This project has been delayed due to lack of a tin, then viola I searched the XLY’s store cupboard, demanded Pear and Ginger Upside Down Tart and Ginger Parkin and the tin was empty.
So there we have it, the Lyles Load, Black Treacle Load, Sweet SWR Baby Load, Johnson and Johnson Soft Smelly Load, By Royal Appointment Load, Sampson’s Strong Dummy Load.
The other problem I encountered was the Liquid Paraffin. Medicinal is only available in small quantities expensive and restricted. I had the XYL out searching the town for own brand Baby Oil, then in Leicester, she reported that even Johnson’s was not around.
Yesterday I took the search to Leicester myself and found J&J 500ml in an Indian shop, the last bottle, has there been a rush on Dummy Load building.
So today with all the bits ready did the hole cutting and assembly.
I left the bottle open on a radiator overnight to drive off the perfume. Baby oil also contains an Alcohol / Palm Oil Emollient, not soluble in water so I judged it should be OK.
I added the usual diode and capacitor to measure power and assembled with the oil, so far so good. I applied fairly low power at 3.5MHz. Good SWR, then bad, and no power reading, the diode had popped. Out came the load dripping with oil and I replaced the diode with a 1n4148, more robust and cheaper, and tested it dry on the bench, the diode went short as soon as I measured the voltage, so did another 1n4148. I have no idea what is going on I have assembled these so many times before with no problems.
So I changed the diode for a sense loop to attach the scope. I will go back and try a BAV21 diode some time I should have put them on my last on line order, I have always used Germanium Diodes. An odd thought now, I was using my Icom IC706 as the test signal source. When I used that for