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CX2SA > SATDIG 16.12.18 03:04l 920 Lines 32803 Bytes #999 (0) @ WW
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From: CX2SA@CX2SA.SAL.URY.SOAM
To : SATDIG@WW
Today's Topics:
1. Re: AO-73 TLM Signal Changed? (JoAnne Maenpaa)
2. Re: Antenna separation on crossboom (Jean Marc Momple)
3. Re: AO-73 TLM Signal Changed? (Hasan al-Basri)
4. Re: Icom IC-9700 in January 2019 (Mail)
5. Re: Antenna separation on crossboom (Jim White)
6. Re: Antenna separation on crossboom (Jean Marc Momple)
7. Re: Antenna separation on crossboom (Jean Marc Momple)
8. Re: Antenna separation on crossboom (Bob Hammond)
----------------------------------------------------------------------
Message: 1
Date: Sat, 15 Dec 2018 09:29:00 -0600
From: "JoAnne Maenpaa" <k9jkm@???????.???>
To: "'Hasan al-Basri'" <hbasri.schiers6@?????.???>
Cc: amsat-bb@?????.???
Subject: Re: [amsat-bb] AO-73 TLM Signal Changed?
Message-ID: <003801d4948a$e7902bd0$b6b08370$@???>
Content-Type: text/plain; charset="us-ascii"
Nayif-1 EO-88 has a strong FUNcube style beacon also. The Nayif dashboard
works like the one for AO-73.
Nayif-1: . 145.940 MHz 1200 bps BPSK FUNcube beacon ~400 mW
What works at my station is I start around 145.941 MHz at AOS and follow the
Doppler downward during the pass.
--
73 de JoAnne K9JKM
k9jkm@?????.???
------------------------------
Message: 2
Date: Sat, 15 Dec 2018 19:44:30 +0400
From: Jean Marc Momple <jean.marc.momple@?????.???>
To: Bob Hammond <propgrinder@?????.???>
Cc: AMSAT <amsat-bb@?????.???>
Subject: Re: [amsat-bb] Antenna separation on crossboom
Message-ID: <ADFE761F-7FB7-46E1-A1CD-8973DE3F4A2F@?????.???>
Content-Type: text/plain; charset=utf-8
Bob,
So that all may fully understand:
Most LEO?s use monopoles or dipoles (on VHF/UHF) which are actually linear
and not circular polarization, but the birds are spinning and tumbling
therefore the polarization can be H, V or any angle. If you use H or V pole
at the ground station the fading may be as high at 30dB therefore it is
recommended to use circular polarization at the ground station as maximum
fade would be around 3 dB whatever the satellite polarization may be.
I suggest that you use RHCP without polarisation switch, except if you wish
to spend some money to experiment with same. I have the possibility to
switch polarization but it is not used at all.
Hope this help.
73
Jean Marc (3B8DU)
> On Dec 15, 2018, at 1:40 AM, Mark D. Johns <mjohns+K0JM@??????.???> wrote:
>
> On Fri, Dec 14, 2018 at 10:58 AM Bob Hammond <propgrinder@?????.???>
> wrote:
>
>>> Do you use polarity switches on your yagis? If you do, is it worth
> the effort?
>
> No and no.
>
> I had polarity switching on long yagis back in AO-10 & AO-13 days and it
> was helpful. But for the LEO satellites we have now, it's rare to have a
> fade so deep that one can't copy.
> --
> Mark D. Johns
> K?JM / M?GZO / ex-9H3DJ / ex-K?MDJ
> Brooklyn Park, MN USA EN35hd
> -----------------------------------------------
> "Heaven goes by favor; if it went by merit,
> you would stay out and your dog would go in."
> ---Mark Twain
>
>
>
> Greg,
>>
>>
>> 73s,
>>
>> Bob
>> W7OTJ
>>
>> On Mon, Nov 26, 2018 at 10:08 AM Greg D <ko6th.greg@?????.???> wrote:
>>
>>> That's pretty much what I did, though with different antennas. Also put
>>> the AO-40 dish on the other side of the rotor from the 23cm helix, so it
>>> went 70cm, 2.4gig, rotor, 23cm, 2m. Put things as far away from each
>>> other as you can, without running out of crossboom.
