GMRS RF Emission list and discussion...

[PastorGary]

Rules Section 95.631a mentions in part >>>

 

 

  (a) A GMRS transmitter must transmit only emission types A1D, F1D, G1D, H1D, J1D, R1D, A3E, F3E, G3E, H3E, J3E or R3E.

 

Not listing the CTCSS and DPS protocols - just voice (telephony):

 

 

A3E = Single channel double sideband amplitude modulation, analog, telephony

 

F3E = Single channel frequency modulation telephony

 

G3E = Single channel phase modulation telephony

 

H3E = Single channel single sideband full carrier telephony

 

J3E = Single channel single sidebane supressed carrier telephony

 

R3E = Single channel, single sideband reduced or variable carrier telephony

 

 

Most everyone here at the Forum is familiar with the 20K0F3E emission standard - we all use it. However, has anyone here ever experimented with AM or Sideband transmissions on GMRS ?  

 

This brings up another RULES issue...

 

Section 95.135a says -

 

 

(a) No station may transmit with more than 50 watts output power.

 

but it does not specify if this is raw carrier power in any AM mode or if a single sideband emission would be limited to 50 watt PEP.  If a 50 watt AM radio is switched over to SSB, the PEP would be running close to 150 watts.

 

Anyone have any opinions, since the Rules seem to be incomplete?

[deputycrawford]

     I am not sure why anyone would need to use AM or Vestigial side band modes but it would be neat to try them out.

 

Jerry

[PastorGary]

SSB would potentially increase the simplex coverage distance but is significantly more prone to ambient noise - negating the increased potential distance.

 

But as you said, it might be cool to experiment with and if Part 95 Certified AM/SSB equipment could ever be found... 

 

John E - Do you know of any such equipment out there these days? 

[Linus]

I have a radio that will transmit SSB on all amateur bands. I have never found anyone to test SSB on the 70 cm amateur band. The same mode on GMRS would be similar. One could modify a 70 cm amateur radio that transmits SSB for GMRS, however that radio would lack FCC certification making it illegal to operate.

[JohnE]

I have never seen anything Am/SSB on UHF in my yrs of doing this. but I live in a very small bubble in the radio world.

[PastorGary]

John - That's what I have experienced as well.

 

No equipment listed on the net anywhere that I could locate.

 

For Hams here at MyGMRS - does anyone ever use SSB on 440 regularly?

[Linus]

I have a Yaesu ft-897 that will transmit SSB on 70 cm band. I have spoken to people about 500 km away on 2 m band using ssb at 50 watts. This is a very unreliable way to communicate over long distances.

I have never received a call back on 70 cm ssb or cw.

[Dave]

For Hams here at MyGMRS - does anyone ever use SSB on 440 regularly?

Prior to my moving to my current location Central Valley of Calif. (mid 90's) I was part of a group that met on 432.100 regularly.

My current location restricts my ability to have towers and antennas for every band, (now only a couple of well concealed vertical antennas), so I haven't been active on 432 ssb since. I do know that several of the hams that I used to chat with regularly on ssb are still active there, but not like it was in the late 70's thru early 90's when there was group activity on a daily basis.

[PastorGary]

Linus and Dave - Thanks for the input.  IF equipment that was approved would be available, it sounds as if it would work fairly well on GMRS - - -  but why bother...LOL...

[zap]

I think the biggest thing is that GMRS and VHF/UHF amateur are (even today) heavily influenced by the commercial market. Commercial AM has been dead since the late 50's above 30 MHz. I can think of a AM/CW/SSB Part 90 Motorola and Kenwood but you'd need a transverter to get them above 30 MHz.