Higher? As far as the ssb filters go, Inrads have consistently had lower
passband ripple whenever I've ran a spectrum on a radio.
73,
Barry N1EU
On Sun, Mar 10, 2013 at 2:15 PM, Jack Van Demark <wn5a@sbcglobal.net> wrote:
> Bob:
> Thanks! Your explanation was a great help for me to understand the history
> and development of the Omni VI series radios. I knew that ripple was a
> design criteria by engineers but was unaware that the Inrad filters were
> higher. I will search the net and find the info you referenced in the last
> paragraph. I have been back operating after a 10 year absence while my son
> played baseball. He graduated about a year ago. I have been slowly
> repairing my older TenTec qrp and cw gear to fund my radio account.
> Thanks again for your time and insight.
> 73
> Jack WN5A
>
>
> On 3/9/2013 7:32 PM, Bob McGraw - K4TAX wrote:
>
>> Well Jack, I've owned two of them and repaired several for other folks.
>> I'm no expert! Just a fixer with one slated to arrive on the bench next
>> week.
>>
>> I don't have specifics about the change between the oven model which was
>> used in my first Omni VI Plus and the TXCO model which was my later Omni VI
>> Plus. The manual I have is 1st printing dated 1/97. It shows the oven
>> crystal. While there's nothing wrong with this implementation, it simply
>> requires DC power to be applied all the time, even though the radio is off,
>> to maintain temperature and stability. Otherwise, it takes a few minutes
>> for the crystal to come up to temperature and stabilize.
>>
>> I see one or more postings referencing the TCXO which is 8/06 so we know
>> it took place between 1997 and 2006. Otherwise, not very specific. I sold
>> my last Omni VI Plus along with the original manual. Wish I'd kept a copy.
>>
>> Here's a link that provides additional information.
>> http://tentecwiki.org/doku.**php?id=563upgrade<http://tentecwiki.org/doku.php?id=563upgrade>
>>
>> The ripple across the top of the filters will or can make a noticeable
>> difference in audio response. I understand the approach toward the INRAD
>> filters were to move to a tighter filter which has steeper slopes and
>> skirts as compared to the standard filters. There seems to be a trade-off
>> in that with the steeper slopes, the carrier is further down on the slope
>> of the filter and the audio response changes and the steeper slope design
>> does contribute to some 3 dB to 6 dB ripple across the top of the filter
>> curve. I have only used stock filters in my radios, but others have come
>> across my bench with the INRAD filters.
>>
>> As N1EU states " There are indeed differences. An early 563 and a late
>> 564 are very different radios in many respects aside form the advertised
>> feature differences. I've spent many hours of A/B comparisons of various
>> vintages of Omni 6/6+ from 1992 to 2001. My conclusion is that any
>> improvements in RX noise/birdies was subtle, if at all audible, and that
>> the earliest units performed as well as the latest units." And Dave, N1LQ
>> states, "The later 564's replaced the crystal oven with a 2ppm TCXO on the
>> logic board, probably the best enhancement TT did to this radio. The
>> crystal oven eventually "cooks out" and will not hold frequency tolerances
>> well. Try aligning one and getting it to hold frequency. The TXCO fixes
>> that problem. Later 564's use significant amounts of SMT construction."
>>
>> Hope this helps.
>>
>> 73
>> Bob, K4TAX
>>
>>
>>
>>
>>
>> ----- Original Message ----- From: "Jack Van Demark" <wn5a@sbcglobal.net>
>> To: "Discussion of Ten-Tec Equipment" <tentec@contesting.com>
>> Sent: Saturday, March 09, 2013 6:42 PM
>> Subject: Re: [TenTec] Totally tricked out Omni VI+ On ebay
>>
>>
>> Bob:
>>> You seem extremely knowledgeable on the 6+. When did they have to switch
>>> to the TCXO's, about what year radio would have them instead of the crystal
>>> oven?
>>> That radio on eBay has all TenTec filters except the additional roofing
>>> filter and circuit board.
>>> Do you use stock TenTec filters in your radios?.
>>> What does the excessive ripple do to the receive audio?
>>> Thanks 73
>>> Jack WN5A
>>>
>>> On 3/9/2013 4:37 PM, Bob McGraw - K4TAX wrote:
>>>
>>>> Nice looking older radio. Has the crystal oven where the later models
>>>> had the TXCO. As to the INRAD filters, I find they have too much ripple
>>>> across the top to suit my taste. Your mileage may vary.
>>>>
>>>> 73
>>>> Bob, K4TAX
>>>>
>>>>
>>>>
>>>> ----- Original Message ----- From: "Barry N1EU" <barry.n1eu@gmail.com>
>>>> To: "Discussion of Ten-Tec Equipment" <tentec@contesting.com>
>>>> Sent: Saturday, March 09, 2013 2:04 PM
>>>> Subject: Re: [TenTec] Totally tricked out Omni VI+ On ebay
>>>>
>>>>
>>>> Caution: if you don't want to deflate your high opinion of what an
>>>>> Omni 6+
>>>>> is worth, don't look at the listing ;-)
>>>>>
>>>>> 73,
>>>>> Barry N1EU
>>>>>
>>>>> On Sat, Mar 9, 2013 at 7:35 PM, Jack Van Demark <wn5a@sbcglobal.net>
>>>>> wrote:
>>>>>
>>>>> Purely an FYI!
>>>>>> If you haven't seen it ,there is a totally tricked out Omni VI+ on
>>>>>> eBay
>>>>>> that will go another couple of days. Wish I had more money in my radio
>>>>>> account. All filter slots filled and International radio roofing
>>>>>> filter
>>>>>> kit installed.
>>>>>> 73
>>>>>> Jack
>>>>>>
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>>>>>>
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