1.2 ghz

[w7...@comcast.net]

Hello

I am trying to get "something" going on 1.2.  I have an IC1271A (10watts).  Not wanting to reinvent the wheel, what is the "best" antenna to use for this band?  I have a four foot dish I plan to use for satellites,  I tried a helix (no go).  I a loop type yagi a good choice?  I want an antenna that will function for terrestial and satellite operation if that is possible.

 

--
73 Bob W7LRD
AMSAT member 28498
Renton

[Eric Smith]

Loopers are the "weapon of choice" for a number of
reasons...

Phase two 55 element loopers together and you will get
equivalent gain of a SIX foot dish!
And a lot less weight/windload on the support structure:-)

If you gots a drillpress and a good selection of drill
bits, a trip to the hardware store and my junkyard will get
you all you need to roll your own... Letssee... four 8
foot sticks of 3/4 inch OUTSIDE diameter aluminum tubing,
something to splice them together with (16 feet will make
59 elements), a couple 5/16 inch bolts an inch and a half
long with nuts to match, (thread pitch not important) a
couple boxes of 4-40 stainless panhead phillips screws and
nylon locking nuts, and a couple strips of 1/4 inch wide,
.030" thick hobby brass (with which you make the driven
element) and that pretty much ends the hardware store
shopping spree. From my junkyard you get Type N female
fittings with
.141 rigid coax to complete the driven element/feedpoint,
and all the 1/4 inch wide aluminum sheet strips to make the
rest of the elements out of. Possibly the N male
terminated 75 ohm cable and the female N "t" connector to
make the phasing harness, if not available elsewhere.

Follow the instructions in the ARRL Antenna Book and in a
couple weekends (if you have a life:-) you got antennas!
If you "don't have a life" and all the stuff, you can
devote all time not spent eating and sleeping to building
the antennas and their phasing/support structures, and
knock it all out in a typical ARRL contest period...

I would leave trussing and mounting choices up to you,
there are several "right" ways to do this, all would depend
on what you got lying around loose or are willing to trade
dead presidents for...

[W7EME BL02 Kapa'a]

Aloha Bob,  Eric puts it straight up for you! However he is very crafty and if you are not, you might want to go visit him and at least to feel confident that precision is in the arena! A single 55 el looper is also quite satisfactory and adding a second and line losses will yield under 3 dB more signal, though vertical stacking could in some qso's give coms where one may leave you with fades (tropo wise). Difficult toss up from my stand point. But look at the E2 he has, that thing is menacing when you see it approaching you and then when the rf hits, yep it's plenty!

 

You could always purchase the costly things to, either way, most would tell you go looper, good directivity, nice F/B, lite weight, rugged and it's kinda cool to look through, tho don't know if others care much about the latter. These things patterns real stay clean too, if you keep your feeders behind them.........

 

GL es cu on 23cm! Jeremy w7eme

[eaglep...@juno.com]

I would like to second the opinion on the loop yagis, they are indeed easy to build,

work great and not as fussy as conventional yagis, no need for a bunch

of insulators and they are less effected by Rain and Snow than yagis.

I wish I had done that first B/4 the M2 35 el yagis.

Mike

WB6FFC

CN-82

[Lynn Burlingame]

I agree, they are good antennas, but I don't like them for roving and
portable. They don't travel well and the elements are forever getting
knocked sideways and/or getting crushed.

FWIW

Lynn
N7CFO

----- Original Message -----
From: <eaglep...@juno.com>
To: <w7...@hawaii.com>
Cc: <kb7...@donobi.net>; <PNW...@googlegroups.com>
Sent: Friday, July 27, 2007 8:55 AM
Subject: [PNWVHFS] Re: 1.2 ghz

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9:56 AM

[Larry Hogue]

Can’t remember any acknowledgement of the unique design and one inherent problem I’ve had in this area… with the Loop antenna mounted in the UP position the Birds landed on mine and squashed, mashed, compressed the elements… Turned them over.   just a thought… 73 Larry

 

-----Original Message-----
From: PNW...@googlegroups.com [mailto:PNW...@googlegroups.com] On Behalf Of eaglep...@juno.com
Sent: Friday, July 27, 2007 8:56 AM
To: w7...@hawaii.com
Cc: kb7...@donobi.net; PNW...@googlegroups.com
Subject: [PNWVHFS] Re: 1.2 ghz

 

I would like to second the opinion on the loop yagis, they are indeed easy to build,

[Mike Lewis]

I would argue the newer generation of the Directive Systems loop yagis stand
up very well to roving, as they are fairly heavy duty loop materials and
boom is of good strength also. I support all my antenna in 2 places
(roving), the rear as usual, and up near the front 1/3rd with a fiberglass
pole structure to withstand the vibration of roving on forest roads. I have
put on many thousands of miles with the same setup now, now damage. The
older thin metal loop yagis dissintegrated in 1-2 trips, giving an excuse to
upgrade all my antennas. I home built the VHF antennas with 1" heavy booms
and 3/16" 6061-T6 rods. Very heavy duty, brush limbs are no problem. the
loopers are placed in the protective zone of the VHF/UHF antennas. I have
only had to tighten some for the looper nuts 1 time since they were built,
they have remained tight ever since.

When building your own looper, consider making a jig for cutting the strips,
and use as heavy of material you can get (within reason).

Mike Lewis
K7MDL
Grid Locator CN87xt
Member of Pacific Northwest VHF Society #C96 (www.pnwvhfs.org)
Member of Microsoft Amateur Radio Club (www.microhams.com)
Visit the K7MDL Amateur Radio Pages web site at
http://mysite.verizon.net/michael_d_lewis/index.html
Elecraft K2 #2633

[Jim Aguirre]

One of the programs at the upcoming Pacific Northwest VHF+ Conference in Bend, Oregon, on the weekend of September 28-30, will be on building high-performance 1.2 GHz Yagis.  The program will focus on building these antennas without using high-tech power tools.  Watch this reflector for conference information by early August.

I have used both loop Yagis and conventional Yagis on 1.2 GHz with great success.  I prefer the conventional Yagi design as I feel they are less prone to damage as noted by some others.  I am currently using a stacked pair of 35-element Yagis that achieve slightly more than 21 dBd gain.

Jim - W7DHC

[Edward Cole]

I concur with Eric.

I used one 45-element 1296 MHz loop yagi (bought from Directive
Systems) to work AO-40 using 9.5w at the antenna. The loop-yagi was
mounted on my satellite rotator cross arm with a 432 x-yagi and
33-inch dish for 2401 MHz.

Now I have two of the 45-element LY mounted up at 52 feet inside my
2m-eme array. I can use them both for terrestrial contacts or
satellite (by elevating my eme array). I run with about 25w at the
2-way divider. I have two short runs of 1/2-inch hardline between
the divider and each antenna to minimize losses and noise figure
(preamp and T/R coax relay are mounted at the 2-way divider with
7/8-inch feedline for the transmit path).

73 Ed - KL7UW

73,
Ed - KL7UW
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