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Best setup for reliable radio communications over 30 or 60 miles?

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TC Talks
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Re: Best setup for reliable radio communications over 30 or 60 miles?

Post by TC Talks » Mon Dec 28, 2020 9:10 pm

What about Marine Frequencies? VHF, high power, no special license.


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Re: Best setup for reliable radio communications over 30 or 60 miles?

Post by Deleted User 14896 » Tue Dec 29, 2020 11:29 am

TC Talks wrote:
Mon Dec 28, 2020 9:10 pm
What about Marine Frequencies? VHF, high power, no special license.
Well, you're not "supposed" to use them shore to shore. I suppose as long as you didn't ragchew on it, you may not get in trouble.



k8jd
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Re: Best setup for reliable radio communications over 30 or 60 miles?

Post by k8jd » Tue Dec 29, 2020 2:04 pm

AGAIN the problem with VHF marine band is that "radio horizon", you need a high tower and gain antenna and still may not be able to reach 60 miles.
VHF marine radios are FM and only up to 25 W , FM is a very poor mode for weak signal work.



km1125
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Re: Best setup for reliable radio communications over 30 or 60 miles?

Post by km1125 » Tue Dec 29, 2020 3:58 pm

I don't think it's the power as much as the radio horizon issue. Marine VHF is good for ~40 miles but that's usually limited by antenna height. That height would have to increase even further to get above the terrain obstructions that you'd have that boats don't need to deal with.



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MWmetalhead
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Re: Best setup for reliable radio communications over 30 or 60 miles?

Post by MWmetalhead » Tue Dec 29, 2020 7:19 pm

What's wrong with the 6 meters band (50 MHz to 54 MHz) ?



bmw
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Re: Best setup for reliable radio communications over 30 or 60 miles?

Post by bmw » Tue Dec 29, 2020 10:21 pm

6 meters is still VHF, and thus, requires higher power and/or a higher antenna.

As a general rule, is there a linear relationship between broadcast distance and frequency, all other things equal? As in, will the same power signal on the same antenna type (say, quarter-length dipole) travel further (groundwave) for every step down in frequency?

NVIS propagation looks interesting. But it also looks like 40 meters is the highest frequency band you can reliable use such propagation on.



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Re: Best setup for reliable radio communications over 30 or 60 miles?

Post by audiophile » Thu Dec 31, 2020 5:37 am

80 meters is probably the band. I talk on it almost every day and 60-150 miles is no sweat with 100 watts and full-size dipole antenna in NVIS mode.

Get a ham license though, you can practice at www.qrz.com with the actual questions on the test.


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Re: Best setup for reliable radio communications over 30 or 60 miles?

Post by audiophile » Thu Dec 31, 2020 5:42 am

Also the CB band could work but you will need beams and to run a SSB radio. Same with six meters.


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Re: Best setup for reliable radio communications over 30 or 60 miles?

Post by audiophile » Thu Dec 31, 2020 6:00 am

bmw wrote:
Tue Dec 29, 2020 10:21 pm
6 meters is still VHF, and thus, requires higher power and/or a higher antenna.

*CORRECT, AND PROBABLY A BEAM TOO.

As a general rule, is there a linear relationship between broadcast distance and frequency, all other things equal? As in, will the same power signal on the same antenna type (say, quarter-length dipole) travel further (groundwave) for every step down in frequency?

*NOT THAT SIMPLE. GROUND WAVE IS EXCELLENT ON LOWER END OF AM BROADCAST BANDS (540 kHz). BY THE TIME YOU GET TO UPPER END OF AM BROADCAST BAND IT'S TERRIBLE IN MANY LOCATIONS (1600 kHz) DEPENDING ON TYPE OF SOIL. ONCE YOU GET TO 80/75 METERS (3800 to 4000 kHz) GROUND WAVE ISN'T VERY HELPFUL BEYOND A FEW MILES! THERE IS A SOMEWHAT OF A DEAD ZONE, WHERE GROUND WAVE DIES OUT AND NVIS HASN'T FULLY KICKED IN YET.

NVIS propagation looks interesting. But it also looks like 40 meters is the highest frequency band you can reliable use such propagation on.
*YES, I WOULD RECOMMEND 80/75 METERS FOR NVIS. THERE WEBSITES THAT SHOW MAXIMUM USABLE FREQUENCY FOR NVIS. http://www.spacew.com/www/fof2.html


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Re: Best setup for reliable radio communications over 30 or 60 miles?

Post by CK-722 » Thu Dec 31, 2020 9:43 am

My high school neighbor at WB8APT, "WB8 Another Powerful Transmitter, running 10 watts QRP", built a low power transmitter, and put a decent ground wave 8 blocks away on 40 meters with a Magnavox AM/SW Portable.


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Re: Best setup for reliable radio communications over 30 or 60 miles?

Post by SolarMax » Thu Dec 31, 2020 10:47 am

CK-722 wrote:
Thu Dec 31, 2020 9:43 am
My high school neighbor at WB8APT, "WB8 Another Powerful Transmitter, running 10 watts QRP", built a low power transmitter, and put a decent ground wave 8 blocks away on 40 meters with a Magnavox AM/SW Portable.
Unless you're connected to a dummy load, ten watts on any HF or VHF band will get you out further than 8 blocks (1/2 mile or so), but not 60 miles ground wave, nor on sky wave, predictably or reliably. And, it's always all about the antenna.
To nit-pick, 5 watts and under is what's commonly regarded as "QRP."

MW- 6 meters can behave similarly to 10m, with spring/summer sporadic-E welcomed by DXers, a problem for local comms, and short local direct range.



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Re: Best setup for reliable radio communications over 30 or 60 miles?

Post by CK-722 » Thu Dec 31, 2020 3:07 pm

He was the one who said 10 watts QRP, not me. This was circa 1969, so I don't know when the 5 watt designation happened. 5 watts? That's what Dale Bickel gave the 106.7 translator for an STA in Petoskey. I guess it's a QRP STA.

Image


Is THAT where they got the idea for the 486-SX?

Same (x, y, z), different (t)

Your bullet missed my trial balloon.

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