The cable company used to use band blocking filters similar in style to these to block out stations, like HBO, that you were not subscribed to. They were installed up on the pole by your service entrance.
Telonic Industries (Telonic Berkeley of late), was once located in Laguna Beach, CA. They used to make filters in a similar cylindrical package. The filters were extremely accurate and extremely expensive. Always wondered about the construction but never dared to find out. Perhaps the same techniques was used there as well.
I think one of the reasons I love RF is how significantly and directly mechanical features can affect signals. Things that would otherwise be just structural, like a brass pipe, or a hole in a piece of metal can become an integral component in a radio system
I like how they gone the most 'low-level' route with moving the wires and making whole capacitors People often overthink things and forget simple ways of making good n robust things
Your enthusiasm is contagious. That's what makes you entertaining to watch, even though you might be teaching on some EE area that is outside of my knowledge and/or interest. Bravo.
I think smooshing the wire around changes the interwinding capacitance not inductance. For a air core inductor I think it’s hard to change the inductance by just stretching the coil by a small amount.
The idea to adjust the wires from those holes come from radio and old analog TV's.. "Air core inductors" on the oscillating parts and modulating section..
One wonder what would be the specification in order to make one for 1.3 Ghz??? I do love the video!!! I was thinking there have to b, some kind of custom tool to extend or compress them inductors in between.....
Thats a significantly wide Gap (maybe 1/4 inch) running down the thin, white, dielectric insulating tube.....What prevents the brass Disc from eventually shorting out to the outer grounded brass tube ??
Close! It's a few miles south of Delaware, on what's known as the Eastern Shore of Maryland, the entire peninsula east of the Chesapeake bay is also known as the Delmarva Peninsula.
A nice band 2 fm filter then, a bit dodgy that adjustment method, it could easily go off tune if you hit it or dropped it, love your v n a wish we could get stuff like that in the UK at a reasonable price
Interesting video. It would seem that if you dropped it on the end, it could change. It would also seem that it couldn't be filled with anything like wax, that would have dialectic properties that increase the capacitance. The best part: the calibration holes aren't even drilled in a straight line. LOL!
You can always pour something on it to make it fixed in place. I am sure it would be possible to make better system for adjustment like screw or something.
@@xyshawnlau5522 , thank you for the interest. I've had some pretty bad health issues. I will at least make an explanation video. I'm flattered that you think I am an engineer. I am just someone who has science and tech interests.
Not as nicely done but a bit like thatis the kenwood lf-30a which is a 30 mhz low pass filter for 0-30 mhz hamradio to avoid interference on your neighbors tv, open inductors and capacitors made out of copper discs and Teflon foil.
The cable company used to use band blocking filters similar in style to these to block out stations, like HBO, that you were not subscribed to. They were installed up on the pole by your service entrance.
Telonic Industries (Telonic Berkeley of late), was once located in Laguna Beach, CA. They used to make filters in a similar cylindrical package. The filters were extremely accurate and extremely expensive. Always wondered about the construction but never dared to find out. Perhaps the same techniques was used there as well.
I think one of the reasons I love RF is how significantly and directly mechanical features can affect signals. Things that would otherwise be just structural, like a brass pipe, or a hole in a piece of metal can become an integral component in a radio system
I like how they gone the most 'low-level' route with moving the wires and making whole capacitors
People often overthink things and forget simple ways of making good n robust things
they don't teach that in school for sure
Your enthusiasm is contagious. That's what makes you entertaining to watch, even though you might be teaching on some EE area that is outside of my knowledge and/or interest. Bravo.
I think smooshing the wire around changes the interwinding capacitance not inductance. For a air core inductor I think it’s hard to change the inductance by just stretching the coil by a small amount.
Very nice, I always wondered how they make these. They are also available in 50Ohms with SMA connectors. Very nice filters.
Salisbury is an American company. It became K&L Filters in Salisbury, MD.
Interesting, thanks for this info, I have seen quite a few K&L filters, that look exactely the same as this one, only in 50 Ohms, that explains it.
K&L is perhaps the most trusty filter manufacturer when very demanding performances are requested. They are truly nomber one...
