Manager


Manager - NA4M
Manager Notes
Reviews Home

Reviews For: Force 12 Sigma-5 vertical dipole

Category: Antennas: HF: Verticals; Wire; Loop

eMail Subscription

Registered users are allowed to subscribe to specific review topics and receive eMail notifications when new reviews are posted.
Review Summary For : Force 12 Sigma-5 vertical dipole
Reviews: 7MSRP: 349.00
Description:
The Sigma 5 is a true Vertical Dipole,  covering 20-17-15-12-10 Meters  -  It has NO Traps,  and is >90% Efficient all bands. Rated at 1,200 w PEP SSB, 700w CW.
At 9' tall,  with an 18" Base Post it's the answer to neighbor and zoning problems. There are NO Radials, and SWR's  are - <1.8:1 on 17-10m, >300 kHz on 20 mtrs. It  comes in 2' Sections for easy shipping, and DX-pedition use. Free Standing, 7 Pounds weight. Simple Assembly - NO Tools - Pre-tuned
Product is in production
More Info: http://www.qth.com/force12
# last 180 days Avg. Rating last 180 days Total reviews Avg. overall rating
0074
N6GEO Rating: 2017-01-22
Good "surf" antenna Time Owned: 0 to 3 months.
I've successfully used a vertical dipole off the bow of my cruiser during CQP and was amazed at how well it performed. I also own a TW4010, so I was happy to recently score a Sigma 5 off of Craigslist for a reasonable price. Mine must have been an early production unit because I found it was badly out of tune and wouldn't match in the correct bands. I ultimately realized the cable color code was in a reverse order to the manual (cable mis-wired at the antenna end). I also found my 15M coils had 5 turns. Looking at Scott Andersen's "Antennas For 100lb DXpeditions", on page 41 (Figure 44) you can see that his 15M coil has only 4 winds. I snipped a loop and now I resonate on 20, 17, 15, and 10M. 24M is still too low by 400kHz and my windings like Andersen's are spread wide. I suspect that this coil too should be shorter although I'm thinking I should calculate something of slightly smaller diameter with the same number of turns. It's a neat antenna, however you've got to be willing to fiddle with it. And if you take it on a DXpedition, don't forget your VNA!
K1QF Rating: 2008-04-20
Disappointed Time Owned: 0 to 3 months.
This product is advertised as "Simple assembly - No tools - Pretuned." The quality of workmanship is extremely disappointing. Three of the four T-bars would not seat in their receptacles. Bolt holes were misaligned. Working with a file, electric drill, and vice grips I finally got it together after almost an hour of repairs and adjustments. It did tune and for that I am grateful.

All in all it looks like a wobbly 8th grade shop project. There appears to be no guarantee or reasonable return policy - otherwise I would send it back.
WV4R Rating: 2004-01-02
Shorty antenna with Quickie Setup time... Time Owned: more than 12 months.
I have had my Sigma5 for about a year now. It comes with 50 foot of control cable which is fine for portable use in the field but No quick connectors on Either end, makes Adding additional cable a dog and pony soldering show and clumsy to pack and coil and uncoil. Out of the box, my unit had objectionably HI SWR. I called Tom, and he sent a Coil Set MOD by return mail and it tuned just fine After a tricky disassembly and soldering show. The center section is THE critical component. This section was Not sealed so just about anything might get into it over time in a permanent outdoor installation. Also, the unit Defaults to 20m when Unpowered and Requires Continuous 12vdc applied to the Relay Bank for all other bands! The assembled unit did not have a Solid Feel to it... I would describe it as just a bit Flimsy for a 'knock-down' unit expecting many assemblies and some hard handling and/or high wind conditions. For it's relatively High cost, I wud have expected just a bit More engineering and design in the unit. So this unit earns a very strong "3" star rating. 73 es God bless, murf/wv4r.
K0COM Rating: 2002-12-02
Very happy with this antenna! Time Owned: 3 to 6 months.
Moved to a CC&R home in the Denver area. Left a 60ft tower and a TH-11 beam behind in the move. I thought the world had ended! I almost sold all my gear. Well, thanks to the Sigm-5 vertical, I'm back to believing there is always hope.

The Sigma 5, along with all my antenna's, are mounted in the attic. As luck would have it, my wife and I found a two store home with a BIG attic. Our entire lot is only 100 x 70 and it's mostly house. CC&R's say no outside tranmitting antenna's in any way. The attic has a 10 ft joice to peak clearance so the antenna just fit. I had to work on the SWR for most all bands, most likely due to being about 25 ft up and in an attic. However, I found a good match on all bands! I mostly run 200 watts from my IC775 and have experienced very good results. Not the DX antenna i was used to, but I did add CY0MM to my worked list this last month.

I have run legal limit and have experienced no RF or interferrence issues considering the location. All in all, I'd recommend this antenna to a friend. good qualtity, easy to assemble, and great performance in just 9ft. in height.

All my contacts can't believe it when I tell them what I'm using.
KA6DWN Rating: 2002-03-01
Excellent Antenna Time Owned: 0 to 3 months.
If your situation is like many of us (CCNR’s, limited space, etc), you may want to look at the Sigma 5 antenna from Force 12. My backyard is only 20’x 50’. I have no space for a dipole like the Windom or G5RV. My only choice was a vertical type antenna. I looked at the Butternut series antennas but read all the posts regarding difficulty tuning and all the radials needed.

The Sigma 5 (vertical dipole, center feed) is only 9ft tall, no radials, no tools, no TUNER and goes up in 5 minutes or less. Efficiently is greater than 95%! I don’t think the other guys can do this! My antenna is mounted in a 5-gallon paint can. I used a 1” OD PCV pipe which the antenna slides right in. I have the option of taking the antenna apart and storing it away. The Sigma 5 is pre-tuned from the factory. It covers 5 bands from 10-20M.

My SWR reading were:

10M 28 MHz 1.1 & 29.7 MHz 1.5
12M 24.89 – 24.99 1.1
15M 21.0 MHz 1.3 & 21.45 MHz 1.7
17M 18.07 MHz 1.2 & 18.168 MHz 1.3
20M 14.0 MHz 3.0, 14.2 MHz 1.3 & 14.35 MHz 2:1. (You can adjust the center frequency for 20M band).

Quality and fit/finish are excellent. The only thing to watch out for is the mounting location. Try to locate the antenna away from the house or fence. Use good quality RG8 type coax. The antenna requires 12V DC 95mA for band control.

My 2nd contact with the Sigma 5 was in the Czeck Republic on 15M. Not bad for a 9ft antenna!!! My next antenna will be the Sigma 40! My hats off to Tom at Force 12 for making a simple and usable antenna!
AD6TF Rating: 2001-10-29
Cool Performance Time Owned: 3 to 6 months.
We used this antenna during 4M1X dxpedition in July 2001 (SA-089). This ant was specifically used for CW operation, and we were able to put this ant up in 5 minutes by using some plastic ties with existing wood pile. Signals from EU and NA were extremely loud, i even worked my country VU2PAI on CW (RST=599). I plan to take this to my VU expedition. Well Done job Tom.

Jig AD6TF
AA7DG Rating: 2001-10-14
The best vertical I have owned! Time Owned: 3 to 6 months.
I have owned several vertical antennas over my 45 years as a ham, and I can honestly say this is the best of the bunch.