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Total 1943 documents matching your query.

281. Re: [RFI] Finding noise source (score: 1)
Author: "Jim Brown" <jim@audiosystemsgroup.com>
Date: Fri, 15 Aug 2008 10:03:45 -0700
In general, you need to get MUCH closer to the noise source to find it on VHF (and you should be listening with an AM detector, if possible). The antenna that is radiating the signal you hear on HF i
/archives//html/RFI/2008-08/msg00021.html (7,736 bytes)

282. Re: [RFI] Finding noise source (score: 1)
Author: "Jim Brown" <jim@audiosystemsgroup.com>
Date: Sat, 16 Aug 2008 12:48:12 -0700
Excellent advice! These conductors are often involved in radiating the trash. Remember that ANY WIRE CARRYING RF CURRENT WILL RADIATE! Just because we CALL a wire "ground" doesn't mean that it isn't
/archives//html/RFI/2008-08/msg00026.html (7,548 bytes)

283. Re: [RFI] BrightHouse & RFI? (score: 1)
Author: "Jim Brown" <jim@audiosystemsgroup.com>
Date: Sun, 24 Aug 2008 08:37:16 -0700
Again, we slip into the trap of viewing TVI as interference with the RF signal. In today's world, that rarely happens. Instead, RF either couples directly into poorly shielded equipment, or excites p
/archives//html/RFI/2008-08/msg00035.html (7,851 bytes)

284. Re: [RFI] 2002 Mazda Millenia (score: 1)
Author: "Jim Brown" <jim@audiosystemsgroup.com>
Date: Wed, 27 Aug 2008 10:23:13 -0700
I found an older Garmin GPS to make a lot of noise on 2M. Don't recall about other bands. 73, Jim K9YC _______________________________________________ RFI mailing list RFI@contesting.com http://lists
/archives//html/RFI/2008-08/msg00038.html (6,810 bytes)

285. Re: [RFI] Low Voltage Patio Lights (score: 1)
Author: "Jim Brown" <jim@audiosystemsgroup.com>
Date: Sun, 07 Sep 2008 07:55:55 -0700
As far as I know, these lights work on 12VAC, which means that any 12V transformer rated for the application would work. Unfortunately, they are physically larger than the switching power supplies, a
/archives//html/RFI/2008-09/msg00006.html (8,826 bytes)

286. Re: [RFI] FCC Class A& B Regs/ was: Low Voltage Patio Lights (score: 1)
Author: "Jim Brown" <jim@audiosystemsgroup.com>
Date: Tue, 09 Sep 2008 10:31:53 -0700
I believe that lighting products fall under Part 18, and which appears to be broad as a barndoor. I hope someone will correct me if I'm wrong. 73, Jim K9YC ___________________________________________
/archives//html/RFI/2008-09/msg00015.html (8,009 bytes)

287. Re: [RFI] New 857, won't TX on 20m - RFI in truck meters and dial lights (kd4e) (score: 1)
Author: "Jim Brown" <jim@audiosystemsgroup.com>
Date: Sun, 14 Sep 2008 09:59:19 -0700
This is very bad advice. A major CAUSE of RFI to auto electrical systems is lousy chassis bonding due to excessive emphasis on painting the chassis parts. The body of a vehicle is a big broad mass --
/archives//html/RFI/2008-09/msg00024.html (7,868 bytes)

288. Re: [RFI] New 857, won't TX on 20m - RFI in truck meters and dial lights (kd4e) (score: 1)
Author: "Jim Brown" <jim@audiosystemsgroup.com>
Date: Sun, 14 Sep 2008 13:03:14 -0700
YES! Jim _______________________________________________ RFI mailing list RFI@contesting.com http://lists.contesting.com/mailman/listinfo/rfi
/archives//html/RFI/2008-09/msg00026.html (7,588 bytes)

289. Re: [RFI] Aims 5000 Watt MSW Power Inverter (score: 1)
Author: "Jim Brown" <jim@audiosystemsgroup.com>
Date: Mon, 15 Sep 2008 10:35:13 -0700
I'll second all of Dale's comments, and add this. What is your final objective? If you could be happy with 500-600 watts RF output on the HF bands, I strongly suggest that you look at a power amp lik
/archives//html/RFI/2008-09/msg00030.html (8,341 bytes)

290. Re: [RFI] Aims 5000 Watt MSW Power Inverter (score: 1)
Author: "Jim Brown" <jim@audiosystemsgroup.com>
Date: Mon, 15 Sep 2008 11:29:26 -0700
Look at the Honda inverter generators. I bought a big one -- 240V, 6kVA, enough to start and run the motors on my well pumps. About $3K. For about $900, you can get a 2kVA unit that will probably run
/archives//html/RFI/2008-09/msg00034.html (8,239 bytes)

