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341. Re: Topband: Using CAT5 in place of coax (was video baluns) (score: 1)
Author: "Rick Karlquist" <richard@karlquist.com>
Date: Mon, 7 May 2012 19:03:17 -0700
I measured 1 dB per 100 feet at 1.8 MHz for my random sample of CAT5. Imagine the loss for 100 Mbit/s data! Rick N6RK _______________________________________________ UR RST IS ... ... ..9 QSB QSB - h
/archives//html/Topband/2012-05/msg00096.html (9,629 bytes)

342. Re: Topband: HI-Z BACK IN BUSINESS (score: 1)
Author: "Rick Karlquist" <richard@karlquist.com>
Date: Thu, 31 May 2012 16:53:14 -0700
Why? Because they may be in business with 1 hand tied behind their back. Or they might have to raise prices to cover licensing. Or they might be prevented from making product improvements. Etc. Rick
/archives//html/Topband/2012-05/msg00252.html (8,246 bytes)

343. Re: Topband: Topband Digest, Vol 113, Issue 46 (score: 1)
Author: "Rick Karlquist" <richard@karlquist.com>
Date: Thu, 31 May 2012 16:59:02 -0700
Whispering gallery mode. The classic whispering gallery room is in the shape of an ellipse, where people at one focus can hear the people at the other focus, but it is on only 1 hop. Antipodal mode i
/archives//html/Topband/2012-05/msg00253.html (7,299 bytes)

344. Re: Topband: RW0CN 160 meter vertical video (score: 1)
Author: "Rick Karlquist" <richard@karlquist.com>
Date: Mon, 4 Jun 2012 17:13:18 -0700
A few comments, in the mode of constructive criticism: 1. The tubing seems to be rather on the small size, and insufficiently stiff. Larger tubing with thin wall is much stiffer than smaller thick wa
/archives//html/Topband/2012-06/msg00031.html (7,695 bytes)

345. Re: Topband: radial wire source (score: 1)
Author: "Rick Karlquist" <richard@karlquist.com>
Date: Tue, 5 Jun 2012 11:05:08 -0700
I used to buy huge spools of #16 tinned copper "bus wire" from Interstate Wire and Cable in Dallas, TX. The price was fairly good compared to building wire from the home store. I built a grid with 3x
/archives//html/Topband/2012-06/msg00043.html (8,149 bytes)

346. Re: Topband: small rx loops and ferrite (score: 1)
Author: "Rick Karlquist" <richard@karlquist.com>
Date: Tue, 3 Jul 2012 14:44:14 -0700
You might want to look at the feed technique described here: http://www.n6rk.com/loopantennas/NCJ_loop_antenna_N6RK.pdf Although this article talks about a shielded loop, it will work equally well on
/archives//html/Topband/2012-07/msg00044.html (7,860 bytes)

347. Re: Topband: High power Transistor question (score: 1)
Author: "Rick Karlquist" <richard@karlquist.com>
Date: Thu, 5 Jul 2012 15:20:55 -0700
See: http://www.nikkemedia.fi/juma-pa1000/ Rick N6RK _______________________________________________ UR RST IS ... ... ..9 QSB QSB - hw? BK
/archives//html/Topband/2012-07/msg00073.html (7,655 bytes)

348. Re: Topband: New Linear amp (score: 1)
Author: "Richard (Rick) Karlquist" <richard@karlquist.com>
Date: Sat, 07 Jul 2012 14:37:38 -0700
The problem with starting with a saturated amplifier and then backing off the power for linearity is that the dissipation actually goes UP when you reduce the output power. The maximum dissipation oc
/archives//html/Topband/2012-07/msg00084.html (8,050 bytes)

349. Re: Topband: Fw: New Linear amp (score: 1)
Author: "Richard (Rick) Karlquist" <richard@karlquist.com>
Date: Sat, 07 Jul 2012 16:44:30 -0700
As the manual explains, the amplifier has two modes, linear and non linear. Linear is only for low duty cycles. It is also worth noting that a tuned amplifier will in general have better drain effici
/archives//html/Topband/2012-07/msg00088.html (7,217 bytes)

350. Re: Topband: Mother of all ferrite common-mode coaxial chokes (score: 1)
Author: "Rick Karlquist" <richard@karlquist.com>
Date: Fri, 13 Jul 2012 11:51:49 -0700
The "silver bullet" when it comes to BNC connectors is to instead use TNC connectors (same connector, only threaded not bayonet). In many cases, it is easy to retrofit BNC equipment with TNC. Rick N6
/archives//html/Topband/2012-07/msg00166.html (10,479 bytes)

