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G8MNY > TECH 07.10.24 07:52l 73 Lines 3542 Bytes #999 (0) @ WW
BID : 17475_GB7CIP
Read: GUEST
Subj: 70cm 27el G3JVL's QLY
Path: IZ3LSV<I0OJJ<GB7CIP
Sent: 241007/0649Z @:GB7CIP.#32.GBR.EURO #:17475 [Caterham Surrey GBR]
From: G8MNY@GB7CIP.#32.GBR.EURO
To : TECH@WW
By G8MNY (Updated Nov 18)
(8 Bit ASCII graphics use code page 437 or 850, Terminal Font)
This is a large horizontally polarised beam with about 20dBd gain! It came out
best in a club garden range test, compaired with other very long boom yagies &
multibeams.
# 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27
# ()()()() () () () () () () () () () () () () () () () () () () () () () () ()
~~~~~n~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
The elements are all 1/8" plated steel loops welded to 2BA bolts to the 3
section 32mm dia ally tube boom.
The driven element is braised on to the round N socket (N Barrel?), then it is
dropped onto a large hole in the boom & a screw fixes it some how & the top all
mastic sealed. There is no need for baluns on QLY as the fraction of a degree
off the horizontal due to inbalance is no loss at all! SWR in mine is still a
good 1:1 after many years!
The boom has three 1/8" thick strip tags weld to it, 1.5" tall & 2" wide for
the 2 ends, with the middle one is 3" wide for a 2" U exhaust clamp.
Reflector 2 is large slotted ally plate (less wind loading) welded up from 39cm
wide strips with vertical support strips to make a 36cm tall reflector & it has
a welded on plug that fits the tube for mounting.
Support struts are 2x 1400x 20mm ally tube flattened & drilled at ends for the
2BA bolts to the welded on ally tags & central 2" U exhaust clamp. Needing
55cm of mast for the support struts.
Ref
2 ---------------------------- D i r e c t o r s -----------------------
Ý 1 D 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 29 21 22 23 24 25
Ý ³ ³ ³ ³ ³ ³ ³ ³ ³ ³ ³ ³ ³ ³ ³ ³ ³ ³ ³ ³ ³ ³ ³ ³ ³ ³ ³
Ý ³ ³ ³ ³ ³ ³ ³ ³ ³ ³ ³ ³ ³ ³ ³ ³ ³ ³ ³ ³ ³ ³ ³ ³ ³ ³ ³
ßßßßÛßßßßßßßßßßßßßßßßÛßßßßßßßß ßßßßÛÛßßßßßßßßßßßßßÛßßß ßßßßßßßßßßßßßßßßßßßßßß
N ~Ä-.._ u _..-Ä~
~Ä-.._ u _..-Ä~
~ßß~
I had measured my one in case I lost a bit. Here are the measurements, all
elements loops taper down in size, so only some of the loop lengths were
measured.
From Loop From Loop
Element End mm Length mm Element End mm Length mm
Reflector 2 0 390x360 Director 12 263
Reflector 1 24 730 Director 13 290
Loop Dipole 31 700 Director 14 317
Director 1 40 630 Director 15 344
Director 2 46 Director 16 371
Director 3 59 Support Tab 383
Director 4 73 Director 17 398
Director 5 82 2nd Joint 408
Director 6 100 Director 18 425 615
Support Tab 117 Director 19 452
Director 7 127 625 Director 20 479
Director 8 154 Director 21 506
Director 9 181 Director 22 533
1st Joint 195 Director 23 560
Director 10 208 Director 24 588
Director 11 235 620 Director 25 615 585
Centre mount 250 End of boom 617
Why Don't U send an interesting bul?
73 De John, G8MNY @ GB7CIP
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