Has AO-85 finally bit the dust?
Last heard report was almost 2 days ago. Before that, the downlink frequency was wobbling +- 5-10 kHz.
Ron W5RKN
Hi Ron,
Many of those reports of nothing heard are when it is in darkness, which is expected. However there are also daylight reports from seasoned operators of the same. Speaking unofficially, AO-85 appears to be on its last legs. The last telemetry was from ZL1WN on the 12th. Ross is in an ideal location with long periods of illumination and few users, allowing the batteries to recover as much as possible. I have copied passes as recently as the 25th where the analog COR mode was working perfectly. Other passes, it was not possible to bring it up at all. With the very marginal power levels, no telling what mode, including off, it might be in. :) It has surprised us in the past, however, so keep watching it.
73,
Alan WA4SCA
<-----Original Message----- <From: AMSAT-BB [mailto:[email protected]] On Behalf Of Ronald <Parsons via AMSAT-BB <Sent: Saturday, December 28, 2019 3:08 PM <To: amsat-bb [email protected] <Subject: [amsat-bb] Has AO-85 finally bit the dust? < < Last heard report was almost 2 days ago. Before that, the downlink <frequency was wobbling < +- 5-10 kHz. < <Ron W5RKN <_______________________________________________ <Sent via [email protected]. 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: https://www.amsat.org/mailman/listinfo/amsat-bb
Ron,
Commands were sent yesterday to re-enable the repeater, with no results. It's likely the batteries have deteriorated far enough the transmitter will not work. We'll keep trying for a while before any sort of announcement, but to be honest, the satellite has been on borrowed time for a while. Please keep listening to signals and telemetry for the time being.
73, Drew KO4MA AMSAT VP Operations
-----Original Message----- From: AMSAT-BB [email protected] On Behalf Of Ronald Parsons via AMSAT-BB Sent: Saturday, December 28, 2019 4:08 PM To: amsat-bb [email protected] Subject: [amsat-bb] Has AO-85 finally bit the dust?
Last heard report was almost 2 days ago. Before that, the downlink frequency was wobbling +- 5-10 kHz.
Ron W5RKN _______________________________________________ Sent via [email protected]. 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: https://www.amsat.org/mailman/listinfo/amsat-bb
I'm trying to understand, under what circumstances is a non-conductive mast necessary at VHF/UHF frequencies. Thinking of the following installs.
1. Circular polarized antenna mounted to the mast at the center of the boom. This is clear, see this advice all the time, fiberglass mast.
2. Same antenna but mounted at the rear end of the boom.
3. Vertical Yagi, elements parallel to a vertical mast, mounted at the center of the boom. I guess, non-conductive wold be required here.
4. Same antenna but rear mounted.
5. Horizontal Yagi, elements perpendicular to a vertical mast, mounted at the center of the boom. I think this is pretty normal install, so a conductive mast would be okay?
6. Same antenna but mounted at the rear of the boom.
The short answer is almost never. Here is a link to an AMSAT Symposium paper form antenna guru Kent Britain, wa5vjb (inventor of the famous cheap yagis). He actually measured the effects. http://www.kk0sd.net/metalboom/metalboom.htm
73, Joe kk0sd
-----Original Message----- From: AMSAT-BB [email protected] On Behalf Of Cathryn Mataga via AMSAT-BB Sent: Monday, December 30, 2019 3:27 PM To: [email protected] Subject: [amsat-bb] When exactly is a non-conductive mast necessary?
I'm trying to understand, under what circumstances is a non-conductive mast necessary at VHF/UHF frequencies. Thinking of the following installs.
1. Circular polarized antenna mounted to the mast at the center of the boom. This is clear, see this advice all the time, fiberglass mast.
2. Same antenna but mounted at the rear end of the boom.
3. Vertical Yagi, elements parallel to a vertical mast, mounted at the center of the boom. I guess, non-conductive wold be required here.
4. Same antenna but rear mounted.
5. Horizontal Yagi, elements perpendicular to a vertical mast, mounted at the center of the boom. I think this is pretty normal install, so a conductive mast would be okay?
