+++++++++++++++++++ Date: Wed, 14 Nov 2001 18:22:36 -0800 From: Wayne Burdick Subject: [Elecraft] a lot of fun for just $20 I have a new vehicle (Honda CRV) that I can't put a permanent antenna on. (The XYL factor.) So I bought an unobtrusive 39" long base-loaded 11-meter mag-mount whip from Radio Shack for $20. Didn't even bother to tune it, since I figured the KAT2 would do the job (and I was in a hurry!). Sure enough, the KAT2 tuned it to close to 1:1 on 15, 12, and 10 meters. Even though the antenna is not very efficient, especially on 15 meters, I worked all over the country on this band during a drive down Highway 1. I'm sure I could have worked Japan on 10 meters, which I heard at S-9, if I'd had an automatic transmission ;) Safe driving on twisty roads sure gets in the way of operating the radio.... If you were thinking about mobile operation, but were worried about the antenna installation, try this simple solution. These small antennas aren't much larger than a 2-meter mag mount, and will definitely provide lots of HF mobile fun. 73, Wayne N6KR ++++++++++++++++++++++ Date: Thu, 15 Nov 2001 08:21:38 -0600 From: =?iso-8859-1?Q?KC=D8IFL?= Subject: Re: [Elecraft] a lot of fun for just $20 I've been wondering what to do this Winter. I've been setting up in the park with a 10M loop ANT and my K2 at lunch time. Just enough time to set up, make a couple contacts, and tear down and get back to the office. The WX here in Missouri has been fabulous as of late, but Ol' man Winter is coming! I've been thinking about a mag-mount ANT so I could set up in the car at lunch time. I'll have to go by RS and try this out. I was thinking about a Hamstick and mag mount also. Ron E KCØIFL +++++++++++++++++++++++ Date: Tue, 16 Apr 2002 15:00:44 -0400 From: Bob Patten To: casey.jay at gte.net Cc: QRP-L Reflector , Elecraft Reflector Subject: [Elecraft] Re: Mobile Antennas Donn Kuse wrote: > I need some recommendations for a good mobile antenna and mount to use > with my K1 (20/40M). Also have a question on the mag mounts. Are any > of them made that don't scratch the surface of a vehicle? Do the mag > mounts provide a half way decent ground? Last mag mount I used was > around 1978 on a 2meter antenna. > I use the Hustler on a three-magnet mag mount. The capacitive ground would be fine for 2M, but for 20M (and especially 40M) you should run as short a braid as you can rig from the feed point of the antenna to the truck bed. The vinyl pads on the mag-mount are not very scratch protective, so I slip each magnet into a plastic baggie before sticking it on the trunk. This arrangement and the Hustler work great for me. If you hear me mobiling around FL the weekend after next, it will be in the Florida QSO Party. K4PG and I will cover 21 counties using N4BP. Rig will be an IC-706 running 100W, mostly CW. We will log by computer (NA) and also use it for rig control. -- 73, Bob Patten, N4BP Plantation, FL E-Mail: n4bp at netzero.net Website: http://www.qsl.net/n4bp QRP ARCI #3412 SOC #1 ARS #799 Whiners #6 FISTS #7871 ++++++++++++++++++ From: "Charles Bland" Organization: Entropy Reduction, Inc To: Elecraft at mailman.qth.net Date: Tue, 16 Apr 2002 14:05:01 -0700 Subject: Re: [Elecraft] Re: Mobile Antennas Reply-To: BlandRanch at BlandRanch.net I would change one thing....... Don't use braid. Jacketed, stranded wire? You bet, but not braid. In my professional role, we require that ground braids be replaced. They can be a source of noise and corrosion, which deteriorates their performance. Chuck Bland ++++++++++++++++++ Date: Tue, 16 Apr 2002 16:15:23 -0500 To: BlandRanch at BlandRanch.net, Elecraft at mailman.qth.net From: Tom Hammond =?iso-8859-1?Q?N=D8SS?= Subject: Re: [Elecraft] Re: Mobile Antennas And a WIDE copper strap, maybe some copper 'flashing' (left over) from a home construction site, should work even better. Tom N0SS +++++++++++++++++++ From: "Stuart Rohre" To: , , "Tom Hammond NØSS" Subject: Re: [Elecraft] Re: Mobile Antennas Date: Tue, 16 Apr 2002 21:20:21 -0500 A sheet of saran wrap slipped under a magnet of a mag mount antenna support will add to the resistance to scratching car finish. 