Base Antenna Basics...

[WSAC829]

It varies. Height is might when it comes to UHF, and GMRS is very much “line of sight”. There are some repeaters up on ridges or mountain tops that can cover over 100 miles. Now that’s not realistic for the average Joe though. Typically 2w-5w handhelds (not frs/gmrs bubble pack radios) will do 1 - 5 miles depending on terrain. Mobile to mobile generally 5 - 10 miles depending on terrain. Base to base can do upwards of 100 miles, again depending on terrain and antenna height.

My current main GMRS repeater antenna is up 50’ in the air. It’s a low power 5 watt repeater run off a solar panel, and it covers about 10 miles. My portable ammo can simplex repeater depends on where i put it. I usually just toss it on my trucks roof out in the woods, and it covers 2 - 5 miles in every direction around it when using handhelds. If i drive up to a ridge or high point around the area of where i’ll be, it would generally have even better coverage.

Like anything radio, height, power, and terrain are big factors in how far your signal will travel.

 

[jcrmadden]

Like anything radio, height, power, and terrain are big factors in how far your signal will travel.

Certainly been my experience...

I'm assuming there's some way of knowing where repeaters are? Some way of knowing what my coverage might look like?

Or is it a try and see sort of thing from one area to another?

If my home brew repeater can't get home we're back to depending on other peoples' gear. Not that it's a bad thing, but it is the goal to cut out as much in the middle as possible.

I'm sure I can make GMRS work, maybe easier, and probably cheaper.

I need to run CB, relic or not, just due to the industry I'm in. I'm not keen on running separate systems IF I can make my pie-in-the-sky CB dream work.

What's a reasonable expectation for mobile to base CB range? Assuming there's ridge to ridge signal sent from a big, clear mouth to a perfect set of ears?

And what does PERFECT base ears look like for capturing a specific, long distance, mobile signal?

 

[slowmover]

Get a topographical map. Translate to different map with easier reference. Wall-size (4x4’ or larger). Maybe a working copy and one permanent.

There’s no reason not to be serious.

LOS signals and how they work out in your area.

15-miles mobile-to-base isn’t remarkable on the Plains. Given some electrojuice it can be significantly farther on AM (Use 150W mobile as top).

Pretty much any antenna at home can give you an idea of how things might work. A quarter-wave on stationary vehicle at house, and better mobile going out to check where one crosses ridges. Landmark references. A starting point.

My son is up to the same thing where he lives in Alaska. Fewer directions one might travel, but the main routes and locations where a signal is solid is the initial goal.

Come at it where you can start pretty much today.

I’m parked in something of a declivity. Have an idea what 108” on the Dodge can do relative to a distant mark (14-16/miles). Now what if I raise my portable SIRIO Boomerang to 30’ feedpoint with some’o dat juice?

“Should” be better isn’t the same as an idea of what “better” means.

.

 

[RFI-EMI-GUY]

this is what I did... I may have everything wrong???? but I think it came out great and works fantastic..... been just over a year so I can give you prices for everything.

Great video, encapsulates all the needed elements. I had a couple side mounts like that in Miami during Hurricane Andrew. They both survived. There was a huge 9 dB fiberglass Andrew collinear on heavy EMT and It only pulled the top most mount away a bit. The second was TV antenna on a swaged mast like the top rail stuff. It did not budge. This despite widespread destruction and 150 MPH winds around us. Good on the grounding. I like the use of the computer monitor bracket. I could use that here. Antenna systems are never cheap unless you are doing horizontal dipoles swinging between trees, and even so, the grounding and bonding still needs to be done.

 

[niceguy71]

Great video, encapsulates all the needed elements. I had a couple side mounts like that in Miami during Hurricane Andrew. They both survived. There was a huge 9 dB fiberglass Andrew collinear on heavy EMT and It only pulled the top most mount away a bit. The second was TV antenna on a swaged mast like the top rail stuff. It did not budge. This despite widespread destruction and 150 MPH winds around us. Good on the grounding. I like the use of the computer monitor bracket. I could use that here. Antenna systems are never cheap unless you are doing horizontal dipoles swinging between trees, and even so, the grounding and bonding still needs to be done.

did you hear any names that sounded familiar in the video?

