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A Question For Antenna Buffs

Posted: Fri Nov 10, 2017 11:33 am
by J3rsdm5
For reasons I fail to comprehend, my 55 inch Maxrad MHB5800 with a ground plane disc only has a range of about 13 miles (about at Howell), and it's not even intelligible until about 7 miles. (Just past Brighton)
Does anyone know what the best possible antenna is that I could purchase, yet not any taller than 10 feet? (To sit on the floor. My antenna sits on my desk, and at 55", it barely touches the ceiling.)
I would spend large amounts of money to hear activity at Plymouth. At that point, I would start streaming online to complete the Plymouth sub scanner coverage.
Thank you!

Re: A Question For Antenna Buffs

Posted: Fri Nov 10, 2017 2:30 pm
by Jetlink
I think your biggest issue is line of sight. The waves you are trying to catch have properties that limit them to line of sight. They aren't like the low frequency waves that follow the curvature of earth or bounce between the ionosphere and the earth.You need to get your antenna above the local obstructions so it can 'see' directly to the distances you are trying to receive. Think 1st level rooftops. Then second level tree tops. Then third level really high (100's of feet like the super scanner) to 'see' around the curvature of the earth a little farther. If there is local terrain blocking the directions you want to receive from you may just be out of luck. My house is at a lake so naturally down in a hole. I only get about 5 miles to the west most days (lake O) but the terrain slopes lower and away (the water course out of the lake runs that direction) to the east so I can hear about 15 miles that way (Grand Ledge).

I ran some Coax and a BNC connector to a CB antenna up in my bonus room above the garage once just for fun. With that little bit of elevation gain I could hear to Elmdale (15 miles) and Fox (25 miles) just for an example. It got me up over the rim of the hole my house sits in and made all the difference.

Re: A Question For Antenna Buffs

Posted: Fri Nov 10, 2017 4:44 pm
by J3rsdm5
Jetlink wrote:I think your biggest issue is line of sight. The waves you are trying to catch have properties that limit them to line of sight. They aren't like the low frequency waves that follow the curvature of earth or bounce between the ionosphere and the earth.You need to get your antenna above the local obstructions so it can 'see' directly to the distances you are trying to receive. Think 1st level rooftops. Then second level tree tops. Then third level really high (100's of feet like the super scanner) to 'see' around the curvature of the earth a little farther. If there is local terrain blocking the directions you want to receive from you may just be out of luck. My house is at a lake so naturally down in a hole. I only get about 5 miles to the west most days (lake O) but the terrain slopes lower and away (the water course out of the lake runs that direction) to the east so I can hear about 15 miles that way (Grand Ledge).

I ran some Coax and a BNC connector to a CB antenna up in my bonus room above the garage once just for fun. With that little bit of elevation gain I could hear to Elmdale (15 miles) and Fox (25 miles) just for an example. It got me up over the rim of the hole my house sits in and made all the difference.
This most likely explains it. I would love to raise the antenna up about 15 feet onto the roof; brain says yes, wallet says no. :/
Just a few houses over, somebody owns two three story antenna towers, yet running a coax cable through five backyards, price, permission, etc...
Thanks for the information!

Re: A Question For Antenna Buffs

Posted: Fri Nov 10, 2017 5:28 pm
by J3rsdm5
If I could get an antenna up on this tower, I could probably hear all the way to Lansing.
http://www.antennasearch.com/sitestart. ... er=1000537

Re: A Question For Antenna Buffs

Posted: Fri Nov 10, 2017 9:55 pm
by hoborich
To sit on the floor. My antenna sits on my desk, and at 55", it barely touches the ceiling.)
This is part of your problem. Indoors is marginal at best. You don't say what kind of siding you have on your house, but aluminum siding will block a lot of signal, if not all of it. There are some VHF antennas that stick on a window with suction cups. Might make some small improvement. Lots of things effect radio and TV reception. My neighbor put a steel roof on his house a few years back and screwed up my TV reception. Probably bounced the signals away from my antenna. I raised it up higher and pointed it in a slightly different direction and was back in business.
If you can put your current antenna outside and even on a short mast, with a coax into the house you should see at least some improvement.

$20 bucks will get you up ten feet. https://www.solidsignal.com/pview.asp?p ... gIUSfD_BwE

You'll need these too. https://www.solidsignal.com/pview.asp?p=SKY32814

Re: A Question For Antenna Buffs

Posted: Sat Nov 11, 2017 2:29 am
by cbehr91
Definitely need to get the antenna outside. One of these on a ventpipe on the roof would do very well, or even if you can't get it outside it would still do well in the attic (providing your siding or roofing material isn't metal). http://www.jpole-antenna.com/shop/railr ... e-antenna/

Re: A Question For Antenna Buffs

Posted: Sat Mar 31, 2018 9:53 am
by Dajudge
I just finished building a 161 mhz J pole for mobile use. It is mounted on a three section 15 foot push up telescopic potable flag pole. Highly recommended for outdoor listening. Adds much range to my scanner. Other comments above are correct. At VHF frequencies (which railroad 161 are) it's all about height. Antenna gain helps but height is the silver bullet. VHF propagation is line of sight. Whatever your antenna can see is how far it can cover. The horizon is its limit. There are many obstacles that block the path the closer to earth you get. One that people commonly disregard are tree leaves. These little packets of humidity really do a lot of absorbing and get hard to penetrate. Best to get above it all. Look around at cellphone towers, all of them are tall for a reason. My 15 foot flag pole is not the best but is better than a hand held rubberduck antenna 5 foot above ground.

Re: A Question For Antenna Buffs

Posted: Sun Apr 01, 2018 2:49 am
by redcrumbox
My full wave loop antenna is positioned 30' below a ridge that is approximately 1400' from my indoor location. I receives a DD 12 miles away. How is this possible?
Dajudge wrote: VHF propagation is line of sight. Whatever your antenna can see is how far it can cover. The horizon is its limit.

Re: A Question For Antenna Buffs

Posted: Sun Apr 01, 2018 8:53 pm
by hoborich
My 15 foot flag pole is not the best but is better than a hand held rubberduck antenna 5 foot above ground.
Lotta leverage on the BNC connection and kinda hard to hold. :lol:

Re: A Question For Antenna Buffs

Posted: Wed Apr 11, 2018 12:52 am
by cbehr91
redcrumbox wrote:My full wave loop antenna is positioned 30' below a ridge that is approximately 1400' from my indoor location. I receives a DD 12 miles away. How is this possible?
Dajudge wrote: VHF propagation is line of sight. Whatever your antenna can see is how far it can cover. The horizon is its limit.
Is the detector location below the ridge too?

Re: A Question For Antenna Buffs

Posted: Wed Apr 11, 2018 1:50 am
by Jim_c
redcrumbox wrote:My full wave loop antenna is positioned 30' below a ridge that is approximately 1400' from my indoor location. I receives a DD 12 miles away. How is this possible?
Dajudge wrote: VHF propagation is line of sight. Whatever your antenna can see is how far it can cover. The horizon is its limit.
Could be knife edge diffraction. Just like the way light spreads out a bit as it shines through a doorway.