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

[Video] Rare MAI-75 USA ISS SSTV Reception - April 2016 Video #3
by John Brier 03 Jun '16

03 Jun '16

https://youtu.be/cUnkrlRJJuw MAI-75 ISS SSTV was mostly only available outside of North America, but there were two passes where it did cover NA on Friday April 15th, 2016. This is one of those passes. Video #1 - Monday Failure and Tuesday Success https://youtu.be/ieR-nmkjeSc Video #2 - Perfect ISS SSTV Images... Almost! https://youtu.be/JoFrVRfc4Ks 73, John KG4AKV

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Re: [amsat-bb] Polarization
by Doug Andrews 02 Jun '16

02 Jun '16

I too have wondered about this. I have not had much trouble hitting SO-50 and some success on AO-85 with a 5 watt handheld and arrow antenna without turning it. Worth a try. DougKG7UNU Sent from my Sprint Samsung Galaxy® Note 4. -------- Original message -------- From: Ken Alexander <k.alexander(a)rogers.com> Date: 5/30/16 4:41 PM (GMT-08:00) To: amsat-bb(a)amsat.org Subject: [amsat-bb] Polarization I clipped this from another message because I didn't want to drag the discussion off course. It's a question I've been wondering about since getting into this a few short weeks ago. I've also read (but haven't tried yet) about the trick of rotating the antenna 90 degrees on transmit, once you've established the best receive orientation. 73 de Bill, KG5FQX So far, with SO-20 I have rotated my Arrow antenna for best reception of the downlink and don't think I've had too much trouble being heard. At the same time I have wondered whether I should twist the antenna when transmitting to orient the 2m elements to give the same polarization as in receive. I don't know if this is a good idea or not, and frankly I have enough trouble remembering calls and grids, tracking the satellite, adjusting frequency and switching back to the correct VFO to worry about one more thing. I've seen that some commercial OSCAR antennas use circular polarization. The antennas I see in the photos of satellites we work are whips. Is the polarization becoming "circularized" as it re-enters earth's atmosphere or something? Comments and observations would be most welcome! 73, Ken Alexander VE3HLS, FN03 _______________________________________________ Sent via AMSAT-BB(a)amsat.org. 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

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KISS-RX AA2TX info
by Joel Caulkins 02 Jun '16

02 Jun '16

Hi, Can anybody point me in the direction of any information on Anthony, AA2TX's Space Radio SDR receiver. I have bought a PCB from Amateurradiokits.in. I need the KISS-RX driver and the WAVE I/O driver for Windows. Any help would be appreciated. -- Joel, KB6QVI

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Re: [amsat-bb] EsHail Microwave transponder satellite
by Edward R Cole 02 Jun '16