72, Stuart K5KVH ++++++++++++++++++ Date: Wed, 17 Apr 2002 11:03:06 -0400 From: Donn Kuse Reply-To: casey.jay at gte.net To: elecraft at mailman.qth.net, Low Power Amateur Radio Discussion Subject: [Elecraft] Re: Mobile Antennas Hi all, Want to thank everyone for their responses to my questions. Seems like most mobilers are using Hamsticks over the Hustler. Still undecided about the mount, bumper, license plate or Tenna Hitch (mounts on trailer hitch). Seems like the license plate mount has more bumper contact. Others were the Screwdriver, Texas Bug Catcher and Outbacker which are out of my price range. For a small portable, seems like the MP-1 is a favorite. Most have added at least 2 additional radials for 40M or 20M. Looks like Force 12 makes a nice one, but way out of my price range.. Thanks again for your input. Hope it has helped others too. 72,73 Donn WB4ZWT 67 and still learning +++++++++++++++++ Date: Wed, 17 Apr 2002 11:56:32 -0400 (EDT) From: "Scott Rosenfeld [N7JI]" To: qrp-l Subject: [124953] Mobile antennas - SCREWDRIVER!!! Indeed, scratching occurs no matter what you put between the magnets and the paint. Different materials create different patterns, that's all. Sand, dust, etc., just find a way to get ground into the paint. (from experience) As for antennas, I have tried Hustlers, Outbackers, Hamsticks, plain-old whips, and (finally) a Screwdriver, which consistently outperforms any of the others tested AND can be tuned while you're driving down the road. Let me just say that, properly installed, the performance increase (esp. on 30/40/80) over any other mobile antenna out there is substantial. Possibly a bug-catcher would do better, but you have to stop to change bands (stop, get out, change tap) so I would still have to go for the Screwdriver-style of unit. Plan on using a heavy-duty mount...but it's worth it. Mine has required virtually no maintenance in the 4 years it's been up. Scott -- Scott Rosenfeld ARS N7JI 541-684-9970 Eugene, OR Land o' much rain If you find me on the air, I'm probably in my car ham at w3eax.umd.edu http://w3eax.umd.edu/~ham +++++++++++++++++ Date: Thu, 18 Apr 2002 02:11:34 -0400 (EDT) From: "Scott Rosenfeld [N7JI]" To: qrp-l Subject: [125009] My life as a mobile operator (all about mobile setups) Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Firstly, let's start by saying that I have been mobile for the past 5+ years, from both coasts and up and down the eastern seaboard, and as far inland as Iowa. I use an IC-706 and TJ Antennas BB-3 Screwdriver. It might just as well be a High Sierra or a DK3 or whatever - the brand isn't important (although mine matches my car's color); the design is. 1) I have worked many thousands of QRP mobile QSOs, including ragchews, contest Qs, DXing (worked about 125 countries mobile, probably 100 QRP). 2) Most of my activity has been on 40, 30, 20, and 15 meters 3) I have used the following: Outbacker (orig. and Perth) Spider Antenna Hustler system (triple resonator adaptors, too) Hamsticks stainless whips 2m & 6m squalos and halos 4) I have used triple and quad-sticker mag mounts, various masts, and (finally) permanently mounted 3/8" steel mounts capable of holding 10+ pound antennas in 85+ mph winds. Here's the story: I have used an Alinco DX-70T, several QRP rigs, and (finally) an IC-706 with 250Hz CW filter. My Bencher sits in the passenger seat and I log with a microcassette recorder. I went through a process of learning about mobiling that led me to the following: - Find a rig that is comfortable for you to use - DO NOT COMPROMISE on the antenna! Remember, this will be you MOST efficient station EVER because you only have 10 feet of feedline! - Ground, ground, ground. Ground the engine block to the frame, the hood to the frame, the trunk to the frame, the exhaust pipe to the frame, the antenna mount to the frame. DO NOT RELY on welds and hinges! - Use ignition suppressor wires to cut down on RFI - Find a radio with a noise blanker - it helps when you're near power lines or if your ignition noise can't be completely killed through grounding As far as choosing antennas, I once traded a rig for an FT-900 with unused TJ BB-3 Screwdriver antenna. I looked at the antenna and said, "who's ever gonna use this thing? Why would I ever mount something so big?" So I got ready to sell the ant and keep the rig. After playing around with hamsticks, hustlers, and the other antennas mentioned above, and trashing my roof's paint job with a multi-sticker antenna, I eventually got a new car (my Neon) and said, "I'm not trashing the paint. I'm doing this right." So I decided to keep the BB-3 and sell the FT-900. I went out