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Today's Topics:
1. Re: NASA's American Student Moon Orbiter... (i8cvs)
2. Re: NASA's American Student Moon Orbiter... (G0MRF(AT)aol.com)
3. P3E (Trevor)
4. Re: NASA's American Student Moon Orbiter... (Edward Cole)
5. Re: NASA's American Student Moon Orbiter... (Edward Cole)
6. AO-51 FM UHF Downlink Power Output? (Brien McCrea)
7. re best transceiver for sats (Angus)
8. Re: re best transceiver for sats (Ronald Nutter)
9. source for LMR 400 UF connectors (Jim Danehy)
10. Re: re best transceiver for sats (i8cvs)
11. Re: NASA's American Student Moon Orbiter... (i8cvs)
12. Re: re best transceiver for sats (ka3hsw(AT)att.net)
13. AMSAT New Mexico Area Coordinator? (Robert L Lasso)
----------------------------------------------------------------------
Message: 1
Date: Fri, 4 Jul 2008 03:14:57 +0200
From: "i8cvs" <domenico.i8cvs(AT)tin.it>
Subject: [amsat-bb] Re: NASA's American Student Moon Orbiter...
To: "AMSAT BB" <amsat-bb(AT)amsat.org>, "Edward Cole"
<kl7uw(AT)acsalaska.net>
Message-ID: <002901c8dd73$600cfaa0$0201a8c0(AT)tin.it>
Content-Type: text/plain; charset="iso-8859-1"
Hi Ed, KL7UW
If we put AO40 at a distance of 400.000 km instead of 60.000 km
from the earth the increase of isotropic attenuation at 2400 MHz is
about 16 dB
Supposing that the AO40 antennas are looking at the earth with the
same squint angle try to remember with how many dB of (S+N)/N
you was normally receiving the downlink of the S2 transponder.
You should remember that the AO40 antenna for the S2 transponder
was a RHCP Helix of only 5 turns with an estimated gain of 8 dBic
By the way AO40 was also equipped with the S1 transponder using
a Short-Backfire antenna RHCP designed by ON6UG with a gain of
18 dBic
Unfortunately the S1 TX has been non-functional since 2001 aug 13
but when the S1 transponder was connected to the 18 dBic Short-Backfire
the S1 downlink was really about 10 dB over the S2 transponder.
If ipotetically we put AO40 at 400.000 km using the S1 transponder
we gain 10 dB over the S2 transponder and this is like to have reduced
the isotropic attenuation to 16 - 10 = 6 dB
To compensate for the rest of 6 dB it is only necessary to double the
diameter of the receiving dish.
In my case if I increase the diameter of my dish from 1.2 to 2.4 meters
i.e from 4 to 8 ft I will receive the S1 transponder from 400.000 km
with the same signal level of the S2 transponder from a distance of
60.000 km
The problem here is the uplink depending on what band we are using
for it.
If we use the L band 1268 MHz then the difference in the isotropic
attenuation between 400.000 km to 60.000 km is again about 16.5 dB
If I want to put into the satellite receiver at 400.000 km the same
signal level that I put on it at 60.000 km I am in trouble because the AO40
23 cm antenna was already a 18 dBic gain dish and so to compensate for
the above increase of path loss for the uplink the only way is to increase
the power or the antenna gain or both at the ground station.
If I use a yagi array's every time I double the numbar of yagi's I gain 3
dB but only in theory and every time I double the power I gain 3 dB
as well.
In my situation in order to put the same signal level into the satellite
receiver at 400.000 km and 60.000 km I should increase my power from
the actual 120 watt at 1268 MHz to 240 watt to get 3 dB and I should
enlarge the actual array of 4 x 23 element yagi to 16 x 23 element yagi
to gain another 6 dB and in total 3+6= 9 dB but in the above situation
I will be still 16.5 - 9 = 7.5 dB weeker than at 60.000 km
By the way I was looking at the many pictures taken on my Spectrum Analyser
when AO40 was operational and using a 4 ft dish helix feed and an overall
noise figure of 0.7 dB for my receiving system I see that the AO40 General
Beacon was at 20 dB of (S+N)/N most of the time while the average of the SSB
traffic was swinging in the range from 10 dB picking to 20 dB over the
noise and sometime over 20 dB with LEILA.
In conclusion if AO40 is transmitting from 400.000 km using the S 1
transponder with the 18 dBic Short-Backfire we gain 10 dB over the S2
Helix antenna and if I double my dish from 4 ft to 8 ft I gain another 6 dB
so that 10+6= 16 dB and the path loss for downlink is totally compensated.