>>>
>>> I was very concerned about having the 70cm beam (uplink) so close -
>>> inches - to the 2.4 ghz dish (downlink), but it was fine. Good input
>>> filtering in the 2.4 ghz Khune preamp, I guess. More recently, Mode L/v
>>> on AO-92 seems ok too, with the 23cm antenna near the 2m, but I have a
>>> lot less power on 23cm than I did with AO-40 on 70cm.
>>>
>>> Greg KO6TH
>>>
>>>
>>> Bob Hammond wrote:
>>>> I'm putting the following antennas on an 8-foot fiberglass crossboom:
>>>>
>>>> M2 2MCP8A, 143-148 MHz C{
>>>> Gulf Alpha 70cm 8x8 CP
>>>> WiMo Helix 23
>>>>
>>>> I'm not sure how to calculate the proper spacing on the crossboom. I
>>>> assume the 2m antenna should go on one end and the 70cm antenna on the
>>>> opposite end. Can I mount the 23cm helical antenna very near the
>> rotator
>>>> without harm since it has the solid reflector behind the helix?
>>>>
>>>> Bob
>>>> W7OTJ
>>>> (was WL7CQX)
>>>> _______________________________________________
>>>> Sent via AMSAT-BB@?????.???. 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
>>>
>>>
>> _______________________________________________
>> Sent via AMSAT-BB@?????.???. 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
>>
> _______________________________________________
> Sent via AMSAT-BB@?????.???. 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
------------------------------
Message: 3
Date: Sat, 15 Dec 2018 09:58:44 -0600
From: Hasan al-Basri <hbasri.schiers6@?????.???>
To: David Johnson <dave@?????.??.??>
Cc: amsat-bb@?????.???
Subject: Re: [amsat-bb] AO-73 TLM Signal Changed?
Message-ID:
<CAM4UQf1Ci9T=1ftScJrTwKi2a1tGnF5OWiov2-uSDFKHMSMLCw@????.?????.???>
Content-Type: text/plain; charset="UTF-8"
David,
Was able to work CW thru AO-73 at EL of 2 deg wiht my X200 collinear.
Tnx info, 73 N0AN
Hasan
On Sat, Dec 15, 2018 at 9:00 AM David Johnson <dave@?????.??.??> wrote:
> Hi,
>
> FC1 has been placed into transponder mode for the holiday season.
>
> 73
>
> Dave, G4DPZ
>
------------------------------
Message: 4
Date: Sat, 15 Dec 2018 11:05:42 -0500
From: Mail <nm3a@????.???>
To: "kb2mjeff@???.???? <kb2m@????.???>
Cc: amsat-bb@?????.???
Subject: Re: [amsat-bb] Icom IC-9700 in January 2019
Message-ID: <4116E381-CD59-4A26-9AEF-F5702FEEA526@????.???>
Content-Type: text/plain; charset=utf-8
If I had a 9100... but I don?t, so I?m going for the 9700. Wish me good luck!
Dan
Sent from here. NM3A
> On Dec 15, 2018, at 09:49, <kb2mjeff@???.???> <kb2mjeff@???.???> wrote:
>
> Probably before most everyone on here's time but the 847 had a very big
problem with the first batch requiring it to be send back to Yaesu to fix.
The first batch had a problem with the RS-232 port not working properly. I'm
glad I waited, then ordered after that was resolved. I remember testing the
radio at HRO to make sure the serial port worked before buying it :-)
> So, yes I will also be waiting for a bit before ordering mine. My Flex
VU5K, and Icom 9100 are doing just fine for the time being...
>
> 73 Jeff kb2m
>
> -----Original Message----- From: H. Stephen Nipper
> Sent: Friday, December 14, 2018 8:41 PM
> To: Kevin Schuchmann
> Cc: amsat-bb@?????.???
> Subject: Re: [amsat-bb] Icom IC-9700 in January 2019
>
> I have had the VAPORS for one ever since they were announced. Its not that
> I couldn't order one, but in the past when I order a new radio in 6 months
> the new A or D version came out, and mine never did have all of the
> features of that newer radio. That happened with my Tand R 599 Kenwood
> Twins, IC-737, my Ft100, FTDX3000. Need I go one.
>
> I am going to wait until they get all of the field mods done, and the list
> of people on the waiting list goes away and the price goes down. My Ft-847
> is working just fine.
>
> So all you that are going to do the trouble shooting on my next radio, I
> thank you in advance.
