I recently posted an inquiry about Force 12 antennas. Unfortunately I erased my original request, but I do have the replies for the masses. The concensus is that the antennas perform & hold up well. The negative for me is that the elements are not at DC ground potential. It would be easy to short the parasitics to ground, but I don't want to butcher the driven elements!! Static discharge is incredible at this QTH due to the dry and windy WX - my HyGain antennas are at least two S units quieter on static than antennas with "isolated from boom" elements. 73, Gator N5RZ rbowen@computek.net Here's the replies: ------------------------------------------------------------ > >At 10:40 AM 4/15/96 -0400, you wrote: >>In a message dated 96-04-15 10:20:07 EDT, you write: >> >>> >>>6) Assembly & associated quality control? "After the sale" support? >>> >>>7) Any other experiences? >>> >> >>Hello Gator,I have 4 of their antennas and seem to be happy with them...but.. >> >>there were missing parts,outdated assembly manuals,poor before sale support >>and about the same after the sale..and late delivery time.. >> >>Tom is a nice guy and I know what he is going through as I have my own small >>buseness and have the same type of problems as there is not enough time for >>Me to do it all..This is not an excuse,but a fact when a buseness grows >>faster than expected..at least I like the antennas!! >>I wish Force 12 well and hope they get their act together soon.. >>good luck.. >> >> >---------------------------------------------------------------------- > >At 08:53 AM 4/15/96 -0500, you wrote: >>Hi All: >> >>I've been re-evluating my antenna setup over the past few months. It looks >>like in the scheme of my reconfiguration, the Force 12 C-4SXL (2el 40 + core >>C3 on a single 23' boom) may be a good replacement for my Cushcraft 402CD at >>112'. >> >>Does anyone have experience with this antenna? I am looking for both >>electrical and mechanical performance items including but not limited to the >>following: >> >>1) Bandwidth on all bands. Especially on 40M. Perfomance on the >>"non-chosen" mode? > >Force 12 states that the only high-band swr-bandwidth compromise for the >C-3S/C-4SXL is with high-end 10-meter bandwidth. I think they quote SWR >bandwidth for the 40-meter loaded dipoles in their catalogue. For what it's >worth, their specs were right on the money with my C-3. > >It'd be interesting to try their 2-el 40 on a range, or at least to model >it. There's a fair bit of degradation of F/B across 20 meters on the C-3, >which is full-sized, so it stands to reason that the shortened 40 would be >worse.\ > >> > >>2) Any comparisons to other 40M antennas? >> >>3) Mechanical considerations? Any of you had these antennas go through a >>nasty windstorm? >> >My C-3 went through a fairly substantial ice-storm this winter. It appeared >to follow the bend-but-don't break philosophy. At one point the 20-meter >elements were bending about 30 degrees. You can get any of their antennas >ruggedized for higher wind rating, I believe. > > >>4) I would like to continue using my T2X - good enough for this antenna? >> > >Should be - they're very light. > >>5) Are the elements (incuding driven element) at DC ground potential? > >No -- all of the elements are insulated from the boom. > >Other >>experiences with the feed systems? > >The C-3 feed system couldn't be simpler - you just drive the 20-meter driven >element directly from the 1:1 current balun. It really is a 50-ohm >feedpoint, and since the C4SXL uses two feedlines, it oughta look like a C-3 >on 20-10. > >I have no info on the 40-meter dipole feed system, but plan to order one >this summer to install on my C-3, turning it into a C-4. Unfortunately, the >C-4 to C4XL or C4-SXL conversion isn't a field mod. Ah well ... > >> >>6) Assembly & associated quality control? "After the sale" support? > >Mostly very positive. I can't imagine ever using anything but pop rivets >again to assemble elements. Easy and fast, and even if you screw up they're >easy to drill out and replace. I also love the boom to element brackets, >which are pop riveted at the factory for perfect alignment, and the cast >aluminum boom-to-mast mount that really makes it easy to get the antenna up >on the mast. > >Also in their favor is the fact that their antennas are test-assembled at >the factory and mating sections are all marked. However ... on my antenna >the pop-rivet holes were evidently hand-drilled, and fairly random. No >harm, no foul, because as long as you got the pieces together, everything >fit, but it looked a little scrappy. Some people also worry about the >effect of sunlight on the pvc pipe that they use to insulate the elements. >Guess it's too soon to know. > >> >>7) Any other experiences? >> >I've found N6BT very accessible and ready to talk about his designs. On >the other hand, I know they have had delivery problems so you probably >shouldn't count on their quoted lead-times. > >----------------------------------------------------------------------------- > >In a message dated 96-04-15 10:20:03 EDT, you write: >>Does anyone have experience with this antenna? I am looking for both >>electrical and mechanical performance items including but not limited to the >>following: > >Hiya, Ralph -- > > I've spent a bunch of time in the last year with Tom Schiller, installed >several of his antennas (a C-4XLD in about 10 days) and have recently become >a Force 12 dealer. To make a long story short, I feel that the era of the >trapped antenna is coming to a close with the advent of new trapless designs >such as F12. I've talked to a number of users and they all think that >they're great (add in a little "newness" factor). If you believe what Tom >says about his antennas and his competitors, he does make a pretty good case >for them. >>1) Bandwidth on all bands. Especially on 40M. Perfomance on the >"non-chosen" mode? > > WA7FOE@aol.com has a 3L. Ron likes it and has a 4 vertical phased >array to compare it with. >>2) Any comparisons to other 40M antennas? > > More efficient electrical design with low profile mechanical design. > You've got to discount the F12 gain figures because Tom adds ground gain to >the final number. > >>3) Mechanical considerations? Any of you had these antennas go through a >>nasty windstorm? > > I've heard that Dick K5IU doesn't think that they'll last in Texas but a >big storm (134 MPH winds) in Schiller's county resulted in only one minor >mechanical breakdown of his installed antennas. The F12's are made out of >smaller tubing ala the Cushcraft approach (just let they whip around in the >wind and shed the wind load) and the 3L 40M was the first one that I've ever >been able to pick up myself. > >ld like to continue using my T2X - good enough for this antenna? > > Shouldn't be a problem. >>5) Are the elements (incuding driven element) at DC ground potential? Other >>experiences with the feed systems? > > Don't remember but will look closely when I install the C-4. >>6) Assembly & associated quality control? "After the sale" support? >> > No big problems that I'm aware of except delivery. BTW, the elements >are riveted together so you don't have to measure anything except the 40M >portion. > >------------------------------------------------------------------------------ > >I have no direct experience with them but have seen the arrays at KC2X's >place - he has about a half dozen of their products....they take a different >approach to antenna design than the one I was reared on...they use >lightweight and low wind resistance (i.e. smaller tubing) as better....I am >used to the Telrex mentality using the next size up to ensure it won't >QFU....of course all our antennas weigh a ton! > >The use of severe tapering appears to be a good thing, they use lots of >tapers every few feet creating elements which seem to bounce around >less...they are less likely to go boing when flexed...(that's pronounced >boy-ingk)...when they flex they just seem to fall back to their resting >position without jumpin around. I like that feature. > >The monobanders KC2X has are direct fed, the coax goes straight to the driven >element - no gammas/or any other matching technique....I am not electrically >savvy so I do not know how they pull this off....but the simpler something >that is mechanical in nature is the fewer problems there should be down the >road , it would seem. > >I don't know ship about this antenna but despite the fact that everybody gets >shitty delivery on F12 antennas, always late, they all say they would buy >them again....they must be doing something right! > >------------------------------------------------------------------------------ > >I have a C4XL on the30' boom at 70' and an 80 meter rotatable dipole above it >on a restricted lot. I replaced a KT 34 XA and a 40-2CD. >I think that the 40-2CD is a bit better for 40, I found bandwidth from 7.0 to >7.250 was within acceptable limits. As I remember < 2:1. I