In this condition the General Beacon of AO40 would be received unchanged
at 20 dB over the noise but the average of the SSB traffic would be received
weeker and weeker because the most part of the users would not be able to
increase the EIRP to compensate for the 16 dB more path loss in the uplink
at 1268 MHz
In addition if I improve my own 1268 MHz array from 4 x 23 (24 dBi)
to 8 x 23 element yagi (+3 dB) and using 240 watt (+3 dB) than I would
compensate the path loss in uplink by only 6 dB and my SSB translated
signal in comparison to 60.000 km will be received weeker by
16 - 6 = 10 dB but if before it was received 20 dB over the noise it still
will be audible in SSB about 10 dB over the noise.
With only my actual 4 x 23 (24 dBi) element yagi and the actual 120 watt
I shall receive my own CW from 400.000 km at about 20-16= 4 dB over
the noise.
Without to increase my receiving dish from 4 ft to 8 ft I will loose 6 dB
and my CW signal will be received with a (S+N)/N= - 2 dB but this is
not a problem on CW because skilled operators are able to receive by ears
signal levels that are even weeker.
Best 73" de
i8CVS Domenico
----- Original Message -----
From: "Edward Cole" <kl7uw(AT)acsalaska.net>
To: "AMSAT BB" <amsat-bb(AT)amsat.org>
Sent: Thursday, July 03, 2008 8:28 AM
Subject: [amsat-bb] Re: NASA's American Student Moon Orbiter...
> The gain increase for the antenna would be deltaG = (12/4)^2 = 9, or
> in dB = 10Log(9) = 9.5 dB. You get this gain in Tx and again in Rx
> so the total gain = 19 dB. So this means that the spacecraft will
> need to be 32-19 = 13 dB stronger than AO-40. So perhaps the S/C
> antenna would be larger and maybe the Tx higher power?
>
> Ed - KL7UW
>
> At 08:16 PM 7/2/2008, w7lrd(AT)comcast.net wrote:
> >How would my 12 foot paraclips work for this exercise?
> >73 Bob W7LRD
> >
> >--
> >"if this were easy, everyone would be doing it"
> >
> >-------------- Original message --------------
> >From: "Andrew Glasbrenner" <glasbrenner(AT)mindspring.com>
> >
> > > The moon is roughly 360,000 to 400,000 km away. By comparison, AO-40
had a
> > > apogee of about 60,000km. At 2.4Ghz, that's about 16db difference
> > each way.
> > > Put AO-40 at the moon, and if I'm doing this right, you'd need about
32
> > > times the ground station antenna both coming and going to get
> > with a few db.
> > > I'm gonna need a bigger rotor for sure! I'm sure smarter folks
> > will check my
> > > math....
> > >
> > > 73, Drew KO4MA
> > >
> > > ----- Original Message -----
> > > From: "Joe"
> > > To: "Andrew Glasbrenner"
> > > Cc: "Trevor" ; "AMSAT BB"
> > > Sent: Wednesday, July 02, 2008 6:05 PM
> > > Subject: Re: [amsat-bb] Re: NASA's American Student Moon Orbiter...
> > >
> > >
> > > > what would a sample average link budget be?
> > > >
> > > > Andrew Glasbrenner wrote:
> > > >
> > > >>As far as I can recall we are pursuing both Eagle and the P4
opportunity
> > > >>equally, concentrating on common elements until the details are
ironed
> > > >>out. Neither has been identified as a primary or secondary
objective.
> > > >>
> > > >>I agree a package on a lunar orbiter would be neat, but also that it
is
> > > >>not the best use of what volunteers we have. We need more folks
> > to step up
> > > >>to do things, AND we need to make better use of them when they do.
> > > >>
> > > >>73, Drew KO4MA
> > > >>
> > > >>----- Original Message -----
> > > >>From: "Trevor"
> > > >>To: "AMSAT BB"
> > > >>Sent: Wednesday, July 02, 2008 4:53 PM
> > > >>Subject: [amsat-bb] Re: NASA's American Student Moon Orbiter...
> > > >>
> > > >>
> > > >>
> > > >>>--- On Wed, 2/7/08, Dave hartzell wrote:
> > > >>>
> > > >>>>http://www.spaceref.com/news/viewpr.html?pid=25839
> > > >>>>http://asmo.arc.nasa.gov/
> > > >>>>
> > > >>>>Wouldn't it be fun to have a transponder on this! ;-)
> > > >>>>
> > > >>>Fun yes, but dare I say it, a waste of precious Volunteer
resources.
> > > >>>
> > > >>>All lunar orbits are inherently unstable and will impact after a
couple
> > > >>>of years. The link budget requirements would not attract a mass
user
> > > >>>base.
> > > >>>
> > > >>>I suspect the number of Technically Capable volunteers is already
being
> > > >>>thinly stretched in trying to provide both the primary
> > objective Phase-IV
> > > >>>Lite (funded by Federal Government dollars) and the secondary
objective
> > > >>>the Eagle HEO.
