++++++++++++++++ From: bejones at hursley.ibm.com To: Kevin Cozens Date: Wed, 13 Mar 2002 18:45:25 -0000 Subject: Re: [Elecraft] Questions re: MP-1 antenna Cc: elecraft at mailman.qth.net All excluding 80m coil which I don't have and approx > 1. How much does it weigh? 15 oz - Antenna + radials but no supports or cables +14oz for clamp support and clamp or +8oz for tripod > 2. What size is the bundle of parts for the antenna when disassembled? Longest bit - coil 10.5" 1.25" diameter, Will bundle to about 12" x 3" in all - no coax > 3. How tall is the antenna when assembled? Fully extended (40m band use) about 6' > 4. There seems to be an optional whip for the antenna. What does that do to > the height of the antenna when assembled? How does it affect performance? Whip is part of the antenna > 5. How long are the ground radials and how many are supplied? Are the > radials stiff or flexible pieces of wire (ie. can they be routed around > obstacles)? 4 x 10' flexible - opposite is the problem - trying to fix them as straight as possible - usually need weighting at the ends to stop blowing around > 6. How big is the optional tripod for the antenna? How does it affect > overall height and weight? How stable is the antenna when sitting on the > tripod? Will the antenna need to be anchored when used outdoors even in a > gentle breeze? 14" diameter, 5.5" high. Would be unstable in wind >I am interested in using the antenna for 80 (with the add-on 80m coil) > through 10 meters inclusive. I used to run 100W from my commercial rig in > to a 26-foot tall Butternut vertical and did very well with that > combination. I wonder what it will be like operating from inside a house. > What sort of interference I am likely to cause even at low power levels not > to mention the amount of interference I am likely to receive (the TV and > the lights in the basement are big noise makers). Dunno about 80m - I don't think it is rated at 100W. I used it on the weekend, no TVI or problem noticed inside my sister's house but she may not have had TV, radios on! Operates OK - to gain an extra 1-2 S-points I took it just outside the window clamped to a garden chair. Worked Quebec from central England on 10m - OK so he only gave me a 1 by 1 report but it made the trip across the pond. Worked a few europeans stations and previous weekend when demoing to Boy Scouts inside scout hall worked Algeria (all 10W SSB). Not to noisy and my sister is on a housing estate. No neighbours banged doors! Fits nicely with K2 inside 15.5"x11.5"x5.5" padded aluminium engineers case (about 17 bucks from local hardware store in the UK). Thanks BTW - you made me open the case and drag it out to measure - it was still a little wet from the weekend so had chance to dry it. Brian G0UKB K2 #1115 Brian E Jones Pervasive Computing Specialist IBM HURSLEY ++++++++++++++++ Date: Wed, 13 Mar 2002 22:12:35 +0000 From: "Julian, G4ILO" Subject: [Elecraft] Questions re: MP-1 antenna To: "Elecraft List" Kevin. I had an MP-1. I wasn't impressed with it. It's a short, high-Q tunable whip, like a small version of mobile whips made by many suppliers. Like any mobile whip, it works at best efficiency ONLY when given a really good ground. It's hard to provide it with a good ground in portable or indoor use. When I bought mine, it came with a set of radials made from a 10 foot length of computer ribbon cable split in 4. That isn't a good ground, or even an approximation of one. Most of the time I got high, constantly fluctuating SWR and very poor performance. The people who claim this antenna works well usually seem to use it with a quarter wave counterpoise cut for the band in use. Usually, they also try to elevate some or all of this counterpoise, so that the MP-1 becomes half of a low dipole with one shortened leg. This may be difficult to achieve if indoor operation is your aim. And which is the doing the most radiating in this configuration, the $150 MP-1 or the $1 length of wire, is a matter of conjecture... The MP-1 is pretty small when disassembled, but the size and weight soon goes up once you add a few quarter wave radials to the pack. Assembled it's about 5 foot tall. The whip itself is 4 foot. The telescopic whip is just a replacement for the standard one made from alloy rod that you screw together. Some people may find it more