2 satellite antennas?
I am looking into building 2 omni-directional satellites,just wondering if anyone is familiar with these 2 and can give me their opinions on them? link: http://wb5rmg.somenet.net/k5oe/Eggbeater_2.html http://www.antentop.org/w4rnl.001/turns.html The 2nd link is all can find on it.I have a PDF file I downloaded a while back that has directions on building it.But it's a Turnstile/ moxon and doesn't have the Ground screen. Thanks Rich
On 12/08/20 12:17, [email protected] wrote:
I am looking into building 2 omni-directional satellites,just wondering if anyone is familiar with these 2 and can give me their opinions on them? link:
Hello Rich,
You haven't mentioned which bands, but I assume the pair would be 2m and 70cm.
I've tried the K5OE square eggbeater for 2m and was disappointed. I've found that a "copper cactus" J-Pole (without LNA) for 2m works very well.
An example of reception for the J-Pole: http://www.n0zgo.net/oscar/ao-91.mp4
Are you a member of AMSAT? If so, check out the latest issue (Sep/Oct 2020) of the AMSAT Journal for a 70cm omni-directional solution in the form of 3-D printed antennas.
An example of reception for my 70cm passive Lindenblad design (seek about 7 minutes in for strongest signals): http://www.n0zgo.net/oscar/rs44_20201028_2126Z.mp4
73,
--- Zach N0ZGO
I personally prefer a Lindenblad or quadrafilar helix for an omni antenna. My 2M Lindenblad is approx 10db worse than my Az El tracking CP yagi. If I were relying on an omni, I’d definitely consider using a good GasFET preamp, but ymmv.
73, K4CKB
On Dec 8, 2020, at 4:33 PM, Zach Metzinger [email protected] wrote:
On 12/08/20 12:17, [email protected] wrote: I am looking into building 2 omni-directional satellites,just wondering if anyone is familiar with these 2 and can give me their opinions on them? link:
Hello Rich,
You haven't mentioned which bands, but I assume the pair would be 2m and 70cm.
I've tried the K5OE square eggbeater for 2m and was disappointed. I've found that a "copper cactus" J-Pole (without LNA) for 2m works very well.
An example of reception for the J-Pole: http://www.n0zgo.net/oscar/ao-91.mp4
Are you a member of AMSAT? If so, check out the latest issue (Sep/Oct 2020) of the AMSAT Journal for a 70cm omni-directional solution in the form of 3-D printed antennas.
An example of reception for my 70cm passive Lindenblad design (seek about 7 minutes in for strongest signals): http://www.n0zgo.net/oscar/rs44_20201028_2126Z.mp4
73,
--- Zach N0ZGO
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On 12/08/20 15:54, Chris Busch wrote:
I personally prefer a Lindenblad or quadrafilar helix for an omni antenna. My 2M Lindenblad is approx 10db worse than my Az El tracking CP yagi. If I were relying on an omni, I’d definitely consider using a good GasFET preamp, but ymmv.
Hello Chris,
I haven't attempted the 2m Lindenblad yet, but it's something I'd like to try.
On the LNA front: I'm currently interested in in the Minicircuits PGA103+ device (on W6PQL's page https://tinyurl.com/yyd5mx4b ) for the excellent IIP3. This is an internally-matched E-PHEMT device, much more rugged (and affordable) than GaAsFET devices of the past.
I have a cellphone "watertower" near me, pumping out stuff all over the band, but mostly 600-750 MHz, easily seen as -40dBm signals on a 2m rubber ducky stuck to the front of my spectrum analyzer. Some sort of input filtering, or a crazy-high IIP3 followed by appropriate filtering, is a must at my QTH.