>
>
>
>> On Fri, Dec 14, 2018, 6:17 PM Kevin <wa7fwf@?????.??? wrote:
>>
>> I have been on the reserve list from day one based mostly on the fact of
>> how well my 7300 works, If the 9700 performs as well it will be light
>> years ahead of my 9100.
>>
>> 73, Kevin WA7FWF
>>
>> On 12/14/2018 3:13 PM, John Brier wrote:
>> > The Icom IC-9700 will be released in January 2019 in Japan for 188,000
>> > yen ($1,657 USD).
>> >
>> > "Delivery times may vary, depending on the country or region." "The
>> > IC-9700 is the perfect side-by-side companion to the IC-7300 HF radio.
>> > They are the same size and have almost identical ergonomics. Using the
>> > IC-9700 and IC-7300 creates an ideal, compact radio station covering
>> > the HF, 144, 430 and 1200 MHz bands."
>> >
>> > https://qrznow.com/ic-9700-new-release/
>> >
>> > Who is getting one? :-)
>> >
>> > 73, John Brier KG4AKV
>
>
> ---
> This email has been checked for viruses by AVG.
> https://www.avg.com
>
> _______________________________________________
> Sent via AMSAT-BB@?????.???. 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
------------------------------
Message: 5
Date: Sat, 15 Dec 2018 09:09:40 -0700
From: Jim White <jim@?????????????????.???>
To: amsat-bb@?????.???
Subject: Re: [amsat-bb] Antenna separation on crossboom
Message-ID:
<1e3321ba-9e89-7476-9478-1bfc98c22c34@?????????????????.???>
Content-Type: text/plain; charset=utf-8; format=flowed
I would add to this that there is one workhorse satellite on orbit that
is circular and changes with location.? In the northern hemisphere FO-29
is RHCP when to the south of the station and LHCP when to the north.? It
makes a very large difference.
In addition, while cubesats of the 1U to 3U size typically use a whip
(linear) because there isn't real estate for anything circular, for 6U
and larger a canted turnstile is a better choice and is circular.? In
that case they are typically wired for RHCP when the antenna ends faces
earth but if it tumbles or flips the sense will change.? When facing
away it will be LHCP to the ground station.
This question has been rattling around for at least since the 1990
AMSAT-NA microsats (which were canted turnstiles on the UHF downlink).?
For those satellites the downlink was RCHP in the northern hemisphere
and LCHP in the southern, except for LO-19 which was reversed.? I wrote
a paper on this for the 1991 AMSAT Space Sympoisum (or it might have
been 1992).? So I tend to suggest that folks just getting started with a
hand held antenna a linear antenna is fine because they are a bit
lighter and less cumbersome to handle, and less expensive.? But if you
are building a fixed "base" station I still suggest including sense
switching. It will make a large difference with FO29 and you will be
ready for the next one that uses circular.? Given there are probably 100
in various stages of design and construction and rides are plentiful it
seems worth the investment.
Jim
Jim White, WD0E
jim@?????????????????.???
On 12/15/2018 8:44 AM, Jean Marc Momple wrote:
> Bob,
>
> So that all may fully understand:
>
> Most LEO?s use monopoles or dipoles (on VHF/UHF) which are actually linear
and not circular polarization, but the birds are spinning and tumbling
therefore the polarization can be H, V or any angle. If you use H or V pole
at the ground station the fading may be as high at 30dB therefore it is
recommended to use circular polarization at the ground station as maximum
fade would be around 3 dB whatever the satellite polarization may be.
>
> I suggest that you use RHCP without polarisation switch, except if you
wish to spend some money to experiment with same. I have the possibility to
switch polarization but it is not used at all.
>
> Hope this help.
>
> 73
>
>
> Jean Marc (3B8DU)
>
>> On Dec 15, 2018, at 1:40 AM, Mark D. Johns <mjohns+K0JM@??????.???> wrote:
>>
>> On Fri, Dec 14, 2018 at 10:58 AM Bob Hammond <propgrinder@?????.???>
>> wrote:
>>
>>>> Do you use polarity switches on your yagis? If you do, is it worth
>> the effort?
>>
>> No and no.
>>
>> I had polarity switching on long yagis back in AO-10 & AO-13 days and it
>> was helpful. But for the LEO satellites we have now, it's rare to have a
>> fade so deep that one can't copy.
