Get your own Free Home PageThe following are message posted to Amsat-BB, the Amateur Satellite
mailing list, between October, 1996 and September 1997.
I compiled these messages from the AMSAT-BB
hyperarchive. The messages deal with frequently asked questions and
questions of a unique technical nature the answers to which are not likely
to be found elsewhere.
DSCHULTZ@SSSP.HST.NASA.GOV
Fri, 29 Aug 1997 19:48:47 GMT
Last week David Vari asked:
>Helo all,I picked up this msg.on packet the other day.Can I get some
>help.as to what country,freq,status,tvro,wx,ect these birds are ?
Sorry
>the file is so long.I would like to put them in the satt.directory
of our
>club packet station.
[long list of satellites deleted]
The National Space Science Data Center at http://nssdc.gsfc.nasa.gov/
maintains a Master Catalog of spacecraft. Also visit the GSFC Orbital
Data Bulletin Board at http://oigsysop.atsc.allied.com/index.htm
to see the Satellite Situation Report and other information.
A partial listing of satellites from your e-mail is given below:
(Phil Chien can no doubt fill in the gaps in my memory)
------------------------------------------------------------------------------
Alouette 1
First Canadian Satellite, used for Ionospheric Sounding (transmits
radio pulse downward into ionosphere and measures reflections). Launched
in early 1960's. First non-Soviet, non-USA satellite. Long since ceased
to function. Nice exhibit in Canadian National Science and Technology
museum in Ottawa.
ATS 1
Applications Technology Satellite series, managed by NASA Goddard in
1960's.
One of the ATS birds is still functioning about three decades after
launch.
LAGEOS
Laser Geodynamic Satellite. Orbiting brass sphere covered with corner
cube reflectors, no electronics on board. Reflects laser light pulses,
used to measure distance between different measuring stations, can
measure continental drift rates of about 1 inch per year. Expected
orbital lifetime about 8 million years, contains plaque designed by
Carl Sagan bearing a message for inhabitants of Earth in 8,000,000
AD
GOES
Geostationary Operational Environmental Satellite. Takes the weather
satellite pictures that you see on TV every night.
IUE
International Ultraviolet Explorer. Small astronomical telescope in
geosynchronous orbit, made observations of objects at UV wavelengths.
Launched in 1978, expected lifetime 3 years, operated until 1996.
SeaSat 1
Phased array synthetic aperature radar for ocean surface imaging.
Launched 1978. Failed 3 months after launch when a slip ring on the
solar array rotary joint shorted out, causing spacecraft batteries
to discharge. Large satellite easily visible in twilight sky.
Nimbus 7
Low polar orbit weather satellite.
Cosmos
A general catch-all name for Soviet space missions that they don't
want to talk about. Many were military spy satellites, others were
actual science missions. Some were failed lunar or planetary missions
that failed to leave Earth orbit and were given Cosmos designations
to hide their intended missions.
LandSat
US Earth resources mapping satellites.
DMSP B5D2-1
Defense Meterological Satellite Program. Pentagon version of Nimbus
and NOAA. Produces "classified" weather reports for military services.
IRAS
Infrared Astronomical Satellite. Launched 1983. Joint USA/British/Dutch
project. Mapped the sky at infrared wavelengths for about 1 year until
liquid helium ran out. Discovered dust rings around the star Vega,
also
discovered Earth grazing comet IRAS-Araki-Alcock.
TDRS 1
Tracking and Data Relay Satellite. Relays communications signals from
Space Shuttle and NASA low orbit satellites via control center at White
Sands, New Mexico. Allowed NASA to shut down most of its worldwide
network
of satellite tracking stations. First TDRS failed to reach proper orbit
when Inertial Upper Stage misfired, controllers used tiny gas thrusters
to nudge it into final geosynchronous orbit. Second TDRS was the payload
lost on Challenger's final flight, January 28, 1986.
ERBS
Earth Radiation Budget Satellite. Launched from space shuttle Challenger
mission 41-G in 1984. Measures sunlight at top of Earth's atmosphere
and
reflected radiation from Earth. Still operating after 13 years in orbit.
Can be seen at end of shuttle's robot arm in Imax movie "The Dream
is Alive"
NOAA 9
National Oceanic and Atmospheric Administration. USA low orbit weather
satellite. Pictures often received by amateurs. See Dallas Remote Imaging
Group for info.
SPOT 1
French Earth resources mapping satellite, similar function to US
Landsat. SPOT was primary payload on Ariane launch that carried
first 4 Amsat Microsats- Pacsat, LUsat, Webersat and Dove
Meteor 2-16
Russian Meterological satellite
Glonass 36
Global Navigation Satellite System. Russian navigation satellite
network, function similar to US Global Positioning System.
METEOSAT 3
European geostationary weather satellite.
GPS BII-01
USA Global Positioning Satellite, Block 2.
INTERCOSMOS 24
Russian Communications relay satellite.
COBE
Cosmic Background Explorer. Launched 1989, made highly precise measurements
of 3 degree Cosmic Microwave Background Radiation from the Big Bang,
eventually found small regions of the early universe that were warmer
and denser than other areas.
Kvant-1
Kvant-2
Kristall
Priroda
Spektr
Research modules launched seperately and docked to form MIR orbital
complex. Should have keplerian elements same as MIR core module.
LUCH (Altair-2)
Communications relay satellite used by MIR cosmonauts.
PegSat
Satellite carried by first Pegasus rocket launch. Launched 1990, carried
Pegasus booster flight instrumentation and a Barium chemical release
experiment (see CRRES).
