VHF Scanner Antenna recommendations

[ckm554]

Hey all, I am looking for an antenna that will allow me to monitor the Yosemite National Park "Park Net" (172.65mhz) repeater from my home in the Central Valley of CA. The Park Net repeater is located about 80miles from my house. My house is at 80ft while the repeater is at 11,000ft and I have essentially line of sight (on a very clear day) with the repeater. I am currently using a "Workman DB1 2M/440" mag mount antenna inside my house with a PRO-137 scanner. I receive most local VHF/UHF public safety and repeaters great but the Yosemite Park Net repeater comes in very weak most of the time. I am willing to mount outdoors if necessary. Any recommendations?

Thanks

Chris

 

[mmckenna]

Getting it out of the house and up a bit higher would certainly help. I'd suggest, however, using an antenna specifically designed for permanent mount on a mast, chimney, etc. Use some decent coaxial cable, not the RG-58 that comes with most mobile antennas. On VHF, RG-8 would be just fine. If you were going to ever want to monitor UHF or 800MHz, you may want to go a step better with the LMR-400 coax as it will have a bit less loss at the those higher frequencies.
But, for monitoring VHF, the differences between the RG-8 and higher priced cables is going to be minimal.

Also, if all you want to monitor is just that specific repeater, you could go with a directional antenna oriented so it's looking at the peak where the repeater is located. That will boost the signal quite a bit and improve reception. Likely a good omni-directional antenna outside the house and up high with good cable will be sufficient.
One easy way to test would be to take your current set up outside and up on the roof. See if the signal improves, if it does, you won't need much to pull this guy in.

Good luck.

 

[W8RMH]

This antenna mounted outside, as high as possible, and aimed at the transmitting tower, should do the trick.

 

[popnokick]

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The Laird yagi beam antenna suggested by W8RMH is probably going to work to get the Yosemite repeater. However because it is a UNIdirectional (not OMNIdirectional) antenna, it may not pick up signals that are coming from sources that are not along the directivity path/beamwidth between you and Yosemite. Mmckenna's suggestion is to test first with an omnidirectional antenna. If you can get your mag mount antenna, a cookie sheet (or other metal plate for use as a ground plane) up on the roof with your scanner... And can then receive Yosemite... A good outdoor omnidirectional scanner antenna permanently mounted on the roof is going to do the job.
A simpler step you might be able to do before you move all of your gear to the roof just to test is to take a handheld scanner up on the roof. Use the handheld's antenna and if Yosemite comes in you're good to go with permanent omni, and won't have to lose the things you listen to that are not in the direction of the beam.
If not coming in, connect the mag mount antenna to the handheld. If you can't hear Yosemite with either, you're looking at W8RMH's suggestion.