Good morning all,
Tom. In the photo labeled Whirley-Henbury 8, that sure is a lot of ground beef.
At my location, I am blessed with access to several irrigation canals that lead to a very wide river bank along the Rio Grande (the Mexicans call it the Rio Bravo). Once on the river, the length of the walk is up to you. If one goes north, the distance is 1,007 miles (1,620km) to the headwaters at 37.798045° -107.539187° at 12,599 ft (3,840m) way up in the Colorado Rocky Mountains near Silverton CO. If you have the right vehicle, you can drive most of the way to it, only a 1.5 mile (2.4km) hike up the mountain. If I go south, the distance is only 889 miles (1,340km) where it meets the Gulf of Mexico. Needless to say, I will not be walking anything near that distance, but the opportunity to walk, enjoy the warm sunshine and fresh air in an area where it is easy to avoid human contact is nearly endless. Our high temp has reached 91° (33°C), and our low has dipped to 39° (4°C) at night.
When the wife feels like coming along, we take the dogs and just stick to the canals where the dogs can go nose to nose with horses, cows, sheep, goats and some other creatures.
If I go alone, I like to get out on the river. That is because the banks and flood plane are wide, most of the homes are facing away and the yards are nearly always walled in with a sturdy rock wall. So there is very little chance of human contact going in any direction, and there are no low power lines anywhere near the river. That is important to me, because I go Pedestrian Mobile.
The /PM kit is built around an older military pack frame. The antenna is mounted using a 3/8-24 mirror mount that would normally be used for a CB radio on a truck mirror. The antenna is custom made, the lower section is cut to resonate on about 50.5 MHz (6m-band). Although the pack frame is padded and insulated from the body, body capacitance plays a huge part in the tuning and the antenna is a good bit longer to resonate. The upper section of the antenna is made with an adjustable coil assembly that has a sliding contact to pick the coil tap. With that coil shorted, the upper whip section is cut to resonate on 28.5 MHz. From that, just sliding the coil contact to various points and it can be made to resonate from 10m to 40m. When first working up the antenna, I noticed that when at resonance on any band (X=0 or near zero) The antenna was 20 Ω to 30 Ω. To correct that I added a 2:1 Un-Un, and now it is 40 Ω to 60 Ω when tuned. I wish it could do 60m, but I’m not certain a QRP signal on a mobile whip on 60m would be heard well anyway. This is what it looks like.
To give you a scale, I am 5 feet 9 inches tall (1.75m). I have not measured it, but the antenna is quite tall. It is important to know your area and the places where overhanging wires can be a danger. I am fortunate that there are none in my immediate area, although low trees pose a hazard from time to time when getting to and from the canals.
How does it work? Locally there are a number of us that use 28.445 as a local chat frequency. I was out walking along the river early one evening, chatting with the local guys. We were just talking about the usual stuff between friends. And you know how conversations will ebb and flow. So in one of the silent moments I identified - Kilo Delta Five Kilo Charlie, Pedestrian Mobile. So immediately this strange voice comes back and asks “What is a Pedestrian Mobile?” So I replied with a short description, a QRP radio on a backpack with a vertical antenna, I was presently walking along the Rio Grande river in far West Texas. And the voice comes back - “This is JA4GXX, you are 5 and 5 near Hiroshima Japan, do you have a 10-10 number?”
Another time I was walking through the neighborhood and a neighbor asked what I was hearing. I told him I was just starting out and didn’t hear anything yet. So I was on 10m again, and asI spun the dial I tuned in a voice and all I understood was and listening, QRZ? So I quickly shouted Kilo Delta Five Kilo Charlie, Pedestrian Mobile. And the voice comes back KD5KC you are 5 and 9 on Malpelo Island, what is a Pedestrian Mobile? So I explained it, and he replied "You are a true 5 and 5, amazing signal, enjoy your walk and QRZ, this is HK0NA.
I had to pull out my phone and look where Malpelo Island was.
Anyone can do Pedestrian Mobile. I use the Icom IC-703+ because I have one, and it has the Collins SSB and CW filters installed. I truly wish it also had 2m-SSB. That is something I think I would also enjoy. I’ve considered swapping it for a Yaesu FT-857, but then I would need a much larger battery.
It isn’t like we don’t have the time right now, much of the world is locked in and staying away from crowds. So dig around in your gear. See what you can throw together. Who knows, some day we might get lucky and have a /PM to /PM contact.
Vy73 – Mike – KD5KC – El Paso, TX.