[amsat-bb] Re: Crushcraft A144-10T "VHF Twist" Antenna
domenico.i8cvs at tin.it
Fri Oct 4 20:13:46 PDT 2013
Hi Les, N1LF
To built a polarization switching for a crossed yagi Cushcraft
A144-10 T is unpractical because the antenna and the phasing
harness are using PL connectors and the coax relays are normally
supplied with N type connectors.
You can't remove the PL connectors from the phasing harness
because they are crimped over two 1/4 electrical length of
RG-59/U and one 1/4 electrical lenght of RG-58/U so that
cutting and removing the original PL connectors those 1/4
wavelengt lines will became shorter than 90 degrees.
BTW you can rebuild a new phasing line using six N connectors
for the phasing line, two N female N barrels connectors,a N type
T connector and change the PL with N flanged female connectors
over the gamma match arms of both dipoles.
The cost for all N connectors and coax relay will be higher than
the cost of a new modern crossed yagi available with switching
polarization relay as new in the USA market.
Since your antenna will be mounted inside your large attic and it
will stay high and dry, I suggest you to connect your A144-10 T
as originally designed connecting the phasing harness for RHCP
or LHCP and stay happy with the compromise results obtined.
----- Original Message -----
From: "Les Rayburn" <les at highnoonfilm.com>
To: "i8cvs" <domenico.i8cvs at tin.it>
Sent: Friday, October 04, 2013 5:57 AM
Subject: Re: [amsat-bb] Crushcraft A144-10T "VHF Twist" Antenna
> Thank you for your wise advice. Unfortunately a new cross-polarized
> antenna is not in the cards right now due to budget.
> Would it be possible and practical to build a polarization switching
> relay for the antenna to allow me to rapidly switch between RHCP and LHCP?
> The connectors are not an issue, since it will be mounted inside my
> large attic. It will stay high and dry.
> Les N1LF
> On 10/3/2013 10:39 PM, i8cvs wrote:
> > ----- Original Message -----
> > From: "Les Rayburn" <les at highnoonfilm.com>
> > To: "AMSAT Mailing List" <amsat-bb at amsat.org>; <starcom-bb at star-com.net>
> > Sent: Friday, October 04, 2013 4:18 AM
> > Subject: [amsat-bb] Crushcraft A144-10T "VHF Twist" Antenna
> >> I just acquired a "new" in the-box, never assembled Crushcraft A144-10T
> >> "VHF Twist" antenna. It includes the cabling to allow the user to
> >> left or right hand polarization. My questions are numerous:
> >> 1.) How is the performance on this antenna, compared to more modern
> >> designs?
> > Hi Les,N1LF from Domenico, i8CVS
> > 1) I have used the A144-10T since 1973 and compared to modern
> > type it works no so well because the phasing harness to switch
> > polarizations uses crimped PL connectors and you get water and
> > humidity into it.
> >> 2.) If I were going to install it inside my attic, should I chose left
> >> or right hand polarization?
> > 2) To switch between RHCP and LHCP you must screw and unscrew
> > by hand the phasing harness connectors and since the antenna is not
> > equipped with a polarization switching relay you have not the time
> > to switch polarization while operating the satellite.
> >> 3.) Any caveats or things to watch out for?
> > 3) Do not use the above Cushcraft A144-20 T for the above reason.
> > Buy a modern model of crossed yagi with polarization switching
> > relay between RHCP to LHCP possibly from 2M
> >> Any information that could be provided would be great. I was thrilled
> >> when a friend stopped by and asked me if I'd be interested in the
> >> antenna. Good price too.
> > I understand a good price because it is a old model of antenna
> > wich designe is almost back 30 yars ago. BTW the aluminum is
> > a good quality and witstand on the environment for many years.
> >> --
> >> 73,
> >> Les Rayburn, N1LF
> >> 121 Mayfair Park
> >> Maylene, AL 35114
> >> EM63nf
> >> 6M VUCC #1712
> >> AMSAT #38965
> >> Grid Bandits #222
> >> Southeastern VHF Society
> >> Central States VHF Society Life Member
> >> Six Club #2484
> >> Active on 6 Meters thru 1296, 10GHz & Light
> > 73" de i8CVS Domenico
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