MARS/CAP Mod

[MOGA]

On another board that I frequent, a member began a thread discussing the process that's required to modify a dual band Yaesu radio that I own to transmit out of band. This is apparently known as the MARS/CAP mod. What benefit is achieved by performing the modification? When would the ability be useful? I can't quite figure it out and was hoping some one could shed some light. Thanks.

 

[KK4DAN]

MARS & CAP officially refer to Military Auxiliary Radio System and Civil Air Patrol. Both use frequencies just outside the ham bands in either the VHF or UHF band or both.

MARS:
Military Auxiliary Radio System - Wikipedia, the free encyclopedia
Military Affiliate Radio System (MARS)
USAF MARS Information

CAP:
Civil Air Patrol - Wikipedia, the free encyclopedia
Civil Air Patrol - United States Air Force Auxiliary

You obviously have to be licensed in either respective organization to legally talk on those bands. I'm not sure of the legality of using Ham radio's on the MARS/CAPS frequencies if you are truly licensed to operate there?

Usually with a Mars/Cap mod, the radio is also opened to transmit in frequencies such as the MURS in 151/154mhz range and some of the DOT frequencies in the VHF band along with Marine VHF frequencies. In the UHF band you usually get more Dot Frequencies and the FRS/GMRS frequencies.

Keep in mind its illegal to communicate on any of these above frequencies with an Amateur radio that is not Part certified by the FCC for those respective frequencies.

 

[rfradioconsult]

CAP No longer allows modified ham equipment to operate on their frequencies, all radios must be NTIA compliant. All CAP VHF radio operations are narrowband and P25 Digital.

 

[ecps92]

As for CAP, Yes for Narrowband.
But P25 is not a hard-fast use. All the Repeaters are dual-mode, but much is still conducted in Analog, as many purchased their own radios and went Analog vs P25

CAP No longer allows modified ham equipment to operate on their frequencies, all radios must be NTIA compliant. All CAP VHF radio operations are narrowband and P25 Digital.

 

[kb2crk]

MARS still allows modified ham radios and are also on HF above and below 75 meters and several other places.

 

[K9WG]

MARS still allows modified ham radios and are also on HF above and below 75 meters and several other places.

There was a lot of discussion regarding NTIA compliance for MARS a few years back. Some of us even went and upgraded our HF rigs with the high stability crystals to be in compliance with the then published CAP acceptance list. I think when MARS realized that they would lose most of their membership if compliance was mandated they backed off the requirement. As a side note, at a MARS conference a few years back it was noted that the NTIA mandate was more to accommodate digital modes and the specifications affected the receivers more than the transmitters.

 

[MOGA]

MARS & CAP officially refer to Military Auxiliary Radio System and Civil Air Patrol. Both use frequencies just outside the ham bands in either the VHF or UHF band or both.

MARS:
Military Auxiliary Radio System - Wikipedia, the free encyclopedia
Military Affiliate Radio System (MARS)
USAF MARS Information

CAP:
Civil Air Patrol - Wikipedia, the free encyclopedia
Civil Air Patrol - United States Air Force Auxiliary

You obviously have to be licensed in either respective organization to legally talk on those bands. I'm not sure of the legality of using Ham radio's on the MARS/CAPS frequencies if you are truly licensed to operate there?

Usually with a Mars/Cap mod, the radio is also opened to transmit in frequencies such as the MURS in 151/154mhz range and some of the DOT frequencies in the VHF band along with Marine VHF frequencies. In the UHF band you usually get more Dot Frequencies and the FRS/GMRS frequencies.

Keep in mind its illegal to communicate on any of these above frequencies with an Amateur radio that is not Part certified by the FCC for those respective frequencies.

Thanks for the links. The info contained therein answers all of my questions.

If there's two things that I'm firmly against DIY modding, its radios and firearms. More than anything else I was curious about exactly what the people who are doing these modifications gained by doing so.

 

[N4KVE]

Years ago dual band radios only worked in the specific ham band of the country where they were sold. RX & TX. However some years ago, the radios started being imported with full RX. 118-174, & 400-520, but still tx only in the ham band. So now the radios don't need the mod to listen to aircraft, & public safety. Only to tx where they can't legally do so. Used commercial radios are real cheap these days, & many work just fine in the ham bands. GARY N4KVE

 

[K9WG]

Gary

I had a Kenwood TR2600 handheld that you could cut a wire on and open up the TX. This was in 1985

 

[kb2crk]

There was a lot of discussion regarding NTIA compliance for MARS a few years back. Some of us even went and upgraded our HF rigs with the high stability crystals to be in compliance with the then published CAP acceptance list. I think when MARS realized that they would lose most of their membership if compliance was mandated they backed off the requirement. As a side note, at a MARS conference a few years back it was noted that the NTIA mandate was more to accommodate digital modes and the specifications affected the receivers more than the transmitters.

I was a member of navy mars until november of last year when interference issues kept me from hearing anything. I was using a Kenwood ts-570dg for the mars nets. I am hoping to join again as i found the cause of the noise and fixed it. (two chinese laptop power supplies.)