BPF70/6 bandpass, High side BPF70/6 bandpass, Low side Wide-band performance is very similar, the curves below show the narrow performance of the filters with the same setup as above. I've previously modified the coupling network on a Procom BPF70/6 6-cavity duplexer to make 2 pcs. I can't say if the filter is thermally stable enough for 100% duty cycle use at the rated power, you'll have to do your own tests there. for receivers, or user operated stations).
I can recommend this for general purpose use (e.g. The LBQ-450 is a pretty high performance low cost 3-cavity filter, it has good wide-band and narrow-band performance. I didn't test the filter under power, it's fairly wide so it'll probably be fine as long as you derate the power reasonably. I didn't adjust the tuning so this is the performance you can likely expect if you order one pre-tuned. This performance is perfectly adequate, showing approximately +-20 MHz -60dB performance and good linearity. Measurement results Wide-band performance Narrow performance showing pass-band and near-band attenuation There is no obvious way to adjust the Q of the filter like the superficially similar Procom variants. It's annoying to have the N ports on the sides but this is probably done for technical reasons. The filter in person, no idea what those shiny circles are (they are not tuning ports or fingerprints) Tuning end of the filter This seems to have been perfectly adequate, since the filter was still tuned correctly and looked fine.
Shipping took several weeks as usual, when it arrived it was packaged in a cardboard box containing a smaller styrofoam box. I ordered mine with a spec of 432-435 to cover the Norwegian 70cm band. The table above contains the specification from the eBay listing.
The LBQ-450 filter is sold by several eBay sellers, I bought mine from yee-cssl at a slight discount via an auction listing. I bought a chinese made 3-cavity bandpass filter and decided to measure it and compare it to some home-made modified duplexer filters.
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