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Maximum Wattage?


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#1 alex1

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Posted 21 June 2017 - 11:07 AM

As found on page 70 of the GMRS rules (http://transition.fc...FCC-17-57A1.pdf):

 

(1) The transmitter output power of mobile, repeater and base stations must not exceed
50 Watts.
(2) The transmitter output power of fixed
stations must not exceed 15 Watts.

 

So if I have a repeater set up at my house, it's a fixed station and the 15 watt max applies, right?



#2 Logan5

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Posted 21 June 2017 - 11:41 AM

no it's is a "repeater" and is 50 watts. there is so much confusion of these classifications and associated numbers. I am not even sure my self what particular radio configuration is limited to 15 watt's, I could see 15 watt's for a fixed mobile install. 25 to 50 watt's for a fixed base or repeater.



#3 RF Medic

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Posted 23 June 2017 - 03:18 AM

Hopefully this straightens this out for you:

 

Fixed station: A fixed station, not open to public correspondence, operated by, and for the sole use of those agencies operating their own radio communication facilities in the Public Safety, Industrial, Land Transportation, Marine, or Aviation Radio Services.

 

Base Station - A station at a specified site authorized to communicate with mobile stations.

 

ENGLISH NOW:

50watts is your max Mobile, Base, or Repeater


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#4 mainehazmt

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Posted 28 June 2017 - 03:11 PM

But. Buttttt I'm a ham I'm allowed 1500 watts......
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#5 spd641

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Posted 29 June 2017 - 08:58 AM

But. Buttttt I'm a ham I'm allowed 1500 watts......

Good one and some believe they are allowed to use any band including GMRS with that...William


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#6 n4gix

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Posted 29 June 2017 - 12:39 PM

Good one and some believe they are allowed to use any band including GMRS with that...William

Which is really silly since there exist charts that point out the precise frequencies allowable, along with their useage modes.

I'm so anal about the matter that Saturday during the annual Field Day I asked for an Extra to help me with logging since many of the best signals were in the portions of 15m that I'm not legally allowed to use.
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#7 tps

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Posted 02 March 2018 - 04:05 AM

Here's the way I read it:

 

95.1767(a)(1) Transmitter power of mobile, repeater, and base stations must not exceed 50 watts.

This is for the "main" (a/k/a repeater input/output) channels.

It seems that the term "fixed station" is no longer defined by the new rules, so that 15 watt limit seems meaningless.

It appears that, with low-loss coax and a high-gain antenna, ERP could exceed 50 watts.

 

 

95.1767b limits all stations to 5 watts ERP when transmitting on the 7 interstitial channels at 462 MHz.

 

95.1767c limits all stations to 0.5 watts ERP when transmitting on the 7 interstitial channels at 467 MHz.

 

So one has to take coax loss and antenna gain into account on these channels. If you have low-loss coax and a high-gain antenna, be careful! ERP is calculated using dBi, not dBd.



#8 PastorGary

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Posted 02 March 2018 - 07:22 PM

Current Rules DO ADDRESS "Fixed Stations" - and the Part 90 definition may not be accurate for Part 95 purposes.

 

Refer to Part 95:303 under 'Definitions" -

Fixed station. A station at a fixed location that directly communicates with other fixed stations only.

 

=====================================================================================

 

95.1767   GMRS transmitting power limits.

 

This section contains transmitting power limits for GMRS stations. The maximum transmitting power depends on which channels are being used and the type of station.

(a ) 462/467 MHz main channels. The limits in this paragraph apply to stations transmitting on any of the 462 MHz main channels or any of the 467 MHz main channels. Each GMRS transmitter type must be capable of operating within the allowable power range. GMRS licensees are responsible for ensuring that their GMRS stations operate in compliance with these limits.

(1 ) The transmitter output power of mobile, repeater and base stations must not exceed 50 Watts.

(2 ) The transmitter output power of fixed stations must not exceed 15 Watts.

(b ) 462 MHz interstitial channels. The effective radiated power (ERP) of mobile, hand-held portable and base stations transmitting on the 462 MHz interstitial channels must not exceed 5 Watts.

(c ) 467 MHz interstitial channels. The effective radiated power (ERP) of hand-held portable units transmitting on the 467 MHz interstitial channels must not exceed 0.5 Watt. Each GMRS transmitter type capable of transmitting on these channels must be designed such that the ERP does not exceed 0.5 Watt.

 

 


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#9 n4gix

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Posted 03 March 2018 - 09:37 AM

Do "Fixed Stations" even exist in the GMRS world?

I cannot begin to imagine anyone using their radio at home or office to only communicate with another "Fixed Station..." :unsure:



#10 WRAF213

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Posted 04 March 2018 - 02:38 AM

The rules are a bit hairy when differentiating fixed and base stations, but there are most certainly rules. Imagine you have a few friends or family members that live a few blocks down, and everyone has a base station type of installation. When communicating with only each other, the station class would be considered a fixed station, since all communicating stations are stationary and permanent. These fixed stations are limited to 15 watts, but can use the repeater input channels in simplex mode. If those stations participated in conversation with mobile and/or portable stations, they would be considered base stations and would be authorized 50 watts to make up for the lack of antenna gain or height typical of mobile and portable stations. Base stations, however, would not be authorized to use repeaters, while mobiles and portables are; base stations are expected to communicate on the repeater output (wide area repeaters aren't an expectation of GMRS, but rather repeaters that bring the effective range of portables and mobiles up to par with other base stations).



#11 n4gix

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Posted 04 March 2018 - 11:19 AM

While the explanation from Cornell Law School is certainly cogently stated, in the Real World  actual practice is that a permanent station can be a "base", "fixed station" or a "control station" depending on specific circumstances.

 

When acting as a "fixed station" my power is set to low (about 10 watts out).

 

When acting as a "control station", such as operating as net control, my power is set to only enough to operate the repeater at full quieting (usually low power).

 

When communicating directly with mobile or portables, I am not a "base station" and will use whatever power is required, up to the max allowed.

 

In the final analysis though, no one actually gives a tinker's damn about the nuances of the rules, especially the FCC.


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#12 mainehazmt

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Posted 05 March 2018 - 12:12 PM

Could this 15 watt station possibly be like the “shotgun” setup used during linking repeaters?
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#13 Radioguy7268

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Posted 07 March 2018 - 07:03 PM

In the Part 90 world, the wording "Fixed station" refers to an FX1 designation, which most people would consider a Control Station. Usually a mobile in a tray attached to a power supply (often, and wrongly called a base station). That unit is used at a stationary location to communicate with a distant repeater (often using a directional Yagi antenna).

 

Limiting the power of an FX1 was designed to keep people from interfering with distant repeaters on the same frequency pair. In the old 800/900 Mhz SMR world, it was also used in conjunction with the "20 foot rule" which kept the elevation above ground of an FX1's antenna in a reasonable range.

 

I'm not aware of the term "Fixed station" being defined anywhere in the Part 95 rules, but it makes sense to me that power limitations on a repeater's input are designed to limit interference to distant repeaters on the input frequencies. If you're operating on the 462.xxx output frequency (lower side of the pair) - then you're an FB designation, a Fixed Base - or an FB2, which is a repeater.


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