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Total 22 documents matching your query.

1. [RFI] Choke questions (score: 1): Author: Andy KU7T <ku7t@ku7t.org>; Date: Tue, 21 Jan 2020 15:28:18 +0000; Hi, these may dumb questions (I am a choke newbee, but working myself up to the skillset to build my own to specific needs)... A recommended method and material to use is #31 and a #12 THHN pair of w; /archives//html/RFI/2020-01/msg00105.html (7,222 bytes)
2. Re: [RFI] Choke questions (score: 1): Author: Dave Cole <dave@nk7z.net>; Date: Tue, 21 Jan 2020 07:36:17 -0800; Hi Andy, Take a look at Jim's Choke Cookbook at: http://k9yc.com/2018Cookbook.pdf It is the reference for me... Look at some of his other publications as well... He covers most everything regarding c; /archives//html/RFI/2020-01/msg00106.html (7,726 bytes)
3. Re: [RFI] Choke questions (score: 1): Author: "EDWARDS, EDDIE J via RFI" <rfi@contesting.com>; Date: Tue, 21 Jan 2020 17:32:25 +0000; Andy, Use coaxial cable when making RF chokes for antenna systems. Use THHN (#12 stranded) when making an RF choke for AC power cabling--you can twist the wires making it twisted cable. You can use s; /archives//html/RFI/2020-01/msg00107.html (8,544 bytes)
4. Re: [RFI] Choke questions (score: 1): Author: Jim Brown <jim@audiosystemsgroup.com>; Date: Tue, 21 Jan 2020 10:21:28 -0800; Parallel wires work fine for winding chokes. There's no need for shielding -- the field from the choke is confined to the core. At least half of the chokes in my station are wound with a pair of Tefl; /archives//html/RFI/2020-01/msg00108.html (8,207 bytes)
5. Re: [RFI] Choke questions (score: 1): Author: Jim Brown <jim@audiosystemsgroup.com>; Date: Tue, 21 Jan 2020 10:25:37 -0800; As others have suggested, three tutorials on my website provide the technical background. k9yc.com/RFI-Ham.pdf and http://k9yc.com/CoaxChokesPPT.pdf explain the concepts, and http://k9yc.com/2018Cook; /archives//html/RFI/2020-01/msg00109.html (7,517 bytes)
6. Re: [RFI] Choke questions (score: 1): Author: K9MA <k9ma@sdellington.us>; Date: Tue, 21 Jan 2020 14:47:43 -0600; Back in my spacecraft hardware building career, it was well known that Teflon would "cold flow". Great care was taken where wires went around corners, etc., that there was no pressure on the insulati; /archives//html/RFI/2020-01/msg00110.html (8,711 bytes)
7. Re: [RFI] Choke questions (score: 1): Author: k9yt--- via RFI <rfi@contesting.com>; Date: Tue, 21 Jan 2020 21:06:29 +0000 (UTC); Don't see a specific reference to failure. 72/73, San K9YT Creep and Cold Flow http://www.rjchase.com/fep_handbook.pdf Wire Insulation Selection Guidelines https://nepp.nasa.gov/npsl/Wire/insulation_; /archives//html/RFI/2020-01/msg00111.html (14,581 bytes)
8. Re: [RFI] Choke questions (score: 1): Author: David Eckhardt <davearea51a@gmail.com>; Date: Tue, 21 Jan 2020 21:29:48 +0000; The early comm satellites that went up used Teflon as a substrate for the RF boards. Teflon doesn't do too well in a radiation environment. The MTTF of the first satellites was weeks due to the RF po; /archives//html/RFI/2020-01/msg00112.html (10,535 bytes)
9. Re: [RFI] Choke questions (score: 1): Author: Grant Saviers <grants2@pacbell.net>; Date: Tue, 21 Jan 2020 13:42:48 -0800; It could happen, but I've not experienced it. It was a problem with TFE insulated wire wrap if the wire route was very tight to a post. The spec on posts was 0.002" maximum corner radius and I've nev; /archives//html/RFI/2020-01/msg00113.html (10,451 bytes)
10. Re: [RFI] Choke questions (score: 1): Author: David Eckhardt <davearea51a@gmail.com>; Date: Tue, 21 Jan 2020 21:52:18 +0000; I've found the super-flex insulated 'antenna wire' sold by Davis RF is pretty good for winding larger ferrite cores (bifilar, quadfilar, ...). Also I've repeatedly used RG-142 Teflon coax for winding; /archives//html/RFI/2020-01/msg00114.html (11,156 bytes)
