Re: [amsat-bb] Possible ISS School Contact Experiment (Maryland report)
Both of my school-contact monitoring tests with the arrow were useless.
Both days the 200' tethered JLENS Blimp was aloft radiating megawatts of radar direct Line of Sight to my operating position. Although the radar pings are at 143 and 149 MHz with peaks +70dB above the noise, they do get into all of our Ham VHF radios as a raised noise floor. Just open any radio squelch on any frequency in the 2m band and you will hear it.
So even when the astronauts were 7 bars on the radio, the audio had significant noise from the radar superimposed.
So my report is a null report. Bob, Wb4APR
-----Original Message----- From: Robert Bruninga [mailto:[email protected]] Sent: Tuesday, October 20, 2015 6:06 PM Subject: RE: Possible ISS School Contact Experiment idea? (Thurs)
An ISS school contact… in Michigan on 22 Oct.
This is a great time for those skilled portable "arrow" operators to get data on using fixed vertical arrow beam antennas for ISS voice at or near the horizon.
The test will show if well placed fixed tripod "arrow class" antennas at AOS and LOS and a central turnstyle could possibly make it easier than a full AZ/EL Oscar class antenna at the school.
See the concept paper at http://aprs.org/aos-los-test.html
If your QTH is west of a school contact, then you should test your LOS horizon. If your QTH is east of the school, then you should test your AOS horizon. This is because we want to make sure we are getting voice quality data AT the horizon while the ISS crew is actually speaking.
The desired data is a minute-by-minute log throughout the pass of ISS signal quality (noting nulls or fades) without moving or adjusting the antenna. Your receiver should be right near the antenna (no coax loss). Just orient the beam vertically with an up tilt of 15 degrees. Then aim it at a fixed Azimuth that is half way between AOS (or LOS) and when the ISS rises above (or drops below) 30 degrees elevation to cover the first (or last) portions of the pass.
Leave your antenna fixed throughout the pass. We need to know how well the squelch on your radio eliminates the weak signal when the ISS is outside your particular fixed beam too.
In a real scenario of this full technique, above 30 degrees the ISS is 3 times closer and 10 dB stronger and would be heard fine on a central omni antenna. But that is not part of your horizon performance test. So be sure to choose a good low horizon *and* the horizon you share with the School contact so that there is ISS audio during your particular horizon crossing (AOS or LOS).
An audio recording would make it easier to prepare the log after the pass or you can just make checks or X's every 5 seconds on a piece of paper and summarize it later. Do NOT run open squelch. Set the squelch for normal ham radio operation to silence the radio when the signal would be unintelligible anyway, since we would not want unintelligible noise from one receiver to distract from good audio from the possible others..
If this concept works, then the idea would be to bring in all three receiver speakers (left-to-right) into the auditorium operating position to give equal weight to each receiver but also give a sense of the passage of the ISS. If this test shows any promise, it could not only eliminate all the complexities of long crossed yagis, AZ/EL rotators, big masts and active tracking, but also completely eliminate the problem of long runs of coax from the school gymnasium to the antennas. The coax is eliminated by placing 50W mobile rigs (capable of cross band repeat) at each of the possible three antennas and operating them remotely via 3 UHF HT's indoors on-stage (coupled into the sound system).
So, if you are in range of an ISS school contact, and you have an arrow on a tripod at your QTH, you could collect data on a horizon transition to see if this idea is a possibility.
Again, YOU ARE RECEIVE ONLY. Your test is *independent* of the actual school contact, you are just taking your own receive data wherever you are of how well a FIXED arrow on a tripod can hear the ISS at low elevations. Be sure to find a place with a good horizon at AOS(or LOS) to set your antenna.
If we learn that there will be any significant fades or loss of signal, then this idea fails... But if it works, then the two arrows, tripods, three crossband-repeating mobile rigs and three UHF HT's could be made into a suitcase GOKIT to standardize some school contacts with a lot less work.
Just an idea Bob, WB4APR US Naval Academy
For those interested in this project there is another opportunity for Central US tomorrow
An International Space Station school contact has been planned with participants at Daggett Montessori School K-8, Fort Worth, Texas on 29 Oct. The event is scheduled to begin at approximately 14:12 UTC. It is recommended that you start listening approximately 10 minutes before this time. The duration of the contact is approximately 9 minutes and 30 seconds. The contact will be direct between NA1SS and K5COW. The contact should be audible the mid U.S, and adjacent areas. Interested parties are invited to listen in on the 145.80 MHz downlink. The contact is expected to be conducted in English.
