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Total 27 documents matching your query.

1. [TowerTalk] Common-mode choke (score: 1): Author: GW4BLE <steve.gw4ble@btconnect.com>; Date: Sun, 18 May 2014 19:15:02 +0100; Hi, Need to make common-mode choke to give maximum impedance at 28 MHz, coax is RG-213, but unsure of Fair-Rite part number for mix-43 toroids (order would be to mouser, so an appropriate part number; /archives//html/Towertalk/2014-05/msg00314.html (7,388 bytes)
2. Re: [TowerTalk] Common-mode choke (score: 1): Author: Drax Felton <draxfelton@gmail.com>; Date: Sun, 18 May 2014 14:17:31 -0400; 623-5943003801. Sent from my iPhone _______________________________________________ _______________________________________________ TowerTalk mailing list TowerTalk@contesting.com http://lists.contes; /archives//html/Towertalk/2014-05/msg00315.html (8,176 bytes)
3. Re: [TowerTalk] Common-mode choke (score: 1): Author: GW4BLE <steve.gw4ble@btconnect.com>; Date: Sun, 18 May 2014 19:54:20 +0100; Wow! quick reply, many thanks. Steve GW4BLE Sent from my iPhone 5S _______________________________________________ _______________________________________________ TowerTalk mailing list TowerTalk@con; /archives//html/Towertalk/2014-05/msg00316.html (8,211 bytes)
4. Re: [TowerTalk] Common-mode choke (score: 1): Author: "Marsh Stewart" <marsh@ka5m.net>; Date: Sun, 18 May 2014 14:15:05 -0500; See Appendix 1 on page 46 of RFI-Ham.pdf by Jim Brown K9YC for Fair-Rite part numbers. www.audiosystemsgroup.com/RFI-Ham.pdf Marsh, KA5M Hi, Need to make common-mode choke to give maximum impedance a; /archives//html/Towertalk/2014-05/msg00318.html (8,346 bytes)
5. Re: [TowerTalk] Common-mode choke (score: 1): Author: Steve Hunt <steve@karinya.net>; Date: Mon, 19 May 2014 12:45:30 +0100; Steve, You say you want maximum common-mode impedance at 28 MHz. The best I've achieved is around 15,000 Ohms using 9 turns of RG58 on an FT240-61 core, Mouser part 623-5961003801. Replace the RG58 w; /archives//html/Towertalk/2014-05/msg00337.html (8,236 bytes)
6. Re: [TowerTalk] Common-mode choke (score: 1): Author: Jim Brown <jim@audiosystemsgroup.com>; Date: Mon, 19 May 2014 07:08:20 -0700; I don't trust any impedance measurements of chokes wound on #61, including my own, simply because the Q is so high. Even the slightest stray capacitance moves the resonance, and it's the resonance th; /archives//html/Towertalk/2014-05/msg00341.html (9,133 bytes)
7. Re: [TowerTalk] Common-mode choke (score: 1): Author: Steve Hunt <steve@karinya.net>; Date: Mon, 19 May 2014 17:07:18 +0100; That's right - to get meaningful results you need to understand the stray capacitance added by the test structure. Steve G3TXQ _______________________________________________ ________________________; /archives//html/Towertalk/2014-05/msg00346.html (8,168 bytes)
8. Re: [TowerTalk] Common-mode choke (score: 1): Author: Jim Lux <jimlux@earthlink.net>; Date: Mon, 19 May 2014 14:08:17 -0700; Steve G3TXQ On 19/05/2014 15:08, Jim Brown wrote: I don't trust any impedance measurements of chokes wound on #61, including my own, simply because the Q is so high. Even the slightest stray capacita; /archives//html/Towertalk/2014-05/msg00359.html (9,398 bytes)
9. Re: [TowerTalk] Common-mode choke (score: 1): Author: Steve Hunt <steve@karinya.net>; Date: Mon, 19 May 2014 22:21:53 +0100; Jim, I don't disagree - I just don't consider a "Q" of 1.3 to be particularly high for a choke! Steve G3TXQ On 19/05/2014 22:08, Jim Lux wrote: I think the take home thing here is that when it's a "c; /archives//html/Towertalk/2014-05/msg00361.html (8,500 bytes)
10. [TowerTalk] Common-mode choke (score: 1): Author: "Jim Thomson" <jim.thom@telus.net>; Date: Mon, 19 May 2014 18:19:16 -0700; Beyond that, if the thing is so sensitive to surrounding structures, how close is your measurement fixture to where it will actually be used? You might optimize performance for your fixture, and it's; /archives//html/Towertalk/2014-05/msg00366.html (8,279 bytes)
