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October 20, 2018, 06:33:45 PM

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nosigma
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« Reply #75 on: May 28, 2018, 08:36:46 PM »

A low Voltage Standing Wave Ratio has nothing to do with how well the signal is getting out.  VSWR simply tells you how close you are to frying your finals due to reflected power.

John

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VirginiaZJ "Frank, Stop. Don't come down here"
Somebody: "Is John in a predicament?"
VirginiaZJ "The front of his Jeep is facing me now"
Somebody: "Yeah, I guess that's a predicament"

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Thought I saw nosigma at eastern mountain sports but it turns out the guys xj had been sideswiped
nosigma
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« Reply #76 on: May 28, 2018, 10:21:49 PM »

Public safety has gone to VHF UHF Digital Mobile Radio (DMR) with an extensive (closed) repeater network using repeater every 2-3 miles) funded by DHS.  OP: If your selling a public DMR system you doing a great disservice to the off road community, unless your installing repeaters every few miles where we wheel.

Focus on the fundamentals.

The higher the frequency the more dependant you are on an unobstructed line of sight.  As long as you only need to talk to people you can see UHF may work.

The higher the frequency the greater the attenuation by folliage.  VHF has ten times the signal loss of HF.  UHF has ten times the signal loss of VHF. Trying to use UHF radios in a dense folliage environment puts you at a huge disadvantage.

HF refracts and diffracts over ridges better than VHF.  VHF refracts and diffracts over ridges better than UHF.  Any 4 watt radio at any frequency will give you solid coms out to 100 miles with a clear line of sight.  I'd you want coms when in a valley you need HF.

A properly installed antenna with either radials or a good ground plane is essential for high effective radiated power and good coms.

The taller the antenna at a given frequency the more gain (effective power) BUT a tall antenna has a narrow elevation beam width which wont get up out of a valley and wont get over a ridgeline.

So why am I so interested in this?  It's my job and a passion.  I am an electromagnetics engineer for the Office of Naval Research.  I solve RF problems for ships, aircraft, satellites, vehicles and personnel.  I have also won two national first places along with a couple seconds in amateur (Ham Radio) VHF UHF competitions. 

Oh yeah, I have wheeled here on the east coast and the west coast (including the Hammers trails) using HF 11m (CB), VHF, UHF (FRS, GMRS & Ham freqs) for coms.  A properly installed (not just vswr tuned) CB is by far the best coms you can have per dollar unless you want to drop a grand on a beam, brick amp and low loss cable.

Enough said, buyer beware.  Have fun.

John
KM4KMU











Logged

VirginiaZJ "Frank, Stop. Don't come down here"
Somebody: "Is John in a predicament?"
VirginiaZJ "The front of his Jeep is facing me now"
Somebody: "Yeah, I guess that's a predicament"

Quote overhead
Thought I saw nosigma at eastern mountain sports but it turns out the guys xj had been sideswiped
Digger571
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War Eagle!
« Reply #77 on: May 28, 2018, 10:40:47 PM »

LOL. John with the mic drop...  Well said sir!   Cheers

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-Paul
R3
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Posts: 493
« Reply #78 on: May 29, 2018, 06:19:22 AM »

John,
Enjoyed your posts... ONR... Science and technology.... They develop technology with in 6.1-6.3 funds early stages of development. Still behind commercial development sadly. Obviously this is your rice bowl and you defend it vigorously.

I guess you will always support analogue technology and anyone who doesn't begets you wrath.

As to EMS having repeater every 2-3 miles.... I don't think so. Repeaters yes but the density is fiscally unfeasible.

Ran to Norfolk this past weekend with a friend in another rig equipped with a Rugged Radio. We easily talked 5-8 miles to each other on US17. Our CB's did not do so well and were clobbered by static and illegal operators.

As Hank proposed, be happy to do an in vehicle test comparison on trails we run.

You don't support this idea?

If CB technology is so good, why not put on a clinic to the club to "fix" their CB issues?

It has always been hard to work with ONR due to the "not invented here" mentally. Your arguments support that. Sadly that mentality has been keeping us firmly behind our adversaries.

When you are ready to do an experiment let me know... I retire for this Urinary Olympiad.

But please feel free to flame on.





