South Arm Stage NEFR Radio Challenge

South Arm NEFR – A Tough Radio Challenge

The South Arm and Icicle Brook stages of the New England Forest Rally (NEFR) present challenging communications issues for radio operators.

What is the Primary Problem?

Look at the topographic map below and pay attention to the steep hill/mountain inside the red circle. The top of it is 1,200 feet higher than the roadway at the start and finish of both stages.

This map includes the South Arm and Icicle Brook stages of the NEFR. The red balloon at the bottom is at the approximate start of South Arm and the finish of Icicle Brook. The purple star is the finish of South Arm and the start of Icicle Brook. The blue hexagon is an ideal location for a radio relay position. The red circle identifies the wretched mountain that tops out around 2,700 feet above sea level (ASL) while the stage roadway hovers around 1,500 feet ASL. Do you think for a moment a 5-watt HT has a chance to conquer this conundrum? Copyright 2019, Google, Inc.

What Can Be Done to Ensure Clear Communications?

You need a tall antenna and lots of power to get a signal from the start to the finish if you intend to conquer the mountain using simplex VHF transmissions. The distance between the start and finish as the crow flies is just under ten miles!

A repeater could be located across Upper Richardson Lake about 2/3rds of the way between the start and finish of the two stages. At this location, it would have a very clear shot of all radio operators along both stages. The tall mountain would not hinder communications whatsoever.

You can also put a repeater in a circling airplane or suspended from a tethered balloon. Both of these options create their own set of very specific problems, not the least of which is cost.

There are other significant issues with repeaters. Here are but a few of the challenges:

Repeaters offer up a sole point of failure. If the repeater fails during the stage no one can communicate. With the current simplex setup, if one operator’s radio or antenna fails, only his position is affected.

Duplexers can be sensitive. They are required in a repeater to make the same-band repeat magic happen. These cans usually don’t like being bumped around traveling on gravel roads that have more potholes than Dunkin has doughnuts.

The provider of the repeater has to set up the repeater, controller, duplexers, etc. as well as the antenna in a short amount of time before the stages run.

The repeater location across Lake Richardson may not be accessible just before the rally. The roads may get washed out and the owner of the road may not repair it in time nor want to invest the money to repair it.

What About an HF Solution?

Yes, you might have great success using high frequency (HF) on 80 meters. All operators would have to have HF equipment and be able to deploy an 80M Near Vertical Incidence Skywave (NVIS) antenna.

The US military relies on NVIS operations in battleground situations. It’s that reliable.

A NVIS antenna can be just a simple thin wire suspended about 5-8 feet in the air. You can drape the antenna over tree branches or bushes. You can also use some simple wood stakes to hold it above the ground.

Here’s a video I recorded in August of 2019 showing how easy it is to build and deploy this antenna. NOTE: This antenna set up flies in the face of the optimal theoretical antenna design created by fancy software. Realize that this antenna you’re about to see works VERY WELL

UPDATE: July 22, 2019 – On Friday, July 19, 2019 I did an 80M NVIS test at the start and finish lines of this stage. I was assisted by Sean Tarbox, N1BOX, and Tim Foy, W1FOY. Sean and Tim, along with Tim’s wife Monica, were just below the start of the South Arm start line. I was a mile beyond the finish line of South Arm.

We established crystal-clear comms using a simple antenna that was about 2 feet off the ground at my end. I was only transmitting with 13 watts out of my Elecraft KX3. Sean and Tim experimented with different power levels up to 50 watts. At 50 watts it was if they were standing next to me. A stunning 5-9 signal report.

Watch these videos to get an idea of how easy it is to do NVIS comms:

If you have ideas, put them in the comments below.

 

 

8 thoughts on “South Arm Stage NEFR Radio Challenge

  1. Again I can provide a repeater I have one on 145.45 PL of 100 with cans and probably can scare up an Auston antenna. Now it will need either a bank of batteries or a generator a Honda 2000 would do with a power supply. It is a mobile Motorola unit so either would work. We did a high gain Antenna one year and a mobile unit as communications point at the highest location it did pretty well. Unless people can park with their mobile units with some type of gain there are going to be dead spots. This is not something I can throw together quickly as the cans are on top of Mt Cranmore in NH right now so if you are interested I would need to know.

  2. Well, if you can pull this off, fantastic. I’d say go for it. The best place for the repeater is across the lake as I describe above. You NEED to get in touch with Matt Kennedy the stage captain if you want to make this enormous investment of resources. I don’t have batteries nor the generator.

    • I can probably borrow a Honda EU2000i from work but if not I own my own 6000 watt generator I’d be willing to haul up.

