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Understanding the requirements for power


Question

Posted

This is just a nitpicky question so I can arrive at a better understanding.

Considering: https://www.ecfr.gov/current/title-47/section-95.1767

(47D/95E/Transmitting Power Limits)

As I read it, the following device restrictions exist:

All GMRS must be type approved.

The 467 Interstitials (8-14) are handhelds only.

The 462 Interstitials (1-7) are for  mobile, handheld, portable, and base only (no fixed, and no repeaters)

The 462 mains (15-22) are for mobile, hand-held portable, repeater, base and fixed stations

The 467 mains (repeater inputs) are for mobile, hand-held portable, control and fixed stations.

 

Additionally the transmit power on each:

467 interstitials: 0.5w

462 interstitials: 5w

462 mains: 15w for fixed, 50w for mobile, base, repeaters. (No mention under the "power" section of handhelds).

467 mains: same power restrictions as the 462 mains.

 

The question is what is the limit for handhelds on the mains? They're omitted from mention under power requirements on the mains.

 

We should intuitively understand that it's not desirable to have a 50w handheld with a rubber duck antenna adjacent to peoples' heads. In fact with the recent introduction of 8w GMRS handhelds (10w in amateur bands), it seems that manufacturers are (responsibly or not) exploring higher power limits than 5w for handhelds. There may be radiation exposure requirements that limit how much power a manufacturer can throw into a radio for the sake of selling "features" to people who don't know better. But within the FCC guidelines, what IS the limit for handhelds on the mains?

 

(We should also know that it really doesn't matter. A theoretical 50w handheld is both unhealthy and more of a hand-warmer / battery-drainer than a radio).

15 answers to this question

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  • 1
Posted
3 minutes ago, Socalgmrs said:

Most 50w adios don’t do 50w so none of this really matters

Most 50Watt GMRS radios do indeed put out 50Watts, within an acceptable +/- % tolerance..

Further important information: You can add a user to your IGNORE list by hovering your mouse over their avatar and then clicking the IGNORE button.  When done with the right users you will limit your MyGMRS experience to only actual helpful replies.

  • 0
Posted
3 minutes ago, dosw said:

The question is what is the limit for handhelds on the mains? They're omitted from mention under power requirements on the mains.

I'm sure the only reason that they are not mentioned is the fact that most are only 5 watts with a few being 8 or 10 watts.

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Posted
45 minutes ago, Lscott said:

You really want an antenna radiating 50 watts at UHF a few inches from your face? The FCC has limits for RF exposure in those situations.

https://www.fcc.gov/general/radio-frequency-safety-0

https://transition.fcc.gov/Bureaus/Engineering_Technology/Documents/bulletins/oet65/oet65b.pdf

 

I thought my post was pretty clear that I do not want 50 watts radiating a few inches from my face. But thanks for the links.

  • 0
Posted
7 hours ago, dosw said:

This is just a nitpicky question so I can arrive at a better understanding.

Considering: https://www.ecfr.gov/current/title-47/section-95.1767

(47D/95E/Transmitting Power Limits)

As I read it, the following device restrictions exist:

All GMRS must be type approved.

The 467 Interstitials (8-14) are handhelds only.

The 462 Interstitials (1-7) are for  mobile, handheld, portable, and base only (no fixed, and no repeaters)

The 462 mains (15-22) are for mobile, hand-held portable, repeater, base and fixed stations

The 467 mains (repeater inputs) are for mobile, hand-held portable, control and fixed stations.

 

 

OK, so what's the difference between a "fixed" station and a "base" station?

  • 0
Posted
1 hour ago, LeoG said:

OK, so what's the difference between a "fixed" station and a "base" station?


The thread in question is not for the faint of heart… only the bravest knights seek this knowledge…

image.jpeg.10e66c09e0c2ef68241c1fd3454ce64e.jpeg

what is your name? What is your quest? What is a fixed station - ahhhhh

  • 0
Posted
11 minutes ago, WRUU653 said:


The thread in question is not for the faint of heart… only the bravest knights seek this knowledge…

image.jpeg.10e66c09e0c2ef68241c1fd3454ce64e.jpeg

what is your name? What is your quest? What is a fixed station - ahhhhh

What I've seen of it the lawyers went nutz in their regulation description.  Calling the same transmitter several different names depending on what they are communicating with.

  • 0
Posted
17 minutes ago, LeoG said:

What I've seen of it the lawyers went nutz in their regulation description.  Calling the same transmitter several different names depending on what they are communicating with.

Maybe, but if I wanted to establish a dedicated wireless intercom or SCADA system between my home and my cabin, setting up two fixed stations is a good solution. I could set it up a full duplex system using the 467 MHz and 462 MHz main channels, using only 15 watts to minimize interference with Yagi antennas pointing at each other. 

  • 0
Posted
13 hours ago, LeoG said:

OK, so what's the difference between a "fixed" station and a "base" station?

You are justified in asking, but no one here can give the official answer.  The answer has to come from Brendan Carr or his employees.  And it matters because fixed station is being used in a twisted interpretation way of using base stations for communicating through repeaters.

  • 0
Posted
31 minutes ago, UncleYoda said:

You are justified in asking, but no one here can give the official answer.  The answer has to come from Brendan Carr or his employees.  And it matters because fixed station is being used in a twisted interpretation way of using base stations for communicating through repeaters.

Since we've heard nothing about someone getting fined for using a base station when a fixed station should have been used or vice versa I doubt anyone at the eff sea sea is going to be coming knocking on any of our doors to check compliance.  It's probably something of a holdover that they copied in for some sort of larger station.

I'm not worrying about it.

  • 0
Posted
13 hours ago, SteveShannon said:

Maybe, but if I wanted to establish a dedicated wireless intercom or SCADA system between my home and my cabin, setting up two fixed stations is a good solution. I could set it up a full duplex system using the 467 MHz and 462 MHz main channels, using only 15 watts to minimize interference with Yagi antennas pointing at each other. 

I like that plan. How far apart are the cabin and your home? 

  • -6
Posted

Who cares.   Gotta say it does not matter at all. I’d say there are many other things to think about then theoretical watt limits for an ht.  Most 8 or even 10w hts don’t put out 8 or 10 watts anyway.  Most 50w adios don’t do 50w so none of this really matters. Especially if you’re buying a type accepted gmrs radio.  Plus a 5w or a 10w really doesn’t matter for distance anyway so why eat battery like you already said for no reason. 

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