 

[RFI-EMI-GUY]

did you hear any names that sounded familiar in the video?

Sure did! Thanks!

 

[jcrmadden]

I don't think I did this thread any favors with my complicated goal explanation, so let's distill it down...

What I am attempting to achieve is a theoretically perfect base antenna specifically designed for receiving long distance local communications from any direction coming from a mobile unit operating at 27.205MHz.

What type of antenna? How long is the antenna? How high should the feed point be?

For the practical side of this little mental exercise lets make a few assumptions...

There is a $2,500 budget BUT it will be bought piecemeal and possihome brewed. This includes the cost of the antenna, the tower, the coax, and the grounding/lightning suppression components, but does not include the radio components.

The base station itself will be in a brick home with a metal roof on a high ridge, but there are three phase power lines and electric fences nearby.

The mobile unit is stationary, but maybe not parked in an ideal spot. There will be trees, there will not be buildings, there may or may not be topographical advantage.

The antenna for the mobile can be swapped out once stationary, and there are multiple options available. Feel free to recommend a combination of antennas as long as it's mobile TX to base RX.

And...

GO.

 

[niceguy71]

I don't think I did this thread any favors with my complicated goal explanation, so let's distill it down...

What I am attempting to achieve is a theoretically perfect base antenna specifically designed for receiving long distance local communications from any direction coming from a mobile unit operating at 27.205MHz.

What type of antenna? How long is the antenna? How high should the feed point be?

For the practical side of this little mental exercise lets make a few assumptions...

There is a $2,500 budget BUT it will be bought piecemeal and possihome brewed. This includes the cost of the antenna, the tower, the coax, and the grounding/lightning suppression components, but does not include the radio components.

The base station itself will be in a brick home with a metal roof on a high ridge, but there are three phase power lines and electric fences nearby.

The mobile unit is stationary, but maybe not parked in an ideal spot. There will be trees, there will not be buildings, there may or may not be topographical advantage.

The antenna for the mobile can be swapped out once stationary, and there are multiple options available. Feel free to recommend a combination of antennas as long as it's mobile TX to base RX.

And...

GO.

I did my Antron 99 with radio and power supply for $1500 ... You can get another 5555 N II for $185 now....
One hell of a system... If you use side band you may get 25 to 30 miles maybe even more

But with that metal roof, you might be able to stick a magnet mount Sirio Performer 5000 on it and do pretty well .. the power lines, sadly are going to really screw you up

 

[slowmover]

What I’ll do GP plan when time to start:

Wave-length from buildings and feedpoint wave-length in air.

Antenna expected to be 23’ feet tall or so.

And unless I find a substitute, it’ll be a 1970’s spec all-metal; likeliest:

@prcguy Post in thread 'Base Antenna Basics...'
Base Antenna Basics...

As @jayinthemojave isn’t any longer making his super duty version.

FWIW, I’d have a second in spare parts ready, and a different design (the cheapie) ready to go up if the first one gets taken down. An antenna known for surviving high winds.

A good place to park the 300HP Rolling GenSet with a 102” ready to go and what’s needed to feed the base station.

Western NC had the problems most highly publicized. Those first few days are critical.



My TT Is a similar problem, but with changing locations. Roof mount looks good (tilt over with a 19’) until I’m parked under trees. Etc. So it’s:

1). Mobile Unit versatility per antenna feed.
2). TT roof plus ability to run coax out hull.
3). The gear & supply necessary to make any 11M combo work above or from something not yet adequately rednecked.

I was packing away my seven (7) sets of fiberglass whips yesterday an extracted the broken 7’ (gave the good one of that old pair to a young driver in another thread hereabouts) and will keep it as more than “a fishing pole” (tool to extract from a narrow depth) as it may yet have function to serve.

.

 

[slowmover]

So my go to “base station antenna” is a telescoping 24’ painters pole in a 5-gal plastic bucket with PVC surrounded by rocks holding a

Small Base Antenna: SIRIO Boomerang W

Each leg about 4’ plus or 9.4’ total https://unicomradio.com/product/sirio-boomerang-w-base-antenna/ Forgotten I had one of these. Am going to be home long enough it’s worth the trouble to me to get a 5-gal bucket holding a painters extendable pole to run it up a ways. Similar to this...

forums.radioreference.com

as it’ll fold up such I can carry it in TT or pickup.

