Fun with cavity filters

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2020-09-30に共有

Some experiments with a 430 MHz cavity filter made in a biscuit tin. More background info here:
www.repeater-builder.com/antenna/pdf/w6nbc-duplexe…
vk6uu.id.au/warg2mduplexer.html
www.radioexperimenter.us/rm-1966-04/kedx.html
pa0nhc.nl/homemadeDuplexfilter2m/duplexfi.html

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コメント (19)

@bendunselman 1ヶ月前

Your infant will love this when grown up.
@MoTown44240 3年前

While in my early learning days about VHF, 1986, I built a poor man's cavity filter for 2m. Like Peter says, it works but not very efficiently. Great video Peter. 72 de KB8AMZ
@MakeDoAndMend1 3ヶ月前

I've just made a Cavity Filter from an old gas bottle. Works a treat. Cheers from old George ps cost to make about a UK pound.
@markhonea2461 1年前

OMG I am so going to get involved with that, this, the most fascinating information I have found in the sea of YouTube.🤓👍
@artemisdefcon 3年前

Nice jobs dude.
@markhonea2461 1年前

I will now watch this again 👍
@markg6jvy135 3年前

Very creative thinking Peter 👏👏👏
@chronobot2001 1年前

Would adding additional mass at the end of the internal tube change the filter frequency?
@markhonea2461 1年前

Would large bore copper pipe work?
@coblecam 3年前

Are there general rules about the diameter of the cavity used? GREAT video! 73!
@chronobot2001 1年前

What if the internal tube was a coil? Longer tube coiled to fit into a smaller space.
@dereklassen4841 8ヶ月前

A few words... The frequency is determined by the length of the inner (not mass, it can be (usually is) hollow). It should be 1/4 wavelengthll long. The Q is set by the ID of the outer (bigger is better), and the conductivity of the inner surfaces (mostly). You want the Impedance to be 50 Ohms - set by the ratio of OD / ID. The end where the connector(s) are (is) must be shorted. The other end needs to be closed only to preclude corrosion. It could be a removable plastic cap. Your milage may vary. 73 de Derek, KN6TD.
@terrybondy1948 3年前

Wow! Suffered 5 adverts to get through this, most of them mandatory.
@ssubaihi 3年前

How it's work , Why Loops ? Still a lot to tell ...
@Max-kn9yi 2年前

Does it matter what end you attach a filter to the antenna?
@SirsenduGhosh1989 3年前

Is it possible to build cavity filter for HF? Just curious 73 de VU3WTJ
@MakeDoAndMend1 3ヶ月前

Many thanks for the inspiration to make filters. I used discarded steel gas bottles. Work a treat. I have posted on here. George 🇬🇧
@gillywild 3年前

I wonder if that was what someone was doing in the cuban embassy? The cricket noises and brain damage always sounded like microwaves to me. I should think a Theremin resonator for microwave frequencies would be quite compact.