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Reviews Categories | Antennas: HF: Vertical, Wire, Loop | Force 12 Sigma GT5 vertical dipole Help


Reviews Summary for Force 12 Sigma GT5 vertical dipole
Reviews: 4 Average rating: 3.8/5 MSRP: $379.00
Description: "The Sigma-GT5 is a heavy duty model of the Sigma-5. It is constructed in 4' lengths, using the larger diameter and thicker wall tubing as in the Sigma-SV5. By the way, the "GT" in Sigma-GT5 stands for "Garden Trellis", as this antenna is strong enough to hang small pots from it in the garden!"
Product is in production.
More info: http://force12inc.com/sigmasv5gt5info-002.htm
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You can write your own review of the Force 12 Sigma GT5 vertical dipole.

K2STV Rating: 0/5 Jun 19, 2012 12:56 Send this review to a friend
Very poor quality!  Time owned: 0 to 3 months
Let me start off by saying that this antenna works like gangbusters!

However, the construction is less than that of an amateur. I dare say you can build this antenna yourself for less than $150, and do a far better job.

To give a clue of what I found was that the box this antenna was shipped in was full of metal shavings. The relay board was not wired as the picture in the manual and due to very poor workmanship arced over when transmitting on 20 meters, and burnt the PCB. The relay board housing is made of PVC pipe and looks like someone knawed it out with false teeth.

I spoke to Mark at Force 12, and it took over a month to send me a new relay board to replace the one that burnt up. This new board was made the same way as the first, and many of the jumpers were burnt with a soldering iron, some burnt down to the wire. I have totally rewired this board and now it is OK.

I do not understand how a company expects to remain in business with such sloppy workmanship!
 
W7GSA Rating: 5/5 Dec 16, 2007 12:16 Send this review to a friend
One Really Great Antenna  Time owned: 6 to 12 months
Most commercially build antennas are over priced and over rated. This one is not. It's build like a tank and preforms like a champ. They should change the name of it from GT-5 to Pile-Up-Buster.
 
NI0C Rating: 5/5 Apr 23, 2007 10:05 Send this review to a friend
Space saving, with good performance  Time owned: 0 to 3 months
After spending several years almost exclusively on the lower bands (160-30m), I wanted something small to add to the backyard for operating the higher frequency bands during the spring and summer months. Another requirement for me was good DX performance with no radials, as I can only deploy radials during the cold weather months (due to our gardens and backyard swimming pool). Vertical dipoles work outstandingly well with no radials.

My son has been using the lighter version (Sigma 5) for several years in his restricted neighborhood, trotting it out from its storage location in the garage. I wanted a more permanent installation, so the GT-5 was the perfect solution for me.

Mine required a couple of tuning adjustements to the 20m coils only to obtain a satisfactory resonance. I also put a bead of coax seal on the top of the PVC coil assembly to keep rain out. If you use a heavy coax cable (I use Buryflex 9914) and try to maintain a somewhat horizontal run (which F12 recommends), you may find it desirable to add a small guy rope opposite the feedpoint to help keep the antenna vertical.

I experimented with several ground mounts, and ended up with the T-bars about seven feet above ground. I didn't want it too high; otherwise the low angle pattern suffers, but I was concerned about safety in the backyard, too.

So, how does it perform? I'm pleased so far, having broken pileups on N8S on three bands with it.

This antenna takes up so little space, and is so unobtrusive, almost anyone could find room for it.


 
WA4DQS Rating: 5/5 May 3, 2003 02:20 Send this review to a friend
Handy solution  Time owned: 0 to 3 months
Iím new to HF, I live in the Los Angeles, California area, on the top floor of a two story duplex, and I had to find a reasonably compact HF antenna solution to get me by until I buy a house and upgrade. Ground radials, dipoles, guy wires, towers and high profile antennas are currently not options. And there is far too much metal, plumbing and wiring in my attic, so no attic dipoles either.

Online research led me to the Sigma GT5 and a few others that I considered.

I chose the Sigma based off of reviews, and also because Iíd read an article the antennaís designer wrote, and I liked the way he thought. I chose the GT5 over the Sigma 5 because I liked the added strength factor.

Although the cost wasnít a real issue, the price did seem high for something that is ostensibly hand-made, and extremely simple Ė aluminum poles, a crude PVC casing for the coils and relays, and two fiberglass insulators. But I wasnít complaining once I had assembled it with no tools in, literally, a few minutes. And although Iíve still got a lot of work to do on the air, so far Iím not complaining about itís performance.

My rig is an Icom 756 Pro II, stock mic, stock power (100w). Iíve got the GT5 mounted just over 20 feet above the ground Ė a situation the manual recommends avoiding since operating it at this height results in a secondary lobe with a very high take-off angle, and increased SWR.

It seems silly to boast of signal reports or breaking through pileups since so much else can affect all that. But when you consider that I would have been perfectly happy if all I could manage for now, at this troublesome location, is 17 and 20 meter contacts with my brother 1,500 miles or so out to sea, then you can see why Iím happy when a guy in Russia gives me a 5-5 on 20 meters, or a ham in Florida gives me 5-9, or another ham on the beach in Puerto Rico, running an old rig on his car battery, also gives me a 5-5 on 17 meters at a time when band conditions seem to be fading Ė and rainwater had increased my SWR some.

Even at this height, with plenty of metal pipes, vents and a TV antenna on the roof, the SWR is very close to those claimed by the manufacturer.

The really great thing about this antenna is that it very easily and quickly breaks-down into a very compact package for transport and portable use*.

I suspect it will accompany me on many camping trips, and I will forever relax in the knowledge that wherever I live, no matter how restrictive the situation, I can probably find a place to put the GT5 and get on the air.

I wanted something that was effective, low profile, rugged and easily portable. I seem to have gotten just that. One day Iíll buy a house where I can pollute the skyline with some serious metal. Until then, Iíll gladly lay low with this simple and functional vertical.

*To further facilitate portable use, I did make one modification; I bought a second 50í length of coax, and a second 50í length of 5-wire relay control cable and added 5-pin plugs to either ends of the five-wire relay control cables. This lets me literally unplug the antenna and control box and operate the antenna at my campsite from the second set of plug-in cables. This spares me the hassle of removing the carefully routed home cables (the control cable comes from Force 12 permanently attached to the antenna) every time I want to take it camping.

John
WA4DQS
 


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