Mark V







MARS and the Yaesu Mark V series Transceivers

Hi everybody. I am the happy owner of a Mark V Field. I have used Dougís excellent site on a number of occasions to look up information on the FT-1000 series of Yaesu radios. Recently I asked Doug if he would be interested in having a small write-up about the Mark V is MARS service. He was said he would be happy to carry the information. So here it is.

First a short word about MARS or the Military Affiliate Radio System. Mars is actually made up of three service affiliated components: Army MARS, Navy-Marine Corps MARS and Air Force MARS. Each service has its own procedures for handling traffic (SSB and digital) but all share common emergency reporting procedures and all co-operate with each other.

In one form or another Mars has been around since prior to World War II. Over these many years, Mars responsibility has changed as technology and requirements have changed. During World War II amateur radio in general and MARS in particular provided a quick availability of trained radio personnel for all the services. In later years MARS principle role was providing morale and welfare support for deployed servicemen and women. This support included MARSGRAMS and phone patches so that service personnel could stay in touch with their families. Today e-mail, satellites, telephones and VoIP have replaced HF radio in terms of morale and welfare. So what is MARS up to today?

Today, Mars has two primary missions. The first is to be a rapid liaison to the military services in support of national defense and homeland security. In the event of an incident occurring in the United States or its territories, immediate reports would be sent to the military services. This is achieved via radio assisted e-mail in the case of Army MARS. The second mission is to handle traffic for civilian emergency services such as the Red Cross, state and local officials and similar entities. Normally ARES/RACES would handle shorter range traffic and provide mobile support with Mars handling longer haul traffic. To accomplish these purposes, MARS members practice traffic nets using multimode communications, Near Vertical Incident Skywave (NVIS) transmissions and advanced netting techniques to include MARS-PCALE which is Automatic Link Establishment (ALE). These activities take place primarily on HF although there are some VHF nets.

For those not familiar with NVIS, it is a technique for sending radio waves straight up into the ionosphere such that a radio umbrella is created reaching out in all directions from the sending station to a radius of 300-500 miles. When conditions are very good, a 25 watt station can have S-9 signals saturate a very large circle. In my case, I have reached out over a thousand miles. The technique was first developed in World War II and now is used extensively by the military.

So what has all this to do with the Mark V Field? With the above background, I would like to share my experiences with the Mark V Field in this service. I have several others types of equipment, but none has served me as well so far as the Field.

My current activities in Oregon Army MARS involve training and acting as a Net Control Station. The way we are set up is that each week there are a series of nets scheduled to accomplish a number of things include training, passing traffic, working with new multimode digital tools, etc. Each net has a primary frequency and an alternate frequency in case propagation is poor. Additional frequencies are also available as necessary. So letís look at the role of a Net Control Station using the Mark V Field.

MARS Frequency Conversion and NTIA compliance

The Mark V and the Field are setup to operate on amateur radio frequencies. However, both units are easily converted to MARS and CAP use without violating the warranty by contacting Yaesu for conversion instructions. Yaesu will ask for a copy of your MARS or CAP license first. At the moment, one does not need to be NTIA compliant for MARS. However, if you plan to work with certain emergency services, e.g. FEMA, or you plan to work with the Civil Air Patrol, you will need to be NTIA compliant. For the Field, that means adding the TCX0-6 high stability crystal.

Multiple Frequency Monitoring

Before starting a net, I set the alternate frequency into the alternate receiver of the Field. The alternate receiver is not top of the line, but it is very effective in monitoring and being able to switch between alternative and primary frequencies. It is also very useful for monitoring other nets or traffic handling on other frequencies. There is also a situation that comes up frequently whereby one has to do frequency checks for propagation. This is normally done by assigning two net members to checkout the alternate frequency. Here it is very useful to be able to monitor both conversations. The fact that filters can be inserted in the alternate receiver is helpful also. I also note that once the MARS modification is done that the frequency split could be up to several MHz and maybe more. This works well since I use a broadband antenna (1.8-30 MHz).

Signal Strength and Noise Control

The Field has a very good front end. While QRM is not a usual problem due to channelized operations, QRN and sever fading frequently are. The first defense is the 18 db attenuator with which I can separate out the signal from the noise. The second is closing down the bandwidth with the filter system. After that the noise fighting circuits come in and they are very effective. NVIS signals can go from noise level to 40 over S-9 very quickly. Iíve never had an overload problem with the Field, although I have with other higher end equipment. I find overall, that with the Field that I am the last one who can still copy after the propagation has gone to blazes.

Digital Modes

I havenít tried everything yet but the Field seems fine with RTTY, PSK31, MT-63, Pactor I, AMTOR, etc. I am about to set it up with it up with TRX Manager for computer control. By the way, MT-63 is very popular with MARS and works very well in mixed mode with SSB. Amateur stations typically donít use mixed mode, but we in MARS find it very important to have several ways to handle traffic. Generally voice is used for short urgent communications and net control. However, as message traffic becomes longer or more complex, digital is critical. As an example, we may have to transmit requests for medicine and similar supplies. It is much more effective and efficient to handle this kind of traffic with digital modes. The chances of mistakes using voice are high and repeats slow the whole process down considerably.

New Modes

As of this writing, Army MARS has not yet approved WinLink 2000 for MARS use although the older version is OK. On the other hand, while WinLink 2000 is very good with Pactor III, it remains very expensive. The new SCAMP mode may solve the expense problem. But there is a new mode that is much in use in the military and other governmental services. It is ALE or Automatic Link Establishment. Without going into detail, ALE facilitates the process of communications by deciding at any given time which frequency is best (out of the group of assigned frequencies) for the assigned net stations to communicate on. (There are also a lot of other features which probably are saved for another time.) The military and commercial equipment to achieve this is quite expensive; however, due to the good work of our British friends, a PC version is becoming available. Hence, like so many other things, software is taking over much of the work of specific hardware. The Mars version of this software is called MARS-PCALE and is available for free. To date, many transceivers have had there software completed by the MARS software group. The Mark V series at the moment only has the basic software completed, not all the special features so I canít report on it yet.


The Mark V Field is the best that I have used so far for MARS work. In addition to a great front end, good noise fighting features, dual receive and other features; the Field can be easily plugged into a high endurance gel cell battery. I have put the Field on DC many times for emergency simulation and other purposes. If Yaesu asked me about some improvements, perhaps I could think of a few like adding six meters without spending $1500 dollars for the transverter and power supply. But that is really not a problem since the Field with the TCXO-6 is a very stable and sensitive platform for some of the new transverters coming on the market.

I guess maybe I should mention something else to be fair. I was first licensed in 1952. I think this means two things. First, I like all my controls in front of me instead of all on menus. And second that I am old and a lot of the new equipment is very difficult for me to operate because of its increasing small size. I may form an alternate opinion after using TRX-Manager; however, being net control can be a fast and furious business, and the equipment needs to be able to keep up with the situation. Your mileage may vary.




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This site was last updated 04/22/20