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References: [ +subject:/^(?:^\s*(re|sv|fwd|fw)[\[\]\d]*[:>-]+\s*)*Topband\:\s+Recycled\s+ferrites\s+for\s+160m\s*$/: 7 ]

Total 7 documents matching your query.

1. Topband: Recycled ferrites for 160m (score: 1)
Author: "G4GED Dave" <radiodave.g4ged@tiscali.co.uk>
Date: Wed, 21 Jan 2009 03:29:14 -0800
Hi Topbanders, My query revolves around the suitability, for 160m applications, of recycled ferrite material extracted from redundant CRT TVs and PC Monitors ? Thanks to the Flat-screen revolution, t
/archives//html/Topband/2009-01/msg00203.html (7,908 bytes)

2. Re: Topband: Recycled ferrites for 160m (score: 1)
Author: Dan Zimmerman N3OX <n3ox@n3ox.net>
Date: Wed, 21 Jan 2009 09:23:29 -0500
If you have an antenna analyzer you can get a decent idea of how the thing works by winding a few turns of wire onto the core and measuring the impedance of that. Shooting for a total impedance arou
/archives//html/Topband/2009-01/msg00209.html (10,332 bytes)

3. Re: Topband: Recycled ferrites for 160m (score: 1)
Author: Dan Zimmerman N3OX <n3ox@n3ox.net>
Date: Wed, 21 Jan 2009 09:24:24 -0500
That should be (M/N)^2 times the impedance you measured... _______________________________________________ Topband mailing list Topband@contesting.com http://lists.contesting.com/mailman/listinfo/to
/archives//html/Topband/2009-01/msg00210.html (7,442 bytes)

4. Re: Topband: Recycled ferrites for 160m (score: 1)
Author: "Jim Brown" <jim@audiosystemsgroup.com>
Date: Wed, 21 Jan 2009 09:38:51 -0800
YES. One VERY important caution. Antenna analyzers typically have stray input capacitance on the order of 10 pF! The equivalent circuit of a ferrite choke is a parallel equivalent circuit, and for mo
/archives//html/Topband/2009-01/msg00216.html (8,914 bytes)

5. Re: Topband: Recycled ferrites for 160m (score: 1)
Author: Dan Zimmerman N3OX <n3ox@n3ox.net>
Date: Wed, 21 Jan 2009 13:09:01 -0500
Jim, you're talking about the finished choke, right? Putting -j11,000 ohms (8pF like my MFJ-259 @ 1.8MHz ) in parallel with 30+j50 or whatever my test winding shows is basically irrelevant. If you t
/archives//html/Topband/2009-01/msg00217.html (8,506 bytes)

6. Re: Topband: Recycled ferrites for 160m (score: 1)
Author: Michael Tope <W4EF@dellroy.com>
Date: Wed, 21 Jan 2009 11:49:27 -0800
For measuring high series impedance, I recommend that you keep the circuit impedances low. Per the recommendation of K9YC, I would shunt a 50 ohm resistor across the generator output to eliminate unc
/archives//html/Topband/2009-01/msg00218.html (10,132 bytes)

7. Re: Topband: Recycled ferrites for 160m (score: 1)
Author: "Jim Brown" <jim@audiosystemsgroup.com>
Date: Wed, 21 Jan 2009 15:30:04 -0800
EXACTLY! There's nothing "magic" about 50 ohms -- it's simply a value that we often get for free built into our spectrum analyzer voltmeter. We could improve accuracy at lower values of unknown Z by
/archives//html/Topband/2009-01/msg00221.html (8,405 bytes)

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