Sunday, September 25, 2016

HPF-225 UHF Airband Filter

At last I got a band pass filter for UHF aircraft band listening at a ham shop near Yokota Air Base.

The instruction says "frequency range of the filter is 200-400MHz and VSWR is less than 2". The body size is 0.787"(30mm)W x 1.181"(20mm)H x 0.709"(18mm)D without SMA connectors.

Today we can find some UHF aircraft band filters but unfortunately they are heavy and not for SMA connectors. By contrast, the HPF225 is compact, light weight and fits for my Uniden BCD436HP scanner without adapters.

On my first look, though 880MHz RF power(3G/LTE digital cellulars) seems not to be eliminated, lower bands such as FM broadcasts, VHF aircrafts, VHF marines, VHF police bases-vehicles and so on look like working properly. No VHF TV broadcasts in my country because they had already moved to UHF band in 2011 for our countries' law.

It tends not to well eliminate high frequency more than 800MHz. I'll check the details.

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