This is why I recommended performance testing above. But if you’re going to get hold of a tower, then . . . .

My ability to leave one area and move my home to another locale entirely is part of no sticks & bricks house.

The road is out, you might want something ready-to-go parked at the river crossing to phone home with more than a mobile antenna.

I already have a couple of MFJ-945e to tune it with.
.

 

[WSAC829]

The base station itself will be in a brick home with a metal roof on a high ridge, but there are three phase power lines and electric fences nearby.

I’ve mentioned this before, but a metal roof makes for a great ground plane. My home base antenna is now a Tram 717 on a mag mount slapped up near the highest point of the roof which is roughly 35-40 feet. I used a barrel connector to attach another 50 feet of RG8U because that was thin and flexible enough to stuff under the siding before running it in to the house. There are power and cable lines within 50 feet of it and i have no electrical noise issues. I get great results on both RX and TX. Roughly 25 miles on AM, or 60 miles on sideband for talking locally. So it will work, and may save you a few dollars, but again, it’s really all trial and error. There is no “one size fits all” perfect setup that everybody swears by. If there was there wouldn’t be hundreds of different brands of antennas, radios, coax, etc.

Now, slightly back off topic…. With GMRS you wont have to worry about “skip” wiping out your channel making it hard to communicate during the day. CB really only gets quiet at night during these solar cycles. So, take that in to consideration. The cost for GMRS radios and antennas might even be cheaper than CB, or at the very least about the same price depending on brands.

Anyway, good luck in your quest. You’ll probably need every bit of that $2500 to see what works best for your needs.

 

[k8niv]

My nephew, has a old super penetrator antenna up, it's about 27ft or so high and he talks all over the place, all time sending me videos where he talks he uses SSB mode mostly but has a 200 wall amplifier..nothing fancy but gets the job done....

 

[jcrmadden]

I've read that a 1/2 wavelength antenna doesn't need a ground plane? Is that accurate?

 

[RFI-EMI-GUY]

I've read that a 1/2 wavelength antenna doesn't need a ground plane? Is that accurate?

To "work" or to work well?

 

[robertwbob]

i got a sirrio 2008 on 2"pipes welded together 35' to base of antenna.hi quality coax about 75' from my house clamped to a steel T post with 2 runs rope guyline in triangle to secure it. first run 15' second run at base of antenna. then in my house a stryker ver II 955 hp and outcomm 200 amp on mfj 30 amp switching power supply .
i get out far n wide very low noise floor and ive got less than $1000 in whole set up

 

[jcrmadden]

To "work" or to work well?

No idea really... I read it here in the forums somewhere, but now I can't find it. Didn't know if there was anything to it at all, or if it was a misconception.

 

[KI4ZNG]

The base station itself will be in a brick home with a metal roof on a high ridge, but there are three phase power lines and electric fences nearby.

I have both very close by my house with no issues.

 

[RFI-EMI-GUY]

No idea really... I read it here in the forums somewhere, but now I can't find it. Didn't know if there was anything to it at all, or if it was a misconception.

It is a very high impedance antenna that needs to be fed via a step up balun to match its impedance to typical 50 ohm impedance. It still needs a return for the current so yes it needs a return to earth. And the earth itself is a ground plane. If you are talking about a portable or vehicle mounted VHF or UHF 1/2 wave, it gets tricky, you still need to have some sort of impedance matching device.

 

[slowmover]

Post in thread 'Newbie Seeking Advice'
Newbie Seeking Advice

 

[jcrmadden]

I know that antennas can be designed to TRANSMIT directionally, but can an antenna be designed to RECEIVE directionally?

I appreciate all the input and ideas that have been shared here.

I've read several posts, in this thread and elsewhere, that allude to an antenna's effectiveness because it gets out well (i.e. this is my antenna and I can talk all over).

That's not the real target here.

There's a Toyota Tacoma parked out in the woods running a 60 watt PEP through a 7' Skipshooter...

That's the only signal I care to capture and I want to hear it at the theoretical limits.

Should I be considering a horizontal antenna?