Revisiting the Trail Friendly Radio

By Mike Herr, WA6ARA
Special to The ARS Sojourner
I guess I started the idea of a trail friendly radio -- now commonly referred to as the “TFR” around the QRP community -- with my whining about how our present QRP radios are built and the difficulty in using them on the trail.

What is a TFR? Simply put it is a radio so configured that it is easy to use on the trail, taking into account the lack of conventional furniture we find ourselves in. Most of the time we do not have a table to sit the radio on, and we have no chair to sit on.

The cover photograph from the January ‘99 edition of The ARS Sojourner shows this. The poor ham (in this case, legendary QRPer Wes Hayward, W7ZOI) is quite comfortable on the ground -- but can he read the display, tune the frequency or adjust the volume without moving the rig around?

More likely he would have to lift the rig to check the frequency, and in so doing push the wrong button and maybe knock it off frequency while adjusting the volume. I know because I’ve done it a dozen times.

Advancement in TFR design has been somewhat dormant since the ARS’ “TRAIL FRIENDLY RADIO CHALLENGE” in November 1996. So, I thought I would stir things up again, looking for new ideas.

I’ve tried a wide variety of rigs while camping and backpacking. I started with lugging about an HW-8 (not a good idea), then a scratch built homebrew rig that went through numerous evolutions. Finally I landed on the NorCal 40. From an operating point of view, it became the rig of choice.

Still, it lacked the TFR features I wanted.

After the last TFR modifications and more fussing with the NorCal 40 on the trail I came up with five basic rules of physical design.


1) The rig should sit nicely on the ground and be stable. 2) Controls should be on the top of the radio and easy to use. 3) Lever switches should be avoided in favor of rotary switches. 4) All I/O ports (antenna, key, etc.) should be easily accessible, preferably on top as well. 5) Each I/O port should be different. For example, use a BNC connector for the antenna; phono jack for the key; coaxial connector for power, etc. That way in the dark hookup will be simple and error free.

Note these say nothing about superhet verses direct conversion, CW vs.SSB, or other mode or circuit considerations. These are only about the physical design between the rig and the human on the trail.

Right now I have two TFRs under construction. The first is the trusty NorCal 40. This rig has been such a pleasure to use it’s a natural for the conversion. If I were going to start from scratch, I would probably use the SST version.

The main board is being pulled out and placed in a simple, unpainted aluminum case. All the controls will be at the top, with rotary switches instead of levers.

I had a KC-1 frequency read out and keyer in the original configuration and will retain it in the new one.

I am going to add an Embedded Research ESP-1 power supply as an optional device. This will allow me to be more power supply tolerant and squeeze the last bit of juice out of the batteries.

All connectors will be on top of the radio and different from one another.

I am also considering adding a screw post strip to back up the connectors. While not convenient nor “different” as in rule 5, it would allow me to strip the wire and connect via the screw post when that pesky BNC gets ripped off while putting the antenna up in the back country (been there, done that).

The second rig is a White Mountain 20 meter SSB rig. It will be used for mountain topping on 6 meters in conjunction with a transverter. In this case the rig will be configured with the controls on the top, digital readout there as well, and the I/O lines on the side.

This was done to better integrate with the transverter, a Ten Tec model. Only the microphone connector will be on the top.

So, what are your Trail Friendly Radio ideas? Each of us have had their own frustrations with rigs, operating and “if it just had this” nagging ideas after each outing.

One of the beauties of amateur radio is we can build our own rigs, modify them to our content, try an idea, modify and try again. As I complete these rigs and use them in the field I’ll report to ARS.

How about you?

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Mike Herr, WA6ARA, is an avid QRPer, builder and expert outdoorsman living in Ridgecrest,CA.