HST
Hubble Space Telescope. The single most important satellite ever launched
by mankind (ah-hem). Discovered first direct evidence of black holes
at
the center of other galaxies, measured distances to Cepheid variable
stars
in Virgo Cluster to determine refined value of Hubble Constant, recorded
impact of comet Shoemaker-Levy 9 at Jupiter 1994. Keeps me off the
streets
at night.
MACSAT 2
Multiple Access Communications Satellite. Launched 1990, US military
store-and-forward satellite.
ROSAT
Roentgen Satellite. German/British/US project to image astronomical
objects
at x-ray wavelengths. Launched 1990
CRRES
Combined Release and Radiation Effects Satellite. Released canisters
of thermite and barium compounds to produce artifical "comet" in Earth's
radiation belts and outside magnetosphere in the solar wind. Sunlight
caused barium atoms to ionize and glow in visible light, allowing magnetic
field lines to be traced in a process similar to another widely known
medical use of barium. Also carried experimental electronic devices
for
exposure to Van Allen belts to determine suitability for use on future
space missions. Launched 1990
Feng Yun1-2
Chinese weather satellite in low polar orbit.
GRO
Gamma Ray Observatory. NASA mission launched April 1991, heaviest
shuttle payload that they will admit to. Studies gamma ray emission
from astrophysical objects, measures mysterious gamma ray bursts,
discovered gamma ray emission from the tops of thunderstorms in
Earth's atmosphere.
ERS-1
European Remote Sensing Satellite. Launched 1991.
SARA
French Radio Astronomy satellite, built by students as class project.
UARS
Upper Atmosphere Research Satellite. Measures upper atmosphere
composition and weather, documents destruction of ozone layer.
Launched 1991.
JERS-1
Japanese Earth Resources Satellite. Launched 1992.
EUVE
Extreme UltraViolet Explorer. Measures light from astronomical
objects in wavelength range between short wave ultraviolet and
x-ray part of electromagnetic spectrum. Launched 1992.
SAMPEX
Solar Anomalous Magnetospheric Particle Explorer. The first of NASA's
Small Explorer class of spacecraft. Launched 1992, measures cosmic
ray
fluxes at the polar cap and radiation belts.
TOPEX
Ocean Topography Experiment. Joint French/USA mission to measure sea
level at centimeter accuracy. Launched 1992.
KO-23
Kitsat-Oscar 23. Korean amateur radio satellite
UFO F2
UHF Follow-On satellite. US military communications satellite.
HST Array
Damaged Hubble Space Telescope Solar Array. Jetisioned by Kathy Thornton
during second EVA of first HST service mission, December 1993, when
it
could not be rolled up for safe return to Earth after removal from
HST.
OKEAN 1-7
Russian ocean remote sensing satellite.
RESURS 1-3
Russian Earth resources mapping satellite.
Microlab 1
Mission to map lightning globally, also measures temperature, humidity
and ion density of upper atmosphere by measuring GPS satellite signals.
OFEQ 3
Israeli military surveillance satellite. Launched 1995. Retrograde
orbit,
satellite moves from east to west unlike most other satellites.
Helios 1A
French military spy satellite.
CERISE
French Microsatellite, built by Surrey Satellite Technologies. Evesdrops
on radio signals for French military intelligence. Made news last year
when it was damaged by a collision with orbital debris.
Prognoz-M2
Russian scientific satellite for study of solar activity, solar wind
and effects on Earth's magnetosphere.
RADARSAT
Canadian synthetic aperature radar for Earth resources mapping.
XTE
X-ray Timing Explorer. Measures x-ray emission from astronomical objects
at high time resolution.
Polar
NASA Space Physics Research satellite, part of International Solar-
Terrestrial Physics program. Launched 1996. Operates in high polar
orbit (22.6 hour period). Provided recent measurements of "small comets"
that enter Earth's atmosphere every few minutes.
See http://smallcomets.physics.uiowa.edu/
MSX
Midcourse Space Experiment. US military Strategic Defense Initiative
experiment to determine performance of missile tracking hardware.
SAX
Italian gamma ray astronomy satellite, recently provided data that
assisted
HST in photographing optical counterpart to gamma ray burst.
MSTI 3
Miniature Seeker Technology Integration. Tests infrared sensors for
US
Air Force.
ADEOS
Advanced Earth Observing Satellite. Japanese/US remote sensing satellite.
Launched August 17, 1996. Failed shortly after launch.
FAST
Fast Auroral Snapshot Timing Explorer. Collects high time resolution
particle and field data in low polar orbit passing directly above region
where aurora is generated in Earth's northern and southern polar regions.
MO-30
Mexico-Oscar 30. Amateur radio digital store and forward satellite,
meteor sounding radar experiment. Failed after launch due to exposure
to extreme cold temperatures during launch.
SAC-B/HETE
Satelite de Aplicaciones Cientificas/High Energy Transient Experiment.
SAC-B was joint Argentina/USA scientific satellite for study of solar
flares, gamma ray bursts, diffuse X-ray cosmic background, and energetic
neutral atoms. Argentina's second satellite (after LU-19). HETE was
a
US satellite for multiwavelength study of gamma ray bursts (GRBs) with
UV, X-ray, and gamma ray instruments. Both satellites failed to seperate
from Pegasus launch vehicle, batteries ran down after solar arrays
could
not be deployed. Launched 1996.
ZEYA
Russian military cartographic mission.
MINISAT 01
Spanish astronomy research satellite, launched April 21, 1997.
CELESTIS
Orbital graveyard launched as secondary payload on Minisat launch (contrary
to news media reports which made it sound like the primary payload).
