Uniden GMR635 FCC ID AMWUT916

This six mile radio says in the FCC specs that it puts out only less than
half a watt...am I reading that right?

Jeff

Jeff wrote:
This six mile radio says in the FCC specs that it puts out only less
than half a watt...am I reading that right?

"six mile radio" is a marketing term. ~500 mw for power output sounds
perfectly plausable for an FRS/GMRS hand held.

In article ,
Travis Jordan wrote:

This six mile radio says in the FCC specs that it puts out only less
than half a watt...am I reading that right?

"six mile radio" is a marketing term. ~500 mw for power output sounds
perfectly plausable for an FRS/GMRS hand held.

Agreed. A lot of the less-expensive FRS/GMRS radios have transmitters
which only deliver the 1/2-watt legal limit for FRS. They can tune
to, and transmit on the GMRS frequencies, but they don't do so at any
higher power than than can do on the FRS-only and FRS/GMRS frequencies.

You could almost certainly get 6 miles of range out of these radios,
if their receivers aren't horribly insensitive (which they sometimes
are) and if you have a completely clear line-of-sight between one
radio and the other (think "standing on a hilltop, talking to a guy
who is standing on another hilltop six miles away that you can see
without obstruction."

At ground level, with buildings and trees around, the range is likely
to be on the rough order of a half-mile or even less.

--
Dave Platt AE6EO
Hosting the Jade Warrior home page: http://www.radagast.org/jade-warrior
I do _not_ wish to receive unsolicited commercial email, and I will
boycott any company which has the gall to send me such ads!

"Jeff" ) writes:
Uniden GMR635 FCC ID AMWUT916

This six mile radio says in the FCC specs that it puts out only less than
half a watt...am I reading that right?

Jeff


You're reading it wrong. The rules limit the power, and there's no
stretching of that. But, the manufacturers can stretch the truth about
the range, if there was a fine print disclaimer next to that range statement
it would likely be under very limited conditions.

Michael VE2BVW

(Michael Black) wrote in
:

"Jeff" ) writes:
Uniden GMR635 FCC ID AMWUT916

This six mile radio says in the FCC specs that it puts out only less
than half a watt...am I reading that right?

Jeff


You're reading it wrong. The rules limit the power, and there's no
stretching of that. But, the manufacturers can stretch the truth
about the range, if there was a fine print disclaimer next to that
range statement it would likely be under very limited conditions.

He actually *is* right. That radio has an ERP of .17 watts on GMRS and .13
watts on FRS. Uniden is notirious for putting out woefully weak radios and
inflating range claims.

In article ,
"Jeff" wrote:

Uniden GMR635 FCC ID AMWUT916

This six mile radio says in the FCC specs that it puts out only less than
half a watt...am I reading that right?

Jeff



Sure, .5 Watt Output, from hilltop to hilltop, can easily span 6 miles.
I have a Part15 Spread Spectrum 2.4Ghz Radio with 100mw Output that
carries 2 ea. T1 Spans (4 Mhz Bandwidth) 16 miles, with 25db Fade
Margins on the link. There are Path Calculation Programs that can
provide excellent information on this issue.

On Wed, 2 Aug 2006, Jeff wrote:

Uniden GMR635 FCC ID AMWUT916

This six mile radio says in the FCC specs that it puts out only less than
half a watt...am I reading that right?

Jeff



Most of the 2 billion cell phones that are in existence in the whole world
(yes, 2 billion! US, China, Russia, even 100 million in India, plus
everywhere else) put out less than one watt. And, I see cellphone towers
spaced, what, ten miles +/- appart all over where I live and most cell
phone calls are not over strict line-of-sight paths. Might not be a
totally fair comparison, but some food for thought.

This six mile radio says in the FCC specs that it puts out only less than
half a watt...am I reading that right?

Most of the 2 billion cell phones that are in existence in the whole world
(yes, 2 billion! US, China, Russia, even 100 million in India, plus
everywhere else) put out less than one watt. And, I see cellphone towers
spaced, what, ten miles +/- appart all over where I live and most cell
phone calls are not over strict line-of-sight paths. Might not be a
totally fair comparison, but some food for thought.

Yup. Raw transmit power isn't the only factor. The tower height is
an essential element of this system.

An interesting web page to read can be found at

http://www.firestik.com/Tech_Docs/dist2horizon.htm

It discusses the distance to the visual horizon, as well as the "radio
horizon" distance based on the antenna height (radio waves can often
travel some distance beyond the visual horizon, for a variety of
reasons).

According to the formula in this page, two radios whose antennas are
located 6' above the ground, will have a radio-horizon distance of a
bit less than 7 miles. At any distance greater than that, the Earth's
surface will block the direct path between the two radios, and
reliable communication (on FRS/GMRS and other UHF frequencies at
least) will probably be difficult or impossible. Add in the effect of
ground clutter (buildings and trees blocking the direct path and
generating reflections) and you end up with a much shorter useful
range.

Raising one radio up onto a building or hill greatly increases the
transmission distance, for at least two reasons - it gets one radio
out of the ground clutter and it increases the radio-horizon
distance. With one radio at 100' and the other at 6', the radio
horizon distance extends out to more than 17 miles.

The horizon distance and the presence of ground clutter often make
more of a practical difference than raw transmit-power level. Going
from 500 milliwatts to 5 watts is a 10:1 increase, which works out to
a clear-line-of-sight range increase of around 3:1 - but if the other
guy is over the radio horizon, you may not actually get any better
communication using the higher power.

--
Dave Platt AE6EO
Hosting the Jade Warrior home page: http://www.radagast.org/jade-warrior
I do _not_ wish to receive unsolicited commercial email, and I will
boycott any company which has the gall to send me such ads!

Uniden GMR635 FCC ID AMWUT916

This six mile radio says in the FCC specs that it puts out only less
than half a watt...am I reading that right?



Specifications with communications distance in them don't mean crap. I
have talked over 90 miles with a 2M 1 watt HT, ( Alamagordo to El Paso ).
Terrain is everything.


Ed K7AAT