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Miricale whip / MFJ-1621 Portable antenna's
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Anthony
Hi Group,
I was wondering if the Miricale whip antenna operates on the same theory as the MFJ's 1621 Potable antenna. It looks like the 2 of them have got an internal antenna tuner, plus the MFJ's version has got a field strength meter. It would be very interesting when we get some feed back on the miricale whip, plus has anybody had any experience with the MFJ's-1621. 72/73's Anthony |
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I have the MFJ 1621 portable antenna here. It is definitely not the
same kind of thing as the Miracle Whip, which from the QST article seems to use a transformer. I lost the sheet of instructions that came with the MFJ but it is basically a 4 foot whip with a built in ATU. I think there is a variable C in series with the RF from the TX, going into a tapped coil. The "field strength" meter is actually pretty useless at QRP power levels, and whatever it measures, it certainly isn't field strength. The whole thing is built to MFJ's usual constructional standards. It is supposed to be used with the supplied 50 foot of coax laid out straight, which makes it not very convenient to use. The reason is the shield of the coax is supposed to act as a counterpoise. I shortened the coax and added a terminal to attach a separate counterpoise or a ground connection but it is not very successful. It seems to work about the same as the ATX, MP-1 and anything else I tried with a 4 foot whip on it. But I don't use it to transmit as without proper grounding or a counterpoise it is difficult to keep RF off the radio. The Miracle Whip should be very interesting as it appears not to need a counterpoise, which would make it very much more convenient to use than the other antennas, especially for the /PM guys and gals. Julian, G4ILO --- In FT817@y..., "Anthony " <aays888@y...> wrote: Hi Group,them have got an internal antenna tuner, plus the MFJ's version has gota field strength meter. It would be very interesting when we get some |
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Cortland
Julian,
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EVERY short monopole needs a counterpoise - and most of the long ones, too. The penalties for not using a counterpoise are reduced efficiency (greatly reduced, for a short monopole) and detuning (more severe for a short monopole). Cortland --- In FT817@e..., g4ilo@q... wrote:
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Well I'm just going by what it said in the QST article, which you've
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probably read yourself. The first user reports will certainly be interesting. Julian, G4ILO --- In FT817@y..., "Cortland" <ka5s@e...> wrote:
Julian, |
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Don
I think you'll find, when all the hoopla is settled down that the Miracle
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whip does no better or worse than all other short whip antennas. Any whip can work without a counterpoise. You have to define the word "work". Bottom line is that the more metal the more capture area the better the antenna. Period. Assuming "all thing being equal and a good match". ----- Original Message -----
From: <g4ilo@...> To: <FT817@...> Sent: Tuesday, July 17, 2001 10:44 AM Subject: [FT817] Re: Miricale whip / MFJ-1621 Portable antenna's I have the MFJ 1621 portable antenna here. It is definitely not theQuestions ) see Please note that your messages and files sent to this group become publicdomain upon submission and may appear anywhere on the Internet or in print without notice or compensation.
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Ed Juge/NM
Julian...
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Can you give me a page reference in the current QST for the Miracle whip "review"? Assuming you mean the August issue, I can't find it. There was an article on how to build one a month or so ago. I saw that. Anxious to hear from some real-world users. It looks too good to be true... and that means it usually is. 73... Ed, W5EJ ----- Original Message -----
From: <g4ilo@...> To: <FT817@...> Sent: Tuesday, July 17, 2001 4:47 PM Subject: [FT817] Re: Miricale whip / MFJ-1621 Portable antenna's Well I'm just going by what it said in the QST article, which you'veQuestions ) see Please note that your messages and files sent to this group become publicdomain upon submission and may appear anywhere on the Internet or in print without notice or compensation.
