How far will various local radio transmissions carry?

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The Lazy L

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Thought a few folks might find my test results informative.

Antennas are mounted in the attic above my garage. Radios are off the shelf with the only modifications is the receiving GMRS/FRS/VHF units have the "Rubber Ducky" antenna removed to use the attic antennas. Garage is within a wooded area, topographically the area is almost flat +- 100 feet.

I used a Voice Activated (VOX) recorder in my communication shack to allow for one-person (me) testing. GMRS, FRS and VHF radios on both ends are hand held. The CB SB mobile antenna is mounted six feet off the ground with a metal ground plane (Kawasaki Mule aluminum roof).

Total distance tested (as the crow flies) was 4.51 miles. Weather was sunny and warm.

I drove the Mule south, stopping at landmarks and addresses. I would radio back to the VOX recorder giving my location in a non-discernible code. On location I would down what "code" was used for which location. Example; "I'm not too far from home" meant I was across from a cell tower. I would use the same code across the four different radio platforms mentioning a number designator for each platform.
#1 = GMRS
#2 = FRS
#3 = VHF
#4 = CB SB

In my communications shack I have a wall mounted topographic map of the area. Home location is marked with a small brass nail. Listening to the recorded messages I was able to ascertain distances. I drew different colored circles around the home location representing the test results below. Circles give the communications operator a idea of what they can expect.

VHF 4 watts. Last clear communication was at .87 miles. I expected VHF to do better (no repeater).

FRS 1/2 Watt. Last clear communication was at 1.02 miles

GMRS 5 watt. Last clear communication was at 2.98 miles

CB SB 12 watts. Last clear communication was at 4 miles


I want to repeat my test going north, east and west but haven't allocated the time to do so.
 
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When you say "wooded area" what kind of trees do you have and how dense are they?
80 meter radio caries further in the fir forests at the same power settings than 2 meter radios. The trees tend to scatter and absorb the 2 meter waves but the 80 meter waves just travel through.
Antenna location could be better. Unshrouded (above the roof), higher, high gain antennas (tuned for each radio), you might even try a series of old "inverted V" antennas to get higher signal to noise ratios.
Your power levels have to be squared to double your distance with all else being the same, so the 12 watt SSB 11 meter has the advantage power wise.
 
I am very surprised the VHF signal Diferent test for sure, but I have gotten well over 5 miles using 2 HT's with the rubber ducks they came with at 5W. Using an upgraded antenna ( not sure of the brand or model), but it is an extendable model that is nearly 4' long fully extended, I was getting much better than 10 miles.
Thanks for the report. Good food for thought.
 
This is an excellent exercise for everyone to do: learn what frequencies work best in what locations near home.

Your ranges seem pretty far off, though. My 5w HT can reliably and clearly hit repeaters well over 5 miles away but that's line-of-sight; the signal isn't going through anything but air. Have you put a SWR meter on your antennas and tuned them? Is your transmitting location in a valley or on otherwise low ground? Something is definitely wonky with your setup that you're not getting any distance.

For folks who may not be familiar, VHF frequency ranges are 30MHz to 300MHz. UHF range from 300MHz to 3000MHz. FRS and GMRS use the same UHF frequencies at ~462MHz. MURS is VHF at ~151MHz. And CB is HF coming in at ~26.9MHz-27.4MHz.
 
We had vhf radios in our trucks. I have talked up to 30 miles away. Both of us on high ground.
 
When you say "wooded area" what kind of trees do you have and how dense are they?
80 meter radio caries further in the fir forests at the same power settings than 2 meter radios. The trees tend to scatter and absorb the 2 meter waves but the 80 meter waves just travel through.
Antenna location could be better. Unshrouded (above the roof), higher, high gain antennas (tuned for each radio), you might even try a series of old "inverted V" antennas to get higher signal to noise ratios.
Your power levels have to be squared to double your distance with all else being the same, so the 12 watt SSB 11 meter has the advantage power wise.

Wooded area was harvested 25 years ago. What survived or grew back are mostly hickory and maple. 75' feet in height. Think of a normal woods with 1 tree left for every 5 taken.

Antenna location could be better, considering I want the antennas concealed the attic location it's the best height option I have.
 
This is an excellent exercise for everyone to do: learn what frequencies work best in what locations near home.

Your ranges seem pretty far off, though. My 5w HT can reliably and clearly hit repeaters well over 5 miles away but that's line-of-sight; the signal isn't going through anything but air. Have you put a SWR meter on your antennas and tuned them? Is your transmitting location in a valley or on otherwise low ground? Something is definitely wonky with your setup that you're not getting any distance.

For folks who may not be familiar, VHF frequency ranges are 30MHz to 300MHz. UHF range from 300MHz to 3000MHz. FRS and GMRS use the same UHF frequencies at ~462MHz. MURS is VHF at ~151MHz. And CB is HF coming in at ~26.9MHz-27.4MHz.

I agree something is "off" on the 2-meter. Base is not in a valley or low ground. Distance location I tried to pick a mix of low and high ground to transmit from. Hand Held is stock, I didn't see any need for a SWR test. Base can hit a repeater at 5 miles plus too. Perhaps I got a bad hand held? Next time the Son is here we will do a two-way test and with a different HT.
 
Are there trees near enough to your shack (or house) that could be used as a discreet mast? A roll-up slim jim 2m/70cm attached to the tree and elevated significantly above your attic might help a lot. I know you know this...I'm just thinkin' out loud. :)

Let us know how future tests go.
 

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