> > > >>>
> > > >>>73 Trevor M5AKA
------------------------------
Message: 2
Date: Thu, 3 Jul 2008 21:44:25 EDT
From: G0MRF(AT)aol.com
Subject: [amsat-bb] Re: NASA's American Student Moon Orbiter...
To: amsat-bb(AT)AMSAT.Org
Message-ID: <c27.3d6c4c7e.359eda79(AT)aol.com>
Content-Type: text/plain; charset="US-ASCII"
In a message dated 04/07/2008 01:16:33 GMT Standard Time,
domenico.i8cvs(AT)tin.it writes:
Hi Ed, KL7UW
If we put AO40 at a distance of 400.000 km instead of 60.000 km
from the earth the increase of isotropic attenuation at 2400 MHz is
about 16 dB etc etc etc.........
Hi Ed / Dom
On the other hand, if you were to reduce path loss by using 70cm as the
uplink band and 2m as the downlink the numbers begin to look quite possible.
Also, if the satellite is orbiting the moon, then it's quite likely that the
attitude will be such that the experimental end of the satellite is pointing
at the moons surface. This probably also means that the communication
antennas are not pointing at the earth, so high gain will not be possible.
Maybe 3
or 4dB is the limit.
So how about 10W of 2m on the satellite and a passband that's say 5kHz wide?
Not good for SSB, but passable for CW or reasonable speed coherent BPSK
Regards
David
------------------------------
Message: 3
Date: Fri, 4 Jul 2008 07:07:10 +0000 (GMT)
From: Trevor <m5aka(AT)yahoo.co.uk>
Subject: [amsat-bb] P3E
To: AMSAT BB <amsat-bb(AT)amsat.org>
Message-ID: <310383.43059.qm(AT)web27204.mail.ukl.yahoo.com>
Content-Type: text/plain; charset=utf-8
At HAM RADIO 2008 AMSAT-DL gave presentations on the P3E and P5A projects
http://www.southgatearc.org/news/july2008/p3e_update.htm
73 Trevor M5AKA
__________________________________________________________
Not happy with your email address?.
Get the one you really want - millions of new email addresses available now at
Yahoo! http://uk.docs.yahoo.com/ymail/new.html
------------------------------
Message: 4
Date: Thu, 03 Jul 2008 23:28:07 -0800
From: Edward Cole <kl7uw(AT)acsalaska.net>
Subject: [amsat-bb] Re: NASA's American Student Moon Orbiter...
To: "i8cvs" <domenico.i8cvs(AT)tin.it>, "AMSAT BB" <amsat-bb(AT)amsat.org>
Message-ID: <200807040728.m647S7oD058764(AT)iris.acsalaska.net>
Content-Type: text/plain; charset="us-ascii"; format=flowed
OK. You provided much more info about the path link parameters than
was originally given.
I find it interesting that you ran 120w into 4x 23-elem yagis to
obtain S/N of 20-dB on mode-LS with S2 on AO-40.
I ran 9.5w to a single 20-dBi loop-yagi and obtained 10-dB S/N on SSB on S2
That seems like quite a difference. Your EIRP=120x251 = 30,120w; My
EIRP=9.5x200 = 1900w a ratio of 15.8:1 or 12-dB
So rounding off it seems that our experience on AO-40 matches.
I guess running 240w on 1296 is a bit beyond the norm for satellite
operators though it about right for eme.
You could keep 120w and increase dish to 16-feet to get the same
results, but most would balk at puttinng up such a dish.
It would seem that a better solution would be having a Moon orbiter
with more EIRP or bigger receiving antenna.
Perhaps the uplink solution would be better at higher frequencies,
but isotropic path loss increases in step with dish gain increase in
freq. balancing out any improvement in S/N.
of course running a narrowband mode takes care of the problem,
whether it be CW or WSJT (or some FEC digital voice mode).
73 Ed
At 05:14 PM 7/3/2008, i8cvs wrote:
>Hi Ed, KL7UW
>
>If we put AO40 at a distance of 400.000 km instead of 60.000 km
>from the earth the increase of isotropic attenuation at 2400 MHz is
>about 16 dB
>Supposing that the AO40 antennas are looking at the earth with the
>same squint angle try to remember with how many dB of (S+N)/N
>you was normally receiving the downlink of the S2 transponder.
>You should remember that the AO40 antenna for the S2 transponder
>was a RHCP Helix of only 5 turns with an estimated gain of 8 dBic
>By the way AO40 was also equipped with the S1 transponder using
>a Short-Backfire antenna RHCP designed by ON6UG with a gain of
>18 dBic
>Unfortunately the S1 TX has been non-functional since 2001 aug 13
>but when the S1 transponder was connected to the 18 dBic Short-Backfire
>the S1 downlink was really about 10 dB over the S2 transponder.