Sent from my Moto Z (2) using Tapatalk


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Cheers
RRR
17 JKURR
4.5 Metal cloak
37 BFG ATs
Dynatrac, PSC, Barnes, Ried, RCV....
next?

"Keep calm and carry on, No Thanks! I would rather raise hell and change the world."
Clifford04X
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Posts: 368
« Reply #79 on: May 29, 2018, 09:51:20 AM »

I don't think he's seen johns Jeep... 

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04 TJ, 5.5" Clayton long arm, Waggy 44 front, 8.8 Rear, 5.13's, Lockers, NP241OR, 36 iroks, Allied beadlocks, Hydro assist, Warn bumpers/sliders, M8000 winch.
overhead
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Crap, someone call Trevor.
« Reply #80 on: May 29, 2018, 10:21:48 AM »

I don't think he's seen johns Jeep... 

I think john has a completely different way of thinking that is coming across weird through text.

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The only thing about a Yj that's reliable is its mechanic.

Joey to Mike- That's more like it! Never done.....just outta money at the moment.

atjeep-Every time a YJ passes inspection, an angel gets it's wings.
Hank
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Posts: 32
« Reply #81 on: May 31, 2018, 03:56:39 AM »

Public safety has gone to VHF UHF Digital Mobile Radio (DMR) with an extensive (closed) repeater network using repeater every 2-3 miles) funded by DHS.  OP: If your selling a public DMR system you doing a great disservice to the off road community, unless your installing repeaters every few miles where we wheel.

Focus on the fundamentals.

The higher the frequency the more dependant you are on an unobstructed line of sight.  As long as you only need to talk to people you can see UHF may work.

The higher the frequency the greater the attenuation by folliage.  VHF has ten times the signal loss of HF.  UHF has ten times the signal loss of VHF. Trying to use UHF radios in a dense folliage environment puts you at a huge disadvantage.

HF refracts and diffracts over ridges better than VHF.  VHF refracts and diffracts over ridges better than UHF.  Any 4 watt radio at any frequency will give you solid coms out to 100 miles with a clear line of sight.  I'd you want coms when in a valley you need HF.

A properly installed antenna with either radials or a good ground plane is essential for high effective radiated power and good coms.

The taller the antenna at a given frequency the more gain (effective power) BUT a tall antenna has a narrow elevation beam width which wont get up out of a valley and wont get over a ridgeline.

So why am I so interested in this?  It's my job and a passion.  I am an electromagnetics engineer for the Office of Naval Research.  I solve RF problems for ships, aircraft, satellites, vehicles and personnel.  I have also won two national first places along with a couple seconds in amateur (Ham Radio) VHF UHF competitions. 

Oh yeah, I have wheeled here on the east coast and the west coast (including the Hammers trails) using HF 11m (CB), VHF, UHF (FRS, GMRS & Ham freqs) for coms.  A properly installed (not just vswr tuned) CB is by far the best coms you can have per dollar unless you want to drop a grand on a beam, brick amp and low loss cable.

Enough said, buyer beware.  Have fun.

John
KM4KMU

I am the OP. I am not selling anything. I originally asked what everyone uses for Comm on trails. Thatís it. I am a HAM as well (KC8KGV) and I work public comm for a living. Also, a slight correction for you. I donít know of any groups that have repeaters every 2-3 miles. That would be wildly expensive. Placed up high and using good propagation mapping its more like 30ish miles around this area. Get into the mountains and down town and itís a little closer but still not 2-3 miles.


Sent from my iPhone using Tapatalk

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Ratty old 1995 YJ with a 2.5, AX5, 4" lift, an 33's.
nosigma
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Posts: 3995
« Reply #82 on: May 31, 2018, 08:43:18 PM »

I am such a tard.  Shocked that Hondo hasnt fired me yet.

 Propellar Head

John

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VirginiaZJ "Frank, Stop. Don't come down here"
Somebody: "Is John in a predicament?"
VirginiaZJ "The front of his Jeep is facing me now"
Somebody: "Yeah, I guess that's a predicament"

Quote overhead
Thought I saw nosigma at eastern mountain sports but it turns out the guys xj had been sideswiped
KensHardware
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Posts: 221
« Reply #83 on: August 30, 2018, 11:08:58 AM »

What John said! Wow. I wish I knew as much as John about this topic.

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