6. Same antenna but mounted at the rear of the boom.
_______________________________________________ Sent via [email protected]. 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: https://www.amsat.org/mailman/listinfo/amsat-bb
In addition, a general rule is that anything behind the reflector element doesn't exist from the antenna's perspective. You can use this to remove all the ground effects when adjusting an antenna for SWR, etc. by aiming it straight up.
Greg KO6TH
Gary via AMSAT-BB wrote:
The short answer is almost never. Here is a link to an AMSAT Symposium paper form antenna guru Kent Britain, wa5vjb (inventor of the famous cheap yagis). He actually measured the effects. http://www.kk0sd.net/metalboom/metalboom.htm
73, Joe kk0sd
-----Original Message----- From: AMSAT-BB [email protected] On Behalf Of Cathryn Mataga via AMSAT-BB Sent: Monday, December 30, 2019 3:27 PM To: [email protected] Subject: [amsat-bb] When exactly is a non-conductive mast necessary?
I'm trying to understand, under what circumstances is a non-conductive mast necessary at VHF/UHF frequencies. Thinking of the following installs.
Circular polarized antenna mounted to the mast at the center of the boom. This is clear, see this advice all the time, fiberglass mast.
Same antenna but mounted at the rear end of the boom.
Vertical Yagi, elements parallel to a vertical mast, mounted at the center of the boom. I guess, non-conductive wold be required here.
Same antenna but rear mounted.
Horizontal Yagi, elements perpendicular to a vertical mast, mounted at the center of the boom. I think this is pretty normal install, so a conductive mast would be okay?
Same antenna but mounted at the rear of the boom.
Sent via [email protected]. 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: https://www.amsat.org/mailman/listinfo/amsat-bb _______________________________________________ Sent via [email protected]. 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: https://www.amsat.org/mailman/listinfo/amsat-bb
Oh, thanks guys. This is eye-opening. It looks like even circular polarized antennas will work with metal masts, if you rotate them 45 degrees.
On 12/30/2019 2:31 PM, Gary wrote:
The short answer is almost never. Here is a link to an AMSAT Symposium paper form antenna guru Kent Britain, wa5vjb (inventor of the famous cheap yagis). He actually measured the effects. http://www.kk0sd.net/metalboom/metalboom.htm
73, Joe kk0sd
-----Original Message----- From: AMSAT-BB [email protected] On Behalf Of Cathryn Mataga via AMSAT-BB Sent: Monday, December 30, 2019 3:27 PM To: [email protected] Subject: [amsat-bb] When exactly is a non-conductive mast necessary?
I'm trying to understand, under what circumstances is a non-conductive mast necessary at VHF/UHF frequencies. Thinking of the following installs.
1. Circular polarized antenna mounted to the mast at the center of the boom. This is clear, see this advice all the time, fiberglass mast.
- Same antenna but mounted at the rear end of the boom.
3. Vertical Yagi, elements parallel to a vertical mast, mounted at the center of the boom. I guess, non-conductive wold be required here.
4. Same antenna but rear mounted.
5. Horizontal Yagi, elements perpendicular to a vertical mast, mounted at the center of the boom. I think this is pretty normal install, so a conductive mast would be okay?
- Same antenna but mounted at the rear of the boom.
Sent via [email protected]. 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: https://www.amsat.org/mailman/listinfo/amsat-bb
Cathryn,
And if you pay attention to all of the caveats in his paper. One saving grace about all of this is it is not EME. If you were working with 250 +/- dB path loss and a passive reflector like the moon you might come to a different conclusion. Just be careful of all of the those 1/2 wavelengths and 1 wavelengths that he speaks about. Especially for the 70 cm uplinks as that isn't very many inches.
The other thing I have seen folks trip over is coax selection. Satellites are not the place to be using RG-8X. Others may have other thoughts I think you are looking at LMR400 or its equivalent or better if it is a permanent installation.
John
On Mon, Dec 30, 2019 at 7:57 PM Cathryn Mataga via AMSAT-BB < [email protected]> wrote:
Oh, thanks guys. This is eye-opening. It looks like even circular polarized antennas will work with metal masts, if you rotate them 45 degrees.
