Jump to content

Maximum Wattage?


alex1
 Share

Recommended Posts

As found on page 70 of the GMRS rules (http://transition.fcc.gov/Daily_Releases/Daily_Business/2017/db0519/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?

Link to comment
Share on other sites

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.

Link to comment
Share on other sites

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

Link to comment
Share on other sites

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.

Link to comment
Share on other sites

  • 8 months later...

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.

Link to comment
Share on other sites

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.

 

 

Link to comment
Share on other sites

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).

Link to comment
Share on other sites

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.

Link to comment
Share on other sites

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.

Link to comment
Share on other sites

  • 2 years later...

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:

I have seen where someone wanted to have a station at their home, dedicated to communication only with their mother. They were going to use Yagi antennas aimed at each other to get better range. I would think those would be considered "fixed stations" by definition give

n in the beginning of Part 95.

Link to comment
Share on other sites

I have seen where someone wanted to have a station at their home, dedicated to communication only with their mother. They were going to use Yagi antennas aimed at each other to get better range. I would think those would be considered "fixed stations" by definition given in the beginning of Part 95.

A “fixed station” means dedicated for communications between fixed points and is usually for purposes of telemetry, linking, or control. In the situation you describe, since both stations could be used to communicate with any other GMRS stations for general traffic, both would be base stations, not fixed, and would have no special power limitations other than those that might be specified for the frequency in use.
Link to comment
Share on other sites

I don't believe that Part 95 properly defines the term "Fixed Station" - which leaves the meaning open to interpretation. To my mind, a Fixed Station operates on the High side of a Frequency Pair - which would be the 467.xxxx frequencies. In other words, they would be transmitting on the repeater inputs -and potentially causing interference if they operated at high power with a high gain directional antenna.

 

Base Stations transmit on the lower side of the Frequency Pair - ie: the 462.xxxx repeater outputs.

 

At least, those are my definitions. The FCC has left us to figure out which ones make sense absent any Part 95 definitions or rulings.

Link to comment
Share on other sites

47 C.F.R. § 2.1 states that a fixed station is station in a fixed service. A Fixed Service is a radiocommunication service between specified fixed points, only.

 

An example of a fixed station in a fixed service would be the 2 stations that RF Link 2 repeaters. They only talk to each other from point to point and their designed/intended purpose is to only talk to each other.

 

A base station of which the operator chooses to only talk to another base station is not a fixed station, because by design, it can talk to all other stations and is not in a fixed service.

Link to comment
Share on other sites

Your choice of 47 C.F.R. § 2.1 says: "a radiocommunication service between specified fixed points, only."

 

Are those "specified fixed points" geographical points on a map? Or are we back to the definition without a defined meaning?

 

I don't agree with Fixed Stations being limited to telemetry or Linking 2 (or more) repeaters. I don't see that conflation contained within Part 95. 

Link to comment
Share on other sites

This discussion is getting a little monotonous. A fixed station is one of a pair that exchange information between those points only. As a Part 90.20 coordinator we licensed many fixed stations which are primarily used to report such things as water levels on a flood gauge or storage tank, control sprinklers on a golf course and the like. Both points had to be identified on the frequency authorization and commonly were low-power, typically 5 watts or less. The only "fixed stations" carrying multiple types of information are microwave.

Link to comment
Share on other sites

Your choice of 47 C.F.R. § 2.1 says: "a radiocommunication service between specified fixed points, only."

 

Are those "specified fixed points" geographical points on a map? Or are we back to the definition without a defined meaning?

 

I don't agree with Fixed Stations being limited to telemetry or Linking 2 (or more) repeaters. I don't see that conflation contained within Part 95. 

 

No.  On land, they are typically geographical locations that don't change, but not exclusively.  EmComm RF network links would be a good example of a land-based fix station that moves. 

 

At sea or land/sea/air combinations, the aeronautical or nautical vessels can also be a fixed station inside of a fixed service.

Link to comment
Share on other sites

This discussion is getting a little monotonous. A fixed station is one of a pair that exchange information between those points only. As a Part 90.20 coordinator we licensed many fixed stations which are primarily used to report such things as water levels on a flood gauge or storage tank, control sprinklers on a golf course and the like. Both points had to be identified on the frequency authorization and commonly were low-power, typically 5 watts or less. The only "fixed stations" carrying multiple types of information are microwave.

 

On the Federal/DOD side, we see things a little differently.  They are not always stationary points.

Link to comment
Share on other sites

I had this very discussion with a buddy that maintains a bunch of state systems. The FCC page isn't very clear. What he said is that a base station is something like a repeater or other radio intended to be permanently installed in a structure. A fixed station while non mobile, is a radio that can be moved around if need be.

 

example, a console mounted dispatch radio versus a mobile radio with a power supply sitting on a desk connected to an outside antenna.

Link to comment
Share on other sites

  • 4 months later...

See 95.303 Definitions

They are more clear about describing the different stations than Part 90 and the old Part 95 rules.

 

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

 

The key word is only. as in they "only ever" talk to each other.

 

Keeping the FIXED stations in the rules is for two reasons.

1. To grandfather any from the old (pre 2017) rules.

2. To lower TPO for stations that are likely to use directional beam antennas (yagis).

     This helps limit all stations to an ERP of around 400 Watts.

 

---------------------

TPO = Transmitter Power Output - what comes out the back of your radio

ERP = Effective Radiator Power   - what comes out of your antenna

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

 Share

×
×
  • Create New...

Important Information

By using this site, you agree to our Terms of Use and Guidelines.