>If ipotetically we put AO40 at 400.000 km using the S1 transponder
>we gain 10 dB over the S2 transponder and this is like to have reduced
>the isotropic attenuation to 16 - 10 = 6 dB
>To compensate for the rest of 6 dB it is only necessary to double the
>diameter of the receiving dish.
>In my case if I increase the diameter of my dish from 1.2 to 2.4 meters
>i.e from 4 to 8 ft I will receive the S1 transponder from 400.000 km
>with the same signal level of the S2 transponder from a distance of
>60.000 km
>
>The problem here is the uplink depending on what band we are using
>for it.
>If we use the L band 1268 MHz then the difference in the isotropic
>attenuation between 400.000 km to 60.000 km is again about 16.5 dB
>If I want to put into the satellite receiver at 400.000 km the same
>signal level that I put on it at 60.000 km I am in trouble because the AO40
>23 cm antenna was already a 18 dBic gain dish and so to compensate for
>the above increase of path loss for the uplink the only way is to increase
>the power or the antenna gain or both at the ground station.
>If I use a yagi array's every time I double the numbar of yagi's I gain 3
>dB but only in theory and every time I double the power I gain 3 dB
>as well.
>In my situation in order to put the same signal level into the satellite
>receiver at 400.000 km and 60.000 km I should increase my power from
>the actual 120 watt at 1268 MHz to 240 watt to get 3 dB and I should
>enlarge the actual array of 4 x 23 element yagi to 16 x 23 element yagi
>to gain another 6 dB and in total 3+6= 9 dB but in the above situation
>I will be still 16.5 - 9 = 7.5 dB weeker than at 60.000 km
>
>By the way I was looking at the many pictures taken on my Spectrum Analyser
>when AO40 was operational and using a 4 ft dish helix feed and an overall
>noise figure of 0.7 dB for my receiving system I see that the AO40 General
>Beacon was at 20 dB of (S+N)/N most of the time while the average of the SSB
>traffic was swinging in the range from 10 dB picking to 20 dB over the
>noise and sometime over 20 dB with LEILA.
>
>In conclusion if AO40 is transmitting from 400.000 km using the S 1
>transponder with the 18 dBic Short-Backfire we gain 10 dB over the S2
>Helix antenna and if I double my dish from 4 ft to 8 ft I gain another 6 dB
>so that 10+6= 16 dB and the path loss for downlink is totally compensated.
>In this condition the General Beacon of AO40 would be received unchanged
>at 20 dB over the noise but the average of the SSB traffic would be received
>weeker and weeker because the most part of the users would not be able to
>increase the EIRP to compensate for the 16 dB more path loss in the uplink
>at 1268 MHz
>
>In addition if I improve my own 1268 MHz array from 4 x 23 (24 dBi)
>to 8 x 23 element yagi (+3 dB) and using 240 watt (+3 dB) than I would
>compensate the path loss in uplink by only 6 dB and my SSB translated
>signal in comparison to 60.000 km will be received weeker by
>16 - 6 = 10 dB but if before it was received 20 dB over the noise it still
>will be audible in SSB about 10 dB over the noise.
>
>With only my actual 4 x 23 (24 dBi) element yagi and the actual 120 watt
>I shall receive my own CW from 400.000 km at about 20-16= 4 dB over
>the noise.
>
>Without to increase my receiving dish from 4 ft to 8 ft I will loose 6 dB
>and my CW signal will be received with a (S+N)/N= - 2 dB but this is
>not a problem on CW because skilled operators are able to receive by ears
>signal levels that are even weeker.
>
>Best 73" de
>
>i8CVS Domenico
>
>----- Original Message -----
>From: "Edward Cole" <kl7uw(AT)acsalaska.net>
>To: "AMSAT BB" <amsat-bb(AT)amsat.org>
>Sent: Thursday, July 03, 2008 8:28 AM
>Subject: [amsat-bb] Re: NASA's American Student Moon Orbiter...
>
>
> > The gain increase for the antenna would be deltaG = (12/4)^2 = 9, or
> > in dB = 10Log(9) = 9.5 dB. You get this gain in Tx and again in Rx
> > so the total gain = 19 dB. So this means that the spacecraft will
> > need to be 32-19 = 13 dB stronger than AO-40. So perhaps the S/C
> > antenna would be larger and maybe the Tx higher power?
> >
> > Ed - KL7UW
> >
> > At 08:16 PM 7/2/2008, w7lrd(AT)comcast.net wrote:
> > >How would my 12 foot paraclips work for this exercise?
