From rwc@frii.com Wed Nov 11 14:25:12 1998 Received: from nss4.CC.Lehigh.EDU ([128.180.1.13]:1609 "EHLO nss4.cc.Lehigh.EDU" ident: "IDENT-NOT-QUERIED") by fidoii.cc.Lehigh.EDU with ESMTP id <53998-49834>; Wed, 11 Nov 1998 09:25:06 -0500 Received: from deimos.frii.com (root@deimos.frii.com [208.146.240.2]) by nss4.cc.Lehigh.EDU (8.9.1a/8.9.1) with ESMTP id JAA58584 for ; Wed, 11 Nov 1998 09:25:05 -0500 Received: from zephyr (ftc-0629.dialup.frii.com [216.17.135.29] (may be forged)) by deimos.frii.com (8.9.1a/8.9.1) with SMTP id HAA09374 for ; Wed, 11 Nov 1998 07:25:02 -0700 (MST) Message-Id: <3.0.5.32.19981111071803.008072e0@mail.frii.com> X-Sender: rwc@mail.frii.com X-Mailer: QUALCOMM Windows Eudora Pro Version 3.0.5 (32) Date: Wed, 11 Nov 1998 07:18:03 -0700 To: "Low Power Amateur Radio Discussion" From: Rod Cerkoney Subject: small loop antennas Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Return-Path: X-Orcpt: rfc822;qrp-l@fidoii.CC.Lehigh.EDU Folks: I read the messages [posted here] about the Rockridge(?) Loop. While researching it I discovered the material about "Small Loop" antennas in the ARRL antenna book. This class of antenna is appealing to me for my limited space conditions. So my question is: Does anybody have significant experience with this class of antenna? Maybe have done some A/B comparison, "Small-Loop vs Dipole/Beam/Inverted-V...etc.? --- 72/3 K0RWC Rod Cerkoney, QRP-L #1764. Fort Collins, CO da di dah From aa5tb@swbell.net Thu Nov 12 00:48:11 1998 Received: from nss4.CC.Lehigh.EDU ([128.180.1.13]:4255 "EHLO nss4.cc.Lehigh.EDU" ident: "IDENT-NOT-QUERIED") by fidoii.cc.Lehigh.EDU with ESMTP id <53383-17832>; Wed, 11 Nov 1998 19:48:02 -0500 Received: from mail-gw1adm.rcsntx.swbell.net (mail-gw1adm.rcsntx.swbell.net [151.164.60.101]) by nss4.cc.Lehigh.EDU (8.9.1a/8.9.1) with ESMTP id TAA06812 for ; Wed, 11 Nov 1998 19:48:01 -0500 Received: from swbell.net (ppp-151-164-43-140.eulstx.swbell.net [151.164.43.140]) by mail-gw1adm.rcsntx.swbell.net (8.8.5/8.8.5) with ESMTP id SAA03849; Wed, 11 Nov 1998 18:47:37 -0600 (CST) Message-ID: <364A3027.1C7BD55C@swbell.net> Date: Wed, 11 Nov 1998 18:47:35 -0600 From: "Steve Yates, AA5TB" Organization: Southwestern Bell Internet Services X-Mailer: Mozilla 4.5 [en]C-SBIS-NC404 (Win95; U) X-Accept-Language: en MIME-Version: 1.0 To: rwc@frii.com CC: Low Power Amateur Radio Discussion Subject: Re: small loop antennas References: <3.0.5.32.19981111071803.008072e0@mail.frii.com> Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Transfer-Encoding: 7bit Return-Path: X-Orcpt: rfc822;qrp-l@fidoii.CC.Lehigh.EDU Rod, I've been playing with small transmitter loops for many years now. I have a lot of information on my web site at: http://home.swbell.net/aa5tb/loop.html If you can't view it or have questions just let me know. 73, Steve Yates AA5TB aa5tb@swbell.net http://home.swbell.net/aa5tb/ Fort Worth, Texas From we6w@qsl.net Thu Nov 12 18:21:53 1998 Received: from nss4.CC.Lehigh.EDU ([128.180.1.13]:4861 "EHLO nss4.cc.Lehigh.EDU" ident: "IDENT-NOT-QUERIED") by fidoii.cc.Lehigh.EDU with ESMTP id <53727-23288>; Thu, 12 Nov 1998 13:21:11 -0500 Received: from palrel3.hp.com (palrel3.hp.com [156.153.255.226]) by nss4.cc.Lehigh.EDU (8.9.1a/8.9.1) with ESMTP id NAA170820 for ; Thu, 12 Nov 1998 13:21:09 -0500 Received: from srmail.sr.hp.com (srmail.sr.hp.com [15.4.45.14]) by palrel3.hp.com (8.8.6 (PHNE_14041)/8.8.5tis) with ESMTP id KAA07517; Thu, 12 Nov 1998 10:21:26 -0800 (PST) Received: from ooringer.sr.hp.com by srmail.sr.hp.com with ESMTP (1.37.109.16/15.5+ECS 3.3) id AA284994859; Thu, 12 Nov 1998 10:20:59 -0800 Received: from ooringer (loranger@ooringer.sr.hp.com [15.4.50.26]) by ooringer.sr.hp.com with SMTP (8.7.6/8.7.3 TIS 5.0) id KAA28422; Thu, 12 Nov 1998 10:20:59 -0800 (PST) Sender: loranger@sr.hp.com Message-Id: <364B270A.5C23@qsl.net> Date: