[Date Prev][Date Next][Thread Prev][Thread Next] - [Date Index][Thread Index][Author Index]

New FT-847, Help with doppler shift please



BBs,

I have been trying to get on a satellite for several years.  At Hamvention, 
I bought an Arrow and was on the FM birds within a week.  That got me 
excited, and I decided to jump into the deep water.

I got an FT-847 from the UPS on Friday and made several FM UO-14
and AO-27 contacts on Saturday AM using the Arrow
Antenna on a camera tripod without the duplexer, of
course.  I listened for FO-20 in vain.  On Sunday, I
made a number of contacts on the FM Birds and heard
myself and traffic on FO-20 and FO-29.  I even heard
someone call me back, but lost the signal before I
could complete the contact.

For grins, having about 10 minutes before I had to go
to an open-house, I set up the arrow antenna toward a
relatively low pass of AO-10.  The satellite had
passed North America and was heading out, but still
about 45 degrees above the horizon.  I heard several
people making contacts, but was pulled (kicking and
screaming) into the car to fulfill my social
obligations before I could try to make a transmission.

QUESTIONS:

I have an effective technique down for changing the
freqs on the FM birds for doppler shift, but have no
good technique for the SSB sats yet.  A little help
here would be appreciated.  Here are my setup and my
questions:

I have the main tuning dial set to transmit freq and
the sub freq to receive.  (I have the two frequencies
set to track each other inverted, and the
sub frequency can be changed alone to deal with
doppler effect.)

I have been starting at the middle of the pass band
and searching for my signal by whistling.  If I
remember right, I have to tune up on the receive
during the early part of the pass from the simple
inverted frequency and that receive frequency drops as
the pass continues...  Seems like if I have the
Transmit set to 145.950 and the receive to 4XX.850 I
have to increase the receive to about 4XX.855 or
4XX.860.  The receive then drops to about .010 below
.850 (4XX.840) by the end of the pass. Is this about
right?

Can the numbers reported as doppler shift on the
tracking programs be used to predict this frequency
shift directly?  Is that useful, or does one just get used to changing the 
frequency to compensate for doppler?

A newbie trying to learn.  (And get it right the first time.),

73s de WS8G (Rick)
________________________________________________________________________
Get Your Private, Free E-mail from MSN Hotmail at http://www.hotmail.com

----
Via the amsat-bb mailing list at AMSAT.ORG courtesy of AMSAT-NA.
To unsubscribe, send "unsubscribe amsat-bb" to Majordomo@amsat.org



AMSAT Top AMSAT Home