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#21
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Shortening PowerFLARM Brick Antenna and GPS cables
Eric,
Exactly correct. The only benefit to trimming the GPS cable is to reduce (in my case, by almost 12 feet) the excess cable that I didn't want to bundle up and keep secure. Mark |
#22
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Shortening PowerFLARM Brick Antenna and GPS cables
On 9/17/2012 5:12 AM, Jim wrote:
The GPS antenna cable doesn't carry high frequency RF, so tidiness is the only value in reducing the length. Eric, so why do we need a GPS antenna wire if the signal from the satellite magically gets to the receiver without the RF signal first going through the antenna wire :=P I'm fairly sure that the GPS antennas are "active" antennas getting phantom dc power from the receiver but I thought they only had an amplifier; are you sure they also have a local oscillator & mixer to convert the RF to an IF (I guess like an LNB)? Amazing for such a cheap device. A lot of antenna "pucks" are not just GPS antennas, but GPS receivers. What comes out of the cable is data, not RF. That's not true of every GPS "puck", of course, but I think it's true of the PF units. Even if it's the active antenna type you mention, because the output is amplified and a lower frequency than the raw GPS signals, the cable loss would be an issue. So, reduce the cable length for tidiness, not signal strength. The dipole antennas are passive, so shortening their cables might improve their output. Without knowing the cable type, I can't say how much, but I'd guess the antenna designers chose cable that did not have significant losses for the length provided. -- Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me) - "Transponders in Sailplanes - Feb/2010" also ADS-B, PCAS, Flarm http://tinyurl.com/yb3xywl |
#23
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Shortening PowerFLARM Brick Antenna and GPS cables
On Monday, September 17, 2012 5:02:43 PM UTC-4, Eric Greenwell wrote:
The GPS antenna cable doesn't carry high frequency RF Wrong. A lot of antenna "pucks" are not just GPS antennas, but GPS receivers. What comes out of the cable is data, not RF. That's not true of every GPS "puck", of course, but I think it's true of the PF units. Wrong. It's an antenna, NOT a receiver. Even if it's the active antenna type you mention, because the output is amplified and a lower frequency than the raw GPS signals Wrong. Please don't speculate where people may take it seriously, even on R.A.S... Thanks, Best Regards, Dave |
#24
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Shortening PowerFLARM Brick Antenna and GPS cables
On 9/17/2012 3:34 PM, Dave Nadler wrote:
On Monday, September 17, 2012 5:02:43 PM UTC-4, Eric Greenwell wrote: The GPS antenna cable doesn't carry high frequency RF Wrong. A lot of antenna "pucks" are not just GPS antennas, but GPS receivers. What comes out of the cable is data, not RF. That's not true of every GPS "puck", of course, but I think it's true of the PF units. Wrong. It's an antenna, NOT a receiver. Even if it's the active antenna type you mention, because the output is amplified and a lower frequency than the raw GPS signals Wrong. Please don't speculate where people may take it seriously, even on R.A.S... Thanks, Best Regards, Dave Well, humph! It wasn't speculation, it was ignorance! So, are most of the GPS pucks are passive antennas, or are they amplified but with no frequency conversion? And is it useful to shorten the cable to increase signal strength? -- Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me) |
#25
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Shortening PowerFLARM Brick Antenna and GPS cables
Outboard antennas are amplified RF, no local mixer/downconversion.
Darryl |
#26
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Shortening PowerFLARM Brick Antenna and GPS cables
Outboard antennas are amplified RF, no local mixer/downconversion.
Darryl |
#27
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Shortening PowerFLARM Brick Antenna and GPS cables
The only ones "outboard receivers" are things like USB connected pucks, where everything lives in the puck.
Darryl |
#28
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Shortening PowerFLARM Brick Antenna and GPS cables
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 |
#29
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Shortening PowerFLARM Brick Antenna and GPS cables
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 |
#30
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Shortening PowerFLARM Brick Antenna and GPS cables
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 |
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