convenient. The tripod is a waste of money. The antenna will blow over in any more than the slightest breeze. Because you want to elevate the whip and its radials as much as possible for best performance, the opportunities for using the tripod are limited at best. I bought the 80m coil but I never worked anyone on 80. An antenna that small is never going to put out much of a signal on that band even with the best ground system in the world, and a quarter wave counterpoise for 80 is a bit of a nuisance. In your situation, Kevin, I'd go for an MFJ magnetic loop. That won't get you on 80, though. If anyone knows of an efficient indoor antenna that works on 80 metres, I'd be interested to learn of it. -- Julian, G4ILO. (RSGB, ARRL, K2 #392) Homepage: http://www.qsl.net/g4ilo Kevin Cozens wrote: Greetings, all. A few people on this list indicated they own or have used an MP-1 antenna. -- snip -- +++++++++++++++++ To: "vsantis at earthlink.net" Cc: elecraft at mailman.qth.net Subject: Re: [Elecraft] Miracle Whip Antenna From: "Steve Lawrence" Date: Wed, 20 Mar 2002 16:31:17 -0500 Vincent, You might want to check out the HFpack Portable Antenna Shootout for some interesting comparisons of small, portable antennas -- the Miracle Whip being one compared. This site might help you sort through the portable antenna options: http://www.hfpack.com/ Also, there's an interesting "home brew" version described: http://www.g4fon.co.uk Look under the "musing on the miracle whip design". The more I study these compact portable antennas, the clearer the compromise in performance over larger antennas becomes. Portability or Performance: pick one! Having said that, there was a recent QST article where QSO's were made on a light-bulb dummy load! I'm not recommending this, but it goes to show that contacts can be made on the extremes of compromise. 73, Steve aa8af +++++++++++++++++ Date: Thu, 21 Mar 2002 01:15:16 +0000 To: vsantis at earthlink.net, "Elecraft (E-mail)" , qrp-l at Lehigh.EDU From: Larry Cahoon Subject: Re: [Elecraft] Miracle Whip concensus Cc: "QRP List (E-mail)" Vince, I think you have to very different location problems. Motels and summer cottages. Seems to me you can usually do a lot more at a summer cottage than you can at most motels. So think in terms of what you can do depending on where you are. All antennas will get out, just some much better than others. Running 5 watts makes it harder, that is all. If you have to use a short antenna, stick to the higher bands. The size constraints are not so bad there. I stay away from 80 meters for that reason, usually preferring 20 meters and up. The Miracle Whip and the Outbacker suffer in comparison to a Hustler as they effectively put the "lumped inductance lower on the antenna. You want that as high as you can get it. The antenna will perform better. For a lot less money than either the Miiacle Whip or the Outbacker you can get a hustler coil for a few bands and a mast. If you are sold on a vertical, I'd go the hustler route, get a mast a long as you can put up and trim the whip to get the SWR where you want it. I use two foot aluminum sections for that kind of stuff. I can just put together as many sections as I want. You will still need some kind of radials. All the mobile antennas rely on the car body to serve that purpose, so you need to replace that with something. That is not to say the Outbacker will not get out. I've got one. I still use it around town for it ease of getting on and off the car without having to guy the thing. I've got 2xWAS mobile to mobile with the thing (at 100 watts). It does work. At least for the summer cottage, I would think of getting one of the 20 foot fishing poles that are out there or the DK9SQ 30 ft. mast and use that to support the center of an invented V or a dipole. I've done that and tied the mast to the deck of the cottage and run the wire out as far as I can, tied ropes to the end to go even further and stuck the ends of the ropes on a tent peg in the ground. Feed that with ladder line. That an a tuner will cover a number of bands. And unless you are at the beach it will usually do a better job for you. 73 de Larry...........WD3P in MD http://www.qsl.net/wd3p/ +++++++++++++++++ Reply-To: "A. Sewell N5NA" From: "A. Sewell N5NA" To: Subject: Re: [Elecraft] Miracle Whip concensus Date: Wed, 20 Mar 2002 19:18:09 -0600 Vince, You may want to take a look at the Buddipole. The plans are located at www.qsl.net/w3ff. It's easy to build and seems to work. I built a portable mast from some 5/8" dowels I cut up into 2' lengths and put 1/2" male/female CPVC connectors on each end so I could screw them all together. 