[Top] [All Lists]

Re: [TenTec] OMNI6 PLUS Alignment procedure needed

To: Discussion of Ten-Tec Equipment <tentec@contesting.com>
Subject: Re: [TenTec] OMNI6 PLUS Alignment procedure needed
From: Ken Brown <ken.d.brown@hawaiiantel.net>
Reply-to: ken.d.brown@hawaiiantel.net,Discussion of Ten-Tec Equipment <tentec@contesting.com>
Date: Sat, 29 Dec 2007 15:44:18 -1000
List-post: <mailto:tentec@contesting.com>
Hi Ron,
> Why not use logic?
If your logic is impeccable, yet built on incorrect premises, you can 
make false conclusions.

For example, in most radios that have a digitally controlled VFO, with 
memories, all of the oscillators in the rig are phase locked to a single 
master oscillator. In that type of rig if you wanted to get the 
frequency calibration just right, and if you have good strong reception 
of WWV or WWVH on 10 MHz ( I'm using 10 MHz in this example, because it 
is a frequency that the Omni VI can also tune to.) you could set your 
VFO to 10.000.00, PBT to hear the beat between your BFO and WWV/WWVH 
carrier, and adjust the master oscillator to get zero beat. No frequency 
counter or other reference standard needed.

If you were to try this with the Omni VI, not realizing that the BFO is 
a separate crystal oscillator, with several trimmer adjustments, you 
could misalign the 20 MHz oscillator to compensate for an off frequency 
BFO. Now after having made that mistake, if you have no way to directly 
measure the BFO frequency, you would have a difficult time getting 
things right. The information to avoid this mistake IS in the Omni VI 
manual. Probably the best way to learn this detail would be to read the 
BFO adjustment procedure. That procedure is in the circuit description 
for the TX AUDIO BOARD. Not the first place a new owner of this radio 
would think of looking for a frequency calibration adjustment. If you go 
to the LOGIC BOARD description, it will tell you that the band select 
crystal oscillators are lock to the 20 MHz oscillator. It does not make 
any mention of the BFO, so it would be easy for a new owner to make the 
mistake of adjusting the 20 MHz oscillator for zero beat of WWV on 10 
MHz, only to find out later the BFO is off.

A step by step procedure could provide the necessary information all in 
one place.


TenTec mailing list

<Prev in Thread] Current Thread [Next in Thread>