In my messages I stated the problem was the #282 250 hz filter in the 6.3 mHz
IF. I was using the 2.4 hz filter in the 9 mhz IF at the time. I do not have a
219 or 221 filter.
On Jul 6, 2011, at 8:48 AM, CSM(r) Gary Huber wrote:
>> Thank you for your input and expertise Gary but I still don't see how the
>> PBT setting would be correct for one filter (500 hz filter - PBT control at
>> either 11 or 1 o'clock depending on >the band) and not correct for the other
>> filter (250 hz) unless the center frequency of the two filters is different.
>
>
> And that can be part of the problem, you do have to know which CW filter you
> have in the 250 HZ Position? There are two that will work, the 219 and the
> 221.
>
> "What's the difference between the 219 and 221 filters?
> If you usually run your CW offset at 500 Hz or less, and want to install both
> the 282 filter and a 9 MHz I-F 250 Hz filter, use the 221 instead of the 219.
> If you normally run CW offset at higher than 500 Hz, use model 219. Only the
> Omni-VI and Omni-VI Plus offer variable CW offset; offset on other Ten-Tec
> transceivers is fixed at 600 to 750 Hz depending upon model. The 221 filter
> is only for use with low CW offset on the Omni-VI and Omni-VI Plus." see
> http://tentecwiki.org/webarchive/filterhelp/
>
> 73 es DX,
>
> Gary - AB9M
>
> -----Original Message-----
> From: Keith Hamilton
> Sent: Tuesday, July 05, 2011 11:40 PM
> To: Discussion of Ten-Tec Equipment
> Subject: Re: [TenTec] Correction
>
> Thank you for your input and expertise Gary but I still don't see how the PBT
> setting would be correct for one filter (500 hz filter - PBT control at
> either 11 or 1 o'clock depending on the band) and not correct for the other
> filter (250 hz) unless the center frequency of the two filters is different.
>
>
> On Jul 6, 2011, at 12:16 AM, CSM(r) Gary Huber wrote:
>
>> Or you could just re-read closely the Ten-Tec owner's manual and note the
>> recommendation to move the PBT to either 11 or 1 o'clock depending upon the
>> band you are using and the sideband the CW is offset from the carrier
>> frequency.....
>>
>>
>> 73 es DX,
>>
>> Gary - AB9M (a 30 year veteran with TT radios)
>>
>> -----Original Message-----
>> From: Ken Brown
>> Sent: Tuesday, July 05, 2011 10:50 PM
>> To: Discussion of Ten-Tec Equipment
>> Subject: Re: [TenTec] Correction
>>
>> Hi Keith,
>>
>> There are three things which determine the audio frequency of the CW
>> note you hear when listening to a CW signal with an Omni VI. Those three
>> things are:
>>
>> 1) The RF frequency of the signal you are listening to,
>>
>> 2) The LO frequency that the Omni VI is generating,
>>
>> 3) The BFO frequency that the Omni VI is generating.
>>
>> The amplitude of the audio you hear is affected by many things. For this
>> discussion the most relevant thing is where the bandpass of the 9 MHz
>> filter is relative to where the LO has converted the incoming RF, AND
>> the setting of the PBT which moves the signals passing through the 9 MHz
>> IF around relative to the center of the 6.3 MHz filter in use.
>>
>> When you have the PBT set for maximum "band noise" amplitude passing
>> through both the 9 MHz IF filter and the 6.3 MHz IF filter, the the two
>> IF bandpasses are as coincident as you can get them. The "center
>> frequency" of this noise should be equal to the sidetone frequency that
>> the Omni VI generates when you key it, and if you zero beat an incoming
>> CW signal to your sidetone when you transmit your signal should be
>> pretty near (in your case, being a piano tuner, damned near exactly)
>> zero beat on the signal you have tuned in.
>>
>> Assuming that the Omni VI LO system is working right there are two
>> things you need to do to get the frequencies to work out right.
>>
>> First you need to use the menu function that sets the sidetone
>> frequency. This controls the offset of the LO system when you switch
>> from receive to transmit, as well as controlling the frequency of the
>> sidetone generated.
>>
>> Second you need to have you BFO crystal oscillators operating at the
>> correct frequencies. The are adjustable with trimmer capacitors.
>>
>> You can always get the 6.3 MHz and 9 MHz IFs coincident by adjusting the
>> PBT control, but when using a narrow 9 MHz filter you are stuck with the
>> tone that passes through it. The best bet is to set your sidetone to
>> match that.
>>
>> You could misalign your BFO to get the tone you prefer, and then set the
>> sidetone to match it, but if you do your frequency readout would be
>> incorrect by the amount you have misaligned the BFO. The BFO changes
>> frequency also between transmit and receive, so you would probably have
>> to misalign both frequencies equally to keep the zero beat with the
>> sidetone exact, and this would result in incorrect frequency display for
>> transmit as well as receive. If you stay far enough from the band edges
>> it would not be a problem.
>>
>> I hope this helps,
>>
>> Ken N6KB
>>
>>
>> Keith Hamilton wrote:
>>> I made a typo in my question. I meant to say I must tune the radio from
>>> 7.040.00 to 7.040.20 to center the 250 hz filter.
>>> Sorry
>>> Keith W8GX
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