also found the >40-2CD a bit better on 17 and 12 meters. I got most states and over 100 >countries with it, although it does not compare to a mono bander for those >bands. >I cannot speak to anyother 40 meter antennae other than my old folded dipole, >no comparison HI >I put up these antennae last summer and we have had some good wwinds this >past winter, although "nasty" I don't know, no tornadoes HI. >T2X, is that a Tailtwister ?? If so, no problem, that is what I use. >There is no isolation except for the driven elements and they are fed thru a >balun. Above all this I have a 26' dual band vhf vertical. So I guess that >thru teh metal to the rotor etc most is at ground potential. >Force 12's are very easy to asemble, but get a rivet puller from Sears, half >the price that they ask at F12. Everything was there and well done. As for >after service support, have not had any reason to find out. >Would rather have monos, but for a combination such as mine, it seems to do >well. > >------------------------------------------------------------------------------- > >>1) Bandwidth on all bands. Especially on 40M. Perfomance on the >>"non-chosen" mode? > >mmmmm - I wonder about this myself. The 40m dipole on the C-4 >does only about 130khz. > >>2) Any comparisons to other 40M antennas? > >It seems to work. > >>3) Mechanical considerations? Any of you had these antennas go through a >>nasty windstorm? > >Not yet but I think it would hold up. > >>4) I would like to continue using my T2X - good enough for this >antenna? > >I dont see why not - the Force 12s are light and very low profile. > >>5) Are the elements (incuding driven element) at DC ground potential? Other >>experiences with the feed systems? > >Nope - they are ALL insulated. I didnt know this and I am >not sure I like it. > >>6) Assembly & associated quality control? "After the sale" support? > >I was VERY impressed while putting the antenna together. I never >used the tape measure. The rivets are GREAT. > >The bandwidth was better then they said it would be on 10/15/20. >The 40m part looks a little hokey and I think I still like >the cushcraft better but they do seem to stay up and it is >all on one boom. If I were putting up antennas it would be >very high on my list of choices. We went with the C-4 at >UT because of the low wind load and getting 10-15-20-40 all >on one boom allowing us to stack 2m and 6m yagis on the mast >without crowding. I am impressed. > >------------------------------------------------------------------------------- > >Hi Gator. I have a c4sxl at about 70' (but on sloping ground so height in >some directions is less). I replaced a Force 12 stack with it and an 80 m >dipole and a c3s at 35' for stacking. It's hard to evaluate the >effectiveness on 40. It is certainly better than my former inverted vee >(with apex at about 55'), but I don't notice the dramatic difference that I >did notice comparing the 80m inverted vee to the rotatable dipole. I think >that is probably because the 80m ant is at a lower height in wavelengths, so >the inv. vee was a poor performer compared to the rotatable diple only 10' >higher than the vee's apex.. > Mechanically it is very strong, though I've only had it up since last >November and we haven't haad any horrible wind storms since then. A T2 >should turn it easily. I have it tuned for CW, but it runs easily thru a >tuner on phone. Generally speaking, all force 12 designs are excellent both >mechanically and electrically, in my experience. > Due to it's smaller size, I doubt the c4sxl will outperform a 402cd, but >you do get the other bands also. Let me know if I can give you more info. > >----------------------------------------------------------------------------- > > >Just got back from Visalia '96. (Funny, seems like I saw YOU there the last >time I attended in 1993...) > >The Force 12 boys had their crankup on display with the beam you mentioned. >It looks cool, lots of wierd looking elements on a reasonably long boom. > >However, the thing looks awful fragile. The 40M elements are about the dia- >meter of the elements on my homebrew 15M beams - no kidding! Force 12 >obviously is counting on the linear loading trusses to hold things up. > >I would never consider installing one of these antennas up here in W8. The >ice would kill it, particularly if it collects on the truss wires. A >Cushcraft 40-2CD looks like a Telrex in comparison... > >Just my opinion - I'd hate to have N5RZ QRT due to wx damage. > > > >