Ways to boost reception/range when scanning Airband and MilAir

Joined
Jul 8, 2021
Messages
3
Location
Upstate New York
I'm looking for ways to boost my scanner's reception/range when scanning the Aviation and MilAir bands. It uses an SMA-F connector. More specifically, I'm looking for a way to listen to the military aircraft refueling at AR-206 (I live under the entrance of it). Any and all help would be appreciated.
 
Joined
Apr 18, 2009
Messages
4,910
Location
CT
Any and all help would be appreciated.
Probably the simplest thing to do is get your antenna to a higher elevation.

The fewer obstructions and ground clutter between the antenna and the transmitter the better.

I have my antenna on a 20 ft mast on my chimney, for example.

Good luck!
 

stantorres

Member
Joined
Feb 22, 2008
Messages
65
Location
Auburn Hills, MI
I spent a couple years trying to solve a similar problem. In the end I was given some advice that worked well. Get an antenna designed specifically for the target frequency and high quality low-loss coaxial cable. The difference was night and day. DPD productions Air Omni ($170) and LMR400 coax ($1.25/ft.). 3 mast sections and a set of wall brackets from Channelmaster. Uniden BC780xlt. If that doesn't do it, nothing else will.
 

mmckenna

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Jul 27, 2005
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16,601
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From the land of sky blue waters!
When it comes to this stuff, the following applies (similar to what was said above)

RF at these frequencies/power levels work by line of sight. If your antenna can see the transmitter, it can likely hear it. If you are using a portable scanner with an antenna screwed on top, you're in about the worst possible situation you can be in. Anything will be an improvement.

Get the antenna up as high as you safely can. Since the line of sight comes into play, the farther over the horizon your antenna can see, the more it can hear. Use online 'distance to horizon' calculators to do the maths. Figure in the height of the aircraft and the height of your antenna.

Antenna gain can help, but it's not everything. Getting a decent 3dB gain antenna for VHF air band shouldn't be a big issue, just make sure your antenna mast will support it.

There is precisely -ZERO- magic involved with antennas. They are all bound by the laws of physics. Be wary of gimmick antennas, or manufacturers that charge extra by selling service specific antennas. The only thing you need to look at is it's frequency coverage (resonance) and how much gain it has. There are a lot of excellent antennas out there that will work very well that will not have the term "air band" in the name. I'm sure DPD makes good stuff, but they are vastly overpriced.

Good coaxial cable. You need to get that signal from the antenna down to your receiver. All coaxial cable has inherent loss. As the frequency goes up, losses go up. As cable length goes up, losses go up. Getting the right coaxial cable for the job is important. For some applications, like VHF, simple RG-6 can work very well and save you a lot of money. If you are more interested in higher frequencies and longer cable length, then higher grade cable may be required. A -LOT- of it depends on your budget, so when asking for recommendations, none of us can really give you useful advice without telling us what your realistic budget is. There's no shame in low budgets, we've all been there.

Proper installation.
I'll say it again, proper installation.
Anyone can be trained to toss up an antenna on the roof. There's a big difference between a half-assed install and a quality install. One may work "well enough", the other will work well and last a long time. Decide how often you want to climb up on the roof of the house and replace antennas or coax. Don't forget about doing it in the winter with snow/ice on the roof. Adjust your plans accordingly.
-Get a good antenna-. Be wary of hobby/ham grade stuff. It can work if budgets are tight, but the antenna is a very important part of your installation. You can cut corners and be replacing it in a few years (probably in the dead of winter), or you can spend a bit more and get a quality antenna and it'll last 10-20 years or more.
-Use good coaxial cable-. Doesn't have to be expensive, but avoid Cheap Chinese Coax. On that note, avoid Cheap Chinese EVERYTHING! Name brand RG-6 may be fine for what you are doing. LMR-400 can be good stuff if you get the name brand. Or, if your cable run is longer, you may need to go to something better.
-Waterproof all your outdoor connections. Yes, all of them. Even the ones that are hard to get to. Anyone that tells you it isn't necessary is running on pure luck. Avoid people like that. Luck has a way of running out at the least opportune times, usually in front of a large crowd with cameras. Not waterproofing your connections will result in water getting inside the cable. Water + copper results in a corroded mess that will destroy your cable and greatly impact performance. Electrical tape isn't sufficient as a waterproof barrier.
-If you are mounting the antenna outdoors, you need to consider lightning protection. It's required by the National Electric code for a very good reason. Again, you'll run into people that tell you it's not necessary. That's someone who's confusing luck with skill.


Use good quality antennas, cable, connectors, etc. and you'll have a good setup. You'll be amazed by how much better a good outdoor antenna works compared to what's included with the scanners.
 
Joined
Jul 8, 2021
Messages
3
Location
Upstate New York
What scanner and antenna do you have? Can you install a balcony antenna or on the roof? Is that the full 118-136MHz band and the full 220-390MHz band?

/Ubbe
I've got a Uniden BCD436HP with a Radioddity RD-331. Airband is 108.000-137.000 MHz and MilAir is 225.000-399.95 MHz. Yeah, I believe I should be able to get an antenna out on the roof, just gotta find one that would work though.
 

