Now that field day is over, I hope everyone that participated had as much fun as they had expected. There is just one more thing to do. Be sure to send in your results and photos.
If you are going to send via email (the preferred method), I will confirm that I have received your email (give me a day or two). If you do not get the confirmation, then something happened and you should resubmit.
The deadline for receiving your submission (either email or postal mail) for AMSAT Field Day is Monday, July 16, 2007 at 11:59 P.M. CDT.
73...bruce
Greetings:
I'm finally going through with my tower plans and will have a platform for my satellite antennas that is for the most part above my trees. I'm trying to do a cost/value/reliability comparison for some Yagis. I want to put them up and have them stay up! They need to be high enough performance to work when we get an HEO satellite up again.
I have found the following antennas:
M squared http://www.m2inc.com 436CP42UG 2MCP22
Gulf Alpha http://www.gulfalphaantennas.com/ 70CM-16ELSat 2M-5ELSat
Hy-Gain http://www.hy-gain.com/ UB-7030SAT VB-216SAT
Does Cushcraft http://www.cushcraft.com still make OSCAR antennas?
I am interested comments from any and all experience with these antennas.
I believe there are lots M Squared's out there -- any complaints?
I have the dual band Gulf Alpha, and it is built ultra durable, but I am concerned if the mono band antennas are big enough.
Does anyone have the Hy-Gain antennas? They look like a bargain?
Any others I missed?
Thanks and 73, Joe kk0sd
Joe,
I recently replaced some 20 year old KLMs with M2s. In most ways, the M2 are BMWs and the KLMs are Yugos, though they did a good job. (I need to do a little refurbishing on the KLMs, and will probably have them for sale if I am satisfied with them.) If you get the longer versions of each M2, recommended, be prepared for poorly written documentation with some cut and past from the shorter versions which is simply wrong in one case, and very confusing in others. You can sort it out by phone easily enough, since M2 does not return e-mail or phone messages in my experience. Still, for drawings dated 2000 to be this seriously in error, and not updated, does not speak well for them.
There were also a few parts, sealing rings for the type F connectors, which were missing. However, because I also ordered the CP switches, which had extras, I had enough. Finally, on the 70 cm unit, there are some very tight bends at the connectors for the phasing and switching lines. These need very gentle installation, and some additional water proofing. There is more than enough length on the 2 meter version. I didn't take the same to work it all out, but if they had added a wavelength to a couple of lines, or perhaps .5 wavelength to several, the needed phasing would have been preserved, and there would be no strain on the connectors.
I checked everything I could think of on the ground, and found the SWR, and the change with polarization, much better than with the KLMs. When I got the 2 meter version up, purely as an accident because of the particular SWR meter I use, I found that there was a 1K ohm or so short between the rf and dc switching lines in the 2 meter unit. I ended up opening the switching unit, easy enough, and found two things. First, the dc lead to the switching relay was just barely touching one of the rf leads. It was easy to move the dc lead away, but the problem was highly visible, and should never have been sold that way. Second, there were a couple of places where the rf wiring was connected using solder bridges because the wires were poorly installed. Again, easily fixed, and totally unacceptable for a unit which lists for $201.
The overall impression is an outstanding design, with great attention to detail, spoiled by some mind boggling carelessness in execution of rather small but important things.
Once you get them up and debugged, they really work well. The KLMs had significant side lobes, and it is obvious that the M2s are quite a bit better from that standpoint, though I can't do AB measurements. While I never had any problems getting into AO-7, FO-29 or VO-52 with the KLMs, I have noticed that I need to back off on the TX power significantly more than before to have a socially acceptable signal strength. The same on AO-51 and the other FM birds. Of course, it is nice to be able to crank up the power when shooting through the trees, or when the bandits are on the AO-51 uplink. Now all I need to really test them are some P3 birds.
Alan WA4SCA
Alan, Thanks for the tips. I just ordered both the M2, 2MCP22 and 436CP42UG and figured they will be a bear to construct. Tips are always helpful when traveling uncharted waters:-)
73's RoD KD0XX
A good friend will come and bail you out of jail, A TRUE friend will be sitting next to you saying.....
"DAMN THAT WAS FUN"
-----Original Message----- From: amsat-bb-bounces@amsat.org [mailto:amsat-bb-bounces@amsat.org]On Behalf Of Alan P. Biddle Sent: Thursday, July 05, 2007 4:47 PM To: amsat-bb@amsat.org Subject: [amsat-bb] Re: Yagi Antenna Comparison
Joe,
I recently replaced some 20 year old KLMs with M2s. In most ways, the M2 are BMWs and the KLMs are Yugos, though they did a good job. (I need to do a little refurbishing on the KLMs, and will probably have them for sale if I am satisfied with them.) If you get the longer versions of each M2, recommended, be prepared for poorly written documentation with some cut and past from the shorter versions which is simply wrong in one case, and very confusing in others. You can sort it out by phone easily enough, since M2 does not return e-mail or phone messages in my experience. Still, for drawings dated 2000 to be this seriously in error, and not updated, does not speak well for them.
