Feb 9, 2001  (updated  Mar 20,2001)

For several years now the NOGA members have heard me talk about creating a human powered QRP station. With ice storms, tornadoes, and hurricanes you never know in Georgia when you might need extended operating power for emergencies.

I had thought about using a small automobile generator (not alternator) from an ancient car. In the back of my mind I knew there was military equipment that used human powered (hand cranked) generators but didn't know where to find them if they still existed. I put a query out on the milsulplus list and someone suggested FAIR RADIO Sales, a mil surplus dealer. So I got their catalogue and found what I thought was just the ticket. A hand crank generator from a SCR-578x (whatever that was). So I called the 800 number and tried to order one but they were out of stock and had no idea when they might get more. So I went back to the milsurplus list with the SCR nomenclature and sure enough a ham in Texas a few in various conditions.  I told him what I needed but said if I could order two then I would restore one for my QRP collection and use the other for the generator section.

The SCR-578x is a "radio set" that goes by the nickname "Gibson Girl". It was tagged that name because of the hourglass (figure 8) shape of the enclosure. The unit is a tube transmitter operating only on the fixed emergency frequency of 500 KHz and had a built-in cam operated morse sender so someone without training could use it. these unit were located in airplanes and ships and were included in life rafts and served as a radio beacon to attract rescue units that might be looking for survivors. The unit contained a mechanical DC generator capable of two voltages ( 150v DC @ 30 mA for tubes power and 28v DC@ 150mA for tube filaments (two 12v tubes in series). I elected to use the 28v section.

First a look a a Gibson Girl in tact:

Click on Image for full-size picture

The round hatch in the lower front contains a reel of wire for deploying a box kite or hydrogen ballon. The switched on the front control the operation mode and there is a manual CW key (black with orange circle) on the panel. The Morse code table is printed on a laminated card on the top of the enclosure. There is an automatic cam-operated mode to allow the standard emergency signal to be keyed while just turning the crank. So the operator did not have to know any Morse Code to use it.
 

Below is  Sam AE4GX in action at NOGA meeting demonstrating the normal cranking position of the emergency transmitter. It's designed to allow you to be in a sitting position in a boat or on land and turn the crank with either hand. It's water tight and has rounded edges to prevent damaging rafts and people.

Click for fulsize picture

Well if you open the front panel and remove it you basically gut the electronics and leave the generator and mechanical parts in the enclosure. so I cut out a similar shaped front panel from duct material and built the charger regulator and control switches in the sheet metal panel. I attached this to the generator power strip. I did have to make a few MODs to get the generator to stay "up" during the auto message cranking cycle ( I defeated it with a jumper).

I have a 5 aHr gell cell mounted to a couple of aluminum angle pieces. Here is a clasp showing the use of the extra contacts on the switches and the small LM317 regulator on the PC board piece.

My front panel has the basic controls for (1) and internal gell cell and (2) an external gell cell (optional). Three switches let you choice the (a) battery to use,  (b) the battery to charge and (c) the battery to monitor for voltage. With two batteries one can be hand charging while the other is being used.  You will need two people to do this unless you are very handy. :-)

Here's a close up view of the front panel, the external volt meter, the external gell cell and the rig (My home-brew all HF band GA Sierra).

Last but not least in the complete picture of the rig setup for emergency operating. All I need is the antenna.

I'll be using this setup for many of many QRP contacts this year. I have built band modules for 80/40/20/15/10/6 and will finish the rest soon.

What's a GEORGIA SIERRA?  Well that's another story!

72's Sam Billingsley  AE4GX  Atlanta, GA  North Georgia QRP club  (NOGA)

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