Shortening PowerFLARM Brick Antenna and GPS cables

A properly terminated transmission line is infinitely long from the
perspective of the transmitter. The reason the unterminated spool of coax
had nothing coming out the end was due to nearly 100% reflections in the
line.


"Mike the Strike" wrote in message
...
Yes, but all feed lines are lossy and at the frequencies we are using here
the lengths of coax are dumb-ass. We don't have an awful lot of signal to
begin with, so throwing half of it away is plain stupid. I remember in my
ham radio days a friend used an unterminated roll of coax as a dummy load
when experimenting up in the GHz range. The signal barely made it to the
other end, making a terminating resistor unnecessary!

Mike

On 9/15/2012 6:56 PM, Dan Marotta wrote:
A properly terminated transmission line is infinitely long from the
perspective of the transmitter. The reason the unterminated spool of
coax had nothing coming out the end was due to nearly 100% reflections
in the line.


"Mike the Strike" wrote in message
...
Yes, but all feed lines are lossy and at the frequencies we are using
here the lengths of coax are dumb-ass. We don't have an awful lot of
signal to begin with, so throwing half of it away is plain stupid. I
remember in my ham radio days a friend used an unterminated roll of coax
as a dummy load when experimenting up in the GHz range. The signal
barely made it to the other end, making a terminating resistor unnecessary!

There should not be any reflections _in_ the line, unless it is
improperly made or damaged. More likely, as Mike suggests, most of the
power was absorbed along the way by the coax itself, so there was
precious little power to be reflected. The coax is effectively
"terminated" by the distributed losses that occur in the center and
outer conductors, and the dielectric.

--
Eric Greenwell - Washington State, USA (change ".netto" to ".us" to
email me)

On Thursday, September 13, 2012 3:34:16 PM UTC-5, kirk.stant wrote:
As anyone who has one can testify, the cables on the dipole and GPS antennas that come with a PowerFLARM Brick are absurdly long - you could almost mount the GPS puck on your tail!



Has anyone any experience in shortening these cables and reattaching the connectors, or is there anyone out there who can do this for a reasonable fee?



Kirk

66

On Sunday, January 27, 2013 10:25:41 AM UTC-8, kirk.stant wrote:
On Thursday, September 13, 2012 3:34:16 PM UTC-5, kirk.stant wrote: As anyone who has one can testify, the cables on the dipole and GPS antennas that come with a PowerFLARM Brick are absurdly long - you could almost mount the GPS puck on your tail! Has anyone any experience in shortening these cables and reattaching the connectors, or is there anyone out there who can do this for a reasonable fee? Kirk 66

The antennas have a crimp connector so it would be hard to remove and reattach the connectors but it may be possible. The GPS end is usually molded so that would be a problem.

http://www.craggyaero.com/cables_&_antennas.htm

Craggy Aero has GPS antennas with a variety of cable lenghts.

Richard
www.craggyaero.com

See pictures of my PowerFlarm antenna cable shortening project at:
https://sites.google.com/site/threeu...flarm-antennas
There are picuters of the opened GPS mouse.
I am also doing some custom bottom-fed dipoles to suit my needs.
3U

Excellent information and pics. I have also shortened the cables folr my brick install and it is easy to do as long as you reasonable soldering skills.

ASW27 BV