[TenTec] Answer to Duke and Vic

[dukeshifi]

You could jumper around the 455 KHz filters. You would get zero SSB suppression and your carrier level would go up, but any distortion caused by the filter would be eliminated. You may need to remove the filters for the test as there may be some shunting effects if the filter is truly bad.

As I recall, there are two 455 KHz ceramic filters in the transmit line. They have different part number. I checked their data sheets and found that they differ only in their bandwidths, just a little. I replaced both with the ones I found from DigiKey (or Mouser) and the result was fine. The radio worked well, was stable and had good audio. I do not know why Ten Tec used two different part numbers unless it was to present a particular sounding audio in the transmitted RF.

I tried to post the data sheet for this series of filters but the image was rejected. Ask me directly if you want to see it. 

I think the correct part number is Murata CFW455I and I thing I got them from a site questcomp, for $16.



Gary

W0DVN

> On Mar 22, 2023, at 11:21 AM, Michael Rutkaus <mrutkaus at gmail.com> wrote:
> 
> Thanks for the hints.
> Duke, yes both USB and LSB distortion.
> Vic, I hope you are right, this is good news which I will try.
> 
> Since writing my previous msg here I searched the group history and pretty
> much determined that I must have the bad 455khz ceramic filter problem. But
> I will try Vic's setting up the underneath mic gain. I doubt if I would
> ever get to findingnew and replace the ceramic filters. Although I seemed
> to have also discussed this here in 2017 and found out that way that I had
> purchased some. But I think there are several kinds and I got just one.
> 
> Again thanks
> Mike
> K4QET
> 
> <https://www.avast.com/sig-email?utm_medium=email&utm_source=link&utm_campaign=sig-email&utm_content=webmail>
> Virus-free.www.avast.com
> <https://www.avast.com/sig-email?utm_medium=email&utm_source=link&utm_campaign=sig-email&utm_content=webmail>
> <#DAB4FAD8-2DD7-40BB-A1B8-4E2AA1F9FDF2>
> _______________________________________________
> TenTec mailing list
> TenTec at contesting.com
> http://lists.contesting.com/mailman/listinfo/tentec