>> --
>> Mark D. Johns
>> K?JM / M?GZO / ex-9H3DJ / ex-K?MDJ
>> Brooklyn Park, MN USA EN35hd
>> -----------------------------------------------
>> "Heaven goes by favor; if it went by merit,
>> you would stay out and your dog would go in."
>> ---Mark Twain
>>
>>
>>
>> Greg,
>>>
>>> 73s,
>>>
>>> Bob
>>> W7OTJ
>>>
>>> On Mon, Nov 26, 2018 at 10:08 AM Greg D <ko6th.greg@?????.???> wrote:
>>>
>>>> That's pretty much what I did, though with different antennas. Also put
>>>> the AO-40 dish on the other side of the rotor from the 23cm helix, so it
>>>> went 70cm, 2.4gig, rotor, 23cm, 2m. Put things as far away from each
>>>> other as you can, without running out of crossboom.
>>>>
>>>> I was very concerned about having the 70cm beam (uplink) so close -
>>>> inches - to the 2.4 ghz dish (downlink), but it was fine. Good input
>>>> filtering in the 2.4 ghz Khune preamp, I guess. More recently, Mode L/v
>>>> on AO-92 seems ok too, with the 23cm antenna near the 2m, but I have a
>>>> lot less power on 23cm than I did with AO-40 on 70cm.
>>>>
>>>> Greg KO6TH
>>>>
>>>>
>>>> Bob Hammond wrote:
>>>>> I'm putting the following antennas on an 8-foot fiberglass crossboom:
>>>>>
>>>>> M2 2MCP8A, 143-148 MHz C{
>>>>> Gulf Alpha 70cm 8x8 CP
>>>>> WiMo Helix 23
>>>>>
>>>>> I'm not sure how to calculate the proper spacing on the crossboom. I
>>>>> assume the 2m antenna should go on one end and the 70cm antenna on the
>>>>> opposite end. Can I mount the 23cm helical antenna very near the
>>> rotator
>>>>> without harm since it has the solid reflector behind the helix?
>>>>>
>>>>> Bob
>>>>> W7OTJ
>>>>> (was WL7CQX)
>>>>> _______________________________________________
>>>>> Sent via AMSAT-BB@?????.???. 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
>>>>
>>> _______________________________________________
>>> Sent via AMSAT-BB@?????.???. 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
>>>
>> _______________________________________________
>> Sent via AMSAT-BB@?????.???. 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
> _______________________________________________
> Sent via AMSAT-BB@?????.???. 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
------------------------------
Message: 6
Date: Sat, 15 Dec 2018 20:17:56 +0400
From: Jean Marc Momple <jean.marc.momple@?????.???>
To: Bob Hammond <propgrinder@?????.???>
Cc: amsat-bb@?????.???
Subject: Re: [amsat-bb] Antenna separation on crossboom
Message-ID: <A415F298-70E8-4C9B-8CB8-6974071F42CF@?????.???>
Content-Type: text/plain; charset=utf-8
Bob,
Sure it will work fine for nearly all birds.
73
Jean Marc (3B8DU)
> On Dec 15, 2018, at 8:08 PM, Bob Hammond <propgrinder@?????.???> wrote:
>
> Thanks Jean Marc. That is exactly the answer I was seeking. I have 2m
and 70cm CP yagis with RHCP.
>
> Bob
> W7OTJ
>
> On Sat, Dec 15, 2018 at 7:44 AM Jean Marc Momple
<jean.marc.momple@?????.??? <mailto:jean.marc.momple@?????.???>> wrote:
> Bob,
>
> So that all may fully understand:
>
> Most LEO?s use monopoles or dipoles (on VHF/UHF) which are actually linear
and not circular polarization, but the birds are spinning and tumbling
therefore the polarization can be H, V or any angle. If you use H or V pole
at the ground station the fading may be as high at 30dB therefore it is
recommended to use circular polarization at the ground station as maximum
fade would be around 3 dB whatever the satellite polarization may be.
>
> I suggest that you use RHCP without polarisation switch, except if you
wish to spend some money to experiment with same. I have the possibility to
switch polarization but it is not used at all.
>
> Hope this help.
>
> 73
>
>
> Jean Marc (3B8DU)
>
> > On Dec 15, 2018, at 1:40 AM, Mark D. Johns <mjohns+K0JM@??????.???
<mailto:mjohns%2BK0JM@??????.???>> wrote:
> >
> > On Fri, Dec 14, 2018 at 10:58 AM Bob Hammond <propgrinder@?????.???