Thu, 12 Nov 1998 18:20:58 +0000 From: Ed Loranger Organization: Electronics Industry X-Mailer: Mozilla 3.0Gold (X11; U; HP-UX B.10.20 9000/725) Mime-Version: 1.0 To: qrp-l@lehigh.edu Cc: aa5tb@swbell.net Subject: Re: small loop antennas Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Transfer-Encoding: 7bit Return-Path: X-Orcpt: rfc822;qrp-l@fidoii.CC.Lehigh.EDU Previously Steve Yates/AA5TB shared with us: >I've been playing with small transmitter loops for many years now. I >have a lot of information on my web site at: >http://home.swbell.net/aa5tb/loop.html Hi Steve, good job on the web page. I like your links at the bottom and recognized them. Since you have started a fine collection of links, one you might want to add is Tony's/ON4CEQ. This is a MUST visit webpage if you are into Small Loops (<.17 wl. circ.) http://gallery.uunet.be/ON4CEQ/ant_en.htm At the very top of the page he has recently added the spiral wound co-planar loop similar to the 160Meter version I built and reported on earlier this year. You may visit my webpage for details in a TEXT-ONLY document there. Again, Tony has a fine small loop TX page. EVEN complete information, with drawings, on building your very own homebrew Butterfly Capacitor for small loops!!! yowsa! -- 72, Ed WE6W (CW only/VP-0); http://www.qsl.net/we6w Santa Rosa, CA QRP-Z#106 QRP-L#1068 AR#112 NC#2227 ARCI#9397 QAA#006 From mikemo@ibm.net Sun Nov 15 00:16:15 1998 Received: from nss4.CC.Lehigh.EDU ([128.180.1.13]:1483 "EHLO nss4.cc.Lehigh.EDU" ident: "IDENT-NOT-QUERIED") by fidoii.cc.Lehigh.EDU with ESMTP id <53356-33508>; Sat, 14 Nov 1998 19:16:02 -0500 Received: from out1.ibm.net (out1.ibm.net [165.87.194.252]) by nss4.cc.Lehigh.EDU (8.9.1a/8.9.1) with ESMTP id TAA198076 for ; Sat, 14 Nov 1998 19:16:01 -0500 From: mikemo@ibm.net Received: from mike (slip-32-101-32-115.fl.us.ibm.net [32.101.32.115]) by out1.ibm.net (8.8.5/8.6.9) with SMTP id AAA108232 for ; Sun, 15 Nov 1998 00:15:57 GMT Message-ID: <364E1C40.2AE1@ibm.net> Date: Sat, 14 Nov 1998 19:11:44 -0500 Reply-To: mikemo@ibm.net X-Mailer: Mozilla 3.01Gold (Win95; U) MIME-Version: 1.0 To: qrp Subject: Small transmitting loop results (long) Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Transfer-Encoding: 7bit Return-Path: X-Orcpt: rfc822;qrp-l@fidoii.CC.Lehigh.EDU Just wanted to post a note regarding some building I did today. I was interested by some recent emails regarding small transmitting loops. Steve, AA5TB posted some software for calculating loop parameters. I built a loop today. The main section is made out of 3/4 inch copper tubing. The loop is 2.6 feet across (that's all I had in the garage). It is mounted on a 2x4 with tie wraps. The driven loop is made of #14 enameled wire, 6 inches across. The tuning cap is a 100 pf air variable with a .075 plate spacing. It took a few hours to build. To test, I stuck the bottom of the 2x4 in the dirt in my back yard. The loop was less than 1' off the ground. Tuned to 20 meters, the swr was under 1.5, but the tuning was SHARP. Cap ended up being set at about 60pF, as predicted by the software. Signal reports were very good for such a small antenna on the ground. I could not get the swr under 4:1 on 15 meters. Is this because the circumference is greater than 1/10 wavelength??? I could not tune on 40 meters due to the small tuning cap, only 100pf. The program says the cap would have to be 250pf to tune on 40 meters. All in all, the program was very accurate and predicted what would happen with the antenna. Performance with such a small antenna was nothing short of amazing on 20 meters. My neighbor asked if I was trying to contact my "people" to come back to earth and get me ;-) I'm going to try a bigger cap (if I can find one) and try on 40 meters. A word of warning, BE CAREFUL! The voltages on the cap and loop at 5 watts on 20 meters