100 Miles with 10mW using an HT?!

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MrGClips

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Watching all sorts of radio related videos I came across a clip where some guy hit a repeater 100 miles (160 Km) away with a handheld Yaesu FT-60 on 10 milliwatt settings with a REGULAR antenna, then had a live voice contact as well!

That is so cool! Unbe-friggin'-lievable!

Of course, he did it from some very high mountain top (2076m high), but still, it's pretty amazing! Or is it fake? Can those radios be set to such low power level at all? Sounds very interesting. 100 miles with 0.01 Watt? Wow! https://www.youtube.com/watch?v=cz5F1QWZ_a0
 

BoxAlarm187

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I've witnessed a trunked system worked from 115 miles away on a 5W Motorola APX7000 from atop a 508' (ASL) building...
 

nd5y

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Unbe-friggin'-lievable!
Maybe it's unbelievable to somebody who knows very little about radio.

Of course, he did it from some very high mountain top (2076m high), but still, it's pretty amazing! Or is it fake?
It's entirely possible. Power isn't that important when you have an unobstructed line of sight path.
There could have been a tropo opening occuring when that video was made.

Can those radios be set to such low power level at all?
He could have set the low power level all the way down. My FT-7800Rs are like that. The repair manual has instructions for accessing the alignment mode menu. You can adjust the power levels and other settings. I assume most of Yaesu's other radios are the same.

It is also possible he did some hardware mod, he could be lying about the distance or power, or he might not know how much power the radio is really putting out.

Don't automatically believe everything on YouTube is true, especially ham radio stuff.
 
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MrGClips

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Then I guess all the Bubble-Pack radio makers can easily claim those ridiculous ranges based upon similar tests under such conditions. High in the mountain, open sky, no interference of any sort.

Then what kind of range can you have with full power on a VHF/UVF HT with a better antenna from a place like that? A thousand miles? Pretty cool either way. :D

And yes, I'm still very ignorant of radios, though I'm taking my Extra exam soon. Still got a lot to learn.
 

AK9R

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The lowest power setting on a stock FT-60 is 0.5 watts (500 milliwatts) at the nominal power supply of 7.2 volts. It may be possible to achieve lower power output by using a power supply with less voltage or by attenuating the power output or by tweaking the default settings in the service menu.

As others have stated, a transmitter with its antenna at approximately 6800 feet above sea level will have a pretty large footprint.
 

jwt873

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I've done over 1500 miles on 10 milliwats. This was on HF using a 3 element beam. I used a tiny transmitter that used a single crystal clock chip running at 28.060 Mhz. (The 10 meter QRP frequency).

With the transmitter in the image below, I've had contacts with California, Oregon and New York. One of the two grey wires on the top goes to the transmitter, the other to the antenna. The blue box below that is a TX/RX relay. The long blue thing under that is a potentiometer used to cut down the signal. The Red/Black wires go to a 6V battery and the Blue/Black wires are for a CW key.

Out of interest there are QRP die hards that go lower. There have been some long distance microwatt QRP contacts. See---> NAQCC - QRP Works

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nd5y

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Then what kind of range can you have with full power on a VHF/UVF HT with a better antenna from a place like that? A thousand miles?
Assuming there is no tropospheric propagation occuring it depends on how high each station is and if the curvature of the earth's surface is in the way. I don't know off hand what the mountain top distance record is. I have heard amateur radio balloons on the 2m band at around 90,000-100,000 feet altitude about 400 miles away and aircraft over 30,000 feet altitude about 300 miles away.
 

MrGClips

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I've done over 1500 miles on 10 milliwats. This was on HF using a 3 element beam. I used a tiny transmitter that used a single crystal clock chip running at 28.060 Mhz. (The 10 meter QRP frequency).

With the transmitter in the image below, I've had contacts with California, Oregon and New York. One of the two grey wires on the top goes to the transmitter, the other to the antenna. The blue box below that is a TX/RX relay. The long blue thing under that is a potentiometer used to cut down the signal. The Red/Black wires go to a 6V battery and the Blue/Black wires are for a CW key.

Out of interest there are QRP die hards that go lower. There have been some long distance microwatt QRP contacts. See---> NAQCC - QRP Works

.

