Phasing 6M & 2M Yagis
Jim Aguirre
am pondering whether to phase each pair using a 2-port power divider
(appropriate for each frequency, of course) or to simply use multiple
quarter-wavelength sections of 75-Ohm coax into a Tee.
If the latter, is there anything readily available that's better than
RG11 for phasing sections? I want to be capable of full KW operation
on both bands.
Using 75-Ohm phasing lines is the least expensive alternative (from a
cash standpoint) but I suspect a power divider might have less loss.
Not sure on that; hence the question.
Anybody got any ideas for me to chew on?
Jim Aguirre, W7DHC
Daly, Greg
with..... Easy to deal with, with hand tools, long life out in the
weather, and phase stable as long as you don't get too crazy with sharp
bend radius
http://www.timesmicrowave.com/content/pdf/lmr/100-103.pdf
http://www.timesmicrowave.com/content/pdf/lmr/96-99.pdf
If you can damage LMR-600 size cable with legal ham kind of power, I'll
be impressed ;-) They claim .9 dB / 100 feet at 150 MHz and average
power spec of 2KW. There are several vendors on line that sell Times
products. Your mileage may vary.
I've also fooled with the LMR-400 size 75 ohm cable. The connectors are
a lot cheaper for LMR-400 / RG11 / RG8 size cable..... If I had far to
go, I'd throw $$ at the transmission line first, then refine the antenna
phasing cables..... If I win the Power ball, it's BIG Heliax to a power
splitter and carefully matched BIG Heliax to each of the antennas.
What do you do about getting around the rotator?
73 DE WB7RSG
Gregory P. Daly
TriQuint Semiconductor
mailto:gd...@tqs.com
Bill W5WVO
> If I win the Power ball, it's BIG Heliax to a power splitter
> and carefully matched BIG Heliax to each of the antennas.
>
> What do you do about getting around the rotator?
I use a modified 6-meter StackMatch II to phase my two 6M yagis. It's
mounted between the two antennas on the mast, and I run Belden 9913F7
flexible coax down to the loop around the rotator. This stuff is very
flexible; the Davis RF Bury-Flex coax is not a substitute for use in a
rotator loop; it's too stiff. (Don't know how flexible the Times coax is;
have never used it.) After trying the Bury-Flex once, I now stick with
Belden 9913F7. Just a lot easier to work with in every way. I'm OK with
paying a little more for it.
If I was running heliax from the shack (which I would if I had a long way to
go, even at 50 MHz), I'd probably just run it up to the point where I had to
make the rotator loop, then run 9913F7 from there on up to the StackMatch
and out to the yagis. I really doubt that using hardline anywhere above the
rotator loop would save you more than a few hundredths of a dB. Really not
worth the trouble IMO.
Bill W5WVO
Tree
>
> Daly, Greg wrote:
>
> > If I win the Power ball, it's BIG Heliax to a power splitter
> > and carefully matched BIG Heliax to each of the antennas.
> >
> > What do you do about getting around the rotator?
>
> I use a modified 6-meter StackMatch II to phase my two 6M yagis. It's
> mounted between the two antennas on the mast, and I run Belden 9913F7
> flexible coax down to the loop around the rotator. This stuff is very
> flexible; the Davis RF Bury-Flex coax is not a substitute for use in a
> rotator loop; it's too stiff. (Don't know how flexible the Times coax is;
> have never used it.) After trying the Bury-Flex once, I now stick with
> Belden 9913F7. Just a lot easier to work with in every way. I'm OK with
> paying a little more for it.
Are you going to continue using the stackmatch? If you are, as long as you
have equal (in electrical length) lengths of 50 Ohm coax from it to the beams
you should be in phase. I would consider that the better solution than a
power divider - since you have the flexability to use three different
antenna configurations.
Tree
Bill W5WVO
did on it to allow me to include 180-degree phasing, to optionally give me
the higher take-off angle (for those rare, really intense Es openings that
produce very short skip of 300-400 miles). It works!
I cut the equal-length coax runs to the yagis, as well as the
half-wavelength delay line that is part of the 180-degree mod, using the
MFJ-259B. Worked well, though not terribly repeatable to within less than
half an inch or so. I don't think it's accurate enough to do any better than
using a ruler and assuming a constant velocity factor. :-) Once again, I
tend to trust the Belden 9913F7 to be as consistent as you can get in this
size coax.