are close to 1000V. I had a 6" piece of wood stuck to the shaft of the tuning cap to avoid a Zap! A remote tuner for the cap is a must. I had to have my son key the transmitter while I adjusted the loop and looked at the swr meter (which was outside too). Thanks for listening, 72 de ku4qo, Mike Maiorana, Palm Harbor, FL From plburbank@kih.net Sun Nov 15 01:04:34 1998 Received: from nss4.CC.Lehigh.EDU ([128.180.1.13]:2643 "EHLO nss4.cc.Lehigh.EDU" ident: "IDENT-NOT-QUERIED") by fidoii.cc.Lehigh.EDU with ESMTP id <53383-31212>; Sat, 14 Nov 1998 20:04:12 -0500 Received: from autoreg.kih.net (autoreg.kih.net [209.209.180.8]) by nss4.cc.Lehigh.EDU (8.9.1a/8.9.1) with ESMTP id UAA116158 for ; Sat, 14 Nov 1998 20:04:02 -0500 Received: from bcotter (har139.kih.net [209.209.187.139]) by autoreg.kih.net (8.9.1a/8.9.1) with SMTP id UAA07210 for ; Sat, 14 Nov 1998 20:00:17 -0500 (EST) Message-Id: <3.0.32.19981114200243.006c6574@kih.net> X-Sender: plburbank@kih.net X-Mailer: Windows Eudora Pro Version 3.0 (32) Date: Sat, 14 Nov 1998 20:02:48 -0500 To: From: Pete Burbank Subject: Re: Small loop results Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Return-Path: X-Orcpt: rfc822;qrp-l@fidoii.CC.Lehigh.EDU Mike-KU4QO, I don't think your loop is too large for 15 meters. Ted Hart defines a STL as circumference less than 1/3 wavelength. I made one slightly larger than yours that loaded well with a gamma match on 15. Recently I completed a 6 1/2 foot dia. copper loop that loads well on 20, 30, 40, and most of 80. It also uses a gamma match. The "sweet spot" to connect the matching conducter worked out to be about 1/8 of the total loop length away from the coax braid connection. (180 degrees from the tuning capacitor). I have never tried the small coupling loop type feed but I remember one builder reporting that the feed loop worked better when "squished" into a more oval shape. Yes, they are amazing close to the ground (that's where foxes hide anyway). GL es 73 Pete W4VCT From we6w@juno.com Sun Nov 15 01:19:05 1998 Received: from nss4.CC.Lehigh.EDU ([128.180.1.13]:2993 "EHLO nss4.cc.Lehigh.EDU" ident: "IDENT-NOT-QUERIED") by fidoii.cc.Lehigh.EDU with ESMTP id <53587-28904>; Sat, 14 Nov 1998 20:18:53 -0500 Received: from m13.boston.juno.com (m13.boston.juno.com [205.231.100.193]) by nss4.cc.Lehigh.EDU (8.9.1a/8.9.1) with ESMTP id UAA95634 for ; Sat, 14 Nov 1998 20:18:53 -0500 Received: (from we6w@juno.com) by m13.boston.juno.com (queuemail) id DT3CQJYX; Sat, 14 Nov 1998 20:17:31 EST To: mikemo@ibm.net Cc: qrp-l@Lehigh.EDU Subject: Re: Small transmitting loop results (long) Message-ID: <19981114.171428.4775.4.we6w@juno.com> References: <364E1C40.2AE1@ibm.net> X-Mailer: Juno 1.49 X-Juno-Line-Breaks: 0-17 From: we6w@juno.com (Ed Loranger) Date: Sat, 14 Nov 1998 20:17:31 EST Return-Path: X-Orcpt: rfc822;qrp-l@fidoii.CC.Lehigh.EDU Excellent Job on everything Mike. And you made the capacitor too. I don't know why you had a problem with SWR on 15 Meters, maybe the loop needs to be a few feet up. I have one also and it works best about 6 feet up. But I worked Alan/KB7MBI's indoor antenna contest this year with it inside the garage only 3 feet off the concrete floor! I get a 1.4:1 SWR from 20 to 10 meters. All in all, excellent report and performance from a quickly homebrewed antenna. These short TX loops are amazing. -ED 72, Ed WE6W QRP-Z#106 http://www.qsl.net/we6w Enjoying Ham Radio every day! Santa Rosa, CA. ___________________________________________________________________ You don't need to buy Internet access to use free Internet e-mail. Get completely free e-mail from Juno at http://www.juno.com/getjuno.html or call Juno at (800) 654-JUNO [654-5866] From aa5tb@swbell.net Sun Nov 15 02:51:10 1998 Received: from nss4.CC.Lehigh.EDU ([128.180.1.13]:1224 "EHLO nss4.cc.Lehigh.EDU" ident: "IDENT-NOT-QUERIED") by