That is absolute madness! Amazing achievements for sure! WOW! :D
 

prcguy

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I know a stock 5w military handheld transmitting with a rubber duckie antenna can get a weak but usable signal through a UHF satellite at 300MHz uplink and 260MHz downlink. That's 22,300mi to the satellite from a walki talki. Or 4,460mi per watt. These radios are usually used with a small 5 to 7dBi gain antenna for very reliable comms through the satellite.
prcguy

Then I guess all the Bubble-Pack radio makers can easily claim those ridiculous ranges based upon similar tests under such conditions. High in the mountain, open sky, no interference of any sort.

Then what kind of range can you have with full power on a VHF/UVF HT with a better antenna from a place like that? A thousand miles? Pretty cool either way. :D

And yes, I'm still very ignorant of radios, though I'm taking my Extra exam soon. Still got a lot to learn.
 
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nd5y

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techman210

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Our users reported a drastic drop in signal strength from a UHF repeater at about 6000'. But the repeater WAS still usable. Even from 40 miles away.

When I got to the site, I measured the output of the transmitter - BEFORE the loss in the circulator, and filters, and the line loss to the 7dB gain antenna.

It was running 0 dBm.

Otherwise known as 1mw, or 0.001 watt.

This is why I tell people when they insist on running 100W from high hilltops that they are usually wasting their money.
 

kayn1n32008

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Our users reported a drastic drop in signal strength from a UHF repeater at about 6000'. But the repeater WAS still usable. Even from 40 miles away.

When I got to the site, I measured the output of the transmitter - BEFORE the loss in the circulator, and filters, and the line loss to the 7dB gain antenna.

It was running 0 dBm.

Otherwise known as 1mw, or 0.001 watt.

This is why I tell people when they insist on running 100W from high hilltops that they are usually wasting their money.


Just went through that with one of our local VHF repeaters. 71Km away, with 10mW out of the PA(before duplexer and 100+m of 7/8" hard line.) and I could still hear it, and it was still usable in the city, and I was still hearing it at my place... PA was replaced this weekend and it is now running at a whopping 17 watts.

I can see needing a PA running 100 watts if being forced to combine into a community antenna(with at least 6dB loss in combining) but to run a 100 watt PA just because it's 'cool' will make an unbalanced repeater in most cases. Here on the prairies, even a 50 watt repeater will be unbalanced. I just finished a business trip into BC, and in the national parks, the VHF Parks Canada repeaters were 4 watts.

I know of a UHF repeater that puts out 12.5 watts before the duplexer, through 100+m of feed line and is very well balanced for a 45w mobile.
 

Project25_MASTR

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OP, look up free space path loss. Bubble pack radios run 500 mW (27 dBm) max on FRS.

Remember, NASA sent video from the moon 250,000+ miles on less than 2W of power (UHF).

Sent from my Venue 7 3730 using Tapatalk
 

MrGClips

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Obviously in free space or using digital modes and various techniques like EME and such, gigantic distances can be reached, but quite frankly, when I hear people talking about everyday range tests, most are happy if they get 3 miles with their HT, and even less with a walkie on full power, so I was VERY impressed when I saw this clip, especially using nothing else but a regular HT with a standard regular antenna, set to the lowest possible power setting in manual mode to 0.01 watt :D , reaching a hundred miles or so. I suspect it was on UHF, but not sure.

Anyhow, I've found that clip and that successful contact pretty cool and made me think why people are so obsessed with more and more transmitting power when in fact, obviously even a fraction is plenty enough with a good antenna placed to the right spot on high enough elevation.

Thanks for the comments, I've learned some interesting things again. :)
 

ElroyJetson

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We're still getting good telemetry and photos from the Voyager 1 and 2 probes and they're both past Pluto. They have 10 watt transmitters.

Granted, the earth stations are, to put it mildly, very sensitive indeed, but the point to be made is that the practical limitation on the useful range of a radio is how far you can get before the signal is reflected or absorbed by terrain obstacles rather than free space signal power level loss due to distance alone.

NASA has flown amateur radio experiments on several shuttle missions and there is an amateur station on the ISS. They use a modified commercial portable radio (Motorola or GE-Harris, etc) and it puts out no more than its usual rated power. The last information I found regarding the ISS amateur radio equipment showed them using an Ericsson M-PA System model equipped with a headset and powered off station power via a battery adapter.

In any event, if you talk to the ISS via amateur radio, the one way signal path is not less than 249 miles and if there are any signal degradation issues, they're atmospheric or non line of sight.
 

kayn1n32008

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Voyager may only transmit woth 10w but the antenna has in excess of 30dB of gain... ERP is a much more useful number in this instance.
 
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