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Re: [TenTec] Re: [Orion] Orion Synthesizer speed

To: tentec@contesting.com
Subject: Re: [TenTec] Re: [Orion] Orion Synthesizer speed
From: Bob Henderson <bob@cytanet.com.cy>
Reply-to: tentec@contesting.com
Date: Mon, 12 Jan 2004 07:47:44 +0000
List-post: <mailto:tentec@contesting.com>
I guess you guys missed my post on this at the end of December. I spoke to Ten Tec about the jerky synthesiser response and they confirmed it to be nothing to do with slow locking of the synthesiser, whether in the interests of low noise or anything else. The effect is caused by the speed with which the control microprocessor can execute instructions. The comments made by Ten Tec on this issue are attached below:-

(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.

73 Bob, 5B4AGN, P3F

Jim Reid wrote:

Comment made:

(4) The synthesizer seems to lock slowly, making rapid frequency excursions sound jerky. Most other modern rigs have fast enough synthesizers that the tuning seems analog. Too bad the Orion can't do this as well.

I believe that this is "on purpose". As I think I understand, from prior posts on this issue, in exchange for a slower synthesizer, we are given very much lower "close in" phase noise which enhances very weak signal detection (also, very low transmitted phase noise as well).

This is a DX'ing trade off some appreciate;  not sure about
contesting as I don't do that.  Fast synthesizers are also
broader bandwidth,  thus more noise  into the signal
path.  Other functions perhaps "compromised" by this
design decision might be the encoder tuning rates and
step size combinations in the "default" design.

There is much more "under the hood" of this creature
that I am still learning/discovering even though I have
had my Orion since the middle of last May!

BTW,  downloaded Carl M's,  N4PY,  V1.07 Orion control
software this morning.  Now we can adjust AGC Threshold
as a "panel" adjustment anytime we wish!  It is now a "virtual"
front panel operator control without need to go into the AGC
menu.  And this can be done when using any of the slow,
med,  fast,  or prog. AGC selections.  Also,  the selected
threshold is "remembered" by band when QSY'ing.
Very neat added function by Carl.

73, Jim KH7M

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