291. Re: [RFI] 20M Heterodyne (score: 1)
Author: "Jim Brown" <jim@audiosystemsgroup.com>
Date: Sat, 20 Sep 2008 11:27:09 -0700
I'm a CW guy, so I know the products that show up in the CW bands. Do you also hear it around 14,029-14,030? Around 21,052? Those are common mode radiation of products of a wired Ethernet system. The
/archives//html/RFI/2008-09/msg00041.html (7,344 bytes)

292. Re: [RFI] 20M Heterodyne (score: 1)
Author: "Jim Brown" <jim@audiosystemsgroup.com>
Date: Sat, 20 Sep 2008 13:39:59 -0700
Probably so. It's a simple matter of coupling from one antenna to another (that is, the Ethernet cable is an antenna), and the proximity and directional patterns of each antenna have a strong effect
/archives//html/RFI/2008-09/msg00042.html (9,827 bytes)

293. Re: [RFI] 20M Heterodyne (score: 1)
Author: "Jim Brown" <jim@audiosystemsgroup.com>
Date: Mon, 22 Sep 2008 11:58:32 -0700
Hi Bill, When Randy (K9OR) and I did this at his QTH several years ago, we knocked it down a lot but didn't kill it. There is almost certainly some direct radiation from the Ethernet boxes themselves
/archives//html/RFI/2008-09/msg00045.html (7,992 bytes)

294. Re: [RFI] RFI (score: 1)
Author: "Jim Brown" <jim@audiosystemsgroup.com>
Date: Tue, 30 Sep 2008 18:33:03 -0700
That's because the cause is common mode current on the coax, not the RF frequency that you're using. In other words, the coax is acting like a long wire antenna. I wouldn't expect a string of beads t
/archives//html/RFI/2008-09/msg00054.html (8,020 bytes)

295. Re: [RFI] Mix 77 Snap-on (score: 1)
Author: "Jim Brown" <jim@audiosystemsgroup.com>
Date: Sun, 05 Oct 2008 06:39:33 -0700
The latest Fair-Rite catalog now lists #31 as the material of choice for suppression at HF. I concur. #43 is slightly better above 10 MHz. #77 is a poor choice compared to #31. Thanks for the input
/archives//html/RFI/2008-10/msg00011.html (8,201 bytes)

296. Re: [RFI] DTV and Powerline RFI (score: 1)
Author: "Jim Brown" <jim@audiosystemsgroup.com>
Date: Mon, 06 Oct 2008 07:59:20 -0700
Yes In recent times, interference to the TV itself is not nearly as common as interference to the audio system. TV sets seem to have gotten better (more robust with respect to RFI), but the audio/vid
/archives//html/RFI/2008-10/msg00022.html (8,069 bytes)

297. Re: [RFI] Weird one (score: 1)
Author: "Jim Brown" <jim@audiosystemsgroup.com>
Date: Sun, 12 Oct 2008 21:11:39 -0700
Rick, Beads do NOTHING at 40-160M -- they are VHF suppressors. Study my RFI tutorial for specific suppression ideas. http://audiosystemsgroup.com/RFI-Ham.pdf 73, Jim K9YC On Sun, 12 Oct 2008 10:14:23
/archives//html/RFI/2008-10/msg00049.html (7,750 bytes)

298. Re: [RFI] Computer RFI on 160 (score: 1)
Author: "Jim Brown" <jim@audiosystemsgroup.com>
Date: Wed, 29 Oct 2008 13:14:35 -0700
I wouldn't expect it to. You need at least 14 turns on a single # 31, and more turns or more toroids in the stack is better. Use my measured data for RG8X on these cores as a starting point. In essen
/archives//html/RFI/2008-10/msg00077.html (8,493 bytes)

299. Re: [RFI] Kenwood TM-D700 (score: 1)
Author: "Jim Brown" <jim@audiosystemsgroup.com>
Date: Wed, 29 Oct 2008 14:52:32 -0700
I'd say so too. It sounds like a problem with inadequate decoupling of the power supply wiring or a pin 1-like problem associated with DC power return. Has nothing to do with it. I agree that going d
/archives//html/RFI/2008-10/msg00084.html (8,652 bytes)

300. Re: [RFI] Kenwood TM-D700 (score: 1)
Author: "Jim Brown" <jim@audiosystemsgroup.com>
Date: Thu, 30 Oct 2008 09:37:37 -0700
from Yes, but that winding will drop some voltage on transmit. I'd try ONLY a BIG capacitor first, then add the inductance only if the cap didn't solve the problem. 73, Jim K9YC _____________________
/archives//html/RFI/2008-10/msg00090.html (8,158 bytes)

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