Two-way Radio Question

[skidoc22]

I have noticed recently that the two-way radios advertised (walkie-talkies for us of the Dick Tracy era) claim to have vastly increased broadcast and reception power. It seems that only a couple of years ago it was unusual to see a six- or seven-mile range while now it is in the double digits. Having used at least three pairs with different ratings, I have not noticed much difference in reception. I am aware there are different bands with different broadcasting power but I thought the limit was a function of the safe levels of radio wave emittence from the radio. Have the receivers improved or have they somehow increased the power safely? Or have they just changed the way they rate the units?

 

[SAR-EMT40]

I have noticed recently that the two-way radios advertised (walkie-talkies for us of the Dick Tracy era) claim to have vastly increased broadcast and reception power. It seems that only a couple of years ago it was unusual to see a six- or seven-mile range while now it is in the double digits. Having used at least three pairs with different ratings, I have not noticed much difference in reception. I am aware there are different bands with different broadcasting power but I thought the limit was a function of the safe levels of radio wave emissions from the unit. Have the receivers improved or have they somehow increased the power safely? Or have they just changed the way they rate the units?

If we are talking about FRS/GMRS they can basically tell you any lie they want to, and they usually do. Maybe someone, once, from one mountaintop to another mountaintop was able to talk to someone, at least they think it was them, and they are using that number. Most handhelds FRS radios are limited by law to .5 watts. They are in the 460MHz range as are GMRS. GMRS handhelds typically transmit around 5 watts.

You are correct that the radiation that you are allowed to absorb varies with frequency. Because the damage that is done to the body varies with the power and frequency. While you would not want to look into the waveguide of a 1.2 GHz transmitter pushing 50 milliwatts, you probably wouldn’t think too much about having a 5 watt antenna near your head if it is in the 144Mhz range.

Keith

 

[gforce]

There are actually three types of walkie-talkies or (HT's) commonly in use. The FRS types require no license and have output power of .5 mw. GMRS types require a license (but no test) and has output power of 1.0-5.0W. Both of these are in the UHF band which is generally a line of sight type of transmission. Thus if you cross a ridge etc. you may loose contact. The third type is a HAM radio which requires a FCC test (but not necessarily morse code) Typical handheld HAM HT's will have 5 watts of output power, and generally have much better antennas. Also HAM radios can take advantage of strategically located repeater stations which can vastly increase range and avoid some of the line of sight issues I mentioned above. So there are definitely differences in the basic types in terms of actual communication capability. I take along a Yaesu VX-7R which is a small waterproof HAM HT. I have talked to people in Boston while hiking in the Whites many times, utilizing various repeater systems. Also it has weather bands etc. which are very helpful. In comparison I have found HAM radio to be a more reliable method of emergency communication than a cell phone (in the whites). While shopping around for a radio in general I would say compare the antenna, output power, and then the reciever.


gforce - KB1GUE

 

[bubba]

Good info above. The other influence is weather -- if claims are made, the reception is on a "perfect" day: clear, 45 degree, zero humidity, etc. Weather plays a large part.

 

[SAR-EMT40]

The third type is a HAM radio which requires a FCC test (but not necessarily morse code)
gforce - KB1GUE

I assumed if skidoc was a ham he wouldn't be asking these questions. That is why I didn't mention it.
As far as suggesting he look at ham radio as a real option I fully agree.

I always carry either my Yaesu FT-50 or my Kenwood TH-F6A

Keith
N1XTK

 

[DougPaul]

Good info above. The other influence is weather -- if claims are made, the reception is on a "perfect" day: clear, 45 degree, zero humidity, etc. Weather plays a large part.

Actually weather has only a small effect over several mile ranges for the frequencies used by FRS radios (which I assume is what the OP was asking about). It can provide long distance paths (tropospheric ducting) under certain conditions. I have heard Kansas and contacted Florida (from the Boston area) using what may have been tropo ducts from my base station on 2M (144 MHz). This distance is very rare--normal range is a few hundred miles or less between base stations with 100 or more watts and elevated high gain antennas. (Hand helds are limited to a few watts and low level antennas.)

While the weather has little effect on FRS radios, trees, particularly if they are wet, have leaves, and/or sap running, will absorb a significant amount of the signal.

I agree with SAR-EMT40--the quoted ranges are pure advertising fiction--your only hope of getting anywhere near those ranges if you both are on mountain tops with a direct line of sight. I tested the range of a pair of FRS radios: 1/2 mile in trees over flat land on a dry day. And in practice, it has frequently been a lot less, partucularly if there is an intervening ridge.

