July 2016 - AMSAT-BB - mailman.amsat.org

Re: [amsat-bb] Mode K (fact and fiction?)
by Robert Bruninga 02 Jul '16

02 Jul '16

> The late John Branegan, GM4IHJ (CDR, Royal Navy) > did a lot of good research on Mode K using the RS birds. > ... an effective way of... satellite DX despite today's low orbits. Thanks! Ill research it. The over the horizon DX aspect is what everyone remembers. And that is what I want to study. My theory is that with the variability of the ionosphere, that just as much as there is enhanced beyond-the-horizon relay some times, there is also times of no-path because the ionosphere at low elevations is bending the path away from the bird. My theory is that hams like DX and remember the GOOD DX, but then conveniently forget all the times when the link was dead. So I think what I hear from "the good ole days" has to be taken with a grain of salt since the dead band days are not as memorable as that rare double bounce hop to timbuktoo. So far, no one has described how often they could not even hear the bird or get into it even though it was in range. I think that is the data that is missing? Bob, WB4APR HFSAT in 2018?

3 2

MY struggles with AO-85
by Ken Alexander 02 Jul '16

02 Jul '16

In several attempts I have yet to hear myself on the AO-85 downlink. finally, after playing with SatPC32 this evening I realized it tells me pretty well exactly where I should be. I ran through an upcoming pass to see what it tells me and the result is tabulated in the following table. First column is time (UTC), second column is the fine freq to 4 decimals and the third column are frequencies I can actually enter in my TH-D72 with its 5 kHz frequency step. 435.170 at AOS confirms what many ops have told me in the last few days. What I forgot was how fast the frequency changes as AO-85 passes through its maximum elevation; the middle 3 minutes will be busy! Anyway, I was pleased to "discover" this and hope the information will give me what I need to finally make a QSO or two. Now I just hope I don't get rained out! 73, Ken Alexander VE3HLS

1 0

Preamps and Polarization Switches
by Fred Castello 01 Jul '16

01 Jul '16

Newbie here and I am trying to put together a station. I have a question about preamps. I am making the following assumptions but please correct me or outline your station feeds if I am incorrect in my assumptions: Most experienced operators are using moderate to high gain yagi antennas, circular polarized. I am thinking of purchasing the M2 LEO pack. I am assuming that most folks are using RF protected preamps to keep from blowing them up on transmit. It would be easier if one knew that they were always going to transmit on 2 meters (for instance) and one could place the NON RF protected preamp on 70 cms. However, since there is a mix of V/U and U/V birds, it would seem the only way to get preamps up at the antenna where they belong is to use RF protected preamps ( with weather and RF protection, significantly more expensive). Is there a role for diplexers here rather than running expensive RF protected switching? Also, I know from my listening on my Elk Antenna that change in polarization can make a pretty significant difference in adequate reception. So, it would also seem that there is a need with these type of antennas (M2 LEO) to have a polarization switching (cost for both antennas almost matches the original cost of the antennas). Do most operators have these switchable polarization switches. My shack is about 60 feet from the top of the roof, so I will have to deal with those losses in spite of using good cable. I was thinking of just starting with the antennas (no preamps, no polarization switching) and see how things go. Any thoughts or advice would be much appreciated. Best Fred Castello, KF4FC

3 2

W3ZM from Escape Velocity 2016 in National Harbor, MD 7/2/16
by Paul Stoetzer 01 Jul '16

01 Jul '16

Good afternoon, ARISS will have a presence at the Escape Velocity 2016 event at the Gaylord National Resort & Convention Center in National Harbor, MD this weekend. To demonstrate space communications to anyone interested, I will work two FO-29 passes tomorrow afternoon (at 16:49 UTC and 18:36 UTC) from outside the convention center using the AMSAT club callsign W3ZM. Please look for me around 435.865 MHz +/- Doppler. I may also work the SO-50 pass at 19:54 UTC. 73, Paul, N8HM

2 1

Office Closed
by Martha 01 Jul '16

01 Jul '16

The AMSAT Office will be closed on Monday, July 4th. We will reopen on Tuesday, July 5th at 10:00 AM -- 73- Martha

1 0

AO-16 telemetry 3 Oct 2010
by Mark L. Hammond 01 Jul '16

01 Jul '16

Hi All, Here is a quick AO-16 update. On Sunday I turned AO-16 long enough to get some telemetry packets. The satellite would remain on for less than one minute after being commanded on. A quick test of the "bent pipe" voice mode repeater was successful. . The "hardware watchdog timer problem" is still evident; as expected, spacecraft temperatures are insufficient to keep the transmitter ON (needs to be above 15 deg C). Orbit projections suggest that satellite illumination conditions will not result in increased temperatures for nearly 10 years. Command stations do periodically turn AO-16 "ON" to check on its condition and see if the hardware timer problem has "automagically" fixed itself (which in not anticipated, but who knows...). AO-16 telemetry 3 Oct 2010 1838 utc PACSAT MBL Telemetry Decoder Ver. 1.3 (c) Mike Rupprecht, DK3WN =============================================================================== (average values) +10V Battery Bus : 0.00 V Battery Charge Reg : 0.55 mA Base Temp : 9.07 °C PSK RF Out : 1.90 W +5V RX Bus : 4.87 V +8.5V RX Bus : 8.49 V +10V RX Bus : 11.24 V Here is another teaser :) Several months ago I commanded the AO-16 S-band transmitter ON; it too remains functional (albeit weak), and was received by me, Drew KO4MA, and Alan WA4SCA. 73, -- Mark L. Hammond [N8MH]

2 1

AO-73/FUNcube mode change
by Jim Heck G3WGM 01 Jul '16

01 Jul '16

Hi Folks, Just to let you know that I have just changed AO-73/FUNcube into full time amateur mode. Enjoy the transponder over the weekend. Plan as normal is to return the sat to auto switching mode on Sunday pm, utc 73 Jim G3WGM

1 0

RS 7/8 foot print
by Bob Cutter 01 Jul '16

01 Jul '16

Does anyone have the diameter of the foot print? 73, Bob KI0G

3 2

AO-40 & AO-16
by w4upd 01 Jul '16

01 Jul '16

Wonder if anyone has taken a shot at trying to see if AO-40 could be activated or even heard. Whether anyone may have heard its local oscillators? Stranger things have happened (AO-07 for one). Also, does anyone know when or if AO-16 can be activated again in its basic boot loader as it was some time ago. Its communications in the mode (FM/DSB/AM) worked really great. However, I believe there was a time issue due to sun angles. Wondering if we are getting close to that time frame again? Reid, W4UPD Amsat: 17002

2 1

France (IN94) on AO-07
by F6GLJ 01 Jul '16

01 Jul '16

Hello, I' ll be on AO-07B for next pass, good foot print for NA<> EU qso 73 Qro de F6GLJ https://www.qrz.com/db/F6GLJ

1 0