02 Jun '16

Comments *** inserted, below: --------------- Date: Thu, 2 Jun 2016 12:05:13 +0200 From: Remco <pa3fym(a)amsat.org> To: amsat-bb(a)amsat.org Subject: [amsat-bb] EsHail Microwave transponder satellite Message-ID: <201606021205.13732.pa3fym(a)amsat.org> Content-Type: text/plain; charset="us-ascii" Having posted my setup at the end of last month and seeing that my mail program wrapped line feeds, decreasing readibility, here again my description and perspective. Es'hail2 will not differ from any other geostationary broadcast satellite in a sense that it's a 'full duplex' repeater with some time delay. I reckon this time delay inhibits actual full duplex operation, just like the TV reporter for a 'live stand up' in the TV news via a satellite link having an earplug with all audio except himself ('N-1'). ***Why? Duplex is totally possible - just listening to your own retransmitted voice might mess up your mind too much. I suggest probably muting the receiver when you talk (simple VOX controlling Rx audio). Rx resumes immediately upon cease of talking. Disable to tune in your signal using carrier. ====snipped Feed: From my perspective the only challenge lies in the 2.4 GHz uplink. That is, to make an S-band feed which phase center coincides with the 10.5 GHz LNB (which has its own 'feed' ;-) ***LNB "is" a feed with block down-conversion (e.g. Low Noise Block-down-converter) I've no fear for isolation issues due to the large frequency difference. ***Probably true as wg for 10-GHz LNB cuts off way above the uplink frequency. I am told that circular polarization (CP) is 'mandatory' for S-band uplink's in general but can't find a verification for this, perhaps somebody else? ***Generally, I am hearing that the s/c will have linear antennas whose orientation will change depending on your lat-long on earth. Common issue for eme'rs separated by large differences in coordinates (term is called spacial loss but refers to polarization angle shift with apparent location in respect to the other station). ***CP should solve this for the ground station; but designing and building a mw CP feed is not easy. Anyway, we're amateurs and creative. So when RHCP uplink is too difficult we make a linear antenna and increase uplink power with 3 dB ;-) ***Huh? That would only be true if s/c is circular pol. If it is linear you could have a loss all the way to 20-dB depending on polarity mismatch (see spacial loss referred to above) But, I follow the published receiver specifications . . . Last week I made a 6 turn LHCP 2.4 GHz helix. (Rule of thumb seems to be 1 turn per 0.1 f/D) Phase center of such a helix is a bit 'foggy' but from what I read lies somewhere between the first and second turn. I've some issues with matching it due to some mechanical boundary conditions of the helix feed point in conjunction with the mounted downlink LNB and relative position of the helix. There is an additional 'transmission line' involved and a 'normal' 1/4-wave stub doesn't give me the desired return loss. So, this needs some fiddling, perhaps with a gamma match or so. ***I used a 33-inch offset fed dish on 2.4-GHz with a 6-1/4 turn helical feed for AO-40. I used brass strap for the first 1/4 WL to match the feed to coax. Matching is done by adjusting the height of the matching section from the ground plane. I ended up with 3/16 inch separation at helix end of matching line. My approach is, the downlink LNB is mounted in the dish 'as usual' and looks through the centre of the uplink helix. ***If the 10-GHz feed is generally cylindrical and smaller diameter than the Helix this will work fine. I used a metal tube with heat sink covering as center support for my helix. 0.7-inch ID tubing is proper diameter for 10-GHz wg. But not sure how well the typical 12-GHz LNB will work inside a helix. ***Other geosat designs are for 5-GHz/10-GHz so not sure how well a Helix will work there. Perhaps the 10-GHz cylindrical wg could serve as center conductor of air-insulated coaxial feed with a simple dipole feed on 5-GHz and 10-GHz horn extending a small way beyond the dipole. This would work better with center-fed dishes of f/d ~ 0.35. Pictures of the prototype feed arrangement can be provided soon. They are on a camera not present here at this moment of writing. ***Attachments to Amsat-BB probably will not go thru; post http link to the photos, instead - please. Remco PA3FYM 73, Ed - KL7UW http://www.kl7uw.com "Kits made by KL7UW" Dubus Mag business: dubususa(a)gmail.com

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Re: [amsat-bb] NO-84 APRStt? (and darned beacons)
by Robert Bruninga 02 Jun '16

02 Jun '16

> It was Qikcom-2 I was reading about... > Maybe WB4APR can update us on the status of the former... > http://aprs.org/qikcom-2.html It is fully integrated and will launch on the same launcher as the two AMSAT FOX satellites no sooner than August. Other than that, I know practically nothing since it was impossible to get a non-disclosure-agreement through the Naval Academy's bureaucracy in under a year. We developed and delieverd the flight unit long before there was any progress on the paperwork. Got my fingers crossed. If it works, it will be the usual PSAT digipeater but will also have a DTMF uplink for Grids and Messages and a Voice downlink of same while also converting them to APRS packets too. We will probably leave the DIGI off and leave it in DTMF and Voice mode due to so many unattended worthless beacons on the uplink that would cut into useful live human contact time... Bob, WB4APR

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Purchased LVB tracker
by Edward R Cole 02 Jun '16

02 Jun '16

I decided to backup my plans to use a very old Unitrac-2000 by purchasing a LVB tracker while in stock at Amsat. If I have problems getting the Unitrac working I can then just use the LVB in its place. Only difference is LVB does not support auto-tuning which the Unitrac handles along with auto-track. If successful with the Unitrac, then I will offer the LVB for sale. 73, Ed - KL7UW http://www.kl7uw.com "Kits made by KL7UW" Dubus Mag business: dubususa(a)gmail.com

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Re: [amsat-bb] AMSAT @ White Mountain Hamfest (Show Low AZ), this Saturday
by Richard Tejera 02 Jun '16

