[TenTec] Orions SO2R in CQ WW RTTY

[Bob Henderson]

I used my Orions SO2R in the WW RTTY this weekend, so I decided to share how
they performed.

Firstly, both radios were on for the full 48 hours of the event and for a
couple of hours before.  I operated the full contest without having to do
any kind of reset at all on either radio.  For me this was unsurprising, as
the only time I do a master reset is when I download new firmware.  Then, I
do it as a matter of course.

Overall, I would say they performed superbly.  One particular thing I
noticed with Orions, which replaced my two FT1kMPs, is that they are better
suited to SO2R in the kind of setup I use.  What does that mean? Well, I
have a rather limited station here.  No multiple towers or anything like
that.  In fact, just one modest crankup with a Force 12 C31XR and a
Cushcraft XM240.  If you're interested you can see my set up at
www.5b4agn.net.  This is a new website and my first attempt at it, so please
excuse it being a little bit raw & obviously unfinished!

The C31XR driven elements for 20/15/10 metres, which are only a matter of
inches apart, are fed with three seperate feeders.  I operate high power
SO2R using these interlaced yagis.  With driven elements so close together
you can imagine the rf field presented to the second radio rx is really
nasty.  Of course, I use band pass filters and stubs to minimise the
problems this causes.  BUT with my two Ft1kMPs I could always feel a
presence on my second radio when transmitting on the first.  What do I mean
by a presence?  Well, modulation of the noise floor I guess.  I also found
that listening on say 20m, within about 10kHz of my 40m second harmonic was
a bit messy.  What I found with Orions this weekend was that I had no sense
of a presence on the second radio when transmitting on the first.  Not only
that but I found myself to have been working about 1 kHz away from the
second harmonic of my 40m signal on 20m without even realising it.  In my
view, this experience speaks volumes for Orion's bomb proof front end and
very low phase noise.

I have only two critiscisms to level at Orion after this weekend of RTTY use
and one of those I suspect may be down to operator error though I'm unsure.

1.  My contesting software is Writelog. I ran both Orions set at 250 Hz b/w
most of the weekend. Whilst tuning around the bands looking for mults etc I
band map wanted stations which don't answer me after a couple of calls.  I
then periodically return to their band mappped frequency to see if their
pile up has subsided.  The problem I found is this:  Every time I clicked
back to a mapped frequency the rx b/w changed.  If I had only one Orion then
I would probably be thinking this was a logging software problem but I
don't, I have two and although the bandwidth changes on both it's not to the
same setting.  On one radio it always goes to a barn door 1 kHz but on the
other it always goes to 300 Hz which isn't so bad.  Though, I'd much rather
it stayed at 250 Hz  where I'd set it.

What determines the b/w set when frequency is changed via the RS232 port?
Why is it 1kHz on one Orion and 300 Hz on the other?  Anyone know the answer
to this mystery?  Should I just RTFM?

2.  Filter shape factor is really the only significant concern I had over
the weekend.  With b/w down at around 250 Hz the DSP shape factor is not far
short of 3:1 which really isn't good enough.  As a consequence, folks could
sidle up real close to Orion's beautifully clean signal and sit there inside
my passband causing me grief.  I spent way too much time over the weekend
inching up or down in frequency to avoid QRM from folks alongside.  This
leads me to the following conclusion:

FOR TOP NOTCH CONTEST GRADE RTTY USE, ORION'S DSP NEEDS TIGHTER SKIRTS.

Incidentally, FWIW the weekend was a lot of fun.  I put in 36 hours and
finished with he following tally:

QSO: 2582;  Points: 7550; State/Prov: 100; Countries: 271; Zones: 94 for a
total score of 3,510,750

I was placed 4th last year in SOAB (HP).  This year my Q's are up by almost
11% but mults are way down and as a consequence so is my claimed score which
is about  5% short.  Things get tough when 10 metres dies!  Hopefully, just
as tough for everyone.  We'll see when the results come out.

73, Bob

Bob Henderson, 5B4AGN, P3F
Giolou, Pafos, Cyprus
Email: bob at cytanet.com.cy
http://www.5b4agn.net