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Subject: HamDigitalDigest 99/304A
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Ham-Digital Digest Sat, 27 Nov 99 Volume 99 : Issue 304
Today's Topics:
2 meter APRS transmitter for rocket (4 msgs)
anyone here using the new SCS PTC-IIE? or on Winlink?? (2 msgs)
Best Windows Terminal Program for WA8DED TNCS
Computer RF noise in HF SSB (2 msgs)
Digital Modes, What a mess
FCC reallocates Ham Band
German packet radio (3 msgs)
Kenwood TS-570D and Kam
PACOMM Packet modems
radio noise
RTTY logging/contest software for KamPlus?
TFX & TXPCX WA8DED emulators for KISS modems (2 msgs)
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We trust that readers are intelligent enough to realize that all text
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policies or positions of any party. Your mileage may vary. So there.
Loop-Detect: Ham-Digital:99/304
----------------------------------------------------------------------
Date: 26 Nov 1999 14:14:46 GMT
From: sims@sauron.msfc.nasa.gov (Herb Sims)
Subject: 2 meter APRS transmitter for rocket
dchapman@postoffice.pacbell.net wrote:
>>
>> I'm looking for a 2meter kit with as much solid state components as
>> possible. Coils have a way of changing their reactance when subjected
>> to 50g's!
If you figure out how to get this to work with GPS we (NASA) would have a
job for you in our branch. We (NASA) can't even get the shuttle to maintain
lock on the GPS satellites during ascent and they only see 3 G's. The other
problem that you have is that above 1000 mph (and in most cases much less) the
GPS receiver will "lock out". This is to keep some nut from putting a bomb in
a cessna and flying like a bomb. I think you need to do a lot more homework
in this area. You can also call me and I'll put you in touch with the real
experts (I am just repeating what I have overheard them talking about on the
current projects we are working on).
Herb
--
-------------------------------------------------------------------------------
-
W. Herb Sims sims@sauron.msfc.nasa.gov
NASA/MSFC/EB56 sims@saruman.msfc.nasa.gov
Huntsville, AL 35812
sims@galadriel.msfc.nasa.gov
KU0C Voice (205) 544 8581
PP-ASEL-IA FAX (205) 544 8483
If someone with multiple personalities threatens to kill himself,
is it considered a hostage situation?
-------------------------------------------------------------------------------
-
>.
------------------------------
Date: Fri, 26 Nov 1999 08:03:22 -0800
From: dchapman@pacbell.net
Subject: 2 meter APRS transmitter for rocket
Herb Sims wrote:
> If you figure out how to get this to work with GPS we (NASA) would have a
> job for you in our branch. We (NASA) can't even get the shuttle to maintain
> lock on the GPS satellites during ascent and they only see 3 G's.
I'm not depending on APRS to locate the position of the rocket during
ascent, I can follow the smoke trail. The only need for APRS will be on
the descent of the rocket, under parachute, to find it when it lands.
And yes, I know GPS altitude readings are not accurate. We have a
different device for this function.
The other
> problem that you have is that above 1000 mph (and in most cases much less)
the
> GPS receiver will "lock out".
Thanks for the tip, if this one does lock out, I can set it up to power
up the GPS only after the rocket reaches apogee.
This is to keep some nut from putting a bomb in
> a cessna and flying like a bomb. I think you need to do a lot more homework
> in this area.
No, I just need to find a 2 meter transmitter on a PC board that will
fit within the 3.75 inch diameter payload section. I'll put the project
together, launch it, and see if it works. Since I'm not spending the
government's money, I'm not that worried if it doesn't.
Thanks,
Dave Chapman
KC6UWP
>.
------------------------------
Date: 26 Nov 1999 20:10:20 GMT
From: John Wiley <jw@physics.gmu.edu>
Subject: 2 meter APRS transmitter for rocket
Herb Sims <sims@sauron.msfc.nasa.gov> wrote:
: dchapman@postoffice.pacbell.net wrote:
:>>
:>> I'm looking for a 2meter kit with as much solid state components as
:>> possible. Coils have a way of changing their reactance when subjected
:>> to 50g's!
: If you figure out how to get this to work with GPS we (NASA) would have a
: job for you in our branch. We (NASA) can't even get the shuttle to maintain
: lock on the GPS satellites during ascent and they only see 3 G's. The other
: problem that you have is that above 1000 mph (and in most cases much less)
the
: GPS receiver will "lock out". This is to keep some nut from putting a bomb
in
: a cessna and flying like a bomb. I think you need to do a lot more homework
: in this area. You can also call me and I'll put you in touch with the real
: experts (I am just repeating what I have overheard them talking about on the
: current projects we are working on).
Im not so sure the Cessna theory is correct... It seems more likely that the
RX is losing
lock because of "financial" concerns... Tracking loop(s) arent holding lock
because of
doppler... Additionally, most Cessnae tend to top out at significantly less
than
1000 MPH... :-> In a situation like the "shuttle", the design environment is
SO
nasty... (high velocity/doppler... passing through several atmospheric layers
with
various scintillation/fading characteristics... Gads... Im pretty sure you
aren't going
to be using a COTS antenna... :-) Im 100% certain that a 130.00 Garvin
receiver ain't
gonna cut it... :-)) Interesting engineering problem though...
Hmmmmmmmmmmmm.... Neat... Better than crossword puzzles...
Best Regards,
-jw
>.
------------------------------
Date: Sat, 27 Nov 1999 11:42:22 GMT
From: anonymoose@ISP.com (Anonymoose)
Subject: 2 meter APRS transmitter for rocket
On 1999-11-26 sims@sauron.msfc.nasa.gov(HerbSims) said:
> We (NASA) can't even get the
>shuttle to maintain lock on the GPS satellites during ascent and
>they only see 3 G's.
Not to mention NASA's inability to do basic conversions between Metric and
Imperial measurements.
> The other problem that you have is that above
>1000 mph (and in most cases much less) the GPS receiver will "lock
>out". This is to keep some nut from putting a bomb in a cessna and
>flying like a bomb.
You don't need GPS or a Cessna to fly like a bomb, just frozen O-rings
To be continued in digest: hd_99_304B
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