02 Jun '16

Are there any good SURpasses during the hamfest? I thought the favorable passes are still in the evening? It's a busy day for me but I may be able to work an early pass. Rick Tejera K7TEJ Saguaro Astronomy Club www.SaguaroAstro.org Thunderbird Amateur Radio Club www.w7tbc.org On June 1, 2016, at 12:14, "Patrick STODDARD (WD9EWK/VA7EWK)" <amsat-bb(a)wd9ewk.net> wrote: Hi! I will have an AMSAT table at the White Mountain Hamfest in Show Low, Arizona, this Saturday, 4 June 2016. The hamfest will be at the Show Low City Hall parking lot, south of US-60 and west of AZ-260 in the center of Show Low. This is a half-day hamfest, scheduled to end "noonish" (around 1900 UTC). During the hamfest, WD9EWK will be on various satellite passes for on-air demonstrations of satellite operating. Please call WD9EWK if you hear me, and be a part of the demonstrations. The hamfest site is in grid DM44. All QSOs will be uploaded to Logbook of the World after the hamfest, and I am happy to send QSL cards to anyone who wishes to receive a card. Please e-mail me the QSO details to get a card. If you're in the log, I will send a card. No need to first mail a card and/or SASE to get my card in return. I should be able to post pictures and other updates during the morning to my @WD9EWK Twitter feed. This is an open feed, which can be viewed in a web browser at: http://twitter.com/WD9EWK if you don't use Twitter. Also, my location should be visible via APRS. I use WD9EWK-9 as my call sign for APRS, and - among other sites - it should be visible at: http://aprs.fi/WD9EWK-9 during my drive to Show Low on Friday evening, as well as at the hamfest Saturday morning. Other than on ISS passes, I won't leave my APRS radio squawking once I have parked at the hamfest. Thanks in advance, and 73! Patrick WD9EWK/VA7EWK http://www.wd9ewk.net/ Twitter: @WD9EWK _______________________________________________ Sent via AMSAT-BB(a)amsat.org. 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

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EsHail Microwave transponder satellite
by Remco 02 Jun '16

02 Jun '16

Having posted my setup at the end of last month and seeing that my mail program wrapped line feeds, decreasing readibility, here again my description and perspective. Es'hail2 will not differ from any other geostationary broadcast satellite in a sense that it's a 'full duplex' repeater with some time delay. I reckon this time delay inhibits actual full duplex operation, just like the TV reporter for a 'live stand up' in the TV news via a satellite link having an earplug with all audio except himself ('N-1'). For us amateurs this means no (significant) Doppler shift, no LSB/USB issues etc. Just point your dish once to 25.5E like (more than) thousands of broadcast satellite viewers do (without technical knowledge at all ;-) Downlink (10.5 GHz): For narrow band usage frequency and stability is paramount. For 10.5 GHz we're helped by the BC satellite industry, offering cheap PLL LNB's with 'HDTV precision'. Imho this precision needs to be increased by injection locking the LNB PLL with e.g. a GPSDO due to the large multiplification factor inside the LNB (e.g. for Octagon 361.111111). Noise figures (NF) of these LNB's are somewhat higher on 10.5 GHz due to (steep) wave guide cut off, but still usable, compared to the ease and price. Uplink (2.4 GHz): A 10W BUC (block up converter) suffices with published specs of the 2.4 GHz receiver above in conjunction with a ca. 75cm dish here. I'm currenly developing a simple 2.4 GHz BUC and will use old UMTS pallets to amplify the desired 2400 MHz output. Picture of my UMTS pallets: http://remco.org/umts.jpg Bear in mind, S-band power is cheap :-) Antenna: One dish, the larger the better. Not for the uplink, but for improving dynamic range at the receiver (downlink) side. I will use a surplus Triax 88cm dish (for portable / 'umbrella' use ;-), f/D is around 0.6 (like most consumer BC satellite dishes). Feed: From my perspective the only challenge lies in the 2.4 GHz uplink. That is, to make an S-band feed which phase center coincides with the 10.5 GHz LNB (which has its own 'feed' ;-) I've no fear for isolation issues due to the large frequency difference. I am told that circular polarisation (CP) is 'mandatory' for S-band uplinks in general but can't find a verification for this, perhaps somebody else? Anyway, we're amateurs and creative. So when RHCP uplink is too difficult we make a linear antenna and increase uplink power with 3 dB ;-) But, I follow the published receiver specifications . . . Last week I made a 6 turn LHCP 2.4 GHz helix. (Rule of thumb seems to be 1 turn per 0.1 f/D) Phase center of such a helix is a bit 'foggy' but from what I read lies somewhere between the first and second turn. I've some issues with matching it due to some mechanical boundary conditions of the helix feed point in conjunction with the mounted downlink LNB and relative position of the helix. There is an additional 'transmission line' involved and a 'normal' 1/4-wave stub doesn't give me the desired return loss. So, this needs some fiddling, perhaps with a gamma match or so. My approach is, the downlink LNB is mounted in the dish 'as usual' and looks through the centre of the uplink helix. Pictures of the prototype feed arrangement can be provided soon. They are on a camera not present here at this moment of writing. Remco PA3FYM

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Re: [amsat-bb] EsHail Microwave transponder satellite
by Edward R Cole 02 Jun '16