Contains cremated remains of Gene Roddenberry, Timothy Leary, Gerard
K.
O'Neill and Krafft Ehricke. Complete passenger manifest found at
http://www.celestis.com/
Progress M-35
MIR space station resupply ship, unmanned version of Soyuz with no
Earth rentry capability.
SeaStar
Multispectral ocean observation satellite.
Soyuz TM-26
Carried relief crew Solovyov and Vinogradov to Mir space station.
1997038B
1997038C
Unidentified objects (catalog number only) are most likely spent rocket
bodies, space debris, or secret military satellites. Objects with the
same number but different suffix letters are separate objects that
were
placed in orbit on the same launch, for example object 1997038A is
the
Soyuz TM-26 manned mission, objects 1997038B and 1997038C would be
the
spent rocket body or some other debris associated with the Soyuz launch.
STS 85
Space Shuttle Mission STS-85. Landed August 19
CRISTA-SPAS
CRyogenic Infrared Spectrometers and Telescopes for the Atmosphere-
Shuttle Pallet Satellite. Deployed by STS-85 as free flyer to measure
composition of upper atmosphere. Recovered by shuttle before landing,
returned to Earth August 19.
PAS 6
Panamsat. Geostationary communications satellite.
ACE
Advanced Composition Explorer. Launched August 25, 1997. Will occupy
a halo orbit around the Earth-Sun L1 Lagrange point. Measures particle
composition of the solar wind upstream from Earth.
Dan Schultz N8FGV
Re: Antenna alignment
Doug (doug@sunrise.alpinet.net)
Thu, 04 Sep 1997 20:11:02 -0600
n2hv@juno.com wrote:
> Having just put up all my antennas a month or so ago, and suspecting
> that
> my alignment may not be dead on, a thought occured to me.
>
> If I was to take my favorite satellite tracking program, and set
it up
>
> for the sun, should I not be able to sight along the boom for
> alignment?
>
> If my array points dead at the sun, then can I conclude that it will
> also
> be dead nuts to all the other birds also?
>
Jerry....this is what I've used successfully here in the windy country:
Take your compass out, stand at the base of your tower and mark
out a line towards due north (true). Have someone head out along
that line and place a stake....(mine is red) as a point of reference
for your array. Set your antennas to north, hike your tower and
see if your arrays point right at the stake, adjusting til they do.
That's close enough for me and one heck of a lot easier on the eyes.
My sat system seems to work (up 'til today when my 435 preamp
died)well with that alignment...or perhaps I was lucky.
Good Luck
Doug, K7YD
Re: Antenna alignment
Chris Setla (ve4gat@ve4gat.ampr.org)
Tue, 09 Sep 97 17:22:15 +0500 (GMT)
I use the moon here just because it's a little safer for the ol'
eyeball! You could use the sun of course but I would suggest looking
at
the shadow cast from the antennas rather than trying to borsight against
the sun. The moon makes it easier as you can sight along the antenna
booms but either would work.
73 de Chris
CP Coffee Can Feed
Ron Long (rlong@magnus.acs.ohio-state.edu)
Fri, 5 Sep 1997 19:36:45 -0400
Jim, wb4gcs wrote:
>I seek info (references mostly) on DESIGN info for the following:
> Obtaining circular polarization in a "coffee can" feed for a
>microwave system. Have read about people doing this for years, but
>never seen HOW.
>
You use two quarter wave stub radiators inside set at right angles and
fed
90 degrees out of phase. A very nice article on this, for L band, was
in
the AMSAT-NA magazine Orbit (a predecessor of the present Journal)
for
March/April 1983. The author was Dr. John DuBois, W1HDX. It might make
a
good article for reprinting in the Journal if space permits.
ron w8gus.
Re: icom 821h pitfalls. Try cheating.
Chris VK6BIK (chrismor@avon.net.au)
Wed, 10 Sep 1997 10:57:37 +0800
Bruce,
It appears to me that a lot of people have not read their manuals yet
- to
the extent that some may even be considering mutilating their brand
new rigs
to provide extended rx which this rig already has; it's in the specs
on
page 55 of the manual !!
I have not hooked up to Mir on 70 cms yet but have heard it on a poor
antenna with no pre-amp (passes over vk are hopeless at present).
Refer to page 31 of the manual, "Offset Frequency", and try the following
"cheating" technique to store appropriate offsets in memory channels;
1. Choose (eg)channel #30 in memo mode, then switch to VFO "A" mode
2. Choose USB mode
3. program in the rx freq., say 437.660 (continuously adjustable in
sideband)
4. enter Duplex ("DUP--" negative offset) (Func, then fm.DUP)
5. still in USB mode, store to memory (MW for 2 secs)(will be saved
to ch
30), then change from vfo to memo mode
6. push spch.SET for 2 secs to enter set mode
7. push FM twice to see the current (standard) offset for this channel
8. adjust this offset by turning the main tuning dial until you have:
dup--
and also 0.020.0 appearing on the dial/frequency indicator screen (use
khz/mhz fast tune system to do this)
9. press SPCH to exit set mode (you will return to memo mode, ch #30)
10. now press FM to swap from USB to FM mode
11. check T (tone) is not enabled, then store to memory again (MW 2
secs)
12. push ptt to check tx freq. You should see 437.640 as tx when you
do this.