<mailto:propgrinder@?????.???>>
> > wrote:
> >
> >>> Do you use polarity switches on your yagis? If you do, is it worth
> > the effort?
> >
> > No and no.
> >
> > I had polarity switching on long yagis back in AO-10 & AO-13 days and it
> > was helpful. But for the LEO satellites we have now, it's rare to have a
> > fade so deep that one can't copy.
> > --
> > Mark D. Johns
> > K?JM / M?GZO / ex-9H3DJ / ex-K?MDJ
> > Brooklyn Park, MN USA EN35hd
> > -----------------------------------------------
> > "Heaven goes by favor; if it went by merit,
> > you would stay out and your dog would go in."
> > ---Mark Twain
> >
> >
> >
> > Greg,
> >>
> >>
> >> 73s,
> >>
> >> Bob
> >> W7OTJ
> >>
> >> On Mon, Nov 26, 2018 at 10:08 AM Greg D <ko6th.greg@?????.???
<mailto:ko6th.greg@?????.???>> wrote:
> >>
> >>> That's pretty much what I did, though with different antennas. Also put
> >>> the AO-40 dish on the other side of the rotor from the 23cm helix, so it
> >>> went 70cm, 2.4gig, rotor, 23cm, 2m. Put things as far away from each
> >>> other as you can, without running out of crossboom.
> >>>
> >>> I was very concerned about having the 70cm beam (uplink) so close -
> >>> inches - to the 2.4 ghz dish (downlink), but it was fine. Good input
> >>> filtering in the 2.4 ghz Khune preamp, I guess. More recently, Mode L/v
> >>> on AO-92 seems ok too, with the 23cm antenna near the 2m, but I have a
> >>> lot less power on 23cm than I did with AO-40 on 70cm.
> >>>
> >>> Greg KO6TH
> >>>
> >>>
> >>> Bob Hammond wrote:
> >>>> I'm putting the following antennas on an 8-foot fiberglass crossboom:
> >>>>
> >>>> M2 2MCP8A, 143-148 MHz C{
> >>>> Gulf Alpha 70cm 8x8 CP
> >>>> WiMo Helix 23
> >>>>
> >>>> I'm not sure how to calculate the proper spacing on the crossboom. I
> >>>> assume the 2m antenna should go on one end and the 70cm antenna on the
> >>>> opposite end. Can I mount the 23cm helical antenna very near the
> >> rotator
> >>>> without harm since it has the solid reflector behind the helix?
> >>>>
> >>>> Bob
> >>>> W7OTJ
> >>>> (was WL7CQX)
> >>>> _______________________________________________
> >>>> Sent via AMSAT-BB@?????.??? <mailto:AMSAT-BB@?????.???>. 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
<http://www.amsat.org/mailman/listinfo/amsat-bb>
> >>>
> >>>
> >> _______________________________________________
> >> Sent via AMSAT-BB@?????.??? <mailto:AMSAT-BB@?????.???>. 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
<http://www.amsat.org/mailman/listinfo/amsat-bb>
> >>
> > _______________________________________________
> > Sent via AMSAT-BB@?????.??? <mailto:AMSAT-BB@?????.???>. 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
<http://www.amsat.org/mailman/listinfo/amsat-bb>
>
------------------------------
Message: 7
Date: Sat, 15 Dec 2018 20:44:51 +0400
From: Jean Marc Momple <jean.marc.momple@?????.???>
To: Jim White <jim@?????????????????.???>
Cc: amsat-bb@?????.???
Subject: Re: [amsat-bb] Antenna separation on crossboom
Message-ID: <C964AE58-D35C-4BD4-98E6-8DCA790D35EB@?????.???>
Content-Type: text/plain; charset=utf-8
Jim,
I tend to disagree about having polarization switch at the base station
(costing several hundreds $, just a questions on own means) for improving
signal (already good and only 3 dB loss/fading), except from only few birds.
I take the example you stated, FO-29 is so strong that even with a magnetic
1/4 wave whip of the roof of my car I made QSO?s 59+ both ways. You rightly
advised that one may start with handhelds, this works for many sats
including FO-29 and fully agree.
I would really appreciate that you send me your paper on this subject and I
will surely have some learning there, this is the beauty of the hobby
sharing experiment and experience make one and all better eventually.
Have a nice end of WE.