--- Zach N0ZGO
I’ve built a couple of PGA103 preamps using W6PQL board. They work great Sure hard to beat for performance/$. Follow it with a band pass filter if necessary. FWIW there is an optional “stabilizing” circuit shown in his schematic. I highly recommend it. I also run them on 3.3v; hardly any performance difference but they sure run cooler at 50ma vs. 100ma Several years ago, I built four PGA103 amps on my own boards without that stabilization circuit, running 5v@100ma. Heatsinking wasn’t good. Every one died. Round file. But these new ones at lower voltage on a board with much better heat dissipation and the input circuitry are doing just fine. I haven’t done noise figure characterization yet. Gain (at 3.3v) is ~20db.
Ed Krome K9EK
Sent from my iPhone
On Dec 8, 2020, at 5:03 PM, Zach Metzinger [email protected] wrote:
On 12/08/20 15:54, Chris Busch wrote:
I personally prefer a Lindenblad or quadrafilar helix for an omni antenna. My 2M Lindenblad is approx 10db worse than my Az El tracking CP yagi. If I were relying on an omni, I’d definitely consider using a good GasFET preamp, but ymmv.
Hello Chris,
I haven't attempted the 2m Lindenblad yet, but it's something I'd like to try.
On the LNA front: I'm currently interested in in the Minicircuits PGA103+ device (on W6PQL's page https://tinyurl.com/yyd5mx4b ) for the excellent IIP3. This is an internally-matched E-PHEMT device, much more rugged (and affordable) than GaAsFET devices of the past.
I have a cellphone "watertower" near me, pumping out stuff all over the band, but mostly 600-750 MHz, easily seen as -40dBm signals on a 2m rubber ducky stuck to the front of my spectrum analyzer. Some sort of input filtering, or a crazy-high IIP3 followed by appropriate filtering, is a must at my QTH.
--- Zach N0ZGO
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On 12/08/20 17:35, Ed Krome wrote:
I’ve built a couple of PGA103 preamps using W6PQL board. They work great Sure hard to beat for performance/$. Follow it with a band pass filter if necessary. FWIW there is an optional “stabilizing” circuit shown in his schematic. I highly recommend it. I also run them on 3.3v; hardly any performance difference but they sure run cooler at 50ma vs. 100ma Several years ago, I built four PGA103 amps on my own boards without that stabilization circuit, running 5v@100ma. Heatsinking wasn’t good. Every one died. Round file. But these new ones at lower voltage on a board with much better heat dissipation and the input circuitry are doing just fine. I haven’t done noise figure characterization yet. Gain (at 3.3v) is ~20db.
Hello Ed,
Good to know! I have a board for a custom LNA which has coax-powered bias and relays that default to "through" when +12 isn't on the coax.
My 70cm LNA uses this board and the MAX2640 LNA, which requires an input bandpass to knock down the cellular and FM stations. That's followed by a 435 MHz SAW filter, then a MAR-3+ gain block, and finally dual anti-parallel PIN diodes (BAR64) to kill the RF from the rig during TX before the relay switches over. Without the PIN diodes, I killed one SAW filter (before adding gain block) and one MAR-3+ during full break-in CW operation.
I plan to put the PGA103 on this same board, and I'll include the stabilization circuit. Might fire it up on the bench w/o and see if it breaks into oscillation.
--- Zach N0ZGO
I never did figure out whether the root cause of failure was oscillation or thermal. None lasted long enough :-( After the second failure on the tower, I got tired of climbing and roasted the next 2 on the bench. I ran all at 5v; slow learner, I guess. Boy, did they get hot. Go with the 3.3v through the speced 22 ohm resistor. Only .165w versus .5w and the performance difference is trivial. BTW I did the bias-T thing with these new ones. No detectable gain difference.
Ed Krome K9EK
Sent from my iPhone
On Dec 8, 2020, at 7:33 PM, Zach Metzinger [email protected] wrote:
On 12/08/20 17:35, Ed Krome wrote:
I’ve built a couple of PGA103 preamps using W6PQL board. They work great Sure hard to beat for performance/$. Follow it with a band pass filter if necessary. FWIW there is an optional “stabilizing” circuit shown in his schematic. I highly recommend it. I also run them on 3.3v; hardly any performance difference but they sure run cooler at 50ma vs. 100ma Several years ago, I built four PGA103 amps on my own boards without that stabilization circuit, running 5v@100ma. Heatsinking wasn’t good. Every one died. Round file. But these new ones at lower voltage on a board with much better heat dissipation and the input circuitry are doing just fine. I haven’t done noise figure characterization yet. Gain (at 3.3v) is ~20db.
