Helo Interop - What is it and how does it work?

[sholt]

Hello,

Potentially stupid question regarding the 'help interop' having done some googling and come up short of an answer (see frequency listing at San Francisco County, California (CA) Scanner Frequencies and Radio Frequency Reference)

Is the helo interop a frequency the news choppers communicate on with ground (i.e. news crews in trucks, etc) or is this an air to air frequency they use when there are multiple choppers up covering the same 'event'?

It is the only freq listed as 'Aircraft' so I wasn't sure if that was the only one used by the choppers themselves, or if they use the other frequencies listed in the 450MHz range for air-ground comms.

I'd love to hear what your experiences are listening in on these news crews and whether they have been useful in determining what a news chopper you see hovering may be covering.

Thanks!

 

[zerg901]

124.30 AM would be an 'aircraft to aircraft' (air to air) freq typically.

News vans use FM radios typically. Aircraft typically have AM radios. AM radios cannot talk to FM radios and vice versa (generall speaking). News helos commonly have a FM radio (at either 160 Mhz or 450 Mhz) to talk to news units on the ground.

If a news van happened to have a aviation band portable AM 2 way radio (maybe $200), then they could talk to a helo (air to ground) - but I have never heard of any news van that was equipped with a AM aviation band portable radio.

The same type of situation applies to wildfires. Wildfire aircraft primarily use AM radios at 120 Mhz. Wildfire ground units typically use 150 Mhz FM radios. Never the two shall meet. To make 'air to ground' comms possible, most wildfire aircraft are equipped with a secondary 150 Mhz FM radio.

 

[sholt]

Hi zerg,

Thanks for clarifying all of that. Makes sense. I'm fairly new to scanning anything outside of aviation band so it sounds like I have a lot to learn about who uses which bands and which are AM/FM, etc. Thanks for getting me started!

 

[W8RMH]

Hi zerg,

Thanks for clarifying all of that. Makes sense. I'm fairly new to scanning anything outside of aviation band so it sounds like I have a lot to learn about who uses which bands and which are AM/FM, etc. Thanks for getting me started!

These AM frequencies are common nationwide for helicopter radio traffic.

123.02500
123.05000
123.07500

 

[inigo88]

"Helo interop" isn't really the best name for it. Think of the Common Traffic Advisory Frequency (CTAF) at any of your local airports (those that are too small to have a control tower). This is the same thing, just over the city of San Francisco and unpublished. My best guess is a bunch of law enforcement and media helicopter pilots just got together and arbitrarily decided on a frequency that wouldn't interfere with ATC, but it's not sanctioned by the FAA.

The national fixed wing air-air freq is 122.75, and the national helicopter air-air freq is 123.025. The problem is when two pilots start telling each other their life stories over the frequency, at the elevation they're flying at the signals can carry for hundreds of miles and render the freq useless for pilots who want to use it for its legitimate purpose. Hence they go looking elsewhere.

The official name (at least among its users) for 124.30 is "Golden Gate Traffic." Another common unofficial/unsanctioned air-air frequency is "FINGERS": 123.45. Great memory aid huh?

 

[sholt]

Another common unofficial/unsanctioned air-air frequency is "FINGERS": 123.45. Great memory aid huh?

That's brilliant. Thank you for that and all of the other information. I might dedicate my scanner to these and other mentioned common frequencies this weekend to see what I get.

Edit - on a tangent, I googled 123.45MHz and got this thread from our very own forums, all about the frequency and associated frequencies. If anything it's entertaining but if you're a relative newbie like me you might learn something, too: http://forums.radioreference.com/tennessee-radio-discussion-forum/195008-what-123-45-mhz.html

 

[SCPD]

124.30 AM would be an 'aircraft to aircraft' (air to air) freq typically.

News vans use FM radios typically. Aircraft typically have AM radios. AM radios cannot talk to FM radios and vice versa (generall speaking). News helos commonly have a FM radio (at either 160 Mhz or 450 Mhz) to talk to news units on the ground.

If a news van happened to have a aviation band portable AM 2 way radio (maybe $200), then they could talk to a helo (air to ground) - but I have never heard of any news van that was equipped with a AM aviation band portable radio.

The same type of situation applies to wildfires. Wildfire aircraft primarily use AM radios at 120 Mhz. Wildfire ground units typically use 150 Mhz FM radios. Never the two shall meet. To make 'air to ground' comms possible, most wildfire aircraft are equipped with a secondary 150 Mhz FM radio.

There is an exception to that on wildland fires. Helitack crews, when in the mode of managing helicopters rather than providing an initial attack force, use VHF-AM radio to talk with airborne helicopters for keeping track of heliport and helispot traffic and providing local air traffic control. They also use AM to arrange for bucket hookups and for other local logistical needs. These air to ground AM frequencies are not usually used until the incident gets large enough to use multiple helicopters at a heliport at the incident or close by when they aren't using a local airport as a heliport. Every helitack truck has a VHF AM radio, usually a portable or handheld that is placed in one of the side compartments and connected to a VHF AM antenna that is permanently installed on the roof of the truck.

By portable I mean that sometimes a mobile will be mounted on a rack with battery power mounted with it. By mounting them in this manner they can be used in different locations on the truck and even at posts away from the truck.

The AM frequencies are used for these purposes because of the congestion of FM air to ground frequencies, which are normally used for firefighter to aircraft communications and not for helitack to air comms. Even with the availability of more air to ground frequencies resulting from narrowbanding the use of VHF AM frequencies for these situations will probably continue.