13. change to ch #31 etc.. in memo mode and repeat all above steps
Remember ch 35 is simplex only and rest below this are to be set to
DUP + in
step 4 above.
channel rx repeater offset freq offset resulting tx
30. 437.660 minus 00.020 437.640 mhz
31. 437.658 minus 00.016 437.642
32. 437.656 minus 00.012 437.644
33. 437.654 minus 00.008 437.646
34. 437.652 minus 00.004 437.648
35. 437.650 simplex 00.000 437.650
36. 437.648 plus 00.004 437.652
37. 437.646 plus 00.008 437.654
38. 437.644 plus 00.012 437.656
39. 437.642 plus 00.016 437.658
40. 437.640 plus 00.020 437.660
Doing this does NOT affect other programmed offsets (eg; on repeater
channels stored in other memories)
Sure hope this works for American rigs - my manual says that USA and
Australian versions are the same !
Plse let me know how you get on.
Rgds
Chris VK6BIK
8 el 2m / 15 el 70cm qaugis [Was: 5 element
2m quagi]
Tovar (tvr@mocha.ecofe.com)
Tue, 9 Sep 1997 23:33:47 -0700
The reference you may want to look at is _QST_, January
1990, pp. 24-27,
"Circularly Polarized Quagi Antennas for Space Communication", Gene
Marcus
(W3PM/GM4YRE). It is implemented by feeding the driven element in two
places, 90 degrees from each other.
__
/ \
/ | \
/ | \
/ +| \
/ || \
/ || \
| ____________/
| +--------\
\ || /
\ || /
\ || /
\ || /
\ || /
\/\/
where the double-lines represent 1/4 wave sleeve baluns. [I dislike
ASCII graphics, too, but don't have a scanner.] This method of
feeding for circular polarization was credited to a QST article by
D.S. Robertson, VK5RN, April 1984, pp. 16-18. (Alas, that is too old
for the Berkeley Public Library, so i've yet to track the article down
myself; i think Palo Alto might have it.)
Two designs are given, intended for AO-13, at 145.9 MHz and 435 MHz,
and
the element lengths and spacing correspond with those given in the
ARRL
Antenna Book [17th Ed.]. The driven element and reflector use #12 TW
copper wire, and there's a phasing harness, which used a Radio Shack
relay to switch right/left polarization at 2 meters and simply used
only right-hand polarization at 70 cm.
I didn't find it hard to build an 8 element version of 70 cm design,
but couldn't really understand the results i got. That merely con-
vinced me that i need to start with things that are much simpler and/or
to find an antenna elmer. So, that's not very conclusive, and what
i
may do later is to try the same feed system on a much simpler quad
to
figure out if i ran into trouble with the feed or the quagi aspect
of
the design. If anyone else tries this project, i'd be interested in
hearing about the results. And it does look as if one can easily
change it into a conventional quagi if the feed mechanism gives you
problems (or one might also try the alternate feed with an existing
quagi).
73's and good luck,
-- KD6PAG
S-Band Downconverter - U.S.
Gregory Beat (gregory.beat@mediaone.net)
Mon, 08 Sep 1997 17:32:21 -0500
Lyle Johnson earlier mentioned an S-Band downconverter
made for Drake that he picked up when in Japan.
Well guess what, Drake has them in Ohio, in stock and available.
What follows is Rich Renken, WA8MNF [at Drake]
response to an inquiry.
Subject: MMDS Down Converters
Date: Mon, 08 Sep 1997 13:32:41 -0700
From: Rich Renken <Rich_Renken@rldrake.com>
Drake has a converter that converts 2.4 Ghz into the cable band
spectrum.
We have a few hams purchase them for AMSAT. There was a ham out
in the
west that purchased a number of them and resold them. We have
not sold any
from here that have been converted to the ham bands.
We are selling them for $50.00 each in quantities of one.
The converter comes with a power inserter and power supply cube.
I have a
quantity in stock and if there are hams interested in purchasing
them send
them my way.
73's
Re: S-Band Downconverter
Lyle Johnson (lylej@azstarnet.com)
Thu, 11 Sep 1997 18:59:19 -0700
I have gathered together all the data I have on this unit. There will
be
more after I get the info from JAMSAT. Please be patient.
Per RL Drake (as posted here by others):
Input: 2500-2686 MHz, Type N connector, 50 Ohms
Output: 222-408 MHz, Type F connector, 75 Ohms
Local Oscillator: 2278 MHz
Noise Figure: 3dB nominal
Small Sig.Gain: 21dB minimum
Power: 13 to 24VDC at 240ma. maximum. supplied by optional
power inserter via output coax cable.
I have additional information which claims that:
1) At 2.4 GHz the gain of the converter drops to about 7dB. Thus, the
need
for another RF amplifier as is done with the mods. This makes up for
the
non-optimum filters for 2.4 GHz Amateur operation.
2) With the default crystal (8.898 MHz), the PLL is as Drake claims,
2278
MHz, meaning 2.4 GHz would come out at 122 MHz.
3) The mods change the crystal to 8.8125 MHz. The x256 PLL provides
an
L.O. of 2256 MHz, converting 2.4 GHz to 144 MHz.
4) Testing of the original unit with an input level of -50 dBm reported
an
output level (gain) of:
2.4 GHz: -43 dBm (+ 7 dB)
2.5 GHz: -27 dBm (+23 dB)
2.6 GHz: -26 dBm (+24 dB)
2.7 GHz: -28 dBm (+22 dB)
5) The LO harmonics are suppressed as: 2nd harmonic -20 dB, 3rd harmonic
-40 dB.
All of the above measurements were done by others and printed on a data
sheet in Japanese characters which I am summarizing above. I did not
take
them and can't personally attest to them.