and got an IC-706 with the narrow filter because it had an SWR meter as well as a keyer and noise blanker, plus the base could go under the passenger seat. I designed the mounting brackets capable of handling a heavy antenna and had a fellow ham make them from steel - NOTE TO SELF - CHOOSE STAINLESS NEXT TIME!!! I mounted the brackets (I had a spare made) in back of the car, hanging from the FRAME. I can stand on them without damaging them. I pulled out the seats and tore up the carpet, and ran cables - power, coax, audio, paddles, rig control - under the carpet and grounded EVERYTHING to everything. After about three months, I was done. That was four years and many thousands of QSOs on all seven continents ago. I don't even have a station at my house because I don't sit still long enough to bother putting one up. The car is thus an ideal setting for my "permanent" station. Just as a test, I used the second antenna hookup to try the Screwdriver out against the other antennas in my stable. I used an A/B switch (also mounted under the seat) to do the testing, and on the S-meter, the difference between the Screwdriver and ANY other antenna I tested, even if tuned for that particular band (i.e. 1:1 SWR) was about 4 S-units. Yes, I was stunned, too, but the ear backed up the meter readings. At that point, I was convinced that expending the effort had been well worth it. So in retrospect, "Anything that is worth doing is worth doing right." You just have to consider whether having a killer HF mobile signal is worth it to you. PHOTOS ON THE WEB: http://w3eax.umd.edu/~ham/neon.html -- Scott Rosenfeld ARS N7JI 541-684-9970 Eugene, OR Land o' much rain If you find me on the air, I'm probably in my car ham at w3eax.umd.edu http://w3eax.umd.edu/~ham ++++++++++++++++++++ Date: Thu, 18 Apr 2002 14:07:41 -0400 From: Bill Coleman To: , "Low Power Amateur Radio Discussion" Subject: [125032] Re: Mobile antennas On 4/18/02 1:43 PM, Upton, Shawn at SUpton at ALLEGROMICRO.com wrote: >The plates require four mounting screws, right? I checked my Saturn, but >the rear plate only has the two upper screw holes for mounting the license >plate. I always figured that that would not be strong enough, for the >hamstick. I did the same analysis on my Saturn. I haven't yet mounted it, but I bought a trunk-lip mount for my Saturn. A fellow contester in this area has been using this method successfully for a while. Bill Coleman, AA4LR, PP-ASEL Mail: aa4lr at arrl.net Quote: "Not within a thousand years will man ever fly!" -- Wilbur Wright, 1901 +++++++++++++++++ Date: Thu, 18 Apr 2002 14:48:53 -0400 From: "John L. Sielke" To: Low Power Amateur Radio Discussion Subject: [125039] Re: Mobile whips On Thursday 18 April 2002 14:30, Jake Brodsky wrote: > >The Hustler system is probably more efficient, since it > >isn't loaded near the bottom like a screwdriver or a Hamstick. > > Bill, if you look closely at a Ham Stick, you'll notice that the > actual loading coil is right below the set-screws of the steel whip. > It's not at the base. > > Judging from what Jerry Sevick wrote about the loading coils in > Hustler antennas, I have to wonder if there is really much improvement > over a ham-stick. -- Well, all the antenna "experts" are really going at this one. Let me just add my totally subjective, unscientific observations. 1. The BEST mobile antenna I use is a Texas Bug Catcher, 4" diameter center coil, capacitive hat, whole thing is about 12', no problem working DX with K1, K2, or even my NC-40A. 2. Second best, oddly is the Hamstik antennas. I have a bumper mount on the "little" car (1981 VW Rabbit Diesel). I have tried both the Hustler and the Hamstick and the Hamstick beat the Hustler. 3. I have used a tuner to compensate for SWR when going from say, CW to phone. I would NOT recommend trying to use a 40M hamstick as a 40-10 antenna, with a tuner. 