[CQ-Contest] Multi 2 locking device, TriPlexers and BPF

Jim Brown k9yc at audiosystemsgroup.com
Tue Jan 10 17:28:45 EST 2017

On Tue,1/10/2017 8:23 AM, W0MU Mike Fatchett wrote:
> Is there an "easy" way to improve the port Isolation in the WX0B six 
> pack?

The only way I know of is replacement. I had one here, replaced it with 
4O3A's 6x2, which was about 20 dB better (measuring both units on the 
bench). Not long after that, 4O3A introduced the new 8x2, and I replaced 
the 6X2 with it. The 8x2 is more than 20 dB better than the 6x2, making 
it 45 dB better than the WX0B unit. Isolation is 100 dB, +/- 3-4 dB, 
depending on which band and which output.

Several years ago, I tried to get specs on the Microham unit. What I 
got, eventually, was rather hard to read plots that showed that the BEST 
case isolation of the 6x2 was quoted in the data sheet as "typical", and 
that other ports were significantly worse (6-10 dB). I asked for a unit 
to measure (to give them the benefit of the doubt), but W4TV insisted 
that I buy one.

Bottom line -- the 4O3A 8x2 is the best I know of. It's very well built, 
the control interface is close to being universal, and the guys in CO 
who distribute it are great to deal with.

I've NOT given any attention to weatherproofing, because my switching is 
all done in the shack. My bandswitching is being done by the band 
decoders in my 5B4AGN TXBPF filter sets.

73, Jim K9YC

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