fidoii.cc.Lehigh.EDU with ESMTP id <53316-31212>; Sat, 14 Nov 1998 21:51:00 -0500 Received: from mail-gw1adm.rcsntx.swbell.net (mail-gw1adm.rcsntx.swbell.net [151.164.60.101]) by nss4.cc.Lehigh.EDU (8.9.1a/8.9.1) with ESMTP id VAA141834 for ; Sat, 14 Nov 1998 21:50:59 -0500 Received: from swbell.net (ppp-151-164-45-135.eulstx.swbell.net [151.164.45.135]) by mail-gw1adm.rcsntx.swbell.net (8.8.5/8.8.5) with ESMTP id UAA05888; Sat, 14 Nov 1998 20:50:53 -0600 (CST) Message-ID: <364E4189.76A5F1E7@swbell.net> Date: Sat, 14 Nov 1998 20:50:49 -0600 From: "Steve Yates, AA5TB" Organization: Southwestern Bell Internet Services X-Mailer: Mozilla 4.5 [en]C-SBIS-NC404 (Win95; U) X-Accept-Language: en MIME-Version: 1.0 To: mikemo@ibm.net CC: Low Power Amateur Radio Discussion Subject: Re: Small transmitting loop results (long) References: <364E1C40.2AE1@ibm.net> Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Transfer-Encoding: 7bit Return-Path: X-Orcpt: rfc822;qrp-l@fidoii.CC.Lehigh.EDU Mike, I don't think your loop is too large at 15 mtrs. It will actually work better when you make it larger in terms of wavelength but it may become large enough that there is appreciable phase change along its circumference to alter its classical small loop radiation pattern. For example, a "small" loop has maximum radiation in line with the plane of the loop while a larger loop such as a quad has its maximum radiation perpendicular to the plane of the loop. You may want to vary the coupling between the two loops. If you make the small coupling loop slightly larger than required, you can find the optimum coupling by rotating the small loop within the plane of the larger loop. You should be able to find a spot where you can find a good match at all of the frequencies for which the antenna will tune to resonance. Once this is found you shouldn't have to change it. Pete W4VCT mentioned that he uses a gamma match. I've used this method before and it works well also. It is especially suited for "plumber's delight" construction. I find though that it sometimes isn't as easy to vary the coupling with this method. I enjoyed your report. Keep us informed of your results. 73, Steve Yates AA5TB aa5tb@swbell.net http://home.swbell.net/aa5tb/ Fort Worth, Texas From rakefet@rakefet.com Sun Nov 15 04:30:37 1998 Received: from nss4.CC.Lehigh.EDU ([128.180.1.13]:3397 "EHLO nss4.cc.Lehigh.EDU" ident: "IDENT-NOT-QUERIED") by fidoii.cc.Lehigh.EDU with ESMTP id <53283-33508>; Sat, 14 Nov 1998 23:30:23 -0500 Received: from sierra.psnw.com (root@sierra.psnw.com [205.199.144.107]) by nss4.cc.Lehigh.EDU (8.9.1a/8.9.1) with ESMTP id XAA199118 for ; Sat, 14 Nov 1998 23:30:22 -0500 Received: from rakefet.com (ct1-40.psnw.com [206.43.246.40]) by sierra.psnw.com (8.9.1/8.9.0) with ESMTP id UAA18918; Sat, 14 Nov 1998 20:29:56 -0800 (PST) Message-ID: <364E58B9.18C8B156@rakefet.com> Date: Sat, 14 Nov 1998 20:29:45 -0800 From: Vic Rosenthal Reply-To: rakefet@rakefet.com Organization: Transparent Software X-Mailer: Mozilla 4.06 [en] (Win98; U) MIME-Version: 1.0 To: mikemo@ibm.net CC: Low Power Amateur Radio Discussion Subject: Re: Small transmitting loop results (long) References: <364E1C40.2AE1@ibm.net> Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Transfer-Encoding: 7bit Return-Path: X-Orcpt: rfc822;qrp-l@fidoii.CC.Lehigh.EDU mikemo@ibm.net wrote: > > I could not get the swr under 4:1 on 15 meters. Is this because the > circumference is greater than 1/10 wavelength??? No, this should work fine. The AEA Isoloop works great on 15 and is about 3' in diameter. To get the SWR down, play with the size and position of the driven loop. For what it's worth, the AEA loop uses a faraday shielded driven loop made of small coax with a gap in the shield. Vic, K2VCO Fresno CA From whalen@swcp.com Sun Nov 15 04:49:23 1998 Received: from nss4.CC.Lehigh.EDU ([128.180.1.13]:3762 "EHLO nss4.cc.Lehigh.EDU" ident: "IDENT-NOT-QUERIED") by fidoii.cc.Lehigh.EDU with ESMTP id <53283-21994>; Sat, 14 Nov 1998 23:49:04 -0500 Received: from kitsune.swcp.com (swcp.com [198.59.115.2]) by nss4.cc.Lehigh.EDU (8.9.1a/8.9.1) with ESMTP id XAA59828 for ; Sat, 14 Nov 1998 23:49:03 -0500 Received: from default (dpm1-38.swcp.com [204.134.5.39]) by kitsune.swcp.com (8.8.8/1.2.3) with SMTP id VAA19225; Sat, 14 Nov 1998 21:48:59 -0700 (MST) Message-ID: <364E5CE8.1C63@swcp.com> Date: Sat, 14 Nov 1998 21:47:36 -0700 From: tom whalen Organization: NERDS X-Mailer: Mozilla 3.01 (Win95; I) MIME-Version: 1.0 To: Low Power Amateur Radio Discussion Subject: Loops Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Transfer-Encoding: 7bit Return-Path: X-Orcpt: rfc822;qrp-l@fidoii.CC.Lehigh.EDU QRPer's! Im really enjoying the discussion on the transmitting loop antenna's. I have been working on one myself, that is 1/4 wave in circumference on the highest freq. of intented use. From what I have read, I should be able to tune it from 28.0 to about 14.0. May build another loop designed for 20m and it will tune thru the 40m band. The only bad thing with my plan is the motor that I will use to drive the var. cap....It's an AC 120v reversable motor...so have to watch where I put my pinkie's!! Will see how it works tomorrow....Maybe I can hear that 10m beacon up in the pine tree and win that tuner that is being offered to the furthest station that hears it! Going to put it together tomorrow, so will post my results. 72, Tom WB5QYT From dfirlik@juno.com Sun Nov 15 21:23:56 1998 Received: from nss4.CC.Lehigh.EDU ([128.180.1.13]:4650 "EHLO nss4.cc.Lehigh.EDU" ident: "IDENT-NOT-QUERIED") by fidoii.cc.Lehigh.EDU with ESMTP id <53573-34160>; Sun, 15 Nov 1998 16:23:08 -0500 Received: from x15.boston.juno.com (x15.boston.juno.com [205.231.100.28]) by nss4.cc.Lehigh.EDU (8.9.1a/8.9.1) with ESMTP id QAA58664 for ; Sun, 15 Nov 1998 16:23:07 -0500 From: dfirlik@juno.com Received: (from dfirlik@juno.com) by x15.boston.juno.com (queuemail) id DT5HN74Y; Sun, 15 Nov 1998 16:22:39 EST To: QRP-L@LEHIGH.EDU Date: Sun, 15 Nov 1998 15:53:00 -0500 Subject: Re: Loops Message-ID: <19981115.162155.4678.0.dfirlik@juno.com> References: <364E5CE8.1C63@swcp.com> X-Mailer: Juno 1.49 X-Juno-Line-Breaks: 0-8,14-17 Return-Path: X-Orcpt: rfc822;qrp-l@fidoii.CC.Lehigh.EDU On Sat, 14 Nov 1998 21:47:36 -0700 tom whalen writes: >QRPer's! > >The only bad thing with my plan is the motor that I will use to drive >the var. cap....It's an AC 120v reversable motor...so have to watch >where I put my pinkie's!! > This summer I purchased two early model cordless screwdrivers at flea markets for a buck for a 2.5 volt model and 2 bucks for a 3.7 volt unit. Both were inoperative when purchased due to shorted nicad cells. The motors and planetary reduction units would be ideal for driving the tuning capacitor of a loop antenna. Check out your local flea markets and auction houses. Don K8AQZ Grand Rapids MI ___________________________________________________________________ You don't need to buy Internet access to use free Internet e-mail. Get completely free e-mail from Juno at http://www.juno.com/getjuno.html or call Juno at (800) 654-JUNO [654-5866] From kenk@primenet.com Mon Nov 16 18:46:18 1998 Received: from nss4.CC.Lehigh.EDU ([128.180.1.13]:2973 "EHLO nss4.cc.Lehigh.EDU" ident: "IDENT-NOT-QUERIED") by fidoii.cc.Lehigh.EDU with ESMTP id <53444-55346>; Mon, 16 Nov 1998 13:45:50 -0500 Received: from smtp01.primenet.com (daemon@smtp01.primenet.com [206.165.6.131]) by nss4.cc.Lehigh.EDU (8.9.1a/8.9.1) with ESMTP id NAA91286 for ; Mon, 16 Nov 1998 13:45:49 -0500 Received: (from daemon@localhost) by smtp01.primenet.com (8.8.8/8.8.8) id LAA08433 for ; Mon, 16 Nov 1998 11:45:45 -0700 (MST) Received: from ip-19-238.yum.primenet.com(207.218.19.238), claiming