TenTec
[Top] [All Lists]

Re: [TenTec] Omni VI frequency jumping/drifting

To: Discussion of Ten-Tec Equipment <tentec@contesting.com>
Subject: Re: [TenTec] Omni VI frequency jumping/drifting
From: Greg S via TenTec <tentec@contesting.com>
Reply-to: Discussion of Ten-Tec Equipment <tentec@contesting.com>
Date: Thu, 28 Jun 2018 20:48:40 -0400
List-post: <mailto:tentec@contesting.com>
They certainly do interact....now you know why Paul Clinton would tell folks, 
if it is working well, don’t worry about a few 10’s of cycles between friends. 
Greg, KC8HXO 
Sent from my Linux device

> On Jun 28, 2018, at 19:07, Stan Gammons <s_gammons@charter.net> wrote:
> 
> Well, after tweaking C31 to try to get the 10 Mhz signal closer; it seems to 
> be more or less behaving now...  The jump on 30 meters is gone even though I 
> was unable to get the lock signal to match the other bands.  The 160 meter 
> coil had to be adjusted in order to get the lock signal to be stable.  So 
> far, FT8 signals on 40 meters is decoding every time.  Looks like the BFO 
> trimmers need adjusting though.  When I flip between LSB and USB while tuned 
> to WWV, the tone changes. Looks like it's about 30 hz off on LSB and about 
> twice as much on USB. Adjusting those is kind of a pain since they seem to 
> interact with one another :(
> 
> 
> 73
> 
> Stan
> KM4HQE
> 
> 
>> On 06/28/2018 05:23 PM, Stan Gammons wrote:
>> Hi Gary,
>> 
>> I have the 10 Mhz signal. It seems to want to flop between 10,000.000 and 
>> 10,000.001 to 10,000.002 at times.  For some reason it kills the receive 
>> when I connect the counter, a Leader LDC-823S, to pin 9 of U12.  I have to 
>> turn the rig off and back on to get the receive to work again.
>> 
>> I take it U13 is the MC145170P1 chip next to connector 88?  If so, it looks 
>> like I have 160 meter problems since the signal on pin 11 is there for a 
>> fraction of a second, then it's disappears and reappears.  On all of the 
>> other bands, except 30 meters, the waveform looks nearly the same.  On  30 
>> meters the waveform is wider.  I haven't tried adjusting the coil to see if 
>> I can get 30 meters to match the other bands.  Strange thing though on 30 
>> meters is FT8 still decodes even though it jumps about 100 hz for a very 
>> brief time.  I'll try adjusting the coil and pulling the board to see if it 
>> has any bad solder joints.  Still need to clean the connectors like Bob 
>> described in another post.
>> 
>> 
>> 73
>> 
>> Stan
>> KM4HQE
>> 
>> 
>>> On 06/28/2018 08:40 AM, k4mt1950@charter.net wrote:
>>> Stan:
>>> I have had the exact same problem with my Omni VI. There is a
>>> procedure to properly adjust band crystals. It is:
>>> Omni VI Lock PulseRig should be on for at least 1/2 hour.Check 10MHz
>>> REF at pin 9 of U12.Adjust 10MHz REF with C31.Check for lock pulse at
>>> pin 11 of U13, Scope probe on x10 position; .2 volts per div, and .1us
>>> time/div.Adjust L12 thru L21 on Xtal Osc. LO Mixer Bd. for the
>>> narrowest wave form.
>>> I did this but it did not help. I tuned in WWV and watched it on a
>>> waterfall and you could see carrier drifting back and forth. I was
>>> missing over half of the FT8 decodes as a result.
>>> What I found is PLL circuit on logic board is very temp sensitive. I
>>> tried to locate a part but the entire thing is that way. I found by
>>> putting a very small fin blowing across logic board completely
>>> eliminated the drift cycling.
>>> FT8 now works perfectly. Put the fan along the right side (looking
>>> from front) and not back panel. Back panel heats up during TX and when
>>> I put my fan there the problem got worse when I went into TX.
>>> Afraid its a design flaw and cant be fixed any other way.
>>> Gary K4MT
>>> 
>>>     -----------------------------------------From: "Stan Gammons"
>>> To: "Discussion of Ten-Tec Equipment"
>>> Cc:
>>> Sent: Wednesday June 27 2018 7:38:42PM
>>> Subject: [TenTec] Omni VI frequency jumping/drifting
>>> 
>>>   Hi Everyone,
>>> 
>>>   My Omni VI has decided to throw a few more fits. First the frequency
>>>   jumped on 30 meters, but FT8 signals still decode fine. So I let it
>>> go
>>>   and didn't mess with it. Lately 40 meters has started throwing fits
>>> and
>>>   it's much worse than 30 meters. Looking at the FT8 waterfall, at
>>> times
>>>   it will drift during the 15 seconds and it's bad enough the FT8
>>> signal
>>>   won't decode. I sent another email to the list with the waterfall pic
>>> 
>>>   attached, but the message was too large and got rejected. I tried
>>>   tweaking the coils on the crystal oscillator board. It might have
>>>   helped 30 meters a little. Doesn't seem to have done much/anything
>>> for
>>>   40 meters though. Crystals gone bad maybe? If so, anyone know a
>>> source
>>>   now that ICM is no more?
>>> 
>>>   73
>>> 
>>>   Stan
>>>   KM4HQE
>>> 
>>>   _______________________________________________
>>>   TenTec mailing list
>>>   TenTec@contesting.com
>>>   http://lists.contesting.com/mailman/listinfo/tentec
>>>   />
>>> _______________________________________________
>>> TenTec mailing list
>>> TenTec@contesting.com
>>> http://lists.contesting.com/mailman/listinfo/tentec
>> 
>> _______________________________________________
>> TenTec mailing list
>> TenTec@contesting.com
>> http://lists.contesting.com/mailman/listinfo/tentec
> 
> _______________________________________________
> TenTec mailing list
> TenTec@contesting.com
> http://lists.contesting.com/mailman/listinfo/tentec

_______________________________________________
TenTec mailing list
TenTec@contesting.com
http://lists.contesting.com/mailman/listinfo/tentec
<Prev in Thread] Current Thread [Next in Thread>