02 Jun '16

Dual-band feed arrangements have been done on dishes used for eme. A classic is 432/1296 feed of VK3UM or similar arrangement 432/2304: crossed dipole feed on 432 with cyl 1296 horn in the center of a large circular reflector plane. But higher in mw wg horn feeds are normal. Hard to get two horns in the same spot (focus). However, I have a cylindrical wg horn made by W1GHZ which feeds 24-GHz via wg into a smaller diameter wg section opening into a larger section which is fed 10-GHz via wg coax probe. But this is not designed for dual-band duplex operation. At NASA duplex operation was accomplished using wg diplexers which cut-off RF at a higher frequency thru phasing techniques. 2.115-GHz Tx/2.295-GHz Rx. Another famous NASA operation used something called a dichroic plate. The plate was put across the mouth of a feehorn so that only 8.4 GHz signals would penetrate the fine holes in the plate but reflect 2.2 GHz. The Plate was angled to reflect the lower frequency to another horn positioned to look at the plate. Of course the dish was 64m in diameter so the subreflector did not have to be small (about 3m to memory). That was used in 1974 for an experiment on MA-10 encounter at Venus. I believe the 5G/10G sats are being designed with a 1m ground dish as standard. 1m offset dishes are common to the current Direct-TV/Dish Net market. Here in AK 1m to 1.2m dish is std on houses (I have a 1.2m). I also have our old Dish-Net dish which is 1.8m sitting on a pole with nothing hooked up. Unfortunately, ExHail will not be above horizon in Alaska. 73, Ed - KL7UW http://www.kl7uw.com "Kits made by KL7UW" Dubus Mag business: dubususa(a)gmail.com

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Re: [amsat-bb] EsHail Microwave transponder satellite
by Luc Leblanc 02 Jun '16

02 Jun '16

In the AO-40 era i was using this setup to mount one dish and one BBQ grill antenna on the same mount. I could also mount another smaller dish on this mounting. See pictures on http://www.qsl.net/ve2dwe/ Luc Leblanc VE2DWE > > I asked a manufacturer of feeds (...) and they said > > a dual feed was not possible. Uplink is circular and > > downlink is linear using a normal LNB. > > But linear is a subset of "circular", so, couldn´t we use a dish that is 40% > larger (to make up the 3 dB loss of going linear) and use a linear feed on > the uplink so it can be cross polarized with the downlink and thus get maybe > 20 dB of isolation? Maybe that 20 dB of isolation is still not enough? > > Bob, WB4aPR > > However many Europeans may have one dish for TV anyway. It is relatively > easy to mount two LNBs on one dish for 2 different satellite positions, so > one dish for household TV with a second LNB for Eshail sat, The LNB that is > offset from prime focus will see a smaller gain than prime focus so a > slightly larger dish may be needed and a separate dedicated dish for > circular uplink. That is not to say it could not be done, but to have both > at the same focal point is not a good idea. > > A rotator is not needed for EsHail as it is proper geostationary. > > Zilvinas > So do you currently have satellite TV, how big, and what satellite is it > pointing at? > Also what is your location? > > On 01/06/2016, Robert Bruninga <bruninga(a)usna.edu> wrote: > > Im not following this closely, but if the bands were cross polarized, > > it should be possible...? > > Bob, WB4APR > > > > -----Original Message----- > > From: AMSAT-BB [mailto:amsat-bb-bounces@amsat.org] On Behalf Of John > > Toscano > > Sent: Wednesday, June 01, 2016 1:23 PM > > To: Zilvinas Atkociunas > > Cc: amsat-bb(a)amsat.org > > Subject: Re: [amsat-bb] EsHail Microwave transponder satellite > > > > I don't think it is possible to create a dual-band dish feed that > > covers > > 2.4 and 10.5 GHz. AMSAT folks are working hard on a 5G/10G dual-band > > feed, and that is difficult. Even more complicated is your desire to > > use a commercial 10G satellite TV LNB as one of the two feeds. I think > > you are going to have to use two antennas for those 2 bands. The 10G > > dish with satellite TV LNB for one of them, and either a separate dish > > or a loop yagi or something else for the uplink. A Yaesu Az/El rotor > > can handle a pair of antennas, in fact it is almost a re > > > > On Wed, Jun 1, 2016 at 6:19 AM, Zilvinas Atkociunas < > > zilvinas.atkociunas(a)gmail.com> wrote: > > > >> Hi all, > >> > >> Any ideas how to use two antennas with single dish ? (one of them SAT > >> LNB) > >> > >> LY2SS >

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