Again, when I have more information I'll pass it on. I've answered a
LOT
of requests for information by individuals, it seems there is enough
interest to post this to the group. Now, I've got to go silent on this
topic until I get more information from our colleagues. Meanwhile,
I'll
get back to work on RUDAK...
73,
Lyle
Good comments on lead-acid battery charging.
The main point to remember is that neither constant-current nor
constant-voltage charging is ideal. Indefinite constant-current
charging will boil the battery dry. Constant voltage charging at a
voltage low enough to avoid excess gassing (e.g., 13.8V for a 6-cell
battery) is better, but it's suitable only for maintaining an already
charged battery (float charging). It won't bring a battery all the
way
up from a discharge.
What you really want is a smart battery charger designed specifically
for lead acid batteries. They switch automatically between constant
current (recharge) and constant voltage (maintenance) modes, with a
timed high-voltage (15+ V) "equalize" mode for use every month or two
to make sure all of the cells are brought to full charge. These smart
chargers are available in marine supply stores. While they're not as
cheap as an unregulated automotive charger or a bunch of Dayton
surplus Lambda power supplies, they do work much better.
In some cases you can find these chargers built in to AC inverters with
automatic cutover, making very nice UPSes.
Phil
Re: Need IC-821H out of band mods
Roberto Manderioli (rmander@geocities.com)
Mon, 09 Jun 1997 17:02:06 +0200
At 23.12 04/06/97 -0700, you wrote:
>On Wed, 4 Jun 1997, Jim Dawdy wrote:
>
>> Looking for out of band rx mod for the Icom 821H
>
>Per the artsci mods book, cut resistor D101 for 144 RX expansion (136-174)
>and D103 for 440 RX expansion (420-460) (D105 and D107 for corresponding
>TX expansion.)
>
>These are on the display board.
>
>Bob
AO-10 Website
Stacey Mills (w4sm@cstone.net)
Sun, 08 Jun 1997 14:27:32 -0400
Dear Group,
Several people have asked about what we might be able to discern re.
AO-10's current attitude, illumination. I've run some routines and
put
this information on one of my web pages, along with a lot of other
AO-10
related stuff, FAQ's etc at:
http://www.cstone.net/~w4sm/AO-10.html
As time permits, I'll update this with some more historical information.
The information regarding attitude must be taken with a large "grain
of
salt", but it's based on what little we can determine.
..it's interesting to postulate how AO-10's attitude may have changed
fairly
dramatically in the last few months.
....Enjoy.
Try QST August1996 73 Steve W2ZBY
On Tue, 10 Jun 1997 08:04:07 -0700 David Covert <davecove@microsoft.com>
writes:
>
>Can someone point me to some plans for a homebrew 435MHz quadrafilar
>antenna? (one of the twisted eggbeater kind, not the spherical
>eggbeater
>type)
>
>73,
>Dave KB5GOG
Hi,
A flat dweller has asked me for advice on whether he could work the
digital satellites using omni-directional antennas.
Sometime ago there was an interesting thread about the Egg Beater
antenna. There weren't very many reports from actual users, but I
gathered that reception of the signals was likely to be marginal on
70 cm., especially for the 9600 FM birds. A good pre-amp is
desirable.
In 1989 I built a turnstyle for two metres. Crossed two element
yagis with wide spaced reflectors (3/8 wavelength). The theory was
that the wide spacing would reduce the vertical gain, and increase
the gain at lower elevations, where signals are weaker. Although it
worked for OSCARs 9 and 11, signals were rather weak, so I prefered
the extra gain of my six element crossed Yagi.
My own conclusions were that these antennas are better suited to
satellites with strong signals, such as DOVE. Unattended reception
of
OSCAR-11 might give some useful results, using a recorder operated
by
receiver squelch, so that all passes could be recorded (although I
haven't tried it).
Does anyone else have actual operating experience with these
antennas? Which type is best Turnstyle, Eggbeater, Quadrifilar helix
or Lindenblad?
73 Clive G3CWV
RE: Omni directional antennas for digital
birds
Hoskin, Richard J (RHoskin@vitgitn1.telstra.com.au)
Mon, 30 Jun 1997 10:37:00 +1000
Gday Clive,
I'm using a vertical J-Pole with a mast-head preamp for 70cms and some
good quality hardline coax. This works fine for me with an average
of
50% efficiency on KO23 & 25. The J-Pole is not so good for passes
below
about 12deg or above about 75 deg elevation. But most of the time the
sat is in the 10 to 50 deg elevation anyway.
The transmit antenna is a 2mtr collinear which is mounted at a lower
height and about 10ft away from the Rx antenna to stop Rx descencing.
I
was using a Diamond dual band vertical (X-200 I think) for a time for
2mtrs but found it was not being as well received by the sats as the
collinear. I know that the theoretical radiation pattens for 'high
gain'
Omni antennas is supposed to be 'not suitable for satellite work but
as
I'm in the real world and there are lots of reflections of signals
from
surrounding trees and buildings, I thought I'd give it a try. Its fun
to
experiment.
The Radio is an FT736r running 25watts and the doppler shift is
controlled via a PC, Wisp and the interfacing software to the radio
is
FT736R Ver 3.0
To make up for the overall relatively low efficiency rate ( although
some passes have an efficiency of 80%) I run the station 24hrs a day.
This allows me to get all the files I want from the sats, although
it
normally takes a few passes.
I wanted to keep my antennas as simple as possible and to see what can
be done with out spending big buck unnecessarily.
I am in the process of building a Quadrifilar helix for 70cm to see
if
it will increase the reception.
Hope this helps
Regards
Richard.