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Cortland
This isn't adressed SPECIFICALLY to the "Miracle Whip"
(want a sandwich yet?) but to ANY of these miniature money traps. Remember the Gotham verticals? "'All band vertical!' asked [sic] one skeptic. 'Twenty meters is murder these days. Let's see you make a contact on twenty meter phone with low power!' ..." (Jul 1969 CQ, page 112) Imagine the Gotham vertical shrunk from 18 feet to three feet, with corresponding reduction in performance. Of course, the Gotham verticals cost less than twenty bucks. And over elevated radials, or a LOT of 'em, or a swamp, they probably DID work OK. Today they haunt old barns, from which their influence invades the receptive minds of those of us who want small antennas to work like beams. "Let's see you make a contact on low power..." I DID work JA and 3D2AG handheld, with a RS 22-inch ten meter antenna. And in 11 years I may do it again; eventually even a blind worm catches a robin. Saw two JA-made BNC antennas at HRO this weekend, IIRC a 40/15/6 meter and an *80*/20/10 meter whip. They are about 30 inches long. SOMEONE will buy 'em. At $90. Each. GO GOTHAM! Cortland |
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Yes, but there is one other reason for needing a counterpoise with
whip antennas - without one you end up with an RF "hot" radio and it's hard to obtain a good match because it changes as you put your hand near. If the Miracle Whip solves that problem then it will have a benefit, even if it is no better as a radiator. In many operating situations having to lay out and adjust a counterpoise is a damn nuisance. Julian, G4ILO --- In FT817@y..., "Don" <k7ugq@h...> wrote: I think you'll find, when all the hoopla is settled down that theMiracle whip does no better or worse than all other short whip antennas.Any whip can work without a counterpoise. You have to define theword "work". Bottom line is that the more metal the more capture area the betterthe antenna. Period. Assuming "all thing being equal and a good match". |
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I was referring to the article on building the Miracle Whip in the
July issue. The August QST hasn't made it to this side of the pond yet. I can't see as how there can be a review of this antenna yet since the first commercial examples are probably only just on their way out to buyers. Julian, G4ILO --- In FT817@y..., "Ed Juge/NM" <ed@j...> wrote: Julian...whip "review"? Assuming you mean the August issue, I can't find it.There was an article on how to build one a month or so ago. I saw that.be true... and that means it usually is. |
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Ed Juge/NM
Ahhh... okay. I wondered about that. Not sure how much stock to place in
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the conclusions at the end of the building article since it was authored by the guy who is trying to sell them commercially. As I said... anxiously awaiting a "real" review. 73... Ed ----- Original Message -----
From: <g4ilo@...> To: <FT817@...> Sent: Wednesday, July 18, 2001 1:19 AM Subject: [FT817] Re: Miricale whip / MFJ-1621 Portable antenna's I was referring to the article on building the Miracle Whip in theQuestions ) see Please note that your messages and files sent to this group become publicdomain upon submission and may appear anywhere on the Internet or in print without notice or compensation.
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F.B. Nutter, Jr.
I'm happy to see that someone else knows about capture (radiation) area
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in antennas. 72 Fil, W8FIL Don wrote: I think you'll find, when all the hoopla is settled down that the |
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I've ordered one, but it won't ship until August. I won't be too
upset if it doesn't transmit that well. I do a lot of casual listening using the 817 and an HF antenna I can tune just by twisting a knob is something I've been looking for for a long time. Nice thing about the Miracle is that it is continuously tunable, so it will work on the broadcast bands too. Having said that, I suddenly had a brainwave and ordered a PL-259 -> 3/8 adapter which will allow me to mount the MP-1 on the back socket using an elbow adapter. That's also continuously tunable. So perhaps I jumped to get on the Miracle Whip waiting list too soon. Julian, G4ILO --- In FT817@y..., "Ed Juge/NM" <ed@j...> wrote: Ahhh... okay. I wondered about that. Not sure how much stock toplace in the conclusions at the end of the building article since it wasauthored by the guy who is trying to sell them commercially. As I said...anxiously awaiting a "real" review. |
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I have both a MFJ -1621 and MP-1'a and PW-1's. I compared all three
on my K2 817 and the MFJ is down by at least 1 S unit even on receive. I also added a plug for counter poise and tried it with Verns random counter poise and did not improve the performance of the MFJ unit. I made contacts on PW-1 and when I changed to MFJ they could not hear me. It does work OK for a preselector on crystal sets. I have my scouts that are taking the radio nerit badge build crystal sets and the MFJ hepls keep strong signals from overloading detector. IMHO I suspect the Miricale Whip will be similar to MFJ, Verns design is inherantly better desigh. The others are tuned circuits for sure but are not as effective as a loading coil. You can work DX with a light bulb as a antenna, but not too often! .73 Tim O'Rourke KG4CHX |
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