73, Alan N5NA +++++++++++++++++++ Date: Thu, 21 Mar 2002 17:04:18 +0000 From: "Julian, G4ILO" Subject: Re: [Elecraft] Miracle Whip Antenna To: "Elecraft List" Yes, I have one to use with an FT-817. I have written a lot about it on my web site, if you're interested. It's primary value is in its small size, light weight and the fact that it can be used without a counterpoise. All the other small whip antennas need some form of grounding system before they can be used at all, which kind of negates a lot of the portability, light weight and convenience. Obviously, there are compromises involved, but they are nowhere as near as bad as some people would have you believe. I get a bit tired of hearing people who have never even seen a Miracle Whip compare it to a dummy load. But whether it's right for you depends on how much effort you're prepared to put in to erect a better antenna wherever you go. It isn't ideal for any of the Elecraft rigs, though. It's rated for 5 watts, and it's designed to fit on the SO-239 on the back of the FT-817. 73, -- Julian, G4ILO. (RSGB, ARRL, K2 #392) Homepage: http://www.qsl.net/g4ilo "Vincent A. Santis" wrote: Hi, Has anyone tried the MIracle Whip Antenna, if so, I would appreciate any and all comments. ++++++++++++++++++++ From: "Stuart Rohre" To: , Subject: Re: [Elecraft] RFI MP-1 antenna Date: Thu, 21 Mar 2002 14:40:58 -0600 Steve, As to ground plane effectiveness of a car body, that has been modeled and discussed in both IEEE Antennas and Propagation magazine, and in ARRL's QEX, Communications Quarterly. It might have been in Comm Quart. back when CQ ran it. I think a Canadian antenna guy wrote it up. If it was, that would be Jack Belrose. Anyway, the short answer is at lower frequency bands, any antenna on a car is greatly helped if you can fold some counterpoise cut for the band into the underframe of the car or truck. Try for a quarter wave, and as many as you can, but anything is better than the modern vehicle with multitude of plastic, and probable lack of good RF materials and bonding among the body parts. The antenna serves a portable purpose if you need a compact vertical that you can backpack into someplace. If you do not need that short parts capability, then you could build your own antenna that would be just as good, and if full size dipole or others, more efficient. It is a good product, well built, some of my friends have them, and they got good service from vendor. It is a labor of love for the QRP backpackers community. It is not some huge commercial company. It fills a specific portable antenna niche. 72, Stuart K5KVH +++++++++++++++++ Date: Thu, 21 Mar 2002 13:10:03 -0800 From: Eric Swartz WA6HHQ - Elecraft Organization: Elecraft To: Slacret at aol.com Cc: elecraft at mailman.qth.net Subject: Re: [Elecraft] RFI MP-1 antenna The MP-1 is manufactured by SuperAntennas here in California. Elecraft resells the antenna and the full info can be found on our web page. It is unique in the short portable antenna category because it uses a sliding coil to tune the antenna. I personally use the MP1 for a travel antenna. I like it because it breaks down into 12" or less sections and fits in a small laptop PC pouch or my K2 Tac-Pac and can easily be set up in a hotel room or trade show booth. I frequently clamp it at a 45 degree angle outside those hotel windows that open and drop a radial down to the ground or along the window sill. While ALL short antennas will not perform as well as a long wire or full sized dipole, they certainly do work well enough to make a lot of QSO's from the hotel room. (Especially on 30M - 10M where they are most effective.) The MP-1 has an optional longer bottom mast (in the 'mobile kit') that you can use to increase efficiency if you have room. If you have room, several 33' radials increase the performance of the MP-1, and most other shortened verticals. 