Hi Gould,

This is my response to Andrew, which I sent before receiving your reply. But your the guy I really need to address the question to since your the author of the book I'm looking at.

"Thanks for the reply Andrew.

Maybe I'm a bit confused. In my Gould "ECHO" book (Version 1.1 - May 2004) on page 31, Figure 18 "ECHO satellite tray and component layout" it shows the VHF, the 4 element UHF turnstile and the L and S band antennas - - - but it also shows a "multiband antenna" feeding a switch and then the SQRX receiver. The other side of the switch is fed from the L band LNA. The SQRX can tune from 10 to 1300 MHz, and somehow I remember a 28 MHz SSB uplink test. Could be I've got the satellites or modes mixed up.

By the way, that Figure 18 is the only place I can see the "multiband antenna" referenced so maybe it's an error. Figure 16, on page 30 shows the other side of the switch being fed by the VHF antenna. That's probably the right representation.

Can you help straighten me out?

Regards...Bill - N6GHz "

Gould Smith wrote:

As Drew said Stan designed it, with maybe help from Lou.

I was told that it is an L Band antenna with S band stubs. There is a ground plane under it with radials for L and S band. I wasn't able to get specifics about gain when I did the book.

Gould ----- Original Message ----- From: "Andrew Glasbrenner" glasbrenner@mindspring.com To: "Bill Ress" bill@hsmicrowave.com; eagle@amsat.org Sent: Monday, September 03, 2007 8:06 PM Subject: [eagle] Re: AO-51 Multiband Antenna???

...

Stan Wood designed it. It is a dual band L and S antenna, linearly polarized. I'm not sure what sort of "in orbit data" you are looking for, but it is in use whenever the L band uplink or S band downlink is in use including later this month. http://n4hy.smugmug.com/gallery/2107663#108915239 has good pics of the antenna.

Something in particular you'd like to try?

73, Drew KO4MA

----- Original Message ----- From: "Bill Ress" bill@hsmicrowave.com To: eagle@amsat.org Sent: Monday, September 03, 2007 7:54 PM Subject: [eagle] AO-51 Multiband Antenna???

...

Perhaps one of you can detail the "multiband antenna" used with the SQRX receiver aboard AO-51.

A perusal of Gould Smith's "ECHO" makes reference to it but provides no details.

Does anyone have any in orbit data for this mode. What's the current status for its use?

Regards and thanks...Bill - N6GHz

---

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Hi Tom,

Thanks to you also for such a fine detailed description.

I have a two fold interest in learning more about what was planned. One, was getting information on what, if any, wideband antenna configuration was planned - for a potential CubeSat application I working with some folks on.

Now the other is the Pave Paws discussion Juan et. al., have been having today.

So, what you have said about the sensitivity of the SQRX and its ability to hear signals over its whole input band (.5 to 1300 MHz as you stated) leads me to the following suggestion.

On one of the passes just west of California (an Beale AFB), lets set the SQRX on one of the suspected Pave Paws frequencies and have what it hears transmitted down to a bunch of us on the West Coast to track and record what we hear and how the SQRX responds to what could be some high level signals. Might have to use the 2.4 GHz down link since the 435.3 Tx would probably block the SQRX if its trying to listen in the 70 cm satellite band.

Any merit in the thought?

Tom Clark, K3IO wrote:

Bill Ress wrote:

...

Maybe I'm a bit confused. In my Gould "ECHO" book (Version 1.1 - May 2004) on page 31, Figure 18 "ECHO satellite tray and component layout" it shows the VHF, the 4 element UHF turnstile and the L and S band antennas - - - but it also shows a "multiband antenna" feeding a switch and then the SQRX receiver. The other side of the switch is fed from the L band LNA. The SQRX can tune from 10 to 1300 MHz, and somehow I remember a 28 MHz SSB uplink test. Could be I've got the satellites or modes mixed up.

By the way, that Figure 18 is the only place I can see the "multiband antenna" referenced so maybe it's an error. Figure 16, on page 30 shows the other side of the switch being fed by the VHF antenna. That's probably the right representation.

Since I was the provider of a part of this, let me try to straighten out the confusion.

There are 3 physical antennas on Echo; #1 & 2 are on the "bottom" and #3 is on the "top":

1. A 4 element "droopy dipole" 70 cm TX antenna; each element is a canted ¼-wave monopole. The 4 elements are fed from a microstrip hybrid that feeds the 4 elements at phases of 0,90,180 & 270 degrees. Opposite elements are out of phase (i.e. the hybrid acts as a balun). 2 ports are fed from the 2 70cm TX with opposite senses of circular.
2. The combined L-S antenna; L-band can be used for RX thru the SQRX, S-band is TX.
3. A single 18" monopole made with a piece of piano wire stuck into an SMA connector.