  3. I functioned as a relay on South Arm a few times – the location we used was close to where you suggested (North of the hexagon along that same road about even with the “2200” marking at a small dirt road that intersects from the East) it worked pretty well, but was not full coverage of the stage, even with my collinear. I wonder if the hexagon would be a bit better due to proximity to the stage start, which were the harder stations to stay in touch with. My setup compensated for a lot of the HT crowd, but some folks disappeared from time to time mostly due to DC power issues and not understanding how to ‘tune’ and maintain their position once I was in place as far as I could tell

  4. Ok here is the deal I was at “B” south arm with my 18′ Diamond antenna on the back of my truck up about 9 feet. I was at about 1500 feet on the course I had to relay messages to start from the relay radio I heard everyone on the course. I also have HF in my truck and if I had known you were going to use HF and the freq I would have participated.

    • Tim,

      You had to relay because the Start radio operator made a decision on his own to NOT use the 40-foot-tall halyard I had put up in the tree next to the Start radio. That operator had a roof-top antenna. That won’t happen again, trust me.

      The HF was a simple test done by operators who were NOT working the stage. I made that decision on purpose. It would not have been prudent to have South Arm stage operators participating in a test when they’re supposed to be concentrating on the race and the VHF traffic. That’s why you didn’t know anything about the test.

      But no worries, if you have HF capabilities and want to work South Arm and Icicle Brook next year, you’re more than welcome. These two stages will be done with operators who have HF 80 meters and a simple NVIS antenna. They will also have VHF as a backup in case the 80-meter ground wave is not cooperating that day.

      • I don’t trust HF to be reliable particularly during the day. Regardless of the finish and perhaps inadequate antenna deployment I had no problem hearing everyone on VHF @ 1500′ And IMHO a good antenna, location and 50 watts you should be able to work in excess of 20+ miles.Our club repeater is at 1600′ I’m at 450 it’s 16 miles from the qth with about 20 watt trru the cans I can hear it it can hear me with a hand held. Most newish hams do not have HF and if everything needs to be relayed it slows things down. This is my take, years ago we used exactly the same antenna I brought it worked.

        • Tim,

          Well, we’ll find out next year how well the 80M NVIS will work. NVIS is so reliable the US Army and Marines rely on it for battleground comms. If you’re not familiar with NVIS comms, theory, capabilities, I suggest you start your education by reading this excellent NVIS primer.

          What’s more, with enough power, anything between 50 and 100 watts, you can generate a powerful groundwave that will crawl all over that pesky mountain.

          Based on my test last Friday, 80M NVIS should work very well. Have you ever made NVIS contacts? If not, don’t be so quick to pooh-pooh the proven concept. Since you have HF in your vehicle, I suggest you set up a simple NVIS antenna. I’m more than happy to tell you how to do it. You might be pleasantly surprised with the results.

          We will be using 80M NVIS as the primary comms for South Arm (SA) and Icicle Brook (IB) next year. We will use the current VHF system with a relay as a backup – but next year each operator will have all the correct equipment (see below for a list of what each operator will have to have). Without it, they will not be working these two stages. That’s my decision.

          You don’t have to worry about inexperienced operators next year. I already have six HF operators with deep HF experience, the required HF mobile radios, and all with rally experience. They were working with us this year. Over the next eleven months, I’ll recruit no less than six more. So put to rest your fear of inexperienced HF operators.

          What’s more, we’ll be probably relying on a ground wave with the 80M more so than NVIS bounce to the D layer. Propagation should not be an issue

          I talked for months about everyone having a j-pole that would be 40 feet up in a tree at their location on these two stages. You can go back and read my emails to all the operators and stage captains to prove how I recommended this.

          To the best of my knowledge, only one was used at the relay position. I put up a 40-foot halyard at both the start and finish of SA and IB. The stage captains, and or the radio operators at those locations, made the decision NOT to use them.

          That will never happen again. I will mandate that every operator has a 50-watt radio VHF connected to a 450-ohm ladder line antenna at least 30 feet up in a tree.

          I had a clinic on Thursday night to show people how to get the antennas up in trees.

          It’s a volunteer effort and I can’t force people to do things. But believe me, next year – should you decide to volunteer – the ONLY operators that will work South Arm and Icicle Brook will have:

          • 80m HF radio
          • NVIS antenna
          • 50-watt mobile VHF radio
          • 25-foot adjustable painter’s fiberglass pole
          • simple drive-on mast/pole support
          • 450-ohm j-pole with choke
          • 50 feet of coax to connect j-pole to the mobile radio

          You’re going to see another very specific questionnaire next spring that every operator has to fill out. They will list all the equipment they have.

          I’ll know a month before the rally who has what and who’s going to be working SA and IB.

          I’ll end with this. If you want to test your repeater theory next year at SA and IB I’m all for it. The repeater needs to be across Lake Richardson in a place that has a line of sight with all stations on both stages. You can see this easily on Google Maps.

          You’ve got 11 months at this point to gather all the equipment you need to test your repeater hypothesis.

          I’m happy to show you on the map where I feel the repeater should be placed. It’s your job to gather all the equipment, make it work, set it up, etc. I’ve not set up a repeater so I can’t help you with any of it.

          Let me know as soon as possible if you’re planning on doing a repeater test next year.

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