[TenTec] Omni VI+ Frequency Display Problem Only On LSB

[Paul Christensen]

Asymmetrical passband curve of the filter.

Paul, W9AC

----- Original Message ----- 
From: "Barry N1EU" <barry.n1eu at gmail.com>
To: "Discussion of Ten-Tec Equipment" <tentec at contesting.com>
Sent: Friday, June 10, 2011 9:09 AM
Subject: Re: [TenTec] Omni VI+ Frequency Display Problem Only On LSB


> Paul, why would USB sound thinner AFTER alignment?
>
> Barry N1EU
>
> On Fri, Jun 10, 2011 at 8:56 AM, Paul Christensen <w9ac at arrl.net> wrote:
>> Don't be too surprised if after alignment, USB sounds noticeably 
>> "thinner."
>> One reason for this occurrence is an asymmetrical passband of the stock 
>> 2.4
>> kHz filter It's been a very long time (Spring, 1998 to be exact), when I
>> asked INRAD to produce the 2.8kHz @ 9 MHz filter. As I recall, their 
>> filter
>> has significantly better passband symmetry.
>>
>> Here's a quick test: After alignment, momentarily short out the 2.4K @ 9
>> MHz filter with buss wire. Listen for differences in audio passband
>> characteristics between U/LSB. If that re-establishes symmetry, you may
>> want to consider the INRAD filter as a replacement if it's still 
>> available.
>>
>> Paul, W9AC
>>
>> ----- Original Message -----
>> From: "Barry N1EU" <barry.n1eu at gmail.com>
>> To: "Discussion of Ten-Tec Equipment" <tentec at contesting.com>
>> Sent: Friday, June 10, 2011 8:40 AM
>> Subject: Re: [TenTec] Omni VI+ Frequency Display Problem Only On LSB
>>
>>
>>> Adjustment is made to the TX Audio Board, p4-23 of the manual
>>>
>>> 73/GL, Barry N1EU
>>>
>>> On Fri, Jun 10, 2011 at 8:23 AM, Tom Stone <sail8 at verizon.net> wrote:
>>>> Berry,
>>>>
>>>> I set it up as you described below and yes, I can hear a distinct 
>>>> change
>>>> when I switch from USB to LSB.
>>>> Do you have any idea where the BFOs are located, which board? 
>>>> Hopefully,
>>>> Chapter 4 of the Manual will provide
>>>> enough detail to locate them.
>>>>
>>>> Tom
>>>>
>>>> -----Original Message-----
>>>> From: tentec-bounces at contesting.com
>>>> [mailto:tentec-bounces at contesting.com] On Behalf Of Barry N1EU
>>>> Sent: Friday, June 10, 2011 6:55 AM
>>>> To: Discussion of Ten-Tec Equipment
>>>> Subject: Re: [TenTec] Omni VI+ Frequency Display Problem Only On LSB
>>>>
>>>> With PBT control centered at 12 o'clock, tune the Omni 6 to a clear
>>>> frequency such that band noise is clearly audible. Switch back and
>>>> forth between USB and LSB. Does the tonal balance of the noise
>>>> (bass/treble) sound the same between the two modes? If it doesn't,
>>>> this is more evidence that the BFO oscillators need alignment to bring
>>>> them into balance.
>>>>
>>>> 73, Barry N1EU
>>>>
>>>> On Thu, Jun 9, 2011 at 10:24 PM, Tom Stone <sail8 at verizon.net> wrote:
>>>>> Carl,
>>>>>
>>>>> Is that something I can locate and adjust using Chapter 4 of the 
>>>>> manual?
>>>>> I
>>>>> guess if I have to ask, the answer is "no".... :)
>>>>>
>>>>> Tom
>>>>>
>>>>> -----Original Message-----
>>>>> From: tentec-bounces at contesting.com
>>>>> [mailto:tentec-bounces at contesting.com]
>>>>> On Behalf Of Carl Moreschi
>>>>> Sent: Thursday, June 09, 2011 10:17 PM
>>>>> To: Discussion of Ten-Tec Equipment
>>>>> Subject: Re: [TenTec] Omni VI+ Frequency Display Problem Only On LSB
>>>>>
>>>>> The internal BFO frequency adjustment for LSB is off 250 hertz.
>>>>>
>>>>> Carl Moreschi N4PY
>>>>> 121 Little Bell Dr.
>>>>> Hays, NC 28635
>>>>> www.n4py.com
>>>>>
>>>>> On 6/9/2011 9:59 PM, Tom Stone wrote:
>>>>>> Has any owner of an Omni VI+ ever had a problem similar to this? 
>>>>>> (With
>>>>>> the
>>>>>> RIT off, Identical Side tone and Pass Band Tuning set at zero on both
>>>>> rigs)
>>>>>>
>>>>>>
>>>>>>
>>>>>> Switching between my Orion II and Omni VI+ using an Alpha Delta 
>>>>>> switch
>>>>>> on
>>>>>> the same antenna. The Omni was just serviced by Ten Tec.
>>>>>>
>>>>>>
>>>>>>
>>>>>> 160M - LSB - Orion II 1.900.000 For the same voice quality (sounds 
>>>>>> the
>>>>> same)
>>>>>> the Omni had to be tuned to 1.899.75
>>>>>>
>>>>>>
>>>>>>
>>>>>> 80M - LSB - Orion II 3.868.000 For the same voice quality (sounds the
>>>>> same)
>>>>>> the Omni had to be tuned to 3.867.75
>>>>>>
>>>>>>
>>>>>>
>>>>>> Question: What could account for the consistent .25 difference in the
>>>>>> frequency read out? There is no difference when I am in the USB
>>>>> mode.
>>>>>>
>>>>>>
>>>>>>
>>>>>> Would appreciate any available input.
>>>>>>
>>>>>>
>>>>>>
>>>>>> 73, Tom N3XQ
>>>>>>
>>>>>>
>>>>>>
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