@@paolomonai9511 They for sure are the best ones I have.
K&L came first, Salisbury Engineering was started by one of the people who worked there but split off to form their own company.
I live near Salisbury, NC which has a good bit of train/rail engineering, but is better known for Krispy Kreme donuts and Cheerwine soda.
The idea to adjust the wires from those holes come from radio and old analog TV's.. "Air core inductors" on the oscillating parts and modulating section..
Your filter was made in Salisbury Md by a company formally known as K & L microwave
Bill
WB2UFC
Now... Are you going to build one? That fall off is beautiful!
E.F. Johnson made a similar device as a low pass filter to reduce the harmonics of amateur radio transmitters back in the 50s and 60s.
One wonder what would be the specification in order to make one for 1.3 Ghz??? I do love the video!!! I was thinking there have to b, some kind of custom tool to extend or compress them inductors in between.....
rf-tools.com/lc-filter/
Thats a significantly wide Gap (maybe 1/4 inch) running down the thin, white, dielectric insulating tube.....What prevents the brass Disc from eventually shorting out to the outer grounded brass tube ??
Salisbury is in Delaware, USA. A guy from Canada.
Close! It's a few miles south of Delaware, on what's known as the Eastern Shore of Maryland, the entire peninsula east of the Chesapeake bay is also known as the Delmarva Peninsula.
Can you make a video showing how to build a simple band pass filter ?
ua-cam.com/video/5ZIb-0uBqpA/v-deo.html
A nice band 2 fm filter then, a bit dodgy that adjustment method, it could easily go off tune if you hit it or dropped it, love your v n a wish we could get stuff like that in the UK at a reasonable price
CA the VNA you used in one of your videos to show SWR and frequency of an antenna be used to show the Freq Band Pass ?
yes, that is a S21 transmisión measurement
2:07
That’s an ‘instrument’ not a machine. Get it together…
lol, just joshing you :)
Thanks for sharing!!!
Could you recommend some source for learning RF for someone who is still a beginner in ee in general
@@NimbleJack3 thanks!
The Arrl Handbook for Radio Communications
Book by American Radio Relay League
@@IMSAIGuy Ill look for it thanks!
Doesn't everyone have a copy of that book already?
@@xenoxaos1 lots of new electronic fans who are used to Arduinos and built in WIFI and have not seen any RF.
cool!
Probably not UK as we don't have "inc" akaik we have also been metric since the 1970s :)
Now called API Technologies Corp. Several locations in US and UK: www.apitech.com/
I'm betting Salisbury Maryland, a company started by persons who split off from K & L Microwave in the same town.
Interesting video.
It would seem that if you dropped it on the end, it could change. It would also seem that it couldn't be filled with anything like wax, that would have dialectic properties that increase the capacitance.
The best part: the calibration holes aren't even drilled in a straight line. LOL!
You can always pour something on it to make it fixed in place. I am sure it would be possible to make better system for adjustment like screw or something.
Brenda, you're a super engineer, waiting for your new videos.
@@xyshawnlau5522 , thank you for the interest. I've had some pretty bad health issues. I will at least make an explanation video. I'm flattered that you think I am an engineer. I am just someone who has science and tech interests.
American - Salisbury, Maryland
inc isnt uk its usa
Guys were samrter at that time
Just think of the Math involved during the design stage to get the right size's on the Caps before computers.... Most likely a Slide Rule... :)
Or a Smith chart.
Wow❤
Not as nicely done but a bit like thatis the kenwood lf-30a which is a 30 mhz low pass filter for 0-30 mhz hamradio to avoid interference on your neighbors tv, open inductors and capacitors made out of copper discs and Teflon foil.
Very cool construction indeed. I wonder though why did they go into so much trouble. It's not that difficult to build a 90 Mhz filter.
Oh maybe because it's a bandpass one and they wanted to reduce the insertion loss.... Got it.
Lets smoke some herb with it.
Just a typical coaxial filter, I deal with those capable of 100kw. for low pass filters.
🌷🌟🌷
It's UKanian.
Very unique! Enjoyed watching. Thanks.