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27th May 2009, 2:02 pm | #21 |
Rest in Peace
Join Date: Jun 2006
Location: Chard, South Somerset, UK.
Posts: 7,457
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Re: Homebrew Q meter (or very nearly)
OK, Mike - I've now run out of suggestions on this. I'll now leave you to ponder, etc. Come back to us when you decide to move this further. It'll be interesting to see what eventually develops from this.
TTFN. Al. / Skywave. |
27th May 2009, 2:54 pm | #22 |
Retired Dormant Member
Join Date: Mar 2006
Location: Sheffield, South Yorkshire, UK.
Posts: 1,587
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Re: Homebrew Q meter (or very nearly)
Hi Al,
I will get back to you with my next move the interesting link is the middle one that jimmc passed through.The author has designed a purpose Q meter but interestingly he has the same thoughts about capacitor divider and HigZ buffering around the EUT, I think we are going in the right direction because that has been published as a design in the States. There are some good ideas about the construction of the test jig. Thanks for your support Mike |
27th May 2009, 4:17 pm | #23 |
Rest in Peace
Join Date: Jun 2006
Location: Chard, South Somerset, UK.
Posts: 7,457
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Re: Homebrew Q meter (or very nearly)
Whoops! I've just had another after-thought!
I do recall that quite some time back, an article was published in Practical Wireless for a Q-meter; I may be able to dig my copy out (archived ). I know that this is tangential to your approach; would it be of any interest to you? Al. |
27th May 2009, 6:39 pm | #24 |
Retired Dormant Member
Join Date: Mar 2006
Location: Sheffield, South Yorkshire, UK.
Posts: 1,587
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Re: Homebrew Q meter (or very nearly)
Hi Al,
All information is of use, just to prove the approach is not the one take can be just as valuable !! Thanks again Mike |
28th May 2009, 1:59 am | #25 |
Retired Dormant Member
Join Date: Sep 2008
Location: wakefield
Posts: 4
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Re: Homebrew Q meter (or very nearly)
The series resonance method works well, especially out beyond 10MHz where (conventionally) maintaining a high shunt Z becomes a real problem. The kit simply consists of a good quality tuning capacitor, thereby moving the measuring complications onto the spectrum analyser etc.
Only drawback is that the Q is now measured w.r.t. 50ohms and needs some sums doing!. |