is there ANY advantage to having EL capability
for
satellite purposes? What about for working the ISS?
Thanks,
Ken, N6KTH
Sent via [email protected]. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
Sent via [email protected]. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
73, Ed - KL7UW ====================================== BP40IQ 50-MHz - 10-GHz www.kl7uw.com 144-EME: FT-847, mgf-1801, 4x-xpol-20, 185w DUBUS Magazine USA Rep [email protected] ======================================
Hi again folks:
Thanks for the great advice. I guess I'm already more than half way to having a MEO/HEO capable station, so I might as well add the AZ/EL rotor. I have a FT-847 and I've ordered Gulf Alpha 2 Meter 5x5 Circular Polarized yagi and a Gulf Alpha 70CM UHF 8x8 Circular Polarized yagi. Since I'm gone this far, I might as well do it "right" and by a full-service rotor, interface and software. From reading the posts on here about polarization, I'm thinking of having Gulf Alpha add polarization switching capability to the antennas I've ordered, but this would add about $400. Any thoughts?
Ken, N6KTH
-----Original Message----- From: Edward Cole [mailto:[email protected]] Sent: Saturday, January 05, 2008 11:53 AM To: Roger Kolakowski; Ken Owen; [email protected] Subject: Re: [amsat-bb] Re: Antenna advice
Roger what Roger said (sorry for the pun ;-)):
But if you are eventually thinking of operating MEO or HEO satellites then progressing to high(er) gain antennas, circular polarity, az-el tracking, auto-tracking or auto-tuning makes some sense. This is often a financial question so if you are wanting to maximize your satellite station for the future then it may make sense to upgrade to a larger antenna system. OTOH if you want to keep expenses low then use of omni antennas or a fixed-elevation small yagi with an azimuth rotator can be quite usable for the existing Leos and ISS. For P3E and Eagle one will need more (like AO-13/AO-40).
I worked ISS with 50w and a ARX-270 (9-dBd) vertical when ISS was 1500 km away on our southern horizon. This antenna is not optimum for higher elevation passes of satellites, and a 2m 1/4 WL ground plane is better, overall. I used one with a 432-MHz preamp to copy AO-51 Telemetry.
My "AO-40 Satellite Antenna" system is still in the process of set up on a new 10-foot tower. When done it will consist of KLM-22C, M2-436CP42, 33-inch offset-feed dish, and 2.4 GHz corner-reflector. 145 and 435 will have switchable CP. The B5400 az-el rotator will utilize a Unitrac-2000 for auto-tracking and I will add auto-tuning on the FT-847. A 1268 MHz 45-element loop-yagi will round out the satellite suite.
But I did not start out with these antennas in 1985. My station was a CC 10T (later a 20T) and a CC 416T with a manual rotation system (grab the mast and twist or grab the cord and pull to lift the array - cross-boom strapped to a door hinge with cord run thru a pulley. Elevation was established with a series of nails in the wall of the building that the mast was mounted on (pull the cord and hook it on lower nail for higher elevation). Station ran IC-211 (10w) and MM432 (4w) with Commodore-64 satellite predicts (Oscar locator before that). I worked a lot of AO-10 with that set up...oh and the station was set up in a tent in the Alaska bush with a battery for power!
Those were the days,my friend! 73 Ed - KL7UW (back then I was K8MWA/KL7)
At 10:12 AM 1/5/2008, Roger Kolakowski wrote:
Hi Ken...
Of course there are advantages to az/el tracking. With "spot on" TRACKING you will have better signal levels to work with on receive and be able to use less power on transmit.
The disadvantages of az/el are that you do need ACCURATE TRACKING or you
can
possibly worsen your received signal strength from the Sats. ISS is especially a challenge as it is so close to the Earth's surface (~200)
miles
that it's passes can move across your visible sky really quickly.
Your initial inquiry included a "hands off" requirement. That means
tracking
software that controls the rotors automatically. While you are at it you might as well adjust for doppler. Not much on 2 meters but enough, and a requirement on 435.
So...your decision becomes...do you stop operating as you collect this gear,software and fund this transition, or do you take the next step up and set up an AZ rotor while you are contemplating the rest. How much time do you have to accomplish this setup? How much money? What type of antennas
are
you considering? Circular polarization? Antenna gain vs required accuracy?
You have mentioned ISS several times...it can be worked with a HT and a rubber duck...at least on a clear pass. It has been shown many times that one of the best antennas for ISS is a 19" whip over a good groundplane. The same antenna works on 435 also.
Your available time and money should help set your goals for your antenna system and reap the rewards you are satisfied with.
Me...I'm a minimalist ;-)
Roger WA1KAT
----- Original Message ----- From: "Ken Owen" [email protected] To: [email protected] Sent: Saturday, January 05, 2008 11:20 AM Subject: [amsat-bb] Re: Antenna advice
Hi folks:
So, I understand those that say it's not worth "chasing the last 2
percent"
with an elevation rotor. Is there ANY advantage to having EL capability
for
satellite purposes? What about for working the ISS?
Thanks,
Ken, N6KTH
Sent via [email protected]. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite
program!
Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
Sent via [email protected]. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
73, Ed - KL7UW ====================================== BP40IQ 50-MHz - 10-GHz www.kl7uw.com 144-EME: FT-847, mgf-1801, 4x-xpol-20, 185w DUBUS Magazine USA Rep [email protected] ======================================
Does anyone have a suggestion where to find a good price on the G-5500? I notice that Texas Towers has it for $600.
Thanks,
Ken, N6KTH
Ken Owen wrote:
Does anyone have a suggestion where to find a good price on the G-5500? I notice that Texas Towers has it for $600.
Thanks,
Ken, N6KTH
Sent via [email protected]. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
When I bought mine, R&L had the cheapest price, and at least in the brief research I did this morning it still seems to be the case, $589.
http://www.randl.com/cgi-local/cart/cart.cgi?cart=Search&model=G5500&...
Ryan, KB0JQO
participants (7)
-
Anthony Monteiro -
Edward Cole -
Jeff Mock -
Ken Owen -
Robert Bruninga -
Roger Kolakowski -
Ryan Butler