VK3JFK
LA2QAA quad comparisons
Anthony Monteiro (monteira@integnet.com)
Thu, 07 Aug 1997 09:58:41 -0400
In a recent AMSAT Journal article, John Hackett, LA2QAA
recommends the use of a horizontal quad as a good
newcomers or apartment dwellers, satellite antenna.
Several people have contacted me and asked how
this antenna would "stack up" relative to other
antennas like those I analyzed in my article in the
March/April 97 issue. This is a short comparison of the
horizontal quad relative to:
1. a vertical groundplane (with 4 "drooping" radials)
2. a turnstile
3. an eggbeater with a reflector
4. a (single-section) Lindenblad.
These are in order of construction difficulty!
BACKGROUND:
------------
I modeled the quad using the dimensions provided
by LA2QAA. I used the square shape, 525mm per side.
All other antennas were designed for 146 MHz
center frequency.
RADIATION PATTERN:
------------------
The quad's azimuth pattern is similar to a dipole
It has nulls on the sides perpendicular to the feed side.
The gain in the direction of the feed point is
slightly higher by .25 - .5 dB than the opposite side.
The elevation pattern is identical to the turnstile
(in the direction of maximum gain.) This includes
several lobes of about equal gain below 30 degrees.
This pattern is better for satellite use than the
vertical groundplane which has a single low angle
lobe and which drops off above 5 degrees.
POLARIZATION:
-------------
The quad is horizontally polarized like the turnstile.
The loss due to polarization mismatch into a satellite like
FO-20 which is nominally circular is a (roughly)
constant -3dB.
For satellites like RS-15 that are linearly polarized, the
average mismatch loss is -6dB but varies due to
Faraday rotation from 0 to -30dB.
ADJUSTED GAIN
-------------
I assumed the antennas were all mounted so that
the bottom of the antenna was at 20 feet.
The maximum gains at angles below 30 degrees
elevation for each antenna are given below.
These are adjusted for the polarization loss into
FO-20/29. (For RS-15, subtract 3 dB from each antenna.)
Antenna Max Gain (dB)
------- -------------
Quad 3.0
Vertical 3.0
Turnstile 2.5
Eggbeater 4.8
Lindenblad 7.2
COMMENTS:
---------
The quad is not omni-directional so it is
necessary to point it in the general direction
of the satellite. If you are willing to do this,
(which shouldn't be too hard!) this antenna
provides performance slightly better than the turnstile.
Given that this antenna is quite easy to build and
performs better than a vertical or a turnstile,
it would seem a good choice for a beginner or where
space is limited.
Tony - AA2TX
aa2tx@amsat.org
2.4 dish question..
Ed Krome (71611.76@compuserve.com)
Tue, 15 Jul 1997 18:00:37 -0400
Chad:
2.4 dish construction with either aluminum or wood center posts:
I've done it both ways. My present dish uses an alumimum hub with 1/4
Al
rods sticking out (8) that are pulled to .4 f/d by dacron catfish line
th=
at
is attached to a (short) extension ot the pipe sticking out of the
dish
side of the hub. An aluminum pipe (screwed into the hub) extends behind
t=
he
hub abnd is clamped to the crossboom. A 3/4 wood (varnished) dowel
rod
sticks out the front and supports the helix feed. The reflector is
1/4"
mesh "hardware cloth", laid in in 8 segments and wired (stainless wire)
t=
o
the frame skeleton after they are pulled to parabolic shaft. This dish
ha=
s
lasted over 2 years with no deterioration. The previous dish was similar
but all wood. Its center hub broke after 1 1/2 years on the pole.
G3RUH's designs use an aluminum center pipe that extends all the
way trhough the feed. His helix is centered around the pipe.
Try it!
Ed K9EK
2.4 GHz transmit converter
Zack Lau (zlau@arrl.org)
Thu, 17 Jul 1997 08:45:42 -0400
The 2.4GHz converter in the 1997 ARRL Handbook p.23.42
can be adapted for transmit operation. The output of
the 2.4 GHz bandpass filter is a 50 ohm point and the
mixer is bilateral, so one could add a T/R switch and
amplifiers. The ERA MMICs sold by Mini-Circuits ought
to work just fine for driving the May 94 QEX 2 watt amp.
(Hosfelt Electronics had the device on their WWW page)
10 watts is a challenge. Surplus Fujitsu FLL100s may
work, but I think these unmatched devices have a very
low output impedance that is tough to work with--a 6
GHz IMFET might be a better choice. I had to resort to
aluminum backed Duroid circuit boards... with IMFETs up
to 10 GHz I can usually just attach to board to metal
plates with lots of screws... I suppose the rich might
also investigate getting 2.4 GHz IMFETs...
Zack Lau W1VT
Re: 2.4ghz test beacon
Jim Kelly (skeptic@netaxs.com)
Thu, 24 Jul 1997 09:31:33 -0400
Glenn Levey wrote:
> is there any other sat. with a 2.4ghz beacon going i can try with
, > and is the
> beacon on do-17 a cw tone then a ident , or just cw.???? thank you
for
> helping me ..Glenn vk3zgl@amsat.org
Hi Glenn,
I have been monitoring both Dove (DO-17) and UO-11 on 2.4 for several
months now.
According to _How To Use The Radio Amateur Satellites_, Sixth Ed.
1997-1998, by Keith Baker, KB1SF (available from AMSAT), Dove's beacon
on 2401.2205 is 1200 BPS BPSK at 1 watt, but it sounds like a rough-note
CW tone to me, with no ID.
UO-11 has beacon on 2401.500 which sounds like a CW tone to me. it is
much weaker than DO-17.