4. In a moment of idiocy, a year or so ago, I bought one of those SGC QMS-37 tuners, that mounts on the car with a whip, supposed to work all bands...JUNK! Sure, you get nice low SWR, but I switched from the QMS-37 with 8' whip, mounted high on the car, and the Bug Catcher. Signals that were S9 on the Bugcatcher were S1 on the QMS-37. Consider, when you tune your antenna to resonance using the center coil, you have nice low SWR, and the coil radiates. Now, you use an unmatched antenna, tune the SWR down with a nice tuner in a metal box. The coils in the tuner want to radiate, but, duh, they're in a metal box, so only that RF which gets to the "antenna" can do you any good. I know, that's unscientific, and you BSEE's andPHD's can shoot all kinds of holes in it. OK, all you "ex-spurts" Have at it! -------------------------- John L Sielke W2AGN w2agn at w2agn.net http://www.w2agn.net Trustee: W3IYQ Sure you can trust the government! Just ask an Indian! ++++++++++++++++++ Date: Fri, 19 Apr 2002 00:16:03 EDT From: Wb4taj9 at aol.com To: qrp-l at lehigh.edu, frussle at erols.com Subject: [125071] Re: Mobile Whips A few years ago I participated in a group testing mobile antennae. A closed airport was used to allow spacing the antennas about a mile apart to avoid near field effects. A genuine field strength meter, indicating field intensity in volts/meter, was used as a receiver, and some care was taken to feed constant power to the various antennas which were mounted in the same place on the same vehicle. (We would measure the base impedance of each antenna with a General Radio rf bridge, then calculate the base current for a 10 watt input and we used a tuning network to set the current as observed on a General Electric RF amp meter. This is the same method by which AM broadcast stations determine their power. With this nod to science, there were admitedly some loosely controlled aspects of the test. We were measuring ground wave field intensity, not skywave; there were artifacts that affected the performance of the antennas due to where they were mounted on the vehicle. (All were mounted on an 8-ball on the side of a Volvo sedan.) Some anennas might have faired better if they had been mounted differently. But the idea was to keep everything as much the same as possible in an attempt to get some indication of relative efficiency as opposed to determining the best field from each antenna when optimized. For Instance, you wouldn't want to drive down the road with that Bugcatcher sitting on that 8-ball. To the bottom line. All measurements were made on 20 meters. There were no surprising results. Bigger, fatter, taller antennas produced higher field intensities at the field strength meter. I do not have the results before me, but the Texas Bug Catcher was far and away the best. This was the big, ugly version with the loading coil made of tubing, and the top hat and the tall pole. Second best was the Hustler with the Hi-Q loading coil, and right next to it was a homebrew job using ten gauge wire wound around a PVC form. After that were the "skinny" wife-approved antennas, like the small Hustlers, linear loaded antennas, and it seemed that the Outbacker came in last. As I say, I don't have the results here, but I seem to recall that if you normalized the reading of the best antenna, (the Bugcatcher) to 1.0, the big Hustler was just under .7 as was the homebrew, followed by the small Hustler at .4 or so, the linear loaded (don't remember the brands) at .3 to .35 and the outbacker at about .1 to .15. So there was about a 10 dB spread, or 1-1/2 S-units from the greatest to the least. Not really much to fight over, really. One thing I learned from going through this exercise is how important connection quality and grounding are. We saw some huge variations in signal strength until the grounding on the radio and atenna were improved, and some antennas were very sensitive to how they were screwed onto the mount. Removing and replacing the Hustler could change it's performance a lot. This was helped by spraying threads of the coil and the mount with Cramolin to clear up the oxide products. This was several years ago and many of the antennas being discussed in this thread either were not a factor in the market place yet, or were so rare as to be unavailable to the group. I don't want to present this test as exhaustive, or even as an indicator of what results you might experience as all the antennas were at least somewhwat installation sensitive. The relative performance of the antennas might have been different on another band. We were going to make measurements on 40M, but there was too much noise and QRM to get reliable readings. We didn't have a full set of radiators for 15 meters. Since we were measuring the power delivered to the antenna under test after the tuning network (a homemade "T") its efficiency is factored out of the tests. 73 de Bob WB4TAJ/9 ++++++++++++++++++