to be "victoria" via SMTP by smtp01.primenet.com, id smtpd008333; Mon Nov 16 11:45:34 1998 Message-Id: <3.0.5.32.19981116115238.00794470@pop.primenet.com> X-Sender: kenk@pop.primenet.com X-Mailer: QUALCOMM Windows Eudora Light Version 3.0.5 (32) Date: Mon, 16 Nov 1998 11:52:38 -0700 To: qrp-l@lehigh.EDU From: Ken Knecht Subject: Re: Small transmitting loop results (long) Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Return-Path: X-Orcpt: rfc822;qrp-l@fidoii.CC.Lehigh.EDU Evidently I hit the delete key when I shouldn't have and missed earlier discussions on this subject. Where can I get info on these small loops that are being discussed? Book? Web site? Magazine article? Design info anywhere? I've read that these antennas have extremely low resistance, and that it's not a good idea to use conventional air-variable capacitors, and to keep soldered or other joints to a minumum for that reason. Sounds like they'd be hard to construct for a fumbler like me. But I can't afford the prices for those already built. 72, Ken W(NPP From kc5tja@topaz.axisinternet.com Mon Nov 16 19:55:41 1998 Received: from nss4.CC.Lehigh.EDU ([128.180.1.13]:3647 "EHLO nss4.cc.Lehigh.EDU" ident: "IDENT-NOT-QUERIED") by fidoii.cc.Lehigh.EDU with ESMTP id <53691-57904>; Mon, 16 Nov 1998 14:50:38 -0500 Received: from amethyst.axisinternet.com (root@axisinternet.com [207.213.59.10]) by nss4.cc.Lehigh.EDU (8.9.1a/8.9.1) with ESMTP id OAA89210 for ; Mon, 16 Nov 1998 14:50:36 -0500 Received: from amethyst.axisinternet.com (kc5tja@axisinternet.com [207.213.59.10]) by amethyst.axisinternet.com (8.8.8/8.8.5) with SMTP id LAA06739; Mon, 16 Nov 1998 11:46:45 -0800 Date: Mon, 16 Nov 1998 11:46:45 -0800 (PST) From: KC5TJA X-Sender: kc5tja@amethyst.axisinternet.com To: Ken Knecht cc: Low Power Amateur Radio Discussion Subject: Re: Small transmitting loop results (long) In-Reply-To: <3.0.5.32.19981116115238.00794470@pop.primenet.com> Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Return-Path: X-Orcpt: rfc822;qrp-l@fidoii.CC.Lehigh.EDU On Mon, 16 Nov 1998, Ken Knecht wrote: > Where can I get info on these small loops that are being discussed? Book? > Web site? Magazine article? Design info anywhere? I've read that these And I recall, quite distinctly, that the vast majority of people on this list talked me OUT of using an STL because of its horrible efficiency and other technical reasons, the likes of which I do not recall offhand. And now everyone and their grandmother wants to build one? You're all just lucky that I don't (usually) throw temper tantrums on this list. I've never seen such a large degree of "Not Invented Here" syndrome in my life. But as soon as a 'regular' on this list tries one, everyone's just "gotta have it!" First I go looking for support on this list, then I get blasted, then someone else tries the same thing, and he gets all the kudos. The story of my life. :) ========================================================================== KC5TJA/6 | -| TEAM DOLPHIN |- DM13 | Samuel A. Falvo II QRP-L #1447 | http://www.dolphin.openprojects.net Oceanside, CA |...................................................... From mikemo@ibm.net Mon Nov 16 23:23:15 1998 Received: from nss4.CC.Lehigh.EDU ([128.180.1.13]:2236 "EHLO nss4.cc.Lehigh.EDU" ident: "IDENT-NOT-QUERIED") by fidoii.cc.Lehigh.EDU with ESMTP id <53311-57904>; Mon, 16 Nov 1998 18:22:53 -0500 Received: from out1.ibm.net (out1.ibm.net [165.87.194.252]) by nss4.cc.Lehigh.EDU (8.9.1a/8.9.1) with ESMTP id SAA110074 for ; Mon, 16 Nov 1998 18:22:52 -0500 From: mikemo@ibm.net Received: from mike (slip-32-100-34-197.fl.us.ibm.net [32.100.34.197]) by out1.ibm.net (8.8.5/8.6.9) with SMTP id XAA13404 for ; Mon, 16 Nov 1998 23:22:50 GMT Message-ID: <3650B2C3.925@ibm.net> Date: Mon, 16 Nov 1998 18:18:27 -0500 Reply-To: mikemo@ibm.net X-Mailer: Mozilla 