2nd QFH with problems

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Joined: Sun Dec 10, 2017 1:04 am

2nd QFH with problems

Post by jtroutt19 » Sun Dec 10, 2017 1:14 am

Hey guys, been trying to find some help with this QFH I have made. Well its the second one I have made The first one I wasn't happy with and didn't perform either. So here is the deal.

I have this antenna mounted 25 ft in the air outside. I live in a rural area noise floor is low. With it mounted where it is mounted I will see the sat signal on the waterfall but it is really weak. So if I take the antenna off its mount and rotate it I can get a nice strong signal that is almost totally clear of noise. Some times I have to tilt the antenna and rotate it to achieve the same thing. I can even have the antenna inside my house and can tilt it and rotate it and pick up a signal not useable but its there. I am not sure what I am doing wrong here. I have made RHCP antennas before in the 5.8ghz range that work wonderfully, it's frustrating I am having issues with this one. I am using rg-6 coax. and there isn't a whole bunch of it either because the antenna is mounted right above my bedroom window so coax runs down and straight to the computer. Pictures are included. Thanks for any help!
IMG_2710.JPG (1.68 MiB) Viewed 3118 times
IMG_0985.JPG (2.07 MiB) Viewed 3118 times

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Re: 2nd QFH with problems

Post by rtlsdrblog » Wed Dec 27, 2017 2:23 am

It can be hard to troubleshoot an antenna. The only thing I can suggest is double check all connections (obviously), and check continuity through the coax. There was one user before who had poor QFH performance and discovered that the coax was bad/waterlogged.

Alternatively, go simpler with a V-dipole or turnstile. Those are much easier to get right.

Another possible problem is overload from nearby broadcast FM stations. Check to see how strong they are with your QFH. If they're too strong they will desense the 137 MHz band causing poor reception. In that case you'll need to add a BCFM filter.

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