At my location (typical) DO-17 is S8 and UO-11 is S3 on 2.4.
Hope this helps!
Jim Kelly
IRV BAUER wrote:
>
> Where is the best place on the web to find your stations latitude/longitude
> coordinates for accurate data for any tracking program.....Regards,
>
> Irv WA6LVE
A couple of places are:
http://tiger.census.gov
and
http://www.qrz.com
Mike
AO-27 Schedule and Operation
Michael Wyrick (n4usi@amsat.org)
Sun, 6 Jul 1997 12:29:25 -0400
AO-27 Schedule and Operation
----------------------------
This information can be found at www.umbra.com
AO-27 TEPR (Timed Eclipse Power Regulation) States are as follows
As of July 6, 1997
TEPR STATE Time TX Status
----------------------------------------
1 n/a OFF
2 n/a OFF
3 --- OFF
4 21 OFF
5 17 ON at Med Power
6 --- OFF
The TEPR States are defined as follows:
Tepr 1, Started when the satellite Enters the Eclipse
Tepr 2, Started at (tepr 1 time) after the satellite enters the eclipse
Tepr 3, Started at (tepr 1 time) + (tepr 2 time) ...
Tepr 4, Started when the satellite enters the Sun
Tepr 5, Started at (tepr 4 time) after the satellite enters the Sun
Tepr 6, Started at (tepr 4) + (tepr 5) ...
You should note that TEPR states 1,2 and 3 happen during the Night Time
passes and TEPR states 4,5 and 6 happen during the Day time passes.
These
occure during EVERY pass, not just over the U.S.A.
The times assigned to the TEPR states are chosen for the health of the
satellite over operation convenence. Therefore, during parts of the
year the
satellite will turn on late or turn off early as seen by ground stations.
Users are reminded that as an FM-mode repeater, AO-27 is subject to
FM "capture effect" and can only transmit one signal at a time. Users
are asked to cooperate, keep calls short, give breaks so as many
stations as possible can work a pass, and above all, listen before
and while transmitting. The satellite has a very sensitive receiver,
and stations running approximately 25 watts power to moderate-gain
omnidirectional antenna can get a good uplink signal into the
satellite. A sensitive UHF FM receiver with a preamplifier and
an omnidirectional antenna can receive AO-27's downlink with some
fading; moderate-gain directional arrays should provide a solid
receive signal. Remember to correct for the +/- 9 kHz of Doppler
shift on the 436 MHz downlink signal during a pass.
No Doppler correction is needed for the 145.850 MHz uplink signal.
Users are asked not to transmit on 145.85 MHz if they do not hear the
satellite's downlink so as to avoid possible interference to other
satellite uplinks and downlinks on adjacent frequencies.
- Michael Wyrick
N4USI
AO-27 Control Operator
Re: ?dual band antenna with single band
amp?
Andrew Cornwall (cornwaab@ednet.ns.ca)
Sun, 3 Aug 1997 12:53:00 +0000
Hi Bill,
I am using the kind of set up that you are considering with
excellent results. My FT736r feeds a 150W 2 Metre amplifier which
then feeds the 2 meter side of a duplexer. The UHF part of the FT376r
is connected to a preamp which then the connects to the UHF side of
the
dupexer. A multi-band antenna connects to the common I/O of the
duplexer.
I am sending you another message directly which has a hand drawn
diagram of the setup in a zipped BMP file.
If anyone else on bb-amsat would like the diagram I will send it
to you. If there are a lot of requests I will post it (approx. 15K).
--- Andy / VE1COR
cornwaab@ednet.ns.ca
> From: "Bill Jones" <wejones@megalink.net>
> To: <amsat-bb@amsat.org>
> Subject: ?dual band antenna with single band amp?
> Date: Fri, 25 Jul 1997 15:22:23 -0400
> I asked this question to another list, and got no response. Question
is, I
> am considering the use of a dual (2M/440) antenna with my 736, but
would
> like to continue using a 160W 2M power amp/preamp. This combination
seems
> to present problems, in that if I use the power amp before the duplexer,
I
> don't think that the duplexer can survive the power (although the
ratings
> are greater than the power of the amp, I think that the ratings are
not for
> continuous duty), and I wasn't sure if the duplexer would be sufficient
to
> protect the 440 side from the additional power. If I put the amp
after the
> duplexer, I wasn't sure what the implications would be with respect
to
> receiving on 440 while transmitting on 2M, ie it seems like receive
would
> be disabled. Also, I wasn't sure whether there was any problem with
the 2M
> preamp switching out of the system and/or surviving when transmitting
on
> 440?
> Any recomendations on the best way to proceed, or am I better off
> staying with separate 2M and 440 antennas?
> Thanks in advance.
>
> ******************************************
> * Bill Jones Sweden, Maine *
Analytical Graphics announces STK 4.0
ask4stk@stk.com
Mon, 28 Jul 1997 09:31:42 -0400
Dear Satellite Systems Professional,
Because of your interest in our Satellite Tool Kit (STK) software,
Analytical Graphics, Inc, (AGI) has some very important news. A=20
new version of the industry leading software for satellite systems
analysis, STK 4.0, has just been released and it is available for=20
FREE!
This is an extraordinarily powerful and comprehensive new version
that builds on earlier STK releases. AGI is offering you a full
and permanent license to STK for FREE with no obligation to
purchase anything, ever. We don=92t mean to shout, but we really are
quite excited about this. But don=92t take our word for it. Just go
get it. We'=92d love to hear what you think.
