Re: [amsat-bb] Beginners questions

[tlang@xxxxxxxxxxxxxxxxxxxx (Tony Langdon)]

Hello Bob.

01 Mar 00 11:00, you wrote to ALL:

 >> First, can I expect to work any of the FM birds, reasonably, with a
 >> 2 meter vertical or dipole?  (same for 440)

 BB> Yes & No.  I have been using a 20.25 inch vertical whip antenna over a
 BB> ground plane as a dual band 2m and 440 antenna for the satelites for
 BB> about 2 months.  It acts as a 1/4 wave on 2m and as a 3/4 wave on 435
 BB> MHz with a good pattern for satellites.  It has low VSWR on both
 BB> bands.
 BB>
 BB> I have found that using an HT (kenwood with built in 9600 baud TNC), I
 BB> can regularly hear every pass as follows:
 BB>
 BB> AO27 above 25 deg
 BB> UO14 above 20 deg
 BB> UO22 above 25 deg
 BB> KO23 above 15 deg
 BB> KO25 above 20 deg
 BB> TO31 above 10 deg
 BB> SO35 above  5 deg

With handheld antennas, I get UO-14 down to around 3 degrees and SO-35
practically to the horizon.  The reason I am able to get these results with
simple antennas is because they're totally portable (i.e. I can realign them to
suit the bird at the particular moment).  The tri band base antenna will work
very well on SO-35's downlink (have a look on
http://www.qsl.net/vk3jed/sat.html and listen to the more recent .MP3 files,
all recorded off the vertical), but it's not so good on 70cm, unless the
satellite is below 5 degrees (at which point it will outperform the handheld
antennas and hold UO-14 down to 1 degree).

 BB> Almost all of these satellites have shown to be predominantly
 BB> vertically polarized most of the time, so there is no 3dB loss

UO-14 does vary, but mostly vertical when it's low and can be horizontal at
high elevations.

 BB> But it also works in your car and thats a great place to just play ham
 BB> radio...

I think this is the whole point of the exercise. :-)

Tony

.. uncontrollable vowel movements.
--
|Fidonet:  Tony Langdon 3:633/284.18
|Internet: tlang@freeway.apana.org.au
|
| Standard disclaimer: The views of this user are strictly his own.


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