Kris,
These filters are constant impedance designs so the transmitters unwanted
sideband power gets dumped into a load on the Hybrid port. This also helps
with group delay at edges of the filtered response.
... cant see why a ham would make a filter with twice as many cavities than
needed, just to keep SWR low out of band..
The only possible use would be as a combiner for two repeater transmitters
because one hybrid port acts as a wideband input. Problem is, if you are on
2m with two repeaters 60kHz apart each resonator has to be pass F1 and short
F2.
mange tout
Ian
G8PWE
- Original Message -
From: "Kris Kirby"
To:
Sent: Monday, February 22, 2010 6:21 PM
Subject: [Repeater-Builder] Mask filters?
>
> In the commercial world of broadcasting, there is a hybrid filter used
> called a mask filter. The mask filter is two -90 degree hybrids, a dummy
> load, and a pair of bandpass cavities between them. They suppress
> sidebands and keep the TV transmitter's radiation within the 6MHz
> channel.
>
> Has anyone heard of a similar concept used for filtering amateur
> repeaters?
>
> --
> Kris Kirby, KE4AHR
> Disinformation Analyst
>
>
>
>
>
>
> Yahoo! Groups Links
>
>
>
