lost 800 mhz

[jackinthefox]

hi everyone,
i have a discone antenna mounted on my roof. I recently built a detached garage and ran the coax I havebeen using underground to the garage. I had to cut off the plug and re terminate it. I probably cut 6-8 feet off a 100 ft long coax cable. since then I cannot receive any 800 mhz frequencies. any ideas?

 

[lmrtek]

most likely the antenna is just in a dead spot

discones are pretty poor 800 MHz antennas

a dedicated 800 antenna would be better

 

[jim202]

Did you check the coax cable before you cut and put a new connector on it?

Some antennas provide a DC ground to the center conductor and others don't.

My first guess is that the new connector might have a short from shield to ground. If the antenna is easy to get at, I would remove the coax cable from it and do a continuity check from center pin to the shield on your coax cable. Make sure you do not have anything connected at the garage end. The next test would be to short the center pin at the antenna and make sure you see a low resistance in the garage center pin to shield.

You will not see zero Ohms with the cable shorted at the distant end, but it will be on the order of maybe 2 to 4 Ohms or so.

Before doing the tests above, make sure you know what your meter reads when you short the test leads together. You will need to subtract that reading from what you see with the length of coax your trying to test.

 

[jackinthefox]

I will try that thanks