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n4



956 posts

Ultimate Geek
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Topic # 150794 3-Aug-2014 15:30
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Sorry I have tried searching for this but can't find a straight forward answer to the question.

I have been trying to get Freeview Terrestrial going (in addition to the existing DVB-S service we use). We moved into the house a year ago. After testing various pieces of the system, I think I have narrowed the problem down to the UHF antenna. If I disconnect the cable from the masthead amp, and measure the resistance using a multimeter, I get an open circuit (well 1.4 Mohm). The connections on the antenna itself look very corroded. Is that definitely a sign of a problem? By way of comparison, the VHF antenna gives a short circuit (0 ohm) reading. Just looking for confirmation before I get the UHF antenna replaced.




Huawei Mate 7, on 2degrees

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1929 posts

Uber Geek
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  Reply # 1101156 3-Aug-2014 15:39
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You can't use a multimeter to measure the resistance of an antenna. The 75 ohms is impedance and not resistance. Some are open circuit and some directly connected depending on the design. Most UHF antenna I have inspected are inductively coupled and read open circuit on a multimeter but they work perfectly. Check the circuit board in the coupling box at the antenna to see if the tracks are clean or corroded and all connections are OK. That's the only way you can tell.

n4



956 posts

Ultimate Geek
+1 received by user: 74


  Reply # 1101169 3-Aug-2014 16:12
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Damn, thought it might not be straight forward. Thanks for the help, looks like I'll need to get back on the roof :-(




Huawei Mate 7, on 2degrees

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