My 120-mile Hike Carrying Homebrew Tube Transceiver

In the next hour I travel to Chawton in Hampshire, where tomorrow morning I begin a two-week, 120-mile hike largely along the North Downs Way, which snakes across southern England, often following hill ridges and passing through some beautiful countryside. The hike ends in Kent in the village of Wye, which is my QTH.

I am carrying a homebrew, five-tube transmitter-receiver that has been described at length in the Homebrew and Kits forum. My adventure now moves to Ham Radio Discussions because the radio is "finished" and being field-tested on the trail.





The radio is a close replica of the "Hiker's Portable" described by W6YBT in QST, September 1950. It has a three-tube superhet receiver, and a two-tube, crystal-controlled transmitter. My version of this radio has an output of around 700 milliwatts. Power for the B+ is provided by a bank of 15 (yes, fifteen) rechargeable PP3 9V batteries connected in series to give about 125VDC. The 1.25V filaments are powered by four rechargeable AAs in parallel.

The antenna is an end-fed halfwave (EFHW) connected to a PAR Endfedz matchbox.



The radio equipment including all accessories weighs about 3.3 kilos. It all fits in a backpack along with my other travel gear, for a total weight of 8 kilos.



Here's a map of my route. I will be posting about my adventures. This is not primarily a "radio trip" but rather a hiking vacation with a bit of radio thrown in.



I have been QRT for more than three years and my Morse is very rusty, but with any luck it will come back quickly.

Because of the vintage technology involved, and because it's a rapidly completed homebrew project that has not yet had a "shake down cruise," breakdowns and other disappointments are quite likely. I am keeping my fingers crossed!

(The 1R5 pentagrid converter tube in the receiver has a date stamp of April 1945!)

73 de Martin, G3EDM

 

Carry On!

 

That's a lot lighter than I'd have thought it was. Of course, usually when someone mentions tube gear I think heavy boat anchors.

 

I am operating monoband 40m CW and carrying six crystals, with these frequencies:

• 7007.3
• 7013.9
• 7022.4
• 7028.7
• 7036.3
• 7040.5

73 de Martin, G3EDM

 

Wow! Really nice. How are you getting B+ from those 4 Li-ion batteries?

 

I look forward to hearing you on the air!

 

.....Martin's B+ uses 15x9v batteries (chemistry delivers a bit less per battery). The smaller cells are for filament/heater supply.

Philip

 

Sounds like a wonderful effort!

Your frequencies look useful except for 7040.5. 7040 is a big WSPR frequency and any time I listen there it's a din of weak signal heterdodynes!

 

A bit different in Europe. I hear plenty of CW rag chewing around that frequency.

73 de Martin, G3EDM

 

As Philip said, B+ of 125V is from a bank of 15 LiOn PP3 batteries stashed underneath the wooden battery holder.

The four AAs on top are actually NiMH wired in parallel to deliver 1.25V to tube filaments.

73 de Martin, G3EDM

 

Have fun! Even if you're going to do search and pounce, please be sure to send an occasional pristine CQ DE G3EDM so that we can follow your progress on RBN.

 

No S&P with crystal control … my operating will be almost 100% calling CQ.

73 de Martin, G3EDM

 

Nice build quality.

Best of luck on your trip. Stay dry, eh?
_____

For those not having had a chance to visit rural England and the hiking trails found there, here is a channel where the fellow does just that:
Angles Way Long Distance Trail. Part 1 - Gt Yarmouth to Fritton. Woodland Tarp and Bivi Wild Camp. part 1 of 6.

He also does a lot of canoe trips
3 Day Canoe Trip down the River Severn - Day 1. Tarp and Bivvy Woodland Wild Camp. Beef Stew. (1 of 3)

 

7028 you might get some of the spy radios. At Bletchley park we had lots fitted with 3514. 7028. And 14056
I had two of the 25 watt radios. With just a few meters of wire out the window of a hotel I’d make great contacts on Cw. You will have a blast. f5vhz

 

I'm hoping to catch you one or the other time, fantastic rig. Safe voyage and Godspeed!