How to Figure out your transmit range

Yes but I would argue that HF follows the curvature of the Earth better than VHF and higher frequencies. That's why strict LOS calculations aren't the final answer.

Here's a chart for VHF base station to various radios using various power. I believe HF would be higher because again it is my belief that HF waves follow the curvature of the Earth better. Also consider how horribly ineffecient AM transmissions are--almost all the power is in the carrier and not the sidebands. CB SSB radio or even FM radio would very much improve range IMHO.

http://home.earthlink.net/~craigcoffaro/images/RangeChart606X451.gif

 

REAL WORLD ......



Range PROVIDED you take in account that the use of a 1/4 wave whip on CB is standard and on a band like 2 meters a 5db gain mobile antenna is not uncommon is not going to be that much different.

Where you do see advantages to HF is when your antennas are at low heights. MANY 2 meter operators run simple stations and base antennas of little gain and low height.
A RINGO RANGER at 25 foot is about as good as a 1/4 Wave CB ground plane ant 25 foot ranges running about 20 miles. At 2 meters you need capture ariea a 6 foot antenna is not much and with so many running verticals many don't relize how little signal that thing will find .... back in the days of of 2 meter AM stacked 11 elm beams was common ....

HF because of SKIP it is easier to work long distance however VHF/UHF you can use ducting to work stations at 300 miles here in Florida this is common.

VHF requires you put up a good antenna and it clear mosr everything around it do that and when things are right you can work 100 miles just about every night and even skip ....

Yes even FM works on skip ..... Just not as well ....

 

I tend to agree, and that was the point I was trying to make. To my way of thinking, trucker's antennas are at low heights. I think that's the reason that MURS radio did not catch on as a replacement for HF CB radio. MURS operates around 154MHz.

 

On HF we had an ITT MacKay 1KW (continuous power) unit that went to a huge MacKay outdoor tuner unit that was shunt fed to a 35 foot whip about 100 feet above the water with the ship and water as a great ground plane. There were times when I would cover 3/4ths of the globe with it. I would have a station in Malaysia call me and then a station in Europe. I loved to work AMTOR/SITOR with it. That was popular back in the late 80s. It was fun to work stateside stations and tell them that the ship was in the Indian Ocean just off the coast of Sri Lanka. I used commercial gear for all my hamming.

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Im on 20 meters sundays at 9am est 14.300 and have no problem working any control station with 80 watts ....... give a lissen for me.

BUT that is SKIP ..... without SKIP 20 meters is useless at 50 miles .....
Same on 40. 17, 15. 10 and 6 ..........

I have a friend 35 miles south on me we have tried 75, 40, 20, 17 and 10 meters (FM on 10, 6, 2, 1.25 and 3/4 meters ) and guess what band we can work on .......

2 meters and 223 mhz ......

On 10 meters I have worked Germany from the car on 29.600 simplex ...
When there is NO SKIP it dosn't do any better than 146.52 .... or 223.500 .

Because of local antenna laws here ( Hurricane requirements are 125 mph suvival ) and on going fights with a 49mhz phone user I have to restrct my antennas to comply .....

With my new antenna I will have 40 meters to 440 mhz coverage ( 223 mhz included )

Again a well thought out station on VHF/UHF will cover many miles.

 

REQUIRE MURS IN ALL CB RADIOS .......

Instead of it being ILLEGAL and let the truckers see clear quite radio channels and see how fast on the open road it gets used .....

 

That is interesting. But my comparisons between HF and VHF are from a trucker's perspective. I don't think their antennas will be more than about 12 feet off the ground at most. What is the legal amount of power for CB--4 or 5 watts? For MURS it is 2 watts. I would be shocked if the MURS radio would have just as much range if both radios were using the same power and both were using 1/4 wave antennas at the same fixed height. But maybe I am wrong. It would be a very interesting experiement though.

I guess the big problem with MURS is that there just aren't any mobile type units. Everything is handhelds. There were mobile type units but they never caught on. Wal Mart monopolizing the frequencies may have something to do with it. Then a lot of restaurants use those frequencies. The FCC shouldn't let WalMart get away with it. They are using free public frequencies for strictly commercial purposes IMHO. It's not like Wally can't afford to buy their own licensed spectrum.

 

You DON'T use 19 INCH antennas on MURS you use a 5DB gain colinear which is about 4 foot tall .... YES ANTENNA GAIN IS LEGAL ON MURS .
At VHF no one uses a 1/4 wave antenna you use GAIN antennas they STILL are very small. The FCC OUTLAWED MURS with any other band so no one makes them I have a radio shack MURS radio that was adapted from part 90 use.

Range car to car is about 6-10 miles on a flat road and to a good base 10+ even at 2 watts .....

I wonder how far 4 watts would go on CB if no one could get any more power out ......

REAL WORLD ...... 5/8 wave is the shortest antenna you run at High band VHF .

 

Nah, it ain't worth it.

 

You never know what VHF can do untill you try it ....