GPS Down Converter Frequency

[radioman2001]

I have a Tallysman 33-3742-14-01 GPS antenna, and I have to run several hundred feet of coax to the receiver. I want to make sure I use a coax that will work. In past installations I have done mainy on boats the down converter frequency was in the 70mhz or 200mhz range. I have looked online for data sheets, but that info is missing. Does anyone have a knowledge of what frequency range this model converts to.

 

[prcguy]

I believe your specific antenna does not downconvert, it outputs whatever it receives at the same frequency.

I have a Tallysman 33-3742-14-01 GPS antenna, and I have to run several hundred feet of coax to the receiver. I want to make sure I use a coax that will work. In past installations I have done mainy on boats the down converter frequency was in the 70mhz or 200mhz range. I have looked online for data sheets, but that info is missing. Does anyone have a knowledge of what frequency range this model converts to.

 

[radioman2001]

Than I would think 1.5 ghz into over 100 ft of coax (10DB loss ) is going to be a problem. I guess when we turn it on in the next few weeks we will find out. I intend to put an I-soT in line and see.

 

[prcguy]

Not really, the antennas have amplifiers on the order of 30dB or more and will drive a lot of coax. I've installed a few that had 200ft runs of RG-11 coax and everything worked fine.

Than I would think 1.5 ghz into over 100 ft of coax (10DB loss ) is going to be a problem. I guess when we turn it on in the next few weeks we will find out. I intend to put an I-soT in line and see.

 

[radioman2001]

Well it works with 50ft of LMR-400 at another location, but not 150 ft of LDF4-50, unless there is a problem with the coax. Too rainy the last few days to test.

 

[byndhlptom]

According to the antenna data sheet, it is a non amplified antenna, so it probably would not work with a long coax run.

33-3442-14-01 Tallysman Wireless Inc. | RF/IF and RFID | DigiKey

$.02

 

[prcguy]

The data sheets I find say it has a 3 stage LNA with 40dB gain and will work from 2.5VDC to 16VDC. I haven't seen a non amplified GPS antenna since the early 80s.

According to the antenna data sheet, it is a non amplified antenna, so it probably would not work with a long coax run.

33-3442-14-01 Tallysman Wireless Inc. | RF/IF and RFID | DigiKey

$.02

 

[mmckenna]

Well it works with 50ft of LMR-400 at another location, but not 150 ft of LDF4-50, unless there is a problem with the coax. Too rainy the last few days to test.

I'm running several GPS antennas at various locations for NTP.
I've got one running on 50 feet of LMR-400, no issues.
I've got another running on 100 feet of LMR-600, no issues.
I've got one running over about 400 feet of 1/2" heliax, no issues.

As stated, the GPS antennas have a built in amp. I suspect you have a fault in your coax, one of your connections, or something else in the path.

 

[radioman2001]

Well it looks like there was a connector issue, it's all working now. On our wayside sites we used a different model that only has a 12v connection and NMEA output.