Bill W5WVO
cn85be
Go with the 75 Ohm line. Forget the connectors and Tee, just solder it all
together, as close as you can. With two antennas, the feed and two
transformers form a nice triangle when run parallel to each other. Here you
may also include a ground strap to your mast member if you want. Wrap them
all with a few turns of copper wire for a good low inductance and resistive
joint then solder the whole affair. Bring the centers all together in a
uniform manner and solder, as short as you can with reasonable air space
from the center, a quarter inch radius is lovely. Waterproof your work. You
will find this a lower loss system, especially at 144 where that Tee and
connector affair can cost you a 0.5 dB with even a little corrosion. I
prefer this arrangement to the Combiner/Divider schemes. At 432 and up,
ladder line is great too, really low noise temperature over those power
dividers and coax!
73 Jeremy w7eme
-----Original Message-----
From: PNW...@googlegroups.com [mailto:PNW...@googlegroups.com]On Behalf Of
Jim Aguirre
Sent: Monday, August 28, 2006 13:33 PM
To: pnw...@googlegroups.com
Edward R. Cole
is minimal.
On my 2m eme 4x 3WL yagis: I run 7/8-inch Heliax to the tower top below
the az-el rotors. I run LMR-400UF around the rotation points and from my
M2 4-way divider I run eight runs of 18-foot of LMR-400 (slightly better
loss than the UF version). If I were a perfectionists I would run 1/2-inch
heliax or LMR-600 for my stacking lines, but chose to use the lighter and
less expensive LMR-400. My array consists of both H and V polarities so it
takes twice the number of staking lines.
I am in process of tearing down the eme array from the old QTH and the coax
lines are looking great after eight years service. Since I will run 1500w
on eme someday, I chose the M2 divider. But I have run RG-11 on and old
two yagi system successfully.
After some bad results with 9913 (the old air-core spiral insulated
version) I will never go back. LMR-400 is great stuff and not expensive
if you buy in large amounts (>250-feet). I use it for all my receive lines
after the tower-mounted preamps.
For 6m losses are even less. I am going to put up two stacked 3-elem 6m
yagis and run RG-11 matching harness (because I have the coax and will run
only 100w....and am cheap!).
73's Ed - KL7UW
73's,
Ed - KL7UW
=========================================
http://www.qsl.net/al7eb - BP40iq
144-EME: FT-847, mgf-1801/1402, 4xM2-xpol-20, 170w
432-EME: FT-847, mgf-1402, 1x21-ele (18.6 dBi), 60w
=========================================
Bill W5WVO
From: "Edward R. Cole" <al...@acsalaska.net>
To: <pnw...@googlegroups.com>
Sent: Tuesday, August 29, 2006 8:15 AM
Subject: [PNWVHFS] Re: Phasing 6M & 2M Yagis
> After some bad results with 9913 (the old air-core spiral insulated
> version) I will never go back. LMR-400 is great stuff and not expensive
> if you buy in large amounts (>250-feet). I use it for all my receive
lines
> after the tower-mounted preamps.
9913F7 is a whole different animal than the old 9913. Gas-filled foam
dielectric, no water incursion problems, ultra-flexible, very low loss,
impermeable outer jacket, easy to assemble standard UHF or N connectors on
it. (Think I will research the LMR-400UF in comparison, however. Thanks for
the recommendation. Anybody out there with experience with both 9913F7 and
LMR-400UF?)
> For 6m losses are even less. I am going to put up two stacked 3-elem 6m
> yagis and run RG-11 matching harness (because I have the coax and will run
> only 100w....and am cheap!).
Good luck on the 6M stacking. Only way to go! 2 x 3el is IMO a better choice
than a single long 6el, especially if you use a StackMatch or other
switching system so you have some options in take-off angle. And excessive
azimuth sharpness (as in a long-john yagi) can be a downside in many cases
on 6M.
Bill W5WVO
cn85be
Aloha to all:
Got some mail regarding Heliax and other forms of coaxial couplings, less
connectors.
I would first and foremost introduce Lief sm5bsz, he may be found at:
If you are not familiar with this individual and his contributions to the
Lunar and weak signal communities, then you have been missing much are in
for a real treat! He has been a wealth of cutting edge suggestion and
solution/resolve for me for at least 15 years.
On his home page can be found design suggestions for mating any size lines,
without commercial connectors. I have built transitions for 1 5/8 inch to
7/8 inch on a 140 foot run of my up coming 903 system. This line sweeps
better than it did with connectors. An improvement Through of from -28dB
to -29.7dB so says the Anritsu. This is just one instance here, except for
equipment interfacing and where it is essential to make measurements
conveniently, I use no connectors, tnx to Leif.
I cannot say enough about these practices. Eliminating some fifty connectors
across antenna systems on six bands 50 through 23cm has certainly netted me
a combined totally of many dB of otherwise lost signal!
73 Jeremy w7eme