EMRFD Message Archive 10407
Message Date From Subject 10407 2014-11-02 01:21:21 Weddig, Henning-C... AW: AW: [emrfd] Losses in Diplexer? from my own experience with a Q=3 diplexer @ 10.7 MHz:
all values must be as precise as possible to tthe calculated values, especially the inductors to get the "coprrect" return loss AND Insertion loss of the diplexer.
To achive this, a VNA is the best Instrument to check this!
For higher Q´s the Problem might be more sensitive to tolerances !
Von: firstname.lastname@example.org [emrfd] [mailto:email@example.com]
Gesendet: So 02.11.2014 05:06
Betreff: Re: AW: [emrfd] Losses in Diplexer?
Q=10 is workable at frequencies up to about 10 or perhaps 15 MHz; at your 20 MHz it might be better, as others said, to drop the design Q to somewhere in the 1 - 5 range.
Common "Jaycar" ceramics are usually reasonable Q; as Henning said, the inductors might be the problem.
Try #2 (red) iron-powder for the inductors.
The Q=10 diplexer in this 5 MHz mixer/amplifier/diplexer module has 0.4 dB loss;
10408 2014-11-02 01:38:05 kerrypwr Re: AW: AW: [emrfd] Losses in Diplexer?