Those Diamond MX2000 / 3000's look interesting. Nice to hear that they work well in reverse. Great - another thing to add to my list to look at when visiting the candy store.
That's right up my alley since I like building my own antennas specific to each band...
Here I go again - for a guy that doesn't like hanging out in the TV section of Radio Shack, I seem to be spending a lot of time there.....
Found a RS #15-579A "TV Interference Filter" which is just a 54-900 mhz bandpass filter and has a nicely crimped f-connector on a pigtail. Does it work? Seems to. It does attenuate the 42mhz low band systems that I monitor, and probably does so to some extent on the amateur 6-meter band. However I have no way of giving figures to going from full-scale on the 164's s-meter down to 2-bars at 42 mhz.
But I guess if one is getting hammered from an HF or low-band VHF station, this works to provide at least some attenuation down there. It *might* help if you have a long run of feedline acting as an HF antenna in common-mode that isn't choked with ferrites, etc.
But how is the insertion loss? Well, now at least with the tuned splitter AND this "tv interference filter" attached to the input of the splitter, I'm detecting some insertion loss. The good news is that after about 2 minutes of listening to the originally weak vor station, it is still there - but just barely. Took awhile to convince myself that I am actually hearing the morse-id, and not just imagining it.
So it stays inline. My high-vhf operations still seem fine.
Essentially with these two units ganged together, I have a 54-250 mhz bandpass filter on the vhf port without too much insertion loss to affect my operations. So it will stay inline for the time being.
Again, without any test equipment, this is all by ear and no specs to go by.
Fun!