3.01Gold (Win95; U) MIME-Version: 1.0 To: qrp Subject: STL varicap question Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Transfer-Encoding: 7bit Return-Path: X-Orcpt: rfc822;qrp-l@fidoii.CC.Lehigh.EDU First, thanks to all who have given me advice on my STL antenna. I appreciate the info! Several members pointed out that since the radiation resistance of the loop is so low, any resistance in the tuned circuit will degrade performance. The main culprit was pointed out to be the wiper on the air variable cap. Several suggested using a split stator cap in series to eliminate the wiper resistance. Here is the question: If you use two air variable caps in parallel, does the total wiper resistance go down like it would using parallel resistors? So if you had two caps of 100pF and 50 milliohm wiper resistance, would the total be 200 pF at 25 milliohm? Tnx 72 de ku4qo, Mike Maiorana, Palm Harbor, FL From elbc@pivot.net Tue Nov 17 00:53:24 1998 Received: from nss4.CC.Lehigh.EDU ([128.180.1.13]:3295 "EHLO nss4.cc.Lehigh.EDU" ident: "IDENT-NOT-QUERIED") by fidoii.cc.Lehigh.EDU with ESMTP id <53694-27950>; Mon, 16 Nov 1998 19:53:07 -0500 Received: from pogostick.pivot.net (pogostick.cybertours.com [206.97.115.16] (may be forged)) by nss4.cc.Lehigh.EDU (8.9.1a/8.9.1) with ESMTP id TAA103488 for ; Mon, 16 Nov 1998 19:52:52 -0500 Received: from elbc (stan003-248.pivot.net [208.153.17.248]) by pogostick.pivot.net (8.9.1/8.9.1) with SMTP id TAA24272; Mon, 16 Nov 1998 19:40:54 -0500 (EST) Message-ID: <001f01be11c4$87e13c60$f81199d0@elbc> From: "david r" To: , "Low Power Amateur Radio Discussion" Subject: Re: Small transmitting loop results (long) Date: Mon, 16 Nov 1998 19:52:15 -0500 MIME-Version: 1.0 Content-Type: text/plain; charset="Windows-1252" Content-Transfer-Encoding: 7bit X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 5.00.0810.800 X-MimeOLE: Produced By Microsoft MimeOLE V5.00.0810.800 Content-Transfer-Encoding: 7bit Return-Path: X-Orcpt: rfc822;qrp-l@fidoii.CC.Lehigh.EDU ----- Original Message ----- From: Ken Knecht To: Low Power Amateur Radio Discussion Sent: Monday, November 16, 1998 1:52 PM Subject: Re: Small transmitting loop results (long) >Evidently I hit the delete key when I shouldn't have and missed earlier >discussions on this subject. > >Where can I get info on these small loops that are being discussed? Book? >Web site? Magazine article? Design info anywhere? I've read that these >antennas have extremely low resistance, and that it's not a good idea to >use conventional air-variable capacitors, and to keep soldered or other >joints to a minumum for that reason. Sounds like they'd be hard to >construct for a fumbler like me. But I can't afford the prices for those >already built. > >72, Ken W(NPP > Hi ken, Here a great page on the stl's .. good luck I built one several years ago , it worked amazingliy well for the size.. http://gallery.uunet.be/ON4CEQ/ant_en.htm 73 dave kc1di /qrp-l 975 From plburbank@kih.net Tue Nov 17 01:14:05 1998 Received: from nss4.CC.Lehigh.EDU ([128.180.1.13]:4481 "EHLO nss4.cc.Lehigh.EDU" ident: "IDENT-NOT-QUERIED") by fidoii.cc.Lehigh.EDU with ESMTP id <53625-55346>; Mon, 16 Nov 1998 20:13:33 -0500 Received: from autoreg.kih.net (autoreg.kih.net [209.209.180.8]) by nss4.cc.Lehigh.EDU (8.9.1a/8.9.1) with ESMTP id UAA150158 for ; Mon, 16 Nov 1998 20:13:30 -0500 Received: from bcotter (har156.kih.net [209.209.187.156]) by autoreg.kih.net (8.9.1a/8.9.1) with SMTP id UAA22022 for ; Mon, 16 Nov 1998 20:10:11 -0500 (EST) Message-Id: <3.0.32.19981116201252.006cec20@kih.net> X-Sender: plburbank@kih.net X-Mailer: Windows Eudora Pro Version 3.0 (32) Date: Mon, 16 Nov 1998 20:12:56 -0500 To: From: Pete Burbank Subject: More Small Loop info Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Return-Path: X-Orcpt: rfc822;qrp-l@fidoii.CC.Lehigh.EDU The June 1986 QST article by Ted Hart has a wealth of info on small transmitting loops including sizing for frequency desired, materials and construction details, matching, a discussion on the capacitor and mounting. He also has written a book on STLs available from AntennaX. 