I'm sorry we didn't get in touch, but my cell phone died while we were out there.
Were were listening on 146.610, but didn't hear anything except the time. Maybe we weren't using it correctly?
If you could get all of that material tomorrow, that would be excellent. We do have access to sanding paper, a file, and a grinding wheel, though.
On Mon, Apr 21, 2008 at 11:26 PM, F. Kevin Feeney fkf1@cornell.edu wrote:
Were you transmitting in just one direction or from TS to D7 and then from D7 to TS?
Via packet, only TS to D7 (some were sent the other way, but we were told having attenuators on the RX side would give us unreliable data). By voice, both directions, and while that signal was fuzzy at higher attenuation, it never completely cut out. For the packets, we always received them on the radio, but the number recorded was the amount passed on to the computer.
Why list the power settings in each radio if you are only transmitting from the TS2000 to the D7? That confused me.
Just for completeness.
How successful have you been at running the radios in 9600 baud mode in previous testing? If you don't have many weeks of positive results in that mode at this point with whatever antennas, I'd be very wary of committing to a launch.
Not very. We could complete the mission at 1200 baud, though, it would just take longer to move data back and forth.
so what are the power listings for each radio telling us? To me I think I'm seeing that your circularly polarized antenna isn't quite as good in horizontal mode as in vertical? You have to have less attenuation in place to get two good packets per two tries for the same power settings in horizontal as for vertical. looks like about a 15 db difference? (30 vs 45?) That says your circular antenna "circularity" is suspect. Is it a helix? Crossed yagis with phasing harness? Is it up in the air off the support structure? Are the feedlines trailed out the back of the antenna, or do they come down through the elements to the mast?
I'm sorry that I wasn't clear, but all our rotations were in the direction of the other station. So, if an observer were looking at us from the side,
Vertical: "satellite" | XXXXX- Ground
Horizontal: "satellite" -- XXXXX-Ground
45 deg: "satellite" / XXXXX-Ground
So we didn't really test the circularity of the ground antenna, but the gain pattern of the rubber duck.
Wait - were you testing the loop during any of this? I thought all of the measurements were made with the rubber duck only in three orientations, vertical, horizonatal and 45 degree. Where is the loop data shown?
The loop data is the 10 dB figure mentioned in my first email. Under these same conditions on Friday, the loop only worked up to 10dB.
Also, I can use a network analyzer tomorrow at 2PM. Is it worth analyzing the square loop antenna at this point?
-Nate
Hi Nate...
Now that you have made some progress and secured some successful communication, it might be time to optimize your base (control) station.
You mentioned in your first post that you were using "RG-8" coax but not how long a run of it you had. At 435 mHz, RG-8/U is no where near optimal and connectors do matter. Type "N" connectors would be best and a less lossy coax might help you find those "missing" dB.
How long is your coax run and is it continuous or does it have splices?
Roger WA1KAT
----- Original Message ----- From: "Nathaniel S. Parsons" nsp25@cornell.edu To: "Amateur Radio Club" hamradio-l@list.cornell.edu; amsat-bb@amsat.org; gs@cusat.cornell.edu; tc@cusat.cornell.edu; "Dan Oltrogge" Oltrogge@1earthresearch.com Sent: Monday, April 21, 2008 11:43 PM Subject: [amsat-bb] Re: Ridge Test Results
I'm sorry we didn't get in touch, but my cell phone died while we were out there.
Were were listening on 146.610, but didn't hear anything except the time. Maybe we weren't using it correctly?
If you could get all of that material tomorrow, that would be excellent.
We
do have access to sanding paper, a file, and a grinding wheel, though.
On Mon, Apr 21, 2008 at 11:26 PM, F. Kevin Feeney fkf1@cornell.edu
wrote:
Were you transmitting in just one direction or from TS to D7 and then
from
D7 to TS?
Via packet, only TS to D7 (some were sent the other way, but we were told having attenuators on the RX side would give us unreliable data). By
voice,
both directions, and while that signal was fuzzy at higher attenuation, it never completely cut out. For the packets, we always received them on the radio, but the number recorded was the amount passed on to the computer.
Why list the power settings in each radio if you are only transmitting from the TS2000 to the D7? That confused me.
Just for completeness.
How successful have you been at running the radios in 9600 baud mode in previous testing? If you don't have many weeks of positive results in
that
mode at this point with whatever antennas, I'd be very wary of
committing to
a launch.
Not very. We could complete the mission at 1200 baud, though, it would
just
take longer to move data back and forth.
so what are the power listings for each radio telling us? To me I think I'm seeing that your circularly polarized antenna isn't quite as good in horizontal mode as in vertical? You have to have less attenuation in
place
to get two good packets per two tries for the same power settings in horizontal as for vertical. looks like about a 15 db difference? (30 vs
45?)
That says your circular antenna "circularity" is suspect. Is it a helix? Crossed yagis with phasing harness? Is it up in the air off the support structure? Are the feedlines trailed out the back of the antenna, or do
they
come down through the elements to the mast?
I'm sorry that I wasn't clear, but all our rotations were in the direction of the other station. So, if an observer were looking at us from the side,
Vertical: "satellite" | XXXXX- Ground
Horizontal: "satellite" -- XXXXX-Ground
45 deg: "satellite" / XXXXX-Ground
So we didn't really test the circularity of the ground antenna, but the
gain
pattern of the rubber duck.
Wait - were you testing the loop during any of this? I thought all of
the
measurements were made with the rubber duck only in three orientations, vertical, horizonatal and 45 degree. Where is the loop data shown?
The loop data is the 10 dB figure mentioned in my first email. Under these same conditions on Friday, the loop only worked up to 10dB.
Also, I can use a network analyzer tomorrow at 2PM. Is it worth analyzing the square loop antenna at this point?
-Nate _______________________________________________ Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
participants (2)
-
Nathaniel S. Parsons -
Roger Kolakowski