Jean Marc (3B8DU)
> On Dec 15, 2018, at 8:09 PM, Jim White <jim@?????????????????.???> wrote:
>
> I would add to this that there is one workhorse satellite on orbit that is
circular and changes with location. In the northern hemisphere FO-29 is
RHCP when to the south of the station and LHCP when to the north. It makes
a very large difference.
>
> In addition, while cubesats of the 1U to 3U size typically use a whip
(linear) because there isn't real estate for anything circular, for 6U and
larger a canted turnstile is a better choice and is circular. In that case
they are typically wired for RHCP when the antenna ends faces earth but if
it tumbles or flips the sense will change. When facing away it will be LHCP
to the ground station.
>
> This question has been rattling around for at least since the 1990
AMSAT-NA microsats (which were canted turnstiles on the UHF downlink). For
those satellites the downlink was RCHP in the northern hemisphere and LCHP
in the southern, except for LO-19 which was reversed. I wrote a paper on
this for the 1991 AMSAT Space Sympoisum (or it might have been 1992). So I
tend to suggest that folks just getting started with a hand held antenna a
linear antenna is fine because they are a bit lighter and less cumbersome to
handle, and less expensive. But if you are building a fixed "base" station
I still suggest including sense switching. It will make a large difference
with FO29 and you will be ready for the next one that uses circular. Given
there are probably 100 in various stages of design and construction and
rides are plentiful it seems worth the investment.
>
> Jim
>
> Jim White, WD0E
> jim@?????????????????.???
> On 12/15/2018 8:44 AM, Jean Marc Momple wrote:
>> Bob,
>>
>> So that all may fully understand:
>>
>> Most LEO?s use monopoles or dipoles (on VHF/UHF) which are actually
linear and not circular polarization, but the birds are spinning and
tumbling therefore the polarization can be H, V or any angle. If you use H
or V pole at the ground station the fading may be as high at 30dB therefore
it is recommended to use circular polarization at the ground station as
maximum fade would be around 3 dB whatever the satellite polarization may be.
>>
>> I suggest that you use RHCP without polarisation switch, except if you
wish to spend some money to experiment with same. I have the possibility to
switch polarization but it is not used at all.
>>
>> Hope this help.
>>
>> 73
>>
>>
>> Jean Marc (3B8DU)
>>
>>> On Dec 15, 2018, at 1:40 AM, Mark D. Johns <mjohns+K0JM@??????.???> wrote:
>>>
>>> On Fri, Dec 14, 2018 at 10:58 AM Bob Hammond <propgrinder@?????.???>
>>> wrote:
>>>
>>>>> Do you use polarity switches on your yagis? If you do, is it worth
>>> the effort?
>>>
>>> No and no.
>>>
>>> I had polarity switching on long yagis back in AO-10 & AO-13 days and it
>>> was helpful. But for the LEO satellites we have now, it's rare to have a
>>> fade so deep that one can't copy.
>>> --
>>> Mark D. Johns
>>> K?JM / M?GZO / ex-9H3DJ / ex-K?MDJ
>>> Brooklyn Park, MN USA EN35hd
>>> -----------------------------------------------
>>> "Heaven goes by favor; if it went by merit,
>>> you would stay out and your dog would go in."
>>> ---Mark Twain
>>>
>>>
>>>
>>> Greg,
>>>>
>>>> 73s,
>>>>
>>>> Bob
>>>> W7OTJ
>>>>
>>>> On Mon, Nov 26, 2018 at 10:08 AM Greg D <ko6th.greg@?????.???> wrote:
>>>>
>>>>> That's pretty much what I did, though with different antennas. Also put
>>>>> the AO-40 dish on the other side of the rotor from the 23cm helix, so it
>>>>> went 70cm, 2.4gig, rotor, 23cm, 2m. Put things as far away fromo/amsat-bb
>> _______________________________________________
>> Sent via AMSAT-BB@?????.???. 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
> _______________________________________________
> Sent via AMSAT-BB@?????.???. 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
------------------------------
Message: 8
Date: Sat, 15 Dec 2018 08:08:15 -0800
From: Bob Hammond <propgrinder@?????.???>
To: jean.marc.momple@?????.???
Cc: amsat-bb@?????.???
Subject: Re: [amsat-bb] Antenna separation on crossboom
Message-ID:
<CAKoB7OqcHxu3VZwzdMqDUcLu8o_=qqQaMKPK1aezM0dQcJGewA@????.?????.???>
Content-Type: text/plain; charset="UTF-8"
Thanks Jean Marc. That is exactly the answer I was seeking. I have 2m and
70cm CP yagis with RHCP.