I believe the confusion is about #3. This is the 2M RX antenna. The coax passes thru a -10dB direction coupler, thence into an LNA and a 4-way power splitter to feed the 4 separate 2M RX.

The directional coupler was added at the last minute (provided by me, glued in place by Chuck Green). Originally the plan had been to use a hi-Z 10M preamp (fabricated by Stan) to provide for a 10M RX with the SQRX (SQ = "SpaceQuest") in SSB mode. However, 2 days before it left the USA, Lyle, Chuck, Mark and I decided that the performance was not good, so we elected to use a passive directional coupler instead. Although the 18" whip is a poor match at 10M, we decided it worked better than the Hi-Z preamp, and it meant that the 18" whip could be used anywhere in the 0.5-1300 MHz range covered by the SQRX (albeit with marginal sensitivity).

Since this scheme allows the SQRX to work on 2M, Drew has done some excellent work using the SQRX to do a global map of the 2M environment as seen from space. Not surprisingly, the RFI levels are quite high over south-east Asia (high power cordless phones & fisherman using 2M hardware. I was quite surprised to see that the area over Darfur was also a hot spot!

The relay Bill noted is a SPDT SMA coax relay that selects either the 18", -10dB spigot or L-band from the L/S diplexer.

73, Tom

Hi Chuck,

Thanks for your comments and thanks for the pictures links.

Gould has cleared up the mystery. In his "ECHO" issue it had a block diagram which, in addition to the V,U,L and S antennas, it showed a "multiband antenna" going to the SQRX receiver. In Gould's later issue, called "AO-51", the multiband antenna was crossed out. I did not have the most recent version of Gould's work.

Gould says a "multiband antenna" was once planned but later dropped.

I'm looking at a potential CubeSat project where we are considering a wideband (28 MHz to 435 MHz) antenna and naturally that reference caught my eye, knowing that the SQRX receiver covered 10 to 1300 MHz. It begs the question, why have such a wideband receiver if you weren't planning on doing something with it, at least at one time?

So does anyone have any idea what the "wideband antenna" might have looked like?? Was it a SpaceQuest thing or was it one of our guys idea??

Regards...Bill - N6GHz

Chuck Green wrote:

Hi Guys,

Let me take my best shot at what I'm reading here... there is confusion. I think the confusion comes from mixing the term "multi-band" with "variable frequency receive, aka SQRX". They have nothing to do with each other.

The multi-band antenna is an L/S antenna. That's it. It's a beautiful piece of work by Stan.

The SQRX is fed from a splitter that is fed from the VHF antenna. The majority of the antenna signal goes to a preamp and then is split four ways to feed the four VHF receivers. The smaller portion of the antenna signal goes to the SQRX. I believe this antenna was designed by Mark Kanawati, but I'm not sure.

If you want to see a couple of thousand pictures, including many of the internals of the satellite, you can look at my collection at http://bach.as.arizona.edu/gallery/main.php?g2_itemId=3759

I hope this helps, Chuck

Gould Smith wrote:

...

As Drew said Stan designed it, with maybe help from Lou.

I was told that it is an L Band antenna with S band stubs. There is a ground plane under it with radials for L and S band. I wasn't able to get specifics about gain when I did the book.

Gould ----- Original Message ----- From: "Andrew Glasbrenner" glasbrenner@mindspring.com To: "Bill Ress" bill@hsmicrowave.com; eagle@amsat.org Sent: Monday, September 03, 2007 8:06 PM Subject: [eagle] Re: AO-51 Multiband Antenna???

...

Stan Wood designed it. It is a dual band L and S antenna, linearly polarized. I'm not sure what sort of "in orbit data" you are looking for, but it is in use whenever the L band uplink or S band downlink is in use including later this month. http://n4hy.smugmug.com/gallery/2107663#108915239 has good pics of the antenna.

Something in particular you'd like to try?

73, Drew KO4MA

----- Original Message ----- From: "Bill Ress" bill@hsmicrowave.com To: eagle@amsat.org Sent: Monday, September 03, 2007 7:54 PM Subject: [eagle] AO-51 Multiband Antenna???

...

Perhaps one of you can detail the "multiband antenna" used with the SQRX receiver aboard AO-51.

A perusal of Gould Smith's "ECHO" makes reference to it but provides no details.

Does anyone have any in orbit data for this mode. What's the current status for its use?

Regards and thanks...Bill - N6GHz

---

Via the Eagle mailing list courtesy of AMSAT-NA Eagle@amsat.org http://amsat.org/mailman/listinfo/eagle

---

Via the Eagle mailing list courtesy of AMSAT-NA Eagle@amsat.org http://amsat.org/mailman/listinfo/eagle

---

Via the Eagle mailing list courtesy of AMSAT-NA Eagle@amsat.org http://amsat.org/mailman/listinfo/eagle