Hello Ed,
Good to know! I have a board for a custom LNA which has coax-powered bias and relays that default to "through" when +12 isn't on the coax.
My 70cm LNA uses this board and the MAX2640 LNA, which requires an input bandpass to knock down the cellular and FM stations. That's followed by a 435 MHz SAW filter, then a MAR-3+ gain block, and finally dual anti-parallel PIN diodes (BAR64) to kill the RF from the rig during TX before the relay switches over. Without the PIN diodes, I killed one SAW filter (before adding gain block) and one MAR-3+ during full break-in CW operation.
I plan to put the PGA103 on this same board, and I'll include the stabilization circuit. Might fire it up on the bench w/o and see if it breaks into oscillation.
--- Zach N0ZGO
AMSAT-BB mailing list -- [email protected] View archives of this mailing list at https://mailman.amsat.org/hyperkitty/list/[email protected] To unsubscribe send an email to [email protected] Manage all of your AMSAT-NA mailing list preferences at https://mailman.amsat.org
I’ve been using a homebrew Lindenblad with PGA103 broadband preamp for a few months now. I also run a 5-el (homebrew from DG7YBN design) yagi with preamp on an az-only rotator. There appears to be ~6 dB difference in signal strength, but the Lindenblad gets from 65 to as much as 90% of the number of frames from the yagi over a 24 hour period. I think that is quite good. Of course performance varies with sat elevation. Each feeds a separate FCDP+ to an RP3B, running FIAB. Each combination has been tested for very similar decoding characteristics. This is a fairly rf-quiet area, so broadband preamp is ok. I used to use the the FCD-RP3 setup on a 137 WXSAT QFH with a fairly narrow band preamp (but it is really good on WXSAT; good pics at ~1 degree elevation). It was much worse than the lindenblad of foxtelem. But better than nothing! Haven’t tried J pole. Yet.
Ed Krome K9EK
Sent from my iPhone
On Dec 8, 2020, at 4:34 PM, Zach Metzinger [email protected] wrote:
On 12/08/20 12:17, [email protected] wrote:
I am looking into building 2 omni-directional satellites,just wondering if anyone is familiar with these 2 and can give me their opinions on them? link:
Hello Rich,
You haven't mentioned which bands, but I assume the pair would be 2m and 70cm.
I've tried the K5OE square eggbeater for 2m and was disappointed. I've found that a "copper cactus" J-Pole (without LNA) for 2m works very well.
An example of reception for the J-Pole: http://www.n0zgo.net/oscar/ao-91.mp4
Are you a member of AMSAT? If so, check out the latest issue (Sep/Oct 2020) of the AMSAT Journal for a 70cm omni-directional solution in the form of 3-D printed antennas.
An example of reception for my 70cm passive Lindenblad design (seek about 7 minutes in for strongest signals): http://www.n0zgo.net/oscar/rs44_20201028_2126Z.mp4
73,
--- Zach N0ZGO
AMSAT-BB mailing list -- [email protected] View archives of this mailing list at https://mailman.amsat.org/hyperkitty/list/[email protected] To unsubscribe send an email to [email protected] Manage all of your AMSAT-NA mailing list preferences at https://mailman.amsat.org
Thanks for the posts.Zack I am a member.I will check out that issue.I checked out the recordings and my Cushcraft 2 bander did pretty good,Not quite as nice as the Jpole but now I have some issues.Since I added a mast for my dipole which is about 2 feet next to it,my signals have been almost impossible to hear.I assume it must be the mast effect the pattern of the vertical? Rich
participants (4)
-
Chris Busch -
Ed Krome -
marzo7088＠yahoo.com -
Zach Metzinger