You can download it from our web site at http://www.stk.com. Or=20
request a CD-ROM by calling 1-888-ASK-4STK (1-888-275-4786) in the
United States, 44 (0) 181 299 3435 in Europe, or 610-594-6939 from
everywhere else. E-mail requests (be sure to include your name,
address, and phone) can be sent to ask4stk@stk.com.
We believe this initiative will help unite the worldwide satellite
community by providing satellite systems analysts with a common
tool for communication and collaboration. There is plenty of=20
helpful information available on the AGI web site, like details=20
on STK's features, info about AGI, a comprehensive knowledge base=20
for technical support, and a discussion forum that puts you in
touch with other STK users. Now, there's no better time to join=20
your professional colleagues and help yourself to the power of STK.
If you are no longer involved in satellite systems, we regret any
inconvenience this message may have caused. =20
Analytical Graphics, Inc.
660 American Ave., Suite 200
King of Prussia, PA 19406
Voice: 610-337-3055
Fax: 610-337-3058
Web: www.stk.com
email: info@stk.com
Inexpensive antennas
David Guimont (WB66LLO@postoffice.worldnet.att.net)
Mon, 4 Aug 1997 21:26:19 +0000
I've had several questions regarding the list below, and have answered
them
directly.
The files are located at http://users.aol.com/dguimont if others are interested.
Do not hesitate to contact me directly if you have questions.
Briefly, the descriptions located there:
Briefly, file descriptions located here:
FILE DESCRIPTION
describe.txt The file you are reading.
collina.zip Inexpensive collinear J-pole for
437 MHz.
microant.zip Satellite antenna comparisons plus
inexpensive matching device.
quadsend.zip Quadrifilar antennas for amateur
and weather satellites.
toron5a.zip 5th annual AMSAT convention jewelry
contest, with pictures.
tt22l.zip Test procedures for jewelry contest.
73 Dave, WB6LLO disagree; I learn
Re: Path Loss Calculation
DSCHULTZ@SSSP.HST.NASA.GOV
Tue, 5 Aug 1997 20:46:32 GMT
Kevin Uhlir asks:
>For a line of sight path on the earth, in the atmosphere, what is the
=
>pathloss calculation for VHF & above?
>If there are too many variables to consider, what is the path loss
in a =
>vacuum in free space?
According to the Satellite Experimenter's Handbook, path loss in free
space
is:
Path Loss (dB) = 10 * log10 (4 * PI * R / L ) ^ 2
where R = range
L = wavelength (in the same units as range)
You would need to consult a radio engineering textbook to see if
there is a correction for the presence of air. I would guess that it
would be small at the frequencies that we use.
Dan Schultz N8FGV
Re: 145mHz QRN
Dave Metz (Dave.Metz@mut1.muscanet.com)
Thu, 14 Aug 1997 09:22:21 -0600
> From: Dan James <danj@marvin.com>
> To: "'Amsat BB'" <amsat-bb@AMSAT.org>
> Subject: 145mHz QRN
> Date: Wed, 13 Aug 1997 23:42:57 -0500
>
> Amsat-BB,
>
> As a recent newcomer to satellite operation I have enjoyed almost
all
> the analog birds from the RS and FO series to AO-10. In fact, AO-10's
> recent strong signals have been a wonderful addition to my satellite
> enjoyment. However, I (like many of you), suffer at times from terrible
> powerline noise problems. Many times the local QRN is S-9 or better.
>
> In my case the noise seems to be coming from a nearby (1/8 mile)
> sub-station. I have recently talked with their technical representative
> who seems supportive of my problem and will soon be coming by to
> take a better look (and listen).
>
> What I need is some feedback from some of you who may have gone
> through the same situation, and what measures you took to combat
the
> interference. Any ideas you have may help!
>
Dear Dan,
Our local power company has been very helpful in tracking down and fixing
QRM
problems. Most are due to bad joints and grounding problems. They know
from long experince that RFI preceeds a serious failure. Tightening
a connector
is a lot easier and cheaper than a major outage.
Our company sends out an engineer with a interesting RFi sniffer. Its
a commercial
300Mhz AM receiver with a small hand held beam. It works pretty well.
I usually give
him the azmuths to the noise and he tracks them down. Yes, they still
tap on poles
with a mallet like in the old days. They also have a infrared viewer
to look for local
heating from arcing, but mostly the receiver does the job.
Keep calling and it that does not work, have your niebors call and tell
them they
have TVI!
> See you on the birds,
>
> --Dan KE0DH--
> danj@marvin.com
> ke0dh@amsat.org
Re: Icom IC-820 H vs. IC 821H
Duane Naugle (duane_naugle@smtpgate.mitchell.com)
Wed, 27 Aug 1997 17:21:12 -0700
I'll try to list the differences, this may not be exhaustive.
IC-820H IC-821H
High or Low power adjustable power (6-45W)
116 Memory channels 160 Memory channels
Internal Switches for: Menu Selection of:
1200 vs 9600 packet 1200 vs 9600
main vs sub audio@acc main vs sub audio
ALC vs UP/DOWN ?
No microphone Mic. included
No CW keyer Adjustable CW keyer
No 9600 on Satellite mode 9600 on Satellite mode
No narrow CW on Satellite Narrow CW on Satellite(available)
No Sub band transmit Sub band transmit
Sub band always on Sub band can be shut off
Basically I'd characterise the IC-820H as an excellent all-mode dual-band
rig which can work analog and 1200 bps digital satellites. The IC-821H
is a
more serious satellite rig which fixed shortcomings in the IC-820H
and added a
few features. You have to decide whether it's worth the close to $600
price
differential. This is only my opinion. 73
Duane, KO6BT
Get your own Free Home Page