The tubing I got was from the old junkyard (Carr's) on Taylor St
Montpelier, before Capitol Steel moved to the Junction. I got a big
wooden box full for about what I expected to pay for enough to build one
antenna. It is quite thin, and somewhat brittle. I think there are
three diameters, all about the same tube thickness. It is "harder" than
typical TV elements. I have no idea what the alloy is but it seems
adequate. I lugged it to Hoss-Traders a few times and sold a lot of them
maybe Larry bought some from me?
The +- 5/16' (or maybe it's 3/8") tubes seem to be the best size. The
larger tubes are too big and the smaller tubes bend too easily. I used
a lot of them building the big muti-loop 6m (two loops vertical) and 2M
(four loops vertical) array with Multi-band multi-loop reflector, and
sets of multi-loop directors. It had three short booms for 6M
reflector-driven element distance. So If all four of the wavelength 6M
loops were counted as two 1/2 wl elements it would have the approximate
equivalent of 8 elements on 6M (not bad for a boom about 5' long). The
3, four loop, 2M loop stacks were placed where the old DL6WU
calculations would place them for reflector driven and director. So if
12 loops each count as 2 1/2 wl elements it would have the equivalent of
24 elements on 2M. There is no question... it did not have that kind of
gain... but it worked very well and turned with a TV rotator. It was an
ugly looking thing with bent 1/4" rod at all of the corners held in
place by stainless hose clamps and "split tubing". It was a nightmare
to tune the first time. But it made some long haul QSO's Well past
NYC. I would have to look at the logs, but NJ, Penn, and Maryland come
to mind for both 6M and 2M. The other ends may have been a
mega-stations.... I was running 160W on 2 and 100W on 6. I still have
most of the antenna parts but the wind that broke it up also bent over
the stainless (milking parlor) vertical mast that it was assembled on,
as well as sending parts of elements all over the field. For some
reason my 100W 6M multi-mode doesn't transmit anymore, and the 160W 2M
brick smoked a transistor a long time ago (transmitted into a
defective/shorted MFJ antenna switch), so I have not been on VHF SSB for
quite a while. I no longer use any MFJ switches and will never again use
one.
On 04/26/2017 05:50 PM, GRANT D TAYLOR wrote:
So Ed, did I misunderstand what Cathy proposes?- Sure sounded like she was planning on a Quagi antenna. Maybe she SHOULD plan on a Quagi and thus not worry about 3 foot long driven and reflector elements?
If your tubing came from K1LPS (Which is where my 3 foot pieces came from it's likely NOT 6061-T6 and in any event too light for a 2M antenna that is meant to last. Best to stick with what commercial manufacturers use.
de W1AIM
Fn34uj and elsewhere
On Wed, 26 Apr 2017 15:31:52 -0400
Ed Hutchinson <ehutch@xxxxxxxxx> wrote:
That was 3' not 3" sections....
On 04/26/2017 03:12 PM, Ed Hutchinson wrote:
I think 3' ends up being an inch or two short for driven and reflector elements on 2M anyway. I have lots of 3" sections (more than a hundred) of aluminum tubing (in several small diameters), it is very light and quite strong but a bit hard to work with (and too short for all of the elements of a 2M beam). Most is larger than 1/4".
On 04/26/2017 01:13 PM, GRANT D TAYLOR wrote:
Followup to my email sent to Cathy: I checked the aluminum pile(s) and didn't see any 1/8 aluminum rod. However, thinking back on various antenna projects here, I'd say 1/8 inch is a bit small for anything below 70cm band. Cushcraft, Directive Systems and K1FO all used 3/16" rod.... even on 70cm. And so did I for past antenna construction. For that reason I DO have several 6ft lengths of 3/16" here. Additionally, I have a very large quantity of 3/8" tubing which is what Swan and later KLM used for their antenna elements. Those pieces are all 36" which is too short for a 2M reflector or DE, but with a Quagi would be fine for directors. But it's thin wall and not 6061T-6, so perhaps a bit light for 2M elements, and would need a dowel or reinforcement mid way if it would be bolted to a boom.
If there's a chance any of these antennas might be used on the weak signal part of the band I could perhaps make a donation of either 3/16 or 3/8... Would really like to work someone in addition to W1GHZ for that FN34 multiplier! And Terry, At Directive Systems, could probably sell you some 3/16 rod. Not sure about cost or shipping however.
73,
Chip
W1AIM
FN34uj and elsewhere
On Wed, 26 Apr 2017 01:53:25 +0000 (UTC)
Catherine James <catherine.james@xxxxxxx> wrote:
We need to purchase some 36" rods, 1/8" diamater, for antenna construction. Ideally these would be aluminum, though steel or copper would work. They will become director elements in an 8-element quagi.
I haven't been able to find a place that will sell 36" aluminum rods in 1/8" diameter. I can find them in stainless steel from Grainger or other sources, but they'll be heavier and conduct less well.
Cost is important so that everyone in the club can afford to build one of these antennas.
Any suggestions for sources?
73,
Cathy
N5WVR