[TowerTalk] Need recommendations for a 40-10m. Yagi
wes_n7ws at triconet.org
Sun May 6 16:08:06 EDT 2018
I have a little OB7-3 that I bought never assembled, still in the box, from a
contester friend who was going to use it for a "multiplier" antenna. He changed
his mind and sold it to me for half what he paid for it, which was still pricey
I had an issue with QC and wrote a review on eham documenting it. I immediately
got an email from "blue ocean", not trying to rectify the issue, but accusing me
of improperly storing the antenna. Since it had been in my friend's garage
(along with several German cars), in the still strapped carton, I disagreed. He
continued to give me so much grief, I asked that the review be removed.
Even with the very short boom, there is a bit if sag at the joint, and yes, the
boom to mast clamps are similar to muffler clamps. The way the elements are
assembled in my opinion makes swaging unnecessary and the loose fit makes it
easy to telescope the tubing for shipping purposes. I can't fault the
operational performance and it models well, but I wouldn't buy another OptBeam.
On 5/6/2018 11:31 AM, john at kk9a.com wrote:
> On my OptiBeam 40m antennas there is no swaging, just a bolt that goes
> though the element. The square boom mounts to the aluminum plate with a
> square u-bolt and it's impossible for the mast to spin. The boom to boom
> joints were just a couple of internal plates. I have had no issues with any
> of these things but perhaps they are with larger beams. Momobeam uses a
> similar square boom except they have slots in the boom for coupling and I
> have recently seen one that moved out of alignment. I agree that finding
> metric tubing in the US is very difficult. Since DX Engineering now sells
> OptiBeam perhaps they can obtain replacement parts. I always found OptiBeam
> owner, DF2BO to be a pleasure to work with.
> John KK9A
> Jim Thomson VE7RF wrote:
> ## Several folks have had severe issues with the way optibeam splices
> their square boom sections together. I dont like their boom to mast
> assys, it uses 2 x muffler clamps for the mast. Nobody uses muffler
> clamps for anything these days, esp the types with sheet metal saddles, as
> depicted. https://www.dxengineering.com/parts/dbo-ob12-4w-p JKs
> version wont budge or slip on any mast. Optibeam uses METRIC tubing
> sizes for the elements..and also the square and also their round booms.
> Unlike 6063-T832, 39 ksi yield strength...... or 6061-T6, which uses 40
> ksi yield strength..and both using standard tubing sizes and wall thickness,
> METRIC tubing does not telescope with a snug fit. They make a sloppy fit
> and have to be either shimmed, or swaged.... pita. The deal breaker for
> myself is that METRIC tubing is a bitch to find in Both Canada..and the
> USA. A buddy finally found one source for metric tubing in the usa....and
> it was special order, and expensive. That may have changed. So even if
> you can find replacement METRIC tubing in the usa, next up you will have to
> get the ends carefully swaged. Any swaging process has to be done dead one.
> Too little or too much, and you are in trouble..esp if too much.
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