On 12/30/2019 2:31 PM, Gary wrote:
The short answer is almost never. Here is a link to an AMSAT Symposium
paper form antenna guru Kent Britain, wa5vjb (inventor of the famous cheap yagis). He actually measured the effects.
http://www.kk0sd.net/metalboom/metalboom.htm
73, Joe kk0sd
-----Original Message----- From: AMSAT-BB [email protected] On Behalf Of Cathryn Mataga
via AMSAT-BB
Sent: Monday, December 30, 2019 3:27 PM To: [email protected] Subject: [amsat-bb] When exactly is a non-conductive mast necessary?
I'm trying to understand, under what circumstances is a non-conductive
mast necessary at VHF/UHF frequencies. Thinking of the following installs.
- Circular polarized antenna mounted to the mast at the center of the
boom. This is clear, see this advice all the time, fiberglass mast.
Same antenna but mounted at the rear end of the boom.
Vertical Yagi, elements parallel to a vertical mast, mounted at the
center of the boom. I guess, non-conductive wold be required here.
Same antenna but rear mounted.
Horizontal Yagi, elements perpendicular to a vertical mast, mounted
at the center of the boom. I think this is pretty normal install, so a conductive mast would be okay?
- Same antenna but mounted at the rear of the boom.
Sent via [email protected]. 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: https://www.amsat.org/mailman/listinfo/amsat-bb
Sent via [email protected]. 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: https://www.amsat.org/mailman/listinfo/amsat-bb
I used a copper boom for many years. The antennas were oriented in an "X" pattern. The vertical mast was aluminum. Several thousand satellite contacts later, what can I say? If it works, use it. Have a polarization switch on 70cm. You need it. And yes, pay attention to connectors and coax!
Andy W5ACM
-----Original Message----- From: AMSAT-BB [mailto:[email protected]] On Behalf Of John Kludt via AMSAT-BB Sent: Monday, December 30, 2019 8:21 PM To: Cathryn Mataga [email protected] Cc: [email protected] Subject: Re: [amsat-bb] When exactly is a non-conductive mast necessary?
Cathryn,
And if you pay attention to all of the caveats in his paper. One saving grace about all of this is it is not EME. If you were working with 250 +/- dB path loss and a passive reflector like the moon you might come to a different conclusion. Just be careful of all of the those 1/2 wavelengths and 1 wavelengths that he speaks about. Especially for the 70 cm uplinks as that isn't very many inches.
The other thing I have seen folks trip over is coax selection. Satellites are not the place to be using RG-8X. Others may have other thoughts I think you are looking at LMR400 or its equivalent or better if it is a permanent installation.
John
On Mon, Dec 30, 2019 at 7:57 PM Cathryn Mataga via AMSAT-BB < [email protected]> wrote:
Oh, thanks guys. This is eye-opening. It looks like even circular polarized antennas will work with metal masts, if you rotate them 45 degrees.
On 12/30/2019 2:31 PM, Gary wrote:
The short answer is almost never. Here is a link to an AMSAT Symposium
paper form antenna guru Kent Britain, wa5vjb (inventor of the famous cheap yagis). He actually measured the effects.
http://www.kk0sd.net/metalboom/metalboom.htm
73, Joe kk0sd
-----Original Message----- From: AMSAT-BB [email protected] On Behalf Of Cathryn Mataga
via AMSAT-BB
Sent: Monday, December 30, 2019 3:27 PM To: [email protected] Subject: [amsat-bb] When exactly is a non-conductive mast necessary?
I'm trying to understand, under what circumstances is a non-conductive
mast necessary at VHF/UHF frequencies. Thinking of the following installs.
- Circular polarized antenna mounted to the mast at the center of
the
boom. This is clear, see this advice all the time, fiberglass mast.
Same antenna but mounted at the rear end of the boom.
Vertical Yagi, elements parallel to a vertical mast, mounted at
the
center of the boom. I guess, non-conductive wold be required here.
Same antenna but rear mounted.
Horizontal Yagi, elements perpendicular to a vertical mast,
mounted
at the center of the boom. I think this is pretty normal install, so a conductive mast would be okay?
- Same antenna but mounted at the rear of the boom.
Sent via [email protected]. 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: https://www.amsat.org/mailman/listinfo/amsat-bb
Sent via [email protected]. 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: https://www.amsat.org/mailman/listinfo/amsat-bb
_______________________________________________ Sent via [email protected]. 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: https://www.amsat.org/mailman/listinfo/amsat-bb
On 2019-12-31 12:00 a.m., Andy via AMSAT-BB wrote:
I used a copper boom for many years. The antennas were oriented in an "X" pattern.
