[TenTec] TenTec CW filters or Inrad?

[Darwin, Keith]

Good data Dave, Thanks!

What I see is the TT is a bit wider and the skirts aren't as steep but the ultimate rejection is much better than the Inrad.  Between the two, I'd go TenTec.  Am I missing something?

How do the filters sound?  Is one more or less prone to ringing?

- Keith -

-----Original Message-----
From: Dave Bowker [mailto:dbowker at mail.sjv.net] 
Sent: Friday, November 18, 2005 1:36 PM
To: Darwin, Keith
Subject: [TenTec] TenTec CW filters or Inrad?

Keith,

The attached µSoft Word file compares the TT #217 (9 MHz/500 Hz/750 Hz offset) with an Inrad #753 (9 MHz/400 Hz/600 Hz offset).  The little blip in the middle of the passband (on the center frequency of the trace is not a filter anomaly, but the tracking generator marker, and its exact frequency is displayed in the TG digital readout to illustrate how the filter centers about that frequency).  The scan is 200 Hz/division.

Note the anomaly with the TT #753 when installed in a VI Opt-3 or VI+.  This is due to the construction of the Inrad filters, and Inrad is aware of this.  They do not separate the input side ground from the output side ground, as is done in the TT filters, and when installed in a VI/VI+ there is a minor ground/ground loop problem.  However, the anomaly is 50 dB down on the low side and 60 dB down on the high side skirts, and in normal ham operation, the human ear cannot discern this anomaly.  IMHO, it is a "no problem".

You be the judge!

73, Dave, K1FK
Fort Kent, ME