> > >73 Bob W7LRD
> > >
> > >--
> > >"if this were easy, everyone would be doing it"
> > >
> > >-------------- Original message --------------
> > >From: "Andrew Glasbrenner" <glasbrenner(AT)mindspring.com>
> > >
> > > > The moon is roughly 360,000 to 400,000 km away. By comparison, AO-40
>had a
> > > > apogee of about 60,000km. At 2.4Ghz, that's about 16db difference
> > > each way.
> > > > Put AO-40 at the moon, and if I'm doing this right, you'd need about
>32
> > > > times the ground station antenna both coming and going to get
> > > with a few db.
> > > > I'm gonna need a bigger rotor for sure! I'm sure smarter folks
> > > will check my
> > > > math....
> > > >
> > > > 73, Drew KO4MA
> > > >
> > > > ----- Original Message -----
> > > > From: "Joe"
> > > > To: "Andrew Glasbrenner"
> > > > Cc: "Trevor" ; "AMSAT BB"
> > > > Sent: Wednesday, July 02, 2008 6:05 PM
> > > > Subject: Re: [amsat-bb] Re: NASA's American Student Moon Orbiter...
> > > >
> > > >
> > > > > what would a sample average link budget be?
> > > > >
> > > > > Andrew Glasbrenner wrote:
> > > > >
> > > > >>As far as I can recall we are pursuing both Eagle and the P4
>opportunity
> > > > >>equally, concentrating on common elements until the details are
>ironed
> > > > >>out. Neither has been identified as a primary or secondary
>objective.
> > > > >>
> > > > >>I agree a package on a lunar orbiter would be neat, but also that it
>is
> > > > >>not the best use of what volunteers we have. We need more folks
> > > to step up
> > > > >>to do things, AND we need to make better use of them when they do.
> > > > >>
> > > > >>73, Drew KO4MA
> > > > >>
> > > > >>----- Original Message -----
> > > > >>From: "Trevor"
> > > > >>To: "AMSAT BB"
> > > > >>Sent: Wednesday, July 02, 2008 4:53 PM
> > > > >>Subject: [amsat-bb] Re: NASA's American Student Moon Orbiter...
> > > > >>
> > > > >>
> > > > >>
> > > > >>>--- On Wed, 2/7/08, Dave hartzell wrote:
> > > > >>>
> > > > >>>>http://www.spaceref.com/news/viewpr.html?pid=25839
> > > > >>>>http://asmo.arc.nasa.gov/
> > > > >>>>
> > > > >>>>Wouldn't it be fun to have a transponder on this! ;-)
> > > > >>>>
> > > > >>>Fun yes, but dare I say it, a waste of precious Volunteer
>resources.
> > > > >>>
> > > > >>>All lunar orbits are inherently unstable and will impact after a
>couple
> > > > >>>of years. The link budget requirements would not attract a mass
>user
> > > > >>>base.
> > > > >>>
> > > > >>>I suspect the number of Technically Capable volunteers is already
>being
> > > > >>>thinly stretched in trying to provide both the primary
> > > objective Phase-IV
> > > > >>>Lite (funded by Federal Government dollars) and the secondary
>objective
> > > > >>>the Eagle HEO.
> > > > >>>
> > > > >>>73 Trevor M5AKA
------------------------------
Message: 5
Date: Thu, 03 Jul 2008 23:51:05 -0800
From: Edward Cole <kl7uw(AT)acsalaska.net>
Subject: [amsat-bb] Re: NASA's American Student Moon Orbiter...
To: G0MRF(AT)aol.com, amsat-bb(AT)amsat.org
Message-ID: <200807040751.m647p5M6081821(AT)hermes.acsalaska.net>
Content-Type: text/plain; charset="us-ascii"; format=flowed
At 05:44 PM 7/3/2008, G0MRF(AT)aol.com wrote:
>
>In a message dated 04/07/2008 01:16:33 GMT Standard Time,
>domenico.i8cvs(AT)tin.it writes:
>
>Hi Ed, KL7UW
>
>If we put AO40 at a distance of 400.000 km instead of 60.000 km
>from the earth the increase of isotropic attenuation at 2400 MHz is
>about 16 dB etc etc etc.........
>
>
>Hi Ed / Dom
>
>On the other hand, if you were to reduce path loss by using 70cm as the
>uplink band and 2m as the downlink the numbers begin to look quite possible.
>
>Also, if the satellite is orbiting the moon, then it's quite likely that the
>attitude will be such that the experimental end of the satellite is pointing
>at the moons surface. This probably also means that the communication
>antennas are not pointing at the earth, so high gain will not be
>possible. Maybe 3
>or 4dB is the limit.
>
>So how about 10W of 2m on the satellite and a passband that's say 5kHz wide?
