[Orion] [TenTec] Orion AGC settings

[Bill Tippett]

N5TW wrote:
 >I really have to thank Sinisa for his postings on receiver settings and for
W4ZV for underlining their significance.

         For some reason Sinisa posted a third on the Orion reflector,
so here are all three together (in order):


<http://dayton.akorn.net/pipermail/tentec/2004-February/042164.html>http://dayton.akorn.net/pipermail/tentec/2004-February/042164.html
http://dayton.akorn.net/pipermail/tentec/2004-February/042183.html
http://dayton.akorn.net/pipermail/orion/2004-February/000226.html

         Last night I was listening to YI9ZF on 80 while waiting for him to
move to 160.  He was right at my noise floor and was QRV for quite
awhile before 0200.  It was an excellent chance to play with Orion's AGC
settings, and also to experiment with K6STI's DSP Blaster on Orion's
audio output.

         Here are the AGC settings I found worked best under those conditions:

Threshold 95 uV
Hang .63
Decay 20 dB/S

Using these, I could take Kas from about 339 to 449, and I seemed to
be hearing better than most.  At times he dropped below my noise floor
to the point that I thought he had gone QRT.  Then he would again rise
above the noise and be OK copy.

         I was frankly astounded at what DSP Blaster would do!  It was not
only helpful for finding Kas' signal using the waterfall display, but
made Q4 copy into solid Q5 copy.  The Coherent CW feature splits the
signal into in-phase and out-of-phase components, and when you listen
to this with stereo headphones, it almost makes the signal sound like
it "jumps" out of the noise, even though it is only a theoretical and
measured 3 dB difference.  I saved both my settings for Orion and
DSP Blaster so I can experiment more with this in the future.

         I got everything set up on 160 after Kas QRT on 80, but he did
not show up on 160 immediately.  Both RA6AX and A45XR had decent
signals and A45XR was peaking 569 at 0229 near his sunrise.  He runs
a kW to a vertical but with just a few radials, so I expected Kas'
100 watts to a 20m high inverted-vee would be much weaker.  I was
amazed to hear Kas on 1837 at 0230 CQ-ing with a 569 signal!  No DSP
or fiddling to copy him 100%, although I had left Orion's settings
as noted above.  I worked him for #311 on Topband and listened to him
for the next 1.5 hours until he QRT at his sunrise just before 0400.
Kas peaked 579 so he was even stronger than A45XR was at his sunrise!
The AGC settings were quite comfortable to use and I could copy most
of the EU and Russian stations Kas was working (UN7AM was 579!), and
even many that he could not copy...I felt like I was VE1ZZ!  The only
major problem was when some strong NA stations would call zero-beat
and of course that took the AGC awhile to settle down afterwards.  I
believe it would be possible to use similar AGC settings in a contest
especially if you didn't have extremely strong stations inside Orion's
passband.  I may give this a try if I decide to do ARRL DX CW on 160.

         Again thanks to Sinisa for causing me to play with the Hang and
Decay settings.  I had discovered the effect of Threshold myself but
probably would not have tried such high settings for Hang if he had
not made those posts.  I've now had Orion nearly 6 months and am
continuing to learn new things about how to use it properly!  I also
continue to learn more about K6STI's DSP Blaster which is a fantastic
program IMHO.

                                                 73,  Bill  W4ZV