73, Eric WA6HHQ ++++++++++++++ Date: Mon, 25 Mar 2002 09:23:45 +0000 From: "Julian, G4ILO" Subject: Re: [Elecraft] Miracle Whip Antenna To: "Elecraft List" Frank, I'm not sure how you can claim to know what's in the minds of everyone on this reflector. Short whips may not be the most efficient antennas you could use, but they have many benefits of convenience, and allow you to get on the air from situations where you otherwise might not do so. It's true that most vertical antennas need a good ground to work against, however the Miracle Whip's transformer matching somehow seems to transfer power quite effectively to the whip without one. Don't ask me how it works, ask the designer. But if you have a MW you can see this quite easily for yourself. You can connect a 4 foot whip to the back of the K2 and you'll hear hardly anything. Even the KAT2 won't match it. If you connect the K2 to the shack ground you will still not get a match on some bands. Even if you do, the MW seems to work as well or better, even without a ground connection. Of course, electrically lengthening the whip to make it resonant changes the situation, but you still need a good ground to make it work. But that's often hard to provide in a temporary location. I'm deeply sceptical of the use of resonant counterpoises with short whips. They seem to act, not as a ground, but as part of the antenna. Indoors, they pick up all sorts of noise from the wiring etc, and doubtless radiate RF into it causing RFI. Outdoors, they probably contribute more to the on-the-air performance than the short loaded whip that is then acting as the other half of a dipole. But if you can put up half a dipole why not go the whole hog and put up a whole one? By accepting the need for a counterpoise or radials you've already lost most of the convenience and mobility offered by a whip. If you want to be able to listen or operate without trailing bits of wire all over the place I think the performance compromises made by the MW are an acceptable trade-off. -- Julian, G4ILO. (RSGB, ARRL, K2 #392) Homepage: http://www.qsl.net/g4ilo ++++++++++++++++++ Date: Wed, 26 Jun 2002 23:30:43 -0700 From: Phil Wheeler Organization: Outstanding To: cyr999 at extremezone.com Cc: Elecraft Subject: Re: [Elecraft] K2100 and MP-1 Tim and Nancy Logan wrote: >Hi folks - has anyone used the K2/100 on full power with the MP-1? Is >there a limitation here? > Good to 150 Watts according to the SuperAntennas webstie. Phil +++++++++++++++++++ From: Tim ORourke To: "'elecraft at mailman.qth.net'" Subject: Re: [Elecraft] K2100 and MP-1 Date: Thu, 27 Jun 2002 07:22:16 -0400 I have run mine mobil at 100 watts for a year without problems. Tim KG4CHX +++++++++++++++++++++ Date: Fri, 05 Jul 2002 13:22:18 -0500 From: Jack Scheinuk To: elecraft at mailman.qth.net Subject: [Elecraft] MP-1 Portable Antenna Evaluation I ordered an MP-1 with the tripod, 80m coil, and mobile kit for use as an emergency antenna during hurricane conditions which affect my area (New Orleans). I set up the antenna on the desk in my study, deployed (or I should say drooped) the radials (they seem to be about 10' each) across furniture. The coil settings shown in the instructions are approximate. I easily found the best (lowest SWR) settings using an MFJ antenna analyzer for both the short (standard) and 2 foot (mobile kit) base rods. The settings on the 2 foot rod are about 1/8 to 1/4 inch less than those with the standard base rod. I tested the various coil settings on all bands with my K2. In each case the lowest setting found with the MFJ analyzer produced an SWR on the K2 of 1.3 or less. I could on each band then move the coil a small amount to achieve 1.0 to 1.1. The MP-1 appears to be a well manufactured product which in my opinion will take abuse. With lousy conditions on 7/3/02 I tested the antenna on the short base and had a 40m qso with Toronto and yesterday with equally poor conditions tested the antenna on the long base and had a 15m qso with an Italian station near Milan - the antenna still on my desk with the radials drooped over furniture. I was able to test the antenna in the 7/3 qso against my GAP Titan vertical (top at 61' aboue ground). I observed a 1 s-unit received signal improvement from the GAP. The Toronto station also reported a 1 s-unit improvement from the GAP on my transmitted signal. The MP-1 is in my opinion a well made outstanding performer in a "very" small portable package. 73 - Jack - W5WSF +++++++++++++++++