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

RE: Need help with FO20 and FO29



Dave Barrows - W8IJ said:

> I still have not been able to make any ssb qsos with the FO20
> and FO29 sats.

> My equipment:

> FT-726 - 10 watts max out
> eggbeater II on 70cm with SSB electronics preamp
> eggbeater II and 11 el cushcraft linear on 2m
> (the cushcraft is vertical and aimed at the horizion so I use the
eggbeater
> for higher elevations)
> approximately 40 feet of LMR400 on all antennas

> alternatively:
> arrow antenna hand held

> I have made cw contacts on FO20 and FO29 with limited success. When
> I do, I still have trouble losing myself in the downlink. This is
partially
> because my signal seems to be weaker than other stations I am hearing
> and partially because when I adjust my transmitter frequency to match
> where I am hearing the other station, I forget to switch to the receive
vfo
> and when the other station starts transmitting, I am trying to tune it in
> with the transmit vfo until I have moved the transmit frequency out of
> range before discovering my mistake.

I can't help you on the operator error part of that (after some more
practice, the switching will become second nature).  I suspect most of your
problem is related to the very weak signals involved.  More on that below...

> Now, on ssb, I can't find myself at all until I do it first on cw. To
transmit
> on cw, both 70cm and 2m vfos must be on cw.

   A CW signal is much easier to find than the SSB you are speaking
yourself.
That's a real bummer that the 726 won't let you have just the TX on CW while
the RX on USB.  At least they got that one right on the 736.

> After I find myself on cw,  I can sometimes switch the 2m vfo to lsb and
> the 70cm vfo to usb, say "aaaaahhhhhh" and zero in my signal.  But I
> lose my signal in the downlink shortly thereafter and have to switch the
> receive vfo back to cw, then switch to the transmit vfo and put it back
> on cw, then find my signal again.

   Again, I suspect this is related to the weak signals.  More below...

> When using the arrow antenna, it is even harder because I have one
> hand tied up moving the antenna's el, az, and polarization as well
> as all the switching, keying with the same hand I use to turn the vfo
> knob on cw, and using the up/down switch on the mike to move the
> frequency on ssb.  Did I mention that I was turning the antenna's el,
> al, and polarization to maximize my signal in the downlink?

   I won't even try all that.  Way too much work by my book.  This is
supposed to be fun!

> Now, I have been told that using 3 watts and an arrow antenna I
> should be able to work ssb with on an overhead pass of the FO birds.
> What am I doing wrong?  I am trying to run my satellite station on a
> shoestring budget.  Will I have to wait until I have more power and
> better antennas to work ssb?

   Yes, it can be done - BUT - It's not easy.  I know I'm going to annoy
some of the "you can do it with an HT and a rubber ducky" crowd with this,
but a bare bones station to work a satellite is a VERY WEAK SIGNAL at best.
Trying to work the linear LEO birds with a low power station with onmi
antennas and no preamp IS going to be an exercise in frustration -
especially for a beginner.  An operation that may be routine for a long
experienced satellite operator may be almost impossible for a beginner.  For
example, I consider "finding myself" in the downlink to be a "5 second
exercise" at worst - I'll bet you take considerable longer than that - I
know I did when I started.
   I have no doubts at all that you have problems finding yourself on SSB.
With your station, you likely find that "strong signal" stations are pretty
weak on your receive, and as you stated, your uplink signal "seems to be
weaker than other stations I am hearing".  That would make you hearing your
downlink VERY WEAK and hence hard for you to find and keep tuned in.  Bear
in mind that I'm not trying to discourage you, but I'm trying to be
realistic.
   The first suggestion I would make is to get a good pre-amp and mount it
AT the receive antenna.  This will likely get your receive strong enough
that most of the rest of your problems disappear.  Also, if you have the
opportunity to operate from a well equipped station and get a little
experience (primarily in getting the doppler corrected) it should make
operating your station easier for you.

73
-------------------------
Jim Walls - K6CCC
k6ccc@amsat.org
http://home.earthlink.net/~k6ccc/
Ofc:  626-302-8515    FAX:  626-302-9999
AMSAT member 32537 / WSWSS member 395

----
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