Band Pass filters for 23cm, the easy way!

[@MatthiasLenardt]

How beautiful! Thanks for sharing. Much love, Matthias

[@Jonny10001]

Thanks for the kind compliment Matthias.

[@MatthiasLenardt]

@@Jonny10001 Your welcome! You are a RF magician 😉 Much love, Matthias ( 73 from DL1NDG )

[@Jonny10001]

Hi Ronald, thanks for the compliment. I used 60x40x2.2mm, not quite the same size as specified by the author but didn’t seem to matter. His designs didn’t go below 23cm so you would have to scale it up in size. But whether that size enclosure would be suitable is an unknown, good luck.

[@rolandboerboom9420]

Awesome video! Clearly and simple explanation! I'm gonna build a filter also, it's not difficult with this video and information. Thanks for sharing!

[@ElPasoTubeAmps]

A beautiful job and what I will duplicate for 1420 MHz for the hydrogen line. Thank you for posting.

[@rwhealthy]

this is an awesome video. Couple of questions: What size aluminum did you use? Will this work for 915Mhz?

[@Jonny10001]

Thanks for the compliment Kleibe.

[@Jonny10001]

I would not think so, the RF is travelling on the surface of the metal not through it.

[@an7ana5]

Lovely video.... do you sell 868 mhz cavity filters ?

[@Jonny10001]

Hi and thanks for the compliment. I don’t make any to sell but you could scale up the dimensions for the frequency you require.

[@piotrr5170]

Can you have really exact parameters to build for 866 to 869mhz-

[@Jonny10001]

No, i’m just an amateur radio operator that likes to tinker, thanks for the compliment.

[@weirdsciencetv4999]

What is the insertion loss like? Gorgeous design btw

[@Jonny10001]

I can’t quote an actual figure but it’s very low, at least at 23cm.

[@NZ2Pepper]

The initial drawing shows the SMAs on the side of the running screws. Yet your assembly shows the other side. Would this make a difference?

[@Jonny10001]

I made the video over a period of time starting with one filter then another one at the end. It didn't seem to make a difference which side the connectors are on but I would stay with the original design to be safe. It could make a difference at higher frequencies.

[@foxbat888]

You could sell this as a kit, perhaps

[@2jpu524]

What was the paper you based this off of? It looks interesting & useful.

[@Jonny10001]

The original article that the construction was based on is:- lea.hamradio.si/~s53mv/cavity/cavity.html

[@2jpu524]

@@Jonny10001 Thank you for sharing this. Much appreciated.

[@kleibe]

Very nice!!!

[@billysgeo]

Can you get this down to 868Mhz?

[@Jonny10001]

You would need to scale everything up in size by 30.50% based on the dimensions for a 1250MHz filter Including the rectangular section. The rods should could remain the same diameter just longer. Probably best to make the housing out of sheet metal pieces as ready made rectangular aluminium of that size may to difficult to find, let me know how you go with it.

[@egbertgroot2737]

Will copper give a better result?

[@TheArtofEngineering]

Microwave RF engineering is black magic! :). Would this work for 70cm? I have a dirty Baofeng I want to clean up. Thanks for sharing VK2AOE.

[@Jonny10001]

Hi, I get many inquiries regarding using the filters on lower frequencies. The design came from a talented gentleman that did the original design and I have supplied the link to his web site. My video was intended just to show construction techniques to make the filters in the easiest way. It should be possible to scale the dimensions up but I don’t have the knowledge to do that. Having said that using basic maths to scale from 23cm to your required frequency would be a good start.

[@TheArtofEngineering]

@@Jonny10001 🙏 for the reply…. Will hit the books! ….

[@SureshKumar-nk2ok]

sir whats the dimension for 20m band

[@Jonny10001]

HUGE !!!

[@michaelhope007]

1.3km long X 200mtr wide X 450mtr deep. The tuning screws are made from 30mtr threaded water pipe.

[@noslidemais]

[@Jonny10001]

This is the revised web site address for the filter dimensions:- lea.hamradio.si/~s53mv/cavity/cavity.html