EMike, KC8YLD E. Michael McCardel, KC8YLD V.P. for Educational Relations, AMSAT-NA
Have you donated to get your Fox-1 Challenge Coin Yet? http://www.amsat.org/?p=3275
On Tue, Oct 27, 2015 at 1:15 PM, Robert Bruninga [email protected] wrote:
Both of my school-contact monitoring tests with the arrow were useless.
Both days the 200' tethered JLENS Blimp was aloft radiating megawatts of radar direct Line of Sight to my operating position. Although the radar pings are at 143 and 149 MHz with peaks +70dB above the noise, they do get into all of our Ham VHF radios as a raised noise floor. Just open any radio squelch on any frequency in the 2m band and you will hear it.
So even when the astronauts were 7 bars on the radio, the audio had significant noise from the radar superimposed.
So my report is a null report. Bob, Wb4APR
-----Original Message----- From: Robert Bruninga [mailto:[email protected]] Sent: Tuesday, October 20, 2015 6:06 PM Subject: RE: Possible ISS School Contact Experiment idea? (Thurs)
An ISS school contact… in Michigan on 22 Oct.
This is a great time for those skilled portable "arrow" operators to get data on using fixed vertical arrow beam antennas for ISS voice at or near the horizon.
The test will show if well placed fixed tripod "arrow class" antennas at AOS and LOS and a central turnstyle could possibly make it easier than a full AZ/EL Oscar class antenna at the school.
See the concept paper at http://aprs.org/aos-los-test.html
If your QTH is west of a school contact, then you should test your LOS horizon. If your QTH is east of the school, then you should test your AOS horizon. This is because we want to make sure we are getting voice quality data AT the horizon while the ISS crew is actually speaking.
The desired data is a minute-by-minute log throughout the pass of ISS signal quality (noting nulls or fades) without moving or adjusting the antenna. Your receiver should be right near the antenna (no coax loss). Just orient the beam vertically with an up tilt of 15 degrees. Then aim it at a fixed Azimuth that is half way between AOS (or LOS) and when the ISS rises above (or drops below) 30 degrees elevation to cover the first (or last) portions of the pass.
Leave your antenna fixed throughout the pass. We need to know how well the squelch on your radio eliminates the weak signal when the ISS is outside your particular fixed beam too.
In a real scenario of this full technique, above 30 degrees the ISS is 3 times closer and 10 dB stronger and would be heard fine on a central omni antenna. But that is not part of your horizon performance test. So be sure to choose a good low horizon *and* the horizon you share with the School contact so that there is ISS audio during your particular horizon crossing (AOS or LOS).
An audio recording would make it easier to prepare the log after the pass or you can just make checks or X's every 5 seconds on a piece of paper and summarize it later. Do NOT run open squelch. Set the squelch for normal ham radio operation to silence the radio when the signal would be unintelligible anyway, since we would not want unintelligible noise from one receiver to distract from good audio from the possible others..
If this concept works, then the idea would be to bring in all three receiver speakers (left-to-right) into the auditorium operating position to give equal weight to each receiver but also give a sense of the passage of the ISS. If this test shows any promise, it could not only eliminate all the complexities of long crossed yagis, AZ/EL rotators, big masts and active tracking, but also completely eliminate the problem of long runs of coax from the school gymnasium to the antennas. The coax is eliminated by placing 50W mobile rigs (capable of cross band repeat) at each of the possible three antennas and operating them remotely via 3 UHF HT's indoors on-stage (coupled into the sound system).
So, if you are in range of an ISS school contact, and you have an arrow on a tripod at your QTH, you could collect data on a horizon transition to see if this idea is a possibility.
Again, YOU ARE RECEIVE ONLY. Your test is *independent* of the actual school contact, you are just taking your own receive data wherever you are of how well a FIXED arrow on a tripod can hear the ISS at low elevations. Be sure to find a place with a good horizon at AOS(or LOS) to set your antenna.
If we learn that there will be any significant fades or loss of signal, then this idea fails... But if it works, then the two arrows, tripods, three crossband-repeating mobile rigs and three UHF HT's could be made into a suitcase GOKIT to standardize some school contacts with a lot less work.
Just an idea Bob, WB4APR US Naval Academy _______________________________________________ Sent via [email protected]. AMSAT-NA makes this open forum available to all interested persons worldwide without requiring membership. Opinions expressed are solely those of the author, and do not reflect the official views of AMSAT-NA. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://www.amsat.org/mailman/listinfo/amsat-bb
participants (2)
-
E.Mike McCardel -
Robert Bruninga