I was recently looking at the website of Bert Modderman, PE1RKI in the Netherlands and I noticed that he is selling cavity filters for the 144 MHz band.
A cavity filter is essentially a hollow tube with tuning rods inside and can usually handle much higher powers than say a lot of the smaller band pass filters on the market which use inductors and capacitors.
The specs for this filter are that it has a 0.2dB insertion loss and it can handle up to 1-kilowatt of RF. It comes supplied with N-type connectors.
I have edited the diagram of the frequency response for the filter to make it clearer.
Signals on the marine band around 156 MHz are down about 18dB. Signals in the VHF air band (~120-130 MHz) are down about 10 - 12 dB.
If we were to extrapolate the shape of the graph down to say FM broadcast band on 88 to 108 MHz then the signals are probably down about 15 - 20 dB.
PE1RKI also makes a version for the 432 MHz band.
More information about the filters can be found HERE
Disclaimer: Just to be clear, this isn't an advertisement. I wasn't paid for this post or I wasn't sent the product for review. I just think this is something VHF operators will be interested in.
PE1RKI also sells a number of amplifiers, filters and antennas for the microwave bands. We all know you can buy lots of gear from websites the likes of Ali Express and eBay but a lot of it is rubbish. It's worth considering supporting small manufacturers and shops in Europe.
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