There were also a few parts, sealing rings for the type F connectors, which were missing. However, because I also ordered the CP switches, which had extras, I had enough. Finally, on the 70 cm unit, there are some very tight bends at the connectors for the phasing and switching lines. These need very gentle installation, and some additional water proofing. There is more than enough length on the 2 meter version. I didn't take the same to work it all out, but if they had added a wavelength to a couple of lines, or perhaps .5 wavelength to several, the needed phasing would have been preserved, and there would be no strain on the connectors.
I checked everything I could think of on the ground, and found the SWR, and the change with polarization, much better than with the KLMs. When I got the 2 meter version up, purely as an accident because of the particular SWR meter I use, I found that there was a 1K ohm or so short between the rf and dc switching lines in the 2 meter unit. I ended up opening the switching unit, easy enough, and found two things. First, the dc lead to the switching relay was just barely touching one of the rf leads. It was easy to move the dc lead away, but the problem was highly visible, and should never have been sold that way. Second, there were a couple of places where the rf wiring was connected using solder bridges because the wires were poorly installed. Again, easily fixed, and totally unacceptable for a unit which lists for $201.
The overall impression is an outstanding design, with great attention to detail, spoiled by some mind boggling carelessness in execution of rather small but important things.
Once you get them up and debugged, they really work well. The KLMs had significant side lobes, and it is obvious that the M2s are quite a bit better from that standpoint, though I can't do AB measurements. While I never had any problems getting into AO-7, FO-29 or VO-52 with the KLMs, I have noticed that I need to back off on the TX power significantly more than before to have a socially acceptable signal strength. The same on AO-51 and the other FM birds. Of course, it is nice to be able to crank up the power when shooting through the trees, or when the bandits are on the AO-51 uplink. Now all I need to really test them are some P3 birds.
Alan WA4SCA
Sent via AMSAT-BB@amsat.org. 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
I have the Gulf Alpha 7x7 70 cm. and 5x5 2M CP satellite antennas, and have no trouble at all working any of the current birds with them. (I see that they now have an 8x8 for 70 cm. instead of the 7x7...) In anticipation of the upcoming HEO birds, I would definitely go with the 16 element CP that you are considering (or more RF).
I seriously doubt that you will find a better-built antenna out there anywhere. Peter's machining of these antennas is first class!
George, KA3HSW
Here's another vote for Gulf Alpha! I've built several of these, and they're great! The elements can be easily removed for storage/transport, and the quality is excellent. I'm going to get one of his 2M/70cm "Dual Band" antennas for Field Day next year. It looks like a larger version of the Arrow, and the extra gain over my eggbeaters will be welcome on Field Day!
73, Jim KQ6EA
--- George Henry ka3hsw@earthlink.net wrote:
I have the Gulf Alpha 7x7 70 cm. and 5x5 2M CP satellite antennas, and have no trouble at all working any of the current birds with them. (I see that they now have an 8x8 for 70 cm. instead of the 7x7...) In anticipation of the upcoming HEO birds, I would definitely go with the 16 element CP that you are considering (or more RF).
I seriously doubt that you will find a better-built antenna out there anywhere. Peter's machining of these antennas is first class!
George, KA3HSW
Sent via AMSAT-BB@amsat.org. 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
Is anyone using these antennas?
Hy-Gain http://www.hy-gain.com/ UB-7030SAT VB-216SAT
What do you think of them?
73, Joe kk0sd Amsat 21357
Hi Joe,
Our UCI CubeSat team (UCISAT) owns both antennas, and the performance has been excellent. A notable use of our 2m beam was when we activated RAFT's radar transponder in a low EL, longshot pass just 3 days before re-entry (http://www.ew.usna.edu/~bruninga/craft/save-raft.html). The combo has worked very well for LEOs, CubeSats, and the ISS. My only gripe is assembly/disassembly of the elements. Each element is secured with lock washers which are difficult (but not impossible) to slide on, and you have to break them off and replace if you need to take the antennas apart for any reason. If you plan to use them for a permanent station, then you just have to worry about the first assembly. If you do pick them up, make sure you take care to line up the elements in the right order before locking down the elements!
Hope that helps. Please let me know if you have any other questions.
73,
Matt Bennett KF6RTB
--- "Gary "Joe" Mayfield" gary_mayfield@hotmail.com wrote:
Is anyone using these antennas?
Hy-Gain http://www.hy-gain.com/ UB-7030SAT VB-216SAT
What do you think of them?
73, Joe kk0sd Amsat 21357
Sent via AMSAT-BB@amsat.org. 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
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participants (7)
-
Alan P. Biddle -
Bruce -
Gary "Joe" Mayfield -
George Henry -
Jim Jerzycke -
Matt Bennett -
Stargate