Proposal for a Simplex Calling Frequency on Two Meters for C4FM Users

We received kind of an unusual request from a Mr. David Huntz NH6SM of Jones, OK. He is proposing a simplex calling frequency of 147.525 MHz, for users of the C4FM mode. If you are not familiar with C4FM, that is a digital voice mode promoted primarily by Yaesu, but there are other manufacturers that make equipment capable of operating on this mode. Yes digital audio is authorized in the two meter band by the FCC. Although the VoIP modes such as D-Star, DMR, P25, as well as C4FM are much more used on 70 CM. According to Mr. Huntz several states have adopted this frequency as a calling frequency for C4FM, and he would like to see Oklahoma join the club. Actually there is a group of C4FM enthusiasts who would like to see this adopted as part of a nationwide two meter band plan. Most likely the ARRL's two meter band plan.

Here is ORSI's stance on this: Our official policy is that we do not get involved with any thing on simplex frequencies. We coordinate repeater frequencies for voice and ATV repeaters. We don't care is the voice is transmitted by digital or analog means. Neither does the FCC, they basically look at a radiotelephony transmission is a radiotelephony transmission, and they don't care if you are transmitting it analog or digital. Now there are certain amateur frequencies where voice transmission by any means is not permitted. Also they have been moving toward regulation by bandwidth anyway over the last few years. In fact at one time they proposed to do that. They would care how you transmitted something, as long as your signal remained within the bandwidth allowed on that frequency band. That proposal didn't get very far. At that time people wanted thins more clearly defined as AM, FM, CW, TV, and RTTY. With the advent of technological advances these lines are getting very blurry, we can now reliably transmit voice, data, and possibly still monochrome images within the bandwidth of a standard 5 kHz deviation FM signal. Also ORSI is not a regulatory body, we will leave that to the FCC, thank you. By the way we don't get involved in packet radio issues either. TAPR and the ARRL do a good job of keeping track of that so we don't get involved.

The only other question, is does anybody know of any area of this state where there is significant FM Simplex activity on 147.525? Mr. Huntz and his group don't want to cause any trouble for anyone.

Bottom line is: ORSI has no "official" stance on how the simplex frequencies are used. What happens on the simplex channels can stay on the simplex channels and we don't care. We are not opposed to Mr. Huntz proposal, but we don't exactly endorse it either. My suggestion was that he talk to the ARRL leadership here in the Sooner state. Also I believe that ARRL has a national VHF advisory committee, that works on the band plans among other things, and they would probably be the people to talk to as far as any national standards go.

Like a number of you I am still trying to figure out some of this what I call digital alphabet soup myself. I know some states are trying to restrict VoIP to certain frequencies. I think that this genie was already let out of the bottle, and right now we coordinate repeater frequencies about the same whether they are digital or analog, bearing in mind that the digital signals tend to carry farther than the analog signals. However, we are collecting data that may allow us to move away from the 90 miles fits all standard. and go more toward a zone of protection based on a combination of the repeaters HAAT and ERP. We also alert surrounding states if the repeater we are coordinating is standard analog or a VoIP machine. See one of the headaches we get into is now with the Yaesu System Fusion machines, they can be either/or on the same frequency and the same physical repeater. On 70 CM we have allowed a few systems to use the split channel. Standard channel spacing on 70 CM has always been 25 kHz. We are allowing some digital audio machines to try maybe going off the trustee's analog machine 12.5 KHz and establish a VoIP machine. On two meters we are sticking with the standard 20 kHz channels form 144.5-145.5 MHz, and 15 kHz channels above 146 kHz.

We would kind of like to know what do you think? Email: