if a 1.5" wider than the boom 1/4" thick 6061 plate (3/4" each side) was
u-bolted permanently to the boom at each element position then clevis
pins could go thru each element and the plate, with a hairpin clip to
hold the pin. U-bolt holes and clevis pin holes separated just enough
to clear the element. One u-bolt should be ok for small - mid size
yagis. Fine adjustment with washers under the clevis head to get a
closer fit.
https://www.mcmaster.com/#clevis-pins/=15q85r2
https://www.mcmaster.com/#standard-hairpin-cotter-pins/=15q88o5
Electrically that is probably ok except for the driven element where
thru bolts and a FR4 boom plate is needed.
This would work on the A4's we use for FD since the elements are drilled
thru for the u-bolts and those holes clear the boom. Enthusiastic u-bolt
tighteners have been known to crush the element tubing, so I have
sleeved all of them internally. With this mount never again a problem.
Use a DX Eng saddle u-bolt on the boom plate and the elements will
always be as co-planer as you make them. Might work for other yagis.
Then there is never an issue with getting the spacing wrong, just
putting the correct elements in the right place, one of which is always
wrong first try at our FD with one A4 cut for CW and a second for SSB.
HNY to all,
Grant KZ1W
On 1/1/2017 7:59 AM, Tom Hellem wrote:
Hi All-
Our radio club is building a yagi to be used mostly for Field Day type
setups.
It's modeled upon the F-12 C-3 line, with the difference being we are not
crazy about the element to boom mounting method with the u-bolts. I would
like to come up with something that is MUCH faster to assemble and
dis-assemble.
We have a few ideas but would sure like to know of any others out there.
Do any of you have some that you would be willing to share with us and the
group?
73 and HNY to all.
Tom
K0SN
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