11. Re: [RFI] Choke questions (score: 1): Author: Jim Brown <jim@audiosystemsgroup.com>; Date: Tue, 21 Jan 2020 16:01:38 -0800; No advantage to this over THHN, and I suspect THHN is cheaper. Also, I find it important to wind 2-wire chokes with two colors to make certain that turns don't get twisted (bad). Also I've repeatedly; /archives//html/RFI/2020-01/msg00115.html (9,733 bytes)
12. Re: [RFI] Choke questions (score: 1): Author: "John K9UWA" <john@johnjeanantiqueradio.com>; Date: Tue, 21 Jan 2020 23:02:34 -0500; Is there a 75 ohm equivalent to RG400 coax? thanks 73 John k9uwa John Goller, K9UWA & Jean Goller, N9PXF Antique Radio Restorations k9uwa@arrl.net Visit our Web Site at: http://www.JohnJeanAntiqueRad; /archives//html/RFI/2020-01/msg00116.html (8,944 bytes)
13. Re: [RFI] Choke questions (score: 1): Author: Jim Brown <jim@audiosystemsgroup.com>; Date: Tue, 21 Jan 2020 22:35:36 -0800; Not that I know of, although are there's at least one sort of like RG142. KZ1W sent me several miniature coaxes to evaluate for chokes for TX 4-squares, the most useful of which seems to be RG179. It; /archives//html/RFI/2020-01/msg00117.html (8,691 bytes)
14. Re: [RFI] Choke questions (score: 1): Author: Gedas <w8bya@mchsi.com>; Date: Wed, 22 Jan 2020 09:59:21 -0500; Another Teflon based coax similar to 50-ohm RG-142 and 75-ohm RG-179 is 75-ohm RG-187. Gedas, W8BYA EN70 Gallery at http://w8bya.com Light travels faster than sound.... This is why some people appear; /archives//html/RFI/2020-01/msg00118.html (9,618 bytes)
15. Re: [RFI] Choke questions (score: 1): Author: Dave Cole <dave@nk7z.net>; Date: Wed, 22 Jan 2020 07:09:14 -0800; Anyone know where to get RG-400 for a decent price? 73, and thanks, Dave (NK7Z) https://www.nk7z.net ARRL Volunteer Examiner ARRL Technical Specialist ARRL Asst. Director, NW Division, Technical Reso; /archives//html/RFI/2020-01/msg00119.html (10,238 bytes)
16. Re: [RFI] Choke questions (score: 1): Author: Gedas <w8bya@mchsi.com>; Date: Wed, 22 Jan 2020 10:31:00 -0500; What kind of length(s) are you looking for and do you want connectors on the end? Many of the RG-400 coax are made in China, there are some US based companies like Harbour Industries etc that special; /archives//html/RFI/2020-01/msg00120.html (11,433 bytes)
17. Re: [RFI] Choke questions (score: 1): Author: Dave Cole <dave@nk7z.net>; Date: Wed, 22 Jan 2020 08:19:21 -0800; Thank Jim, I do care if it came from China, do you have a US based cable you know of? I want to build a few of Jim's chokes, so I want decent cable. No ends needed. 73, and thanks, Dave (NK7Z) https:; /archives//html/RFI/2020-01/msg00121.html (12,413 bytes)
18. Re: [RFI] Choke questions (score: 1): Author: Gedas <w8bya@mchsi.com>; Date: Wed, 22 Jan 2020 12:10:17 -0500; Keep in mind that the vast majority of even high end cables and connectors are now mostly made in China. Some in the Philippines, Malaysia, etc. For example the last batch of brand new Amphenol N-con; /archives//html/RFI/2020-01/msg00122.html (13,825 bytes)
19. Re: [RFI] Choke questions (score: 1): Author: Gary Johnson <gwj@wb9jps.com>; Date: Wed, 22 Jan 2020 09:38:59 -0800; Harbour Industries RG400 is completely acceptable. I bought 100 ft on Ebay from a Chinese supplier. Measured it on my VNWA and extracted the cable parameters, which were actually slightly better than; /archives//html/RFI/2020-01/msg00123.html (8,395 bytes)
20. Re: [RFI] Choke questions (score: 1): Author: donovanf@starpower.net; Date: Wed, 22 Jan 2020 15:05:27 -0500 (EST); We're not discussing a choke operating at very high frequencies, we discussing its performance at 1.8 or 3.5 MHz. At these frequencies, a few feet of 50 ohm transmission line such as RG-142 or RG-400; /archives//html/RFI/2020-01/msg00124.html (9,941 bytes)

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