> Not good for SSB, but passable for CW or reasonable speed coherent BPSK
>
>Regards
>
>David
David,
I think you meant to say 5-Hz vs 5-KHz bandwidth. That is one of the
best ways to improve the link equation and CW or WSJT will work well.
When you lower isotropic path loss by lowering frequency, keeping the
same antenna gain means much bigger antennas. The footprint on a
Moon orbiter would be probably too small to get enough gain on 2m or 70cm.
But this exercise of using AO-40 as a benchmark has its limits. One
should just do the complete pathlink analysis to come up with good
numbers. The one factor that is always there is a big jump in
pathloss due to 400,000 km vs. earth orbit.
Ed
I have a pathlink excell calculator on my website for MRO that can be
modified to work for a lunar orbiter.
http://www.kl7uw.com/raseti.htm
*****************************************************
73, Ed - KL7UW BP40iq, 6m - 3cm
144-EME: FT-847, mgf-1801, 4x-xp20, 185w
http://www.kl7uw.com AK VHF-Up Group
NA Rep. for DUBUS: dubususa(AT)hotmail.com
*****************************************************
------------------------------
Message: 6
Date: Thu, 3 Jul 2008 23:01:02 -0700
From: "Brien McCrea" <brienm(AT)att.net>
Subject: [amsat-bb] AO-51 FM UHF Downlink Power Output?
To: <amsat-bb(AT)amsat.org>
Message-ID: <LEEFLLLAIBKHCMIINAOOGEBCDEAA.brienm(AT)att.net>
Content-Type: text/plain; charset="iso-8859-1"
I read a posting somewhere that said that because of eclipse AO-51's
downlink power would be progressively decreased and then increased over
time. I am unable to find information on what the UHF FM Downlink power has
been set too since the end of May 2008. The reason this is off interest to
me is that up until the beginning of June I was able to easily hear and work
the bird at above 40 degrees, using an M2 Eggbeater antenna, with minimal
drop out. Now even on the highest passes reception is very poor. I get
good reception on all other satellite beacons so I know the station is
working properly. Can anyone tell me what the ouput power curve was during
the June time frame.
Thanks,
Brien
KE7WB
------------------------------
Message: 7
Date: Fri, 4 Jul 2008 12:41:20 +0100
From: "Angus" <angus(AT)young5769.freeserve.co.uk>
Subject: [amsat-bb] re best transceiver for sats
To: <amsat-bb(AT)amsat.org>
Message-ID: <7BAB7C0343E54DDC8D27226284EDF951(AT)GusPC>
Content-Type: text/plain; charset="iso-8859-1"
Hi all,
just wondering what you think is the best transceiver or transceivers for the
satellites. By this I mean to be able to TX and RX at the same time (covering
from 144mhz, 70cm and 23cm), was thinking possibly something like the ICOM
IC910 (with 23cm board added) so that USB downlink and LSB uplink can be done
(can the TS2000 do this also). Or is it better to have 2 seperate radios
altogether, and use one for the uplink and one for the downlink?
Any thoughts or what do you think is the ultimate set up, doing quite well
here with very simple FT817 and old FT480R but using transverter for 23cms.
regards
Gus M0IKB
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------------------------------
Message: 8
Date: Fri, 04 Jul 2008 07:56:01 -0500
From: Ronald Nutter <rnutter(AT)networkref.com>
Subject: [amsat-bb] Re: re best transceiver for sats
To: Angus <angus(AT)young5769.freeserve.co.uk>
Cc: amsat-bb(AT)amsat.org
Message-ID: <486E1DE1.5070707(AT)networkref.com>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
I have done it both ways. I have a IC910H and just bought the 1.2 Ghz
module. If you have seperate radios, that will get you started. You
will need to purchase a 1.2 Ghz transverter unless the radio has that
support in it. If I can operate full duplex vs half duplex, I will go
for full duplex. One feature that I picked up on the 910H was AFC,
which makes operating the FM birds really nice. Once I acquire the
satellite, the radio takes care of keeping it tuned on the downlink.
Ron
KA4KYI
Angus wrote:
> Hi all,
> just wondering what you think is the best transceiver or transceivers for
the satellites. By this I mean to be able to TX and RX at the same time
(covering from 144mhz, 70cm and 23cm), was thinking possibly something like
the ICOM IC910 (with 23cm board added) so that USB downlink and LSB uplink can
be done (can the TS2000 do this also). Or is it better to have 2 seperate
radios altogether, and use one for the uplink and one for the downlink?
> Any thoughts or what do you think is the ultimate set up, doing quite well
here with very simple FT817 and old FT480R but using transverter for 23cms.
