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Discussion in 'Amateur Radio Antennas' started by WA1BXY, Feb 17, 2008.
ANYONE EVER GIVE ONE OF THESE A TRY YET?
Never heard of it. What is it?
And the reviews on Eham.com
Reviews: 34 Average rating: 4.9/5 MSRP: $108 Description: Electrical Half-wave Dipole Antenna
Rotatable - Portable - Stealth - Perfect Backup Antenna
Currently available in 40m, 20m, 10m, and 11m models
Electrical Quarter-wave radiating spiral end elements
Direct feed with 50 ohm coax on resonant band
User selects resonant frequency during tuning process
Can use coax + tuner...or twin lead + tuner
Power tested to 1000 CW watts,
key down for 30 seconds and 1400 Watts PEP
no heat sensed on antenna wire or coax feed point when touched by hand after power testing
NO lossy matching components anyplace in system
10 to 14 dB signal increase in transmit with 90 degree rotation
30 inch boom
Low SWR across band
Sturdy and well built
Weighs only 5 pounds
Uses proprietary #14 gage copper plated alloy wire
Easy assembly - less than 90 minutes
TAK-tenna 40 Multi-Bander also works on 30, 20, 15 and 10 Meters with use of tuner
Tested with Kenwood TS-430 and AT-250 using 50 ohm coax to antenna
Tested with twin lead and other tuner...works fine too
Ah Ha! Now I remember, just didn't remember the thing's name. It's one of those things that are on my 'to-do' list, just haven't gotten that far yet.
Some thoughts and conjectures.
It's a small antenna. Want to say less obtrusive than a full length dipole, but that's debatable . Should be able to be almost over looked cuz it's sort of close to a TV antenna (nuther' debatable thingy). Say it's for HDTV!
It isn't an 'equal' substitute for a 'real-live' antenna, but it's certainly workable as a back-up as claimed by the advertising (I like the fact that 'they' aren't claiming it's the next 'miracle-do-everything-bestest' antenna around). And it can certainly fill an antenna requirement for 'back-up' or those hard to fit places, especially if you don't have the required 'spaces' to start with.
I have no reason to doubt the claims made for this thingy so far. So far, they haven't been that extraordinary, disregarding what the thing looks like. Used with the proper feed line and tuner, the 40 meter version ought'a be usable on bands higher than 40 meters. In that regard, it 'matches' the claims for the G5RV. And also like the G5RV, it don't 'do' miracles.
Like any rotateable 'dipole', it's directional to some extent. Getting it higher than the typical 15-25 foot altitude can't do anything but help that characteristic. I do like the fact that it would only require a 1/4 turn to cover all directions!
Easy to put together? There, I have my doubts, at least for me anyway. I've tried the 'spiral' thingy with other things and it does require paying attention to what you are doing! (Ended up too many times with a gob of spagetti when I've turned loose too soon.) Doesn't sound like it's too difficult though, sort of.
Enough of that. It's still on my 'to-do' list! I wanna see what it'll do. Scale it to size and it ought'a look great for 2 meters on my aluminum foil helmet, don't'cha think??
I was on the air with the guy who makes these on 80m the other night. It's no miracle antenna, but it does radiate. It's a great antenna for people who have no room to work with.
I've seen them up close at the local hamfests, it's solid enough but again, it's not a NASA design. It's plastic tubing for supports and is basically a dipole, center fed with the ends in a spiral. There may be more thought into the dimensions etc for electrical properties, but that's basically what it is.
The guy was running it on a rotor and there was a slight bit of difference within 90 deg turns so it does have some lobes to its pattern.
"10 to 14 dB signal increase in transmit with 90 degree rotation"
that's some funny stuff.
From the night I talked to the guy, it was maybe 1 S-unit as he rotated from peak to dip. Heh, no way it has that level of gain, and I'm close to where he was for sure and he was say an S7 where all the other locals on 100W rigs were S9+10 or better. He was just above the noise level.
maybe there was suppose to be a decimal.
"1.0 to 1.4 dB signal increase in transmit with 90 degree rotation"
that would be more like it. it looks like something comparable to a isotron, which is just as good as a dipole (compared to nothing) just more compact.
What's so funny about it? It does not say the antenna exhibits that much gain. A rotatable dipole will do at least the same thing. Orienting the antenna null towards a station and then rotating it to a peak,even if that peak is down from a dipole, should show a differance of at least 10-14 dB.It is comparing relative losses,not true gains.My external tuned ferrite bar antenna will show better than 30 dB signal increase with a 90 degree rotation on the AM broadcast band. Not bad for an antenna 10 inches long on a wavelength of 200m or more. It's all about the nulls not the gains.
well after all this discusion i have one and its on the tower i see less rx then my windom which is 10ft lower then this antenna and also i see hardley any directivity out of this antenna. as many know i run cw 99.9% of time and on the windom for instance i get an s9 "599" and on this antenna pointing at them away from them on the side no difference i get an s5 to s6"569 559".. so i cant say the it has much directivity. now on foward gain.. once again windom blows it away. i receive 599 and on this antenna i get 549 to same person.. so i does make a great back up portable emergency antenna hands down but for every day use not recomended..
Just like I said,it's not about the gains but the relative losses from peak to nulls.