73 Pete W4VCT Just south of Nonesuch,Ky. From aa5tb@swbell.net Tue Nov 17 01:50:17 1998 Received: from nss4.CC.Lehigh.EDU ([128.180.1.13]:2452 "EHLO nss4.cc.Lehigh.EDU" ident: "IDENT-NOT-QUERIED") by fidoii.cc.Lehigh.EDU with ESMTP id <53317-14380>; Mon, 16 Nov 1998 20:50:03 -0500 Received: from mail-gw1adm.rcsntx.swbell.net (mail-gw1adm.rcsntx.swbell.net [151.164.60.101]) by nss4.cc.Lehigh.EDU (8.9.1a/8.9.1) with ESMTP id UAA111568 for ; Mon, 16 Nov 1998 20:50:02 -0500 Received: from swbell.net (ppp-151-164-42-138.eulstx.swbell.net [151.164.42.138]) by mail-gw1adm.rcsntx.swbell.net (8.8.5/8.8.5) with ESMTP id TAA17111; Mon, 16 Nov 1998 19:49:56 -0600 (CST) Message-ID: <3650D63D.8AA95EF6@swbell.net> Date: Mon, 16 Nov 1998 19:49:49 -0600 From: "Steve Yates, AA5TB" Organization: Southwestern Bell Internet Services X-Mailer: Mozilla 4.5 [en]C-SBIS-NC404 (Win95; U) X-Accept-Language: en MIME-Version: 1.0 To: kenk@primenet.com CC: Low Power Amateur Radio Discussion Subject: Re: Small transmitting loop results (long) References: <3.0.5.32.19981116115238.00794470@pop.primenet.com> Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Transfer-Encoding: 7bit Return-Path: X-Orcpt: rfc822;qrp-l@fidoii.CC.Lehigh.EDU Ken W(NPP, I have a bunch of information on one of my web pages about small transmitting loops. The URL is: http://home.swbell.net/aa5tb/loop.html __ __ KC5TJA/6, I've been experimenting with small transmitting loops for many years. When built properly and understood, they can perform well. This is especially true if you have no room for a large antenna. If you can put up a full size antenna and want the best performance, then by all means do so. A small loop isn't going to out perform a full size antenna at 50 feet but place both antennas at 3 foot in your bedroom and see which performs better. Small loops are a lot fun but can be a lot of frustration as well if you aren't aware of the possible pitfalls and why they work. 73, Steve Yates AA5TB aa5tb@swbell.net http://home.swbell.net/aa5tb/ Fort Worth, Texas From applitech@mcg.net Tue Nov 17 14:24:05 1998 Received: from nss4.CC.Lehigh.EDU ([128.180.1.13]:3529 "EHLO nss4.cc.Lehigh.EDU" ident: "IDENT-NOT-QUERIED") by fidoii.cc.Lehigh.EDU with ESMTP id <53591-36986>; Tue, 17 Nov 1998 09:23:01 -0500 Received: from postoffice.mcg.net ([206.147.121.2]) by nss4.cc.Lehigh.EDU (8.9.1a/8.9.1) with ESMTP id JAA192144 for ; Tue, 17 Nov 1998 09:22:59 -0500 Received: from groucho (i85.cc202.mcg.net [206.10.202.85]) by postoffice.mcg.net (Post.Office MTA v3.5.2 release 221 ID# 0-56468U2500L250S0V35) with SMTP id net; Tue, 17 Nov 1998 08:25:01 -0600 Message-ID: <00b501be1235$c3d16800$a10a5e2c@groucho> Reply-To: "Claton Cadmus" From: applitech@mcg.net (Claton Cadmus) To: , "Low Power Amateur Radio Discussion" Subject: Re: STL varicap question Date: Tue, 17 Nov 1998 07:57:48 -0600 X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 4.72.3110.5 X-MimeOLE: Produced By Microsoft MimeOLE V4.72.3110.3 Return-Path: X-Orcpt: rfc822;qrp-l@fidoii.CC.Lehigh.EDU Mike Maiorana wrote: >Here is the question: If you use two air variable caps in parallel, does >the total wiper resistance go down like it would using parallel >resistors? So if you had two caps of 100pF and 50 milliohm wiper >resistance, would the total be 200 pF at 25 milliohm? The direct answer to your question is, yes. Would I suggest this as a solution to the tuning capacitor in a small loop? No. ---- 73 de KA0GKC Claton Cadmus cla@mcg.net MNQRP #1 Minnesota QRP'ers we're looking for you! Email me or visit this page http://www.qsl.net/mnqrp