Doug
WB2QJE

 

[ChrisB]

Question for hams

Question -

Is the Mt Washington 2m repeater an open machine, in the sense that anyone is welcome to use it if they can tone into it?

cb

 

[SAR-EMT40]

Question -

Is the Mt Washington 2m repeater an open machine, in the sense that anyone is welcome to use it if they can tone into it?

cb

Absolutely. That what open means by the way.

146.655 Negative offset PL 100.0 Hz
Quite good coverage. Not always a really active machine though.

Throw out your call. If I am around and I hear you I will answer. I'm not there all the time though.

Keith
N1XTK

 

[DougPaul]

BTW, there are about 5 2M repeaters in and around the Whites. All open.

Doug

 

[bubba]

Actually weather has only a small effect over several mile ranges for the frequencies used by FRS radios (which I assume is what the OP was asking about).

From the Motorola site product listings of FRS/GMRS radios, this footnote:

Depends on terrain and weather conditions.

Weather can play a significant role in reception. Assuredly, a lower role than terrain, but the post was meant to add weather as an additional factor not previously brought to the forefront in the discussion.

 

[DougPaul]

From the Motorola site product listings of FRS/GMRS radios, this footnote:

Weather can play a significant role in reception. Assuredly, a lower role than terrain, but the post was meant to add weather as an additional factor not previously brought to the forefront in the discussion.

Got an authoritative reference?

Doug
PhD electrical engineer
ham using VHF frequencies since the '60s.
(I've also studied radio signal propagation.)

 

[adkleaddog]

Question;

Does frequency-wavelength have any effect on range, or will "punch" through trees and such? Example, GMRS as opposed to LMR units...

 

[DougPaul]

Question;

Does frequency-wavelength have any effect on range, or will "punch" through trees and such? Example, GMRS as opposed to LMR units...

Yes it does.

* 2 meter ham: 144 MHz
* FRS/GMRS units work at about 460MHz, just below TV channel 14.
* Cell phones, 900MHz, 2400MHz (?), 5000MHz
* GPS 1400MHZ

In this general frequency range, all else being equal, higher frequencies have shorter range and are more sensitive to wet vegetation and intervening terrain.

Doug

 

[adkleaddog]

Yes it does.

* 2 meter ham: 144 MHz
* FRS/GMRS units work at about 460MHz, just below TV channel 14.
* Cell phones, 900MHz, 2400MHz (?), 5000MHz
* GPS 1400MHZ

In this general frequency range, all else being equal, higher frequencies have shorter range and are more sensitive to wet vegetation and intervening terrain.

Doug

Thanks for the info!!

 

[ChrisB]

Freq Coverage Question

Ham guys,

In the Whites, which repeater freq has the best coverage/reliability: 2M, 220
or 440 Mhz?

Which would you pick for an emergency comm?

cb

 

[DougPaul]

In the Whites, which repeater freq has the best coverage/reliability: 2M, 220 or 440 Mhz?

Which would you pick for an emergency comm?

2M and 2M.

2M generally has more coverage and activity that 220 and 440.

The Kenwood F6A covers all three...

Doug

 

[SAR-EMT40]

Ham guys,

In the Whites, which repeater freq has the best coverage/reliability: 2M, 220
or 440 Mhz?

Which would you pick for an emergency comm?

cb

Dave mentioned it and I'll repeat it. 2M is what you want. There are more 2M repeaters scattered across the country than any other type, by a large amount. Now the only problem with that is most really neat radios (with expanded recieve and other neat wiz bang stuff) also include 440 and sometimes 220 or 6 meters. You will notice though that they always have 2M.

Keith

 

[walker]

Hams Work While They Hike

FYI for hams and non-hams alike. Just so everyone knows someone is listening.

The ARRL's WILDERNESS PROTOCOL​

The Wilderness protocol (see page 101, August 1995 QST) calls for wilderness hams to announce their presence on, and to monitor, the national calling frequencies for five minutes beginning at the top of the hour, every three hours from 7 AM to 7 PM while in the back country. A ham in a remote location may be able to relay emergency information through another wilderness ham who has better access to a repeater. Calling Frequencies: 52.525, 146.52, 223.50, 446.00, 1294.50 MHz[/I].

 

[Stan]

USE of GMRS requires an FCC license ... no skill, just the license. Actually, getting the license takes the same skill as bushwhacking Scar Ridge. Go to the FCC website and you'll learn why.

 

[DougPaul]

USE of GMRS requires an FCC license ...

Correct. Unfortunately, the manufacturers sell FRS/GMRS capable radios with no lockouts or other distinctions. The unlicensed user has to remember which channels are legal. I'm sure that many users have illegally used the GMRS channels without realizing it.

Doug