Same here. Run coax along boom too. Been like that since ???forever. Installed my Crushcraft pair like that when I purchased them in 80's and still working today.
Cathryn,
I am going to bow out of this discussion. I thought you had asked a question based on physics but that is clearly not where the discussion is going. The current satellites are actually very forgiving. Like a friend of mine likes to say, "If your SWR is less than 10:1 - call CQ!" There is a long tradition in Amateur Radio of doing whatever works. Maybe not the best electrical engineering effort, maybe not even close, but if it works, what the heck.
Happy New Year and I hope to see you on the birds.
73,
John
On Tue, Dec 31, 2019 at 9:03 AM Bill Booth via AMSAT-BB [email protected] wrote:
On 2019-12-31 12:00 a.m., Andy via AMSAT-BB wrote:
I used a copper boom for many years. The antennas were oriented in an "X" pattern.
Same here. Run coax along boom too. Been like that since ???forever. Installed my Crushcraft pair like that when I purchased them in 80's and still working today.
-- Bill Booth VE3NXK Sundridge ON, Canada 79.23.37 W x 45.46.18 N FN05ns
Visit my weather WebCam at http://www.almaguin.com/wxcurrent/weather.html
Organ and Tissue Donation - The Gift of Life Talk to your family. Your decision can make a difference. _______________________________________________ Sent via [email protected]. 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: https://www.amsat.org/mailman/listinfo/amsat-bb
You've received some excellent information with that link to Kent's articles.
In regard to coax selection (not what you asked about, but some input you received), "better is always better", but the question becomes, "How much better?" The answer is in the math. If running the FM satellites from an HT and your coax is 3' from HT to antenna, using RG8x will result in 0.3 dB of attenuation at 70cm. Using LMR-400 will be "better" at "only" 0.1 dB. In the real world, the 0.2 dB difference is indistinguishable.
My point is not to contradict John's statement. It is to add perspective and a pathway to allow you to decide what is best for your usage. Cheers,Ev, W2EV https://www.timesmicrowave.com/Calculator
On Monday, December 30, 2019, 9:26:47 PM EST, John Kludt via AMSAT-BB [email protected] wrote:
Cathryn,
And if you pay attention to all of the caveats in his paper. One saving grace about all of this is it is not EME. If you were working with 250 +/- dB path loss and a passive reflector like the moon you might come to a different conclusion. Just be careful of all of the those 1/2 wavelengths and 1 wavelengths that he speaks about. Especially for the 70 cm uplinks as that isn't very many inches.
The other thing I have seen folks trip over is coax selection. Satellites are not the place to be using RG-8X. Others may have other thoughts I think you are looking at LMR400 or its equivalent or better if it is a permanent installation.
John
On Mon, Dec 30, 2019 at 7:57 PM Cathryn Mataga via AMSAT-BB < [email protected]> wrote:
Oh, thanks guys. This is eye-opening. It looks like even circular polarized antennas will work with metal masts, if you rotate them 45 degrees.
On 12/30/2019 2:31 PM, Gary wrote:
The short answer is almost never. Here is a link to an AMSAT Symposium
paper form antenna guru Kent Britain, wa5vjb (inventor of the famous cheap yagis). He actually measured the effects.
http://www.kk0sd.net/metalboom/metalboom.htm
73, Joe kk0sd
-----Original Message----- From: AMSAT-BB [email protected] On Behalf Of Cathryn Mataga
via AMSAT-BB
Sent: Monday, December 30, 2019 3:27 PM To: [email protected] Subject: [amsat-bb] When exactly is a non-conductive mast necessary?
I'm trying to understand, under what circumstances is a non-conductive
mast necessary at VHF/UHF frequencies. Thinking of the following installs.
1. Circular polarized antenna mounted to the mast at the center of the
boom. This is clear, see this advice all the time, fiberglass mast.
- Same antenna but mounted at the rear end of the boom.
3. Vertical Yagi, elements parallel to a vertical mast, mounted at the
center of the boom. I guess, non-conductive wold be required here.
4. Same antenna but rear mounted.
5. Horizontal Yagi, elements perpendicular to a vertical mast, mounted
at the center of the boom. I think this is pretty normal install, so a conductive mast would be okay?