> regards
> Gus M0IKB
>
------------------------------
Message: 9
Date: Fri, 4 Jul 2008 09:24:53 -0400
From: "Jim Danehy" <jdanehy(AT)cinci.rr.com>
Subject: [amsat-bb] source for LMR 400 UF connectors
To: <amsat-bb(AT)amsat.org>
Message-ID: <1921129B6380475D83CBA790FECF5CB4(AT)JamesPC>
Content-Type: text/plain; charset="iso-8859-1"
Can someone give me the contact information for a source selling connectors
for LMR products ?
Jim W9VNE
Cincinnati, Ohio
------------------------------
Message: 10
Date: Fri, 4 Jul 2008 15:42:20 +0200
From: "i8cvs" <domenico.i8cvs(AT)tin.it>
Subject: [amsat-bb] Re: re best transceiver for sats
To: "Angus" <angus(AT)young5769.freeserve.co.uk>, "AMSAT-BB"
<amsat-bb(AT)amsat.org>
Message-ID: <003e01c8dddb$ccd756e0$0201a8c0(AT)tin.it>
Content-Type: text/plain; charset="iso-8859-1"
----- Original Message -----
From: "Angus" <angus(AT)young5769.freeserve.co.uk>
To: <amsat-bb(AT)amsat.org>
Sent: Friday, July 04, 2008 1:41 PM
Subject: [amsat-bb] re best transceiver for sats
> Hi all,
> just wondering what you think is the best transceiver or transceivers for
the satellites. By this I mean to be able to TX and RX at the same time
(covering from 144mhz, 70cm and 23cm), was thinking possibly something like
the ICOM IC910 (with 23cm board added) so that USB downlink and LSB uplink
can be done (can the TS2000 do this also). Or is it better to have 2
seperate radios altogether, and use one for the uplink and one for the
downlink?
> Any thoughts or what do you think is the ultimate set up, doing quite well
here with very simple FT817 and old FT480R but using transverter for 23cms.
> regards
> Gus M0IKB
Hi Gus, M0IKB
In my experience 2 separate radios altogheter, and use one for the uplink
and one for the downlink is better !
If you are doing quite well with very simple FT817 and FT480R and using 23
cm transverters I suggest you do not change your setup.
73" de
i8CVS Domenico
------------------------------
Message: 11
Date: Fri, 4 Jul 2008 15:42:47 +0200
From: "i8cvs" <domenico.i8cvs(AT)tin.it>
Subject: [amsat-bb] Re: NASA's American Student Moon Orbiter...
To: "G0MRF David Bowman" <g0mrf(AT)aol.com>, "AMSAT-BB"
<amsat-bb(AT)amsat.org>
Message-ID: <004201c8dddb$d8a00080$0201a8c0(AT)tin.it>
Content-Type: text/plain; charset="iso-8859-1"
----- Original Message -----
From: <G0MRF(AT)aol.com>
To: <amsat-bb(AT)amsat.org>
Sent: Friday, July 04, 2008 3:44 AM
Subject: [amsat-bb] Re: NASA's American Student Moon Orbiter...
>
> In a message dated 04/07/2008 01:16:33 GMT Standard Time,
> domenico.i8cvs(AT)tin.it writes:
>
> Hi Ed, KL7UW
>
> If we put AO40 at a distance of 400.000 km instead of 60.000 km
> from the earth the increase of isotropic attenuation at 2400 MHz is
> about 16 dB etc etc etc.........
>
>
> Hi Ed / Dom
>
> On the other hand, if you were to reduce path loss by using 70cm as the
> uplink band and 2m as the downlink the numbers begin to look quite
> possible.
Hi David, G0MRF
Decreasing the frequency the absolute value of the isotropic attenuation
decreases but the difference in path loss between 400.000 km and 60.000 km
is the same 16.5 dB at any frequency so that to compensate for the above
attenuation using lower frequencies you need bigger antennas both on the
satellite and at the ground station.
>
> Also, if the satellite is orbiting the moon, then it's quite likely that
> the attitude will be such that the experimental end of the satellite is
> pointing at the moons surface. This probably also means that the
> communication antennas are not pointing at the earth, so high gain
> will not be possible.
> Maybe 3 or 4dB is the limit.
This is why it does not make sense to put a transponder orbiting around
the moon just for the simple reason that it's very much more simple
and cheap to put it into a HEO earth orbit.
>
> So how about 10W of 2m on the satellite and a passband that's say
> 5kHz wide? Not good for SSB, but passable for CW or reasonable
> speed coherent BPSK
>
> Regards
>
> David
Only considering the 2 meters downlink suppose to put AO40 at 400.000
km with the antennas pointing at the earth with low squint angle let say
less than 10 degrees.
The gain of the AO40 2 meters antennas was 10 dBi and we put your
10 watt on it.