Bob
W7OTJ
On Sat, Dec 15, 2018 at 7:44 AM Jean Marc Momple <jean.marc.momple@?????.???>
wrote:
> Bob,
>
> So that all may fully understand:
>
> Most LEO?s use monopoles or dipoles (on VHF/UHF) which are actually linear
> and not circular polarization, but the birds are spinning and tumbling
> therefore the polarization can be H, V or any angle. If you use H or V pole
> at the ground station the fading may be as high at 30dB therefore it is
> recommended to use circular polarization at the ground station as maximum
> fade would be around 3 dB whatever the satellite polarization may be.
>
> I suggest that you use RHCP without polarisation switch, except if you
> wish to spend some money to experiment with same. I have the possibility to
> switch polarization but it is not used at all.
>
> Hope this help.
>
> 73
>
>
> Jean Marc (3B8DU)
>
> > On Dec 15, 2018, at 1:40 AM, Mark D. Johns <mjohns+K0JM@??????.???>
> wrote:
> >
> > On Fri, Dec 14, 2018 at 10:58 AM Bob Hammond <propgrinder@?????.???>
> > wrote:
> >
> >>> Do you use polarity switches on your yagis? If you do, is it worth
> > the effort?
> >
> > No and no.
> >
> > I had polarity switching on long yagis back in AO-10 & AO-13 days and it
> > was helpful. But for the LEO satellites we have now, it's rare to have a
> > fade so deep that one can't copy.
> > --
> > Mark D. Johns
> > K?JM / M?GZO / ex-9H3DJ / ex-K?MDJ
> > Brooklyn Park, MN USA EN35hd
> > -----------------------------------------------
> > "Heaven goes by favor; if it went by merit,
> > you would stay out and your dog would go in."
> > ---Mark Twain
> >
> >
> >
> > Greg,
> >>
> >>
> >> 73s,
> >>
> >> Bob
> >> W7OTJ
> >>
> >> On Mon, Nov 26, 2018 at 10:08 AM Greg D <ko6th.greg@?????.???> wrote:
> >>
> >>> That's pretty much what I did, though with different antennas. Also
> put
> >>> the AO-40 dish on the other side of the rotor from the 23cm helix, so
> it
> >>> went 70cm, 2.4gig, rotor, 23cm, 2m. Put things as far away from each
> >>> other as you can, without running out of crossboom.
> >>>
> >>> I was very concerned about having the 70cm beam (uplink) so close -
> >>> inches - to the 2.4 ghz dish (downlink), but it was fine. Good input
> >>> filtering in the 2.4 ghz Khune preamp, I guess. More recently, Mode
> L/v
> >>> on AO-92 seems ok too, with the 23cm antenna near the 2m, but I have a
> >>> lot less power on 23cm than I did with AO-40 on 70cm.
> >>>
> >>> Greg KO6TH
> >>>
> >>>
> >>> Bob Hammond wrote:
> >>>> I'm putting the following antennas on an 8-foot fiberglass crossboom:
> >>>>
> >>>> M2 2MCP8A, 143-148 MHz C{
> >>>> Gulf Alpha 70cm 8x8 CP
> >>>> WiMo Helix 23
> >>>>
> >>>> I'm not sure how to calculate the proper spacing on the crossboom. I
> >>>> assume the 2m antenna should go on one end and the 70cm antenna on the
> >>>> opposite end. Can I mount the 23cm helical antenna very near the
> >> rotator
> >>>> without harm since it has the solid reflector behind the helix?
> >>>>
> >>>> Bob
> >>>> W7OTJ
> >>>> (was WL7CQX)
> >>>> _______________________________________________
> >>>> Sent via AMSAT-BB@?????.???. 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
> >>>
> >>>
> >> _______________________________________________
> >> Sent via AMSAT-BB@?????.???. 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
> >>
> > _______________________________________________
> > Sent via AMSAT-BB@?????.???. 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
>
>
------------------------------
Subject: Digest Footer
_______________________________________________
Sent via amsat-bb@?????.???.
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 member? Join now to support the amateur satellite program!
http://www.amsat.org/mailman/listinfo/amsat-bb
------------------------------
End of AMSAT-BB Digest, Vol 13, Issue 422
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