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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