Suppose that your 2 meter antenna has a gain of 13 dBi and the overall
noise figure of your receiving system is NF= 0,7 dB = 51 kelvin so that
the noise floor into a CW passband of 500 Hz with the antenna looking
at the moon (200 kelvin) is about -178 dBW
Suppose that the station in QSO with you has a 70 cm EIRP capability to
get the full 2 meters 10 watt from the transponder only for you and we
can calculate it later on.
2 meters downlink budged calculation:
Satellite power ................................... + 10 dBW
Satellite antenna gain.......................... + 10 dBi
--------------
Satellite EIRP..................................... + 20 dBW (100 W EIRP)
2 m isotr. attenuation 400.000 km.. -188 dB
--------------
power density received on a ground
isotropic 2 meters antenna..................-168 dBW
2 m ground station antenna gain.........+ 13 dBi
---------------
Power density at 2 m RX input...........- 155 dBW
2 m receiver noise floor......................- 178 dBW
---------------
-
Received CW signal S/N.................... + 23 dB
If we increase the BW to 2500 Hz for a SSB QSO than the noise floor
of the receiving system increases by log (2500/500) = 7 dB i.e.
10
it becames about -171 dB and the SSB signal will be received with a
S/N ratio = 23-7 = 16 dB wich is a very strong SSB signal.
Be aware that the above figures are based on the assumption that the
satellite antennas are pointig toward the earth wich is not the case with
a moon orbiting satellite.
In addition we assume that the station in QSO with you has a 70 cm
EIRP capability in order to get 10 watt from the 2m transponder only
for you.
On the other side if a fixed 10 dBi 2 meters antenna is placed over the
moon and it is oriented toward the earth could easily cover the inclination
X libration window without any adjustement and only from the point of
view of the downlink with 10 watt it can be easily used for a transponder
on the moon.
If you make again the downlink budged calculation considering that
the 2 meter transponder will develope only 2.5 watt for you then you
will realize that the transponder will accomodate 3 more stations if each
one is getting 2.5 watt as well.
In this case your S/N ratio will be still +15.5 dB on CW and +8.5 dB
in SSB and the same is true for the other 3 users.
73" de
i8CVS Domenico
------------------------------
Message: 12
Date: Fri, 4 Jul 2008 10:03:49 -0500
From: <ka3hsw(AT)att.net>
Subject: [amsat-bb] Re: re best transceiver for sats
To: "amsat bb" <amsat-bb(AT)amsat.org>
Message-ID: <001701c8dde7$2aa6af90$0601a8c0(AT)parents>
Content-Type: text/plain; format=flowed; charset="iso-8859-1";
reply-type=original
Having done satellites with separate transceivers (IC-275 and IC-475H);
separate transmitter, receiver, and transverters (Drake B-line twins with
TC-2/SC-2/CC-1); and a single all-mode multi-band transceiver (910H), I
wouldn't trade the 910 for anything! Especially when combined with SatPC32
for full doppler and rotor control... I first used one for Field Day in
2001 (borrowed from the local ham store), and immediately sold my B-line
Drakes, a Yaesu FT-8100R, and a few other things to fund the purchase of my
own!
73,
George, KA3HSW
----- Original Message -----
From: "Angus" <angus(AT)young5769.freeserve.co.uk>
To: <amsat-bb(AT)amsat.org>
Sent: Friday, July 04, 2008 6:41 AM
Subject: [amsat-bb] re best transceiver for sats
> Hi all,
> just wondering what you think is the best transceiver or transceivers for
> the satellites. By this I mean to be able to TX and RX at the same time
> (covering from 144mhz, 70cm and 23cm), was thinking possibly something
> like the ICOM IC910 (with 23cm board added) so that USB downlink and LSB
> uplink can be done (can the TS2000 do this also). Or is it better to have
> 2 seperate radios altogether, and use one for the uplink and one for the
> downlink?
> Any thoughts or what do you think is the ultimate set up, doing quite well
> here with very simple FT817 and old FT480R but using transverter for
> 23cms.
> regards
> Gus M0IKB
>
------------------------------
Message: 13
Date: Fri, 04 Jul 2008 09:18:17 -0600
From: Robert L Lasso <rlasso(AT)zianet.com>
Subject: [amsat-bb] AMSAT New Mexico Area Coordinator?
To: amsat-bb(AT)amsat.org
Message-ID: <486E3F39.70700(AT)zianet.com>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
Is there an AMSAT area coordinator/rep for New Mexico? Need an area
AMSAT person to help with a SAT forum at Albuquerque Hamfest August 15 &
16. I have been asked to do it but still am a bit of a
novice/intermediate level operator at it compared to a more dedicated
SAT operator that is involved with AMSAT.
73,
Robert Lasso W6RQR
------------------------------
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End of AMSAT-BB Digest, Vol 3, Issue 333
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