EEVblog Electronics Community Forum
Electronics => RF, Microwave, Ham Radio => Topic started by: jord4231 on October 05, 2024, 10:54:20 pm
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Hi Just wondering if anyone has had any experience with these?
https://www.aliexpress.com/item/1005005910772893.html (https://www.aliexpress.com/item/1005005910772893.html)
Can't find anyone who's using them for radio related projects anywhere
I have built a balanced L matching unit and the Jennings vac cap I have its a bit too high at minimum C for my needs.
This one fits my requirements but I do wonder about it's mechanical longevity seals etc...
Cheers
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sorry, can't help with those, but the issue with vac caps is the sealing and "how long" they'll mantain it...
as for your Jennings min capacity, did you consider adding a switchable series doorknob to them to lower it when needed ?
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alternatively, you may consider something like the attached, it can be configured as either a T or an L match using S1 and S2; the C3 and C4 fixed caps will have the same value as the max value of C1 and C2 and can be inserted in both configs (L or T) if/when needed; when in T config they'll help reducing losses
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alternatively, you may consider something like the attached, it can be configured as either a T or an L match using S1 and S2; the C3 and C4 fixed caps will have the same value as the max value of C1 and C2 and can be inserted in both configs (L or T) if/when needed; when in T config they'll help reducing losses
Thanks for the reply, I've experimented with series capacitors and while it works I think it will just be easier to get something that goes to around 10p rather than 50p I have linked a video for the project so far if you are interested.
https://youtu.be/PkCmKlOmHHU?si=NObs60NmXud0xFVb
Thanks again
Jordan
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see here
http://ur4ll.net/#caps3_1 (http://ur4ll.net/#caps3_1)
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also see
https://elektrodump.nl/en/49-variable-vacuum-capacitor