Shortening PowerFLARM Brick Antenna and GPS cables

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 Sep 13, 1:34*pm, "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

Kirk:

I have made all of my cables on my PF Brick shorter. It takes having
the right termination tools and crimpers inorder to do this. Contact
me if you are interested in having yours shortened.

Tom

It's probably a lot easier to open the little black box and take a peak at how the cable is soldered at the antenna end. You could probably cut off the excess at the antenna end a lot easier than crimping new connectors. It's a very simple layout. The inner conductor is soldered to one dipole and the shield is soldered to the opposite one. At least the Flarm antenna was done that way and I'd be surprised if the PCAS antenna was any different.

I haven't looked at the GPS antenna other than to remove the two magnets which are hidden under the sticker.

On Thursday, September 13, 2012 6:21:47 PM UTC-7, (unknown) wrote:
It's probably a lot easier to open the little black box and take a peak at how the cable is soldered at the antenna end. You could probably cut off the excess at the antenna end a lot easier than crimping new connectors. It's a very simple layout. The inner conductor is soldered to one dipole and the shield is soldered to the opposite one. At least the Flarm antenna was done that way and I'd be surprised if the PCAS antenna was any different.

On Thu, 13 Sep 2012 20:08:49 -0700 (PDT), "kirk.stant"
wrote:

Except that voids the seal on the box and the future (?) IGC logger.

I assume Mark is talking about the "black box" around the dipole
antenna where the antenna cable terminates, not anything within the
brick box itself.

Bob

On Thursday, September 13, 2012 6:21:47 PM UTC-7, (unknown) wrote:
It's probably a lot easier to open the little black box and take a peak at how the
cable is soldered at the antenna end. You could probably cut off the
excess at the antenna end a lot easier than crimping new connectors.
It's a very simple layout. The inner conductor is soldered to one
dipole and the shield is soldered to the opposite one. At least the
Flarm antenna was done that way and I'd be surprised if the PCAS
antenna was any different.

Except that voids the seal on the box and the future (?) IGC logger.

I haven't looked at the GPS antenna other than to remove the two magnets
which are hidden under the sticker.

I like the idea of removing the magnets, though - thanks!

Kirk
66

Doh! That makes a lot more sense. Interesting idea.

I need to practice my reading more...

Kirk
66

On Thursday, September 13, 2012 11:08:49 PM UTC-4, kirk.stant wrote:
On Thursday, September 13, 2012 6:21:47 PM UTC-7, (unknown) wrote:

It's probably a lot easier to open the little black box and take a peak at how the cable is soldered at the antenna end. You could probably cut off the excess at the antenna end a lot easier than crimping new connectors. It's a very simple layout. The inner conductor is soldered to one dipole and the shield is soldered to the opposite one. At least the Flarm antenna was done that way and I'd be surprised if the PCAS antenna was any different.



Except that voids the seal on the box and the future (?) IGC logger.



I haven't looked at the GPS antenna other than to remove the two magnets which are hidden under the sticker.



I like the idea of removing the magnets, though - thanks!



Kirk

66

OMG magnets? I need to get them out of there too! Good catch.

-Jim

On Thursday, September 13, 2012 4:34:16 PM UTC-4, 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

LOL "absurdly long" is a great way to describe all the antenna wires. I just wound them all up in a tight coil and ty-wrapped them out of the way. I wonder if that is reducing my FLARM range? ...something is. Any ham radio guys of real EE's have an opinion on this?

-Jim

Coiling the cable won't create a problem unless you coil it too tightly.
The cable manufacturer's specifications should list the minimum bending
radius, but I'll bet you're well above that. As long as the characteristic
impedance of the coax matches that of the antenna and there are no shorts or
opens in the line, you should be getting maximum performance. I'd be more
suspicious of antenna placement.

I'm assuming the designers set the antenna length for the frequencies in
question and chose the correct coaxial cable for the application.

BSEE, 1972, but antennas haven't changed much since then...


"Jim" wrote in message
...
On Thursday, September 13, 2012 4:34:16 PM UTC-4, 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

LOL "absurdly long" is a great way to describe all the antenna wires. I just
wound them all up in a tight coil and ty-wrapped them out of the way. I
wonder if that is reducing my FLARM range? ...something is. Any ham radio
guys of real EE's have an opinion on this?

-Jim

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