Re: [TenTec] Orion tuning rates - Further thoughts

[Bob Henderson <bob@cytanet.com.cy>]

This post is aimed at those with an interest in the Orion's step 
size/encoder rate adjustments and in the curious step size changes often 
heard when rotating the tuning dial.

I still find the 2.5 kHz tuning rate (10 Hz & High enc rate) a little 
slow for my liking, preferring instead a 5-10 kHz rate at 10 Hz.  Also, 
I still find the curious changes in step size that I hear when rotating 
the tuning dial to be somewhat disconcerting.  Having said these things, 
I can also say that I have become less uncomfortable with both of these 
factors in day to day use of the radio, through experience.  That said, 
I suppose we humans can get used to an awful lot of things if we have 
to, but that doesn't necessarily make such things good!

None contesters should stop reading now, as your eyes will likely glaze 
over very quickly if you continue.  You have been warned!

My main concern with both of the above is in SO2R contesting.  One of my 
favoured SO2R techniques is to tune quite rapidly accross one band 
looking for pile-ups (multipliers) with my second radio whilst CQing or 
sending exchanges under computer control with the first. I doubt I am 
giving anything away with this, as I am sure it must be a fairly common 
mult-hunting tactic deployed by unassisted SO2R operators.

For those who are still reading but have ignored my warning, I should 
point out that running CW qsos at 3-4 per minute, whilst tuning a 
different band on your second radio (though only whilst you transmit on 
the first) is a demanding multi-tasking environment for an operator to 
work in.  Particularly,  when you consider that many contests are 
straight 48 hour events, in which sleep depravation can become a 
significant factor.

Now, the mathematicians among you will have rapidly deduced that running 
at such rates where a qso only takes around 15 seconds, you are unlikely 
to do better than to silence your 1st radio (due to sending exchanges) 
for longer than at best 6-7 seconds in each 15.  In these 6-7 second 
snatches, the SO2R operator needs to optimise deployment of radio 2 to 
find & work needed multiplier stations.  Does this sound stressful to 
you?  It feels stressful to me, I can tell ya!

To make best of this tactic under these very difficult circumstances the 
fewest possible diversions, irritations and distractions are required, 
together with the best possible tuning rate.

Hence my concern with the 2.5 kHz tuning rate of the Orion and the 
curiously distracting stepping characteristic it displays when tuning at 
anything above a very pedestrian rate.

In previous discussions it was postulated that the curious stepping 
characteristic was due to a long synthesiser lock time, perhaps 
necessary to maintain the extraordinarily low noise figure of the Orion 
synth.  In addition, I wondered if perhaps the encoder output might be 
only 250 pulses per revolution, which would limit tuning rate at 10 Hz 
to the 2.5 kHz currently available.

I have address these questions to Ten Tec and received a very prompt 
response advising the following:

(It probably doesn't need saying but............I couldn't conceive of 
getting such a prompt and detailed reponse to a similar question if 
asked of any of the JA manufacturers.  Ten Tec deserve a great deal of 
credit for this.)

(TT)  The tuning is limited by the amount of overhead in the 
microprocessor, not the synthesizer lock time.

(TT)  Tuning in the Orion was patterened after the Jupiter, which was 
quite acceptable. However, the Orion microprocessor controls many more 
operations and features. The encoder outputs 512 pulses. When tuning 
rapidly, if the microprocessor cannot immediately act upon the tuning 
pulse, the pulses are counted and when there is a break, it updates the 
frequency. That's why rapid tuning sounds different. I understand that 
there are those who would prefer smoother and faster tuning. It is on 
our "wish list" but we have been working on items that we feel are of 
greater interest to more hams.

The above statements would seem to indicate a 5 kHz tuning rate at 10 Hz 
should be possible.  Whether the overhead on the microprocessor due to 
the other workload can be reduced or reprioritised in the firmware to 
solve the manic stepping behaviour is unclear to me, possibly also to 
Ten Tec too at this stage.  Ten Tec clearly do have these items on their 
"Improvements wish list".

If you would like to see work on these things have greater priority, I 
suggest you make your desires known to Ten Tec.

73

Bob, 5B4AGN, P3F


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