351. Re: Topband: Mother of all ferrite common-mode coaxial chokes (score: 1)
Author: "Richard (Rick) Karlquist" <richard@karlquist.com>
Date: Fri, 13 Jul 2012 18:46:35 -0700
Another thing you can do to measure chokes accurately is to simply use a Vector Impedance Meter instead of a network analyzer. Like the HP 4815A. In essence, it uses the VI method, as the name implie
/archives//html/Topband/2012-07/msg00185.html (9,660 bytes)

352. Re: Topband: S21 impedance measurements (score: 1)
Author: "Richard (Rick) Karlquist" <richard@karlquist.com>
Date: Sat, 14 Jul 2012 12:56:24 -0700
I have been doing this for over 30 years, and have taught many others to do it. However, what is "wrong" with the technique is that network analyzers are only specified in terms of an insertable coax
/archives//html/Topband/2012-07/msg00193.html (7,821 bytes)

353. Re: Topband: Chokes, et. al. - what is the attenuation ? (score: 1)
Author: "Richard (Rick) Karlquist" <richard@karlquist.com>
Date: Sat, 14 Jul 2012 15:15:47 -0700
On low bands, the Q of resonant stubs is fairly low. Therefore, the effective common mode impedance of these baluns will not be extremely high. If you want a single band choke, you could get a higher
/archives//html/Topband/2012-07/msg00200.html (8,874 bytes)

354. Re: Topband: S21 impedance measurements (score: 1)
Author: "Richard (Rick) Karlquist" <richard@karlquist.com>
Date: Sat, 14 Jul 2012 18:28:21 -0700
SINCE YOU ASKED, there are a number of unresolved issues here from a strict metrological viewpoint: 1. Your fixture is not an enclosed box. A defined Faraday cage is recommended. The results might be
/archives//html/Topband/2012-07/msg00203.html (9,740 bytes)

355. Re: Topband: FCP model (score: 1)
Author: "Rick Karlquist" <richard@karlquist.com>
Date: Tue, 31 Jul 2012 14:23:32 -0700
A simpler and more relevant test would be to start with a validated FCP installation and put some jumpers across the FCP to turn it into two multiwire conventional radials, then insert a loading coil
/archives//html/Topband/2012-07/msg00422.html (9,050 bytes)

356. Re: Topband: FCP model (score: 1)
Author: "Rick Karlquist" <richard@karlquist.com>
Date: Tue, 31 Jul 2012 14:40:42 -0700
The proposed test was for two radials occupying exactly the same physical space, each radial being half of the previous FCP. Rick N6RK _______________________________________________ UR RST IS ... ..
/archives//html/Topband/2012-07/msg00427.html (8,460 bytes)

357. Re: Topband: FCP model (score: 1)
Author: "Rick Karlquist" <richard@karlquist.com>
Date: Tue, 31 Jul 2012 16:20:22 -0700
Sure I can help. If you want, you can use a corner of my 20 acres to play in or A/B it with a vertical over the big ground screen on site. Rick N6RK _______________________________________________ UR
/archives//html/Topband/2012-07/msg00433.html (9,226 bytes)

358. Re: Topband: FCP model (score: 1)
Author: "Rick Karlquist" <richard@karlquist.com>
Date: Wed, 1 Aug 2012 10:59:46 -0700
I'm fairly skeptical of gull wing radials. We know that if the radial wire started at the feed point and ran vertically parallel to the antenna a few inches away, that the effective length of the ant
/archives//html/Topband/2012-08/msg00014.html (8,571 bytes)

359. Re: Topband: opinion (score: 1)
Author: "Rick Karlquist" <richard@karlquist.com>
Date: Fri, 3 Aug 2012 10:11:31 -0700
That "guy" was Galileo to whom the "Galileo fallacy" refers: "They laughed at Galileo, they laughed at Newton, but they also laughed at Bozo the clown". Rick _________________________________________
/archives//html/Topband/2012-08/msg00062.html (7,190 bytes)

360. Re: Topband: "return" current - what is it? (score: 1)
Author: "Richard (Rick) Karlquist" <richard@karlquist.com>
Date: Sun, 05 Aug 2012 08:42:43 -0700
Confirming Tom's test. When I first built my 230 foot diameter ground screen, consisting of #16 wires on a 3x3 foot grid with crossovers soldered, I put up a 40 meter vertical in the center to test t
/archives//html/Topband/2012-08/msg00119.html (10,781 bytes)

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