Ubbe

Member
Joined
Sep 8, 2006
Messages
6,135
Location
Stockholm, Sweden
108.000-137.000 MHz and MilAir is 225.000-399.95 MHz.
Then the only antenna type that will work satisfactory for those huge frequency ranges are a discone. The bigger ones with 8 bottom elements or more with lengths of almost 3 feet and no top vertical element are the type I would suggest.

You can try that indoors first to see what you can receive. If you have access to the attic you could try it there, monitoring in the attic with the scanner connected with a short coax, as that would make installation so much easier and do not need to consider wind load and snow and ice.

A FM trap filter would probably help and you can use relatively long runs of RG6 coax without getting too much loss for frequencies up to 400MHz if you manage to do a roof installation, which would get you the best signal strengths.

/Ubbe
 
Joined
Jul 8, 2021
Messages
3
Location
Upstate New York
Then the only antenna type that will work satisfactory for those huge frequency ranges are a discone. The bigger ones with 8 bottom elements or more with lengths of almost 3 feet and no top vertical element are the type I would suggest.

You can try that indoors first to see what you can receive. If you have access to the attic you could try it there, monitoring in the attic with the scanner connected with a short coax, as that would make installation so much easier and do not need to consider wind load and snow and ice.

A FM trap filter would probably help and you can use relatively long runs of RG6 coax without getting too much loss for frequencies up to 400MHz if you manage to do a roof installation, which would get you the best signal strengths.

/Ubbe
I decided to try out the Diamond RH77CA, seems to work beautifully for those frequencies. I was able to record an entire a2a refueling session this morning.
 

vagrant

ker-muhj-uhn
Joined
Nov 19, 2005
Messages
2,204
Location
California
While the external antenna recommendations noted above are best, if you are determined to use a rubber duck on the radio, the Diamond SRH320A is a better antenna for military air over the RH77CA and it does not require an adapter.
 

KB2GOM

Member
Joined
Jun 1, 2020
Messages
321
Location
upstate New York
What he said; mmckenna speaks The Truth.

When it comes to this stuff, the following applies (similar to what was said above)

RF at these frequencies/power levels work by line of sight. If your antenna can see the transmitter, it can likely hear it. If you are using a portable scanner with an antenna screwed on top, you're in about the worst possible situation you can be in. Anything will be an improvement.

Get the antenna up as high as you safely can. Since the line of sight comes into play, the farther over the horizon your antenna can see, the more it can hear. Use online 'distance to horizon' calculators to do the maths. Figure in the height of the aircraft and the height of your antenna.

Antenna gain can help, but it's not everything. Getting a decent 3dB gain antenna for VHF air band shouldn't be a big issue, just make sure your antenna mast will support it.

There is precisely -ZERO- magic involved with antennas. They are all bound by the laws of physics. Be wary of gimmick antennas, or manufacturers that charge extra by selling service specific antennas. The only thing you need to look at is it's frequency coverage (resonance) and how much gain it has. There are a lot of excellent antennas out there that will work very well that will not have the term "air band" in the name. I'm sure DPD makes good stuff, but they are vastly overpriced.

Good coaxial cable. You need to get that signal from the antenna down to your receiver. All coaxial cable has inherent loss. As the frequency goes up, losses go up. As cable length goes up, losses go up. Getting the right coaxial cable for the job is important. For some applications, like VHF, simple RG-6 can work very well and save you a lot of money. If you are more interested in higher frequencies and longer cable length, then higher grade cable may be required. A -LOT- of it depends on your budget, so when asking for recommendations, none of us can really give you useful advice without telling us what your realistic budget is. There's no shame in low budgets, we've all been there.

Proper installation.
I'll say it again, proper installation.
Anyone can be trained to toss up an antenna on the roof. There's a big difference between a half-assed install and a quality install. One may work "well enough", the other will work well and last a long time. Decide how often you want to climb up on the roof of the house and replace antennas or coax. Don't forget about doing it in the winter with snow/ice on the roof. Adjust your plans accordingly.
-Get a good antenna-. Be wary of hobby/ham grade stuff. It can work if budgets are tight, but the antenna is a very important part of your installation. You can cut corners and be replacing it in a few years (probably in the dead of winter), or you can spend a bit more and get a quality antenna and it'll last 10-20 years or more.
-Use good coaxial cable-. Doesn't have to be expensive, but avoid Cheap Chinese Coax. On that note, avoid Cheap Chinese EVERYTHING! Name brand RG-6 may be fine for what you are doing. LMR-400 can be good stuff if you get the name brand. Or, if your cable run is longer, you may need to go to something better.
-Waterproof all your outdoor connections. Yes, all of them. Even the ones that are hard to get to. Anyone that tells you it isn't necessary is running on pure luck. Avoid people like that. Luck has a way of running out at the least opportune times, usually in front of a large crowd with cameras. Not waterproofing your connections will result in water getting inside the cable. Water + copper results in a corroded mess that will destroy your cable and greatly impact performance. Electrical tape isn't sufficient as a waterproof barrier.
-If you are mounting the antenna outdoors, you need to consider lightning protection. It's required by the National Electric code for a very good reason. Again, you'll run into people that tell you it's not necessary. That's someone who's confusing luck with skill.


Use good quality antennas, cable, connectors, etc. and you'll have a good setup. You'll be amazed by how much better a good outdoor antenna works compared to what's included with the scanners.
 
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