- Same antenna but mounted at the rear of the boom.
Sent via [email protected]. 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: https://www.amsat.org/mailman/listinfo/amsat-bb
Sent via [email protected]. 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: https://www.amsat.org/mailman/listinfo/amsat-bb
_______________________________________________ Sent via [email protected]. 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: https://www.amsat.org/mailman/listinfo/amsat-bb
On 2019-12-30 20:20, John Kludt via AMSAT-BB wrote:
The other thing I have seen folks trip over is coax selection. Satellites are not the place to be using RG-8X. Others may have other thoughts I think you are looking at LMR400 or its equivalent or better if it is a permanent installation.
I'll chime in with my usual "it depends" statement: Spending a bunch of money on coax and neglecting a good LNA located _at the antenna_ is a shame.
If you have a big spool of RG-8X (or even RG-8) and some few dollars for a preamp (LNA), go for the preamp! 100' of LMR400 has a loss of 2.7dB at 70cm. Without a preamp, you now have an instant 2.7dB (or worse) noise figure, even before you get to the radio's front-end, and you've spent 3x on coax.
Yes, RG-8X loss at 70cm is 8.1dB, which means your radio's 100W signal is only ~15W at the antenna, but that's more than enough to reach a satellite before antenna directional gain is accounted for.
One can always make more TX power (and today's radios are overpowered anyway), but one can never recover signals already lost.
A prototypical LNA for 20 EUR ($22 USD) at http://lna4all.blogspot.com/, and a determined amateur can construct one for less.
Back to building..
--- Zach N0ZGO
On 2019-12-31 05:54, Zach Metzinger via AMSAT-BB wrote:
A prototypical LNA for 20 EUR ($22 USD) at http://lna4all.blogspot.com/, > and a determined amateur can construct one for less.
Following up on this a bit, PA3CSG's web page has a 70cm antenna switch built with cheap relays you might find in consumer electronics:
https://pa3csg.nl/?page_id=1114
This design could easily be combined with the LNA4ALL design into an inexpensive, DC-switched system capable of handling significant power.
--- Zach N0ZGO
I'm sorry - that's way too general of an answer to be accurate. Physics says it's impossible to stick a significant piece of metal in the near field of an antenna and NOT have an effect! The only valid question is HOW MUCH OF AN EFFECT THERE WILL BE!
7 3 Jeff Moore -- KE7ACY CN94
On Mon, Dec 30, 2019 at 2:32 PM Gary via AMSAT-BB [email protected] wrote:
The short answer is almost never. Here is a link to an AMSAT Symposium paper form antenna guru Kent Britain, wa5vjb (inventor of the famous cheap yagis). He actually measured the effects. http://www.kk0sd.net/metalboom/metalboom.htm
73, Joe kk0sd
-----Original Message----- From: AMSAT-BB [email protected] On Behalf Of Cathryn Mataga via AMSAT-BB Sent: Monday, December 30, 2019 3:27 PM To: [email protected] Subject: [amsat-bb] When exactly is a non-conductive mast necessary?
I'm trying to understand, under what circumstances is a non-conductive mast necessary at VHF/UHF frequencies. Thinking of the following installs.
- Circular polarized antenna mounted to the mast at the center of the
boom. This is clear, see this advice all the time, fiberglass mast.
Same antenna but mounted at the rear end of the boom.
Vertical Yagi, elements parallel to a vertical mast, mounted at the
center of the boom. I guess, non-conductive wold be required here.
Same antenna but rear mounted.
Horizontal Yagi, elements perpendicular to a vertical mast, mounted at
the center of the boom. I think this is pretty normal install, so a conductive mast would be okay?
- Same antenna but mounted at the rear of the boom.
Sent via [email protected]. 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: https://www.amsat.org/mailman/listinfo/amsat-bb _______________________________________________ Sent via [email protected]. 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: https://www.amsat.org/mailman/listinfo/amsat-bb
participants (12)
-
Alan -
Andrew Glasbrenner -
Andy -
Bill Booth -
Cathryn Mataga -
Ev Tupis -
Gary -
Greg D -
Jeff Moore -
John Kludt -
Ronald Parsons -
Zach Metzinger