11. Re: [TowerTalk] Common-mode choke (score: 1): Author: Jim Brown <jim@audiosystemsgroup.com>; Date: Mon, 19 May 2014 23:35:19 -0700; In ALL cases where ferrite chokes are used for suppression, it is the resistive component of the impedance that is always useful. A choke that depends only on inductive reactance will resonate with t; /archives//html/Towertalk/2014-05/msg00369.html (10,205 bytes)
12. Re: [TowerTalk] Common-mode choke (score: 1): Author: Jim Brown <jim@audiosystemsgroup.com>; Date: Mon, 19 May 2014 23:54:57 -0700; Sorry, Jim, but string of bead chokes using #31 or #43 simply are not very effective on the HF bands because their resonance is at VHF, and their resistive component at HF is very low. Study k9yc.com; /archives//html/Towertalk/2014-05/msg00370.html (7,352 bytes)
13. Re: [TowerTalk] Common-mode choke (score: 1): Author: Jim Brown <jim@audiosystemsgroup.com>; Date: Tue, 20 May 2014 00:09:24 -0700; I don't disagree - I just don't consider a "Q" of 1.3 to be particularly high for a choke! Nor do I, but the #61 chokes I've measured are in the range of 4-5. Compare the data sheets at the beginning; /archives//html/Towertalk/2014-05/msg00371.html (9,522 bytes)
14. Re: [TowerTalk] Common-mode choke (score: 1): Author: Steve Hunt <steve@karinya.net>; Date: Tue, 20 May 2014 11:23:11 +0100; The OP asked about a 10m choke. Take a look at the Fair-Rite complex permeability charts and you'll see that at 10m the ratio u'/u''for #61 material is 1.3 - that's a _lower_ ratio (lower Q) than #31; /archives//html/Towertalk/2014-05/msg00372.html (9,054 bytes)
15. [TowerTalk] Common-mode choke (score: 1): Author: "Jim Thomson" <jim.thom@telus.net>; Date: Tue, 20 May 2014 07:05:35 -0700; Sorry, Jim, but string of bead chokes using #31 or #43 simply are not very effective on the HF bands because their resonance is at VHF, and their resistive component at HF is very low. Study k9yc.com; /archives//html/Towertalk/2014-05/msg00377.html (9,146 bytes)
16. Re: [TowerTalk] Common-mode choke (score: 1): Author: Jim Brown <jim@audiosystemsgroup.com>; Date: Tue, 20 May 2014 08:02:03 -0700; Yes. I have shown in my tutorial why choking Z on the order of 5K ohms resistive is a suitable design goal for most installations, and W8JI has reminded us of some where that's not enough. The only s; /archives//html/Towertalk/2014-05/msg00378.html (9,545 bytes)
17. Re: [TowerTalk] Common-mode choke (score: 1): Author: TexasRF--- via TowerTalk <towertalk@contesting.com>; Date: Tue, 20 May 2014 11:30:34 -0400 (EDT); Jim, trying to understand the source of the high resistance that is frequently mentioned for choke design. I can see one scenario where a series to parallel conversion might explain it. Say 400 ohms; /archives//html/Towertalk/2014-05/msg00381.html (10,029 bytes)
18. Re: [TowerTalk] Common-mode choke (score: 1): Author: Jim Brown <jim@audiosystemsgroup.com>; Date: Tue, 20 May 2014 08:53:26 -0700; Study the RFI tutorial. It's all there. 73, Jim K9YC _______________________________________________ _______________________________________________ TowerTalk mailing list TowerTalk@contesting.com ht; /archives//html/Towertalk/2014-05/msg00383.html (8,403 bytes)
19. Re: [TowerTalk] Common-mode choke (score: 1): Author: TexasRF--- via TowerTalk <towertalk@contesting.com>; Date: Tue, 20 May 2014 11:58:05 -0400 (EDT); Wish I had the time and patience to wade through all of that. A yes or no would work. 73, Gerald K5GW In a message dated 5/20/2014 8:55:46 A.M. Pacific Daylight Time, jim@audiosystemsgroup.com writes; /archives//html/Towertalk/2014-05/msg00384.html (9,348 bytes)
20. [TowerTalk] Common-mode choke (score: 1): Author: "Jim Thomson" <jim.thom@telus.net>; Date: Tue, 20 May 2014 09:31:24 -0700; Yes. I have shown in my tutorial why choking Z on the order of 5K ohms resistive is a suitable design goal for most installations, and W8JI has reminded us of some where that's not enough. The only s; /archives//html/Towertalk/2014-05/msg00386.html (10,784 bytes)

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