[TenTec] Corsair II PBT Question

[Daniel Schlieper]

Hi Barry,

thank you for the kind advice.

73 Daniel DM3DA

On Tue, 30 Oct 2012, Barry N1EU wrote:

> http://www.inrad.net/product.php?productid=199&cat=90&page=1
>
> The 756/757 will give you a symmetrical, but narrower, passband.  It
> doesn't really make sense to go with one 2.8khz and one 2.4khz filter.
> Go with two filters of the same bandwidth.
>
> I'd definitely go for the 2.8khz filters.
>
> 73,
> Barry N1EU
>
> On Tue, Oct 30, 2012 at 9:36 AM, Daniel Schlieper
> <daniel.schlieper at tuxomania.net> wrote:
>> Hi Dave,
>>
>> I try to find the Inrad 2.8 kHz filter for 6 MHz IF, but cannot see anything
>> suitable on the Inrad website. Do you know the order number?
>>
>> I wonder if this mod actually needs an 2.8 kHz filter. Would the 2.4 kHz
>> filter (Inrad # 756) do as well? Or is the width critical?
>>
>> 73 Daniel DM3DA
>>
>>
>> On Sat, 27 Oct 2012, David and Dianne on Comcast wrote:
>>
>>> Your PBT imbalance problem is likely caused by asymmetrical 2.4 KHz
>>> filters in the Corsair II. This is a long known problem with the CSII, Omni
>>> V and Omni VI's.
>>>
>>> I have had similar experiences with all of the many (!) Corsair II's I
>>> have owed over the years along with an Omni V and Omni VI. L/O and IF stage
>>> alignments will not improve this problem caused the inconsistent performance
>>> and design of the stock TT 2.4 KHz filters.
>>>
>>> The remedy is to replace both 2.4 KHz stock filters with INRAD 2.8 KHz
>>> filters in the 9 and 6 MHz IF stages and to make sure the the local ocs's
>>> are adjusted as`perfectly as possible.
>>>
>>> You will be rewarded with far improved SSB audio fidelity and wonderful
>>> SSB TX audio.
>>>
>>> What you are describing I experienced with all the TT radios of this IF
>>> design that I have owned over the years. The 100% fix is this filter swap.
>>> Pricey but really worth it. Any easy swap out.  You can also install the 2.4
>>> KHz filter board (9 MHz) with sockets to make future filter swapping really
>>> easy.  I think that Barry N1EU documented that mod. (Check out his really
>>> neat CSII wiki site at http://corsair.wikidot.com/corsair-9mhz)
>>>
>>> I have a last production run Omni V and last production run CSII that I
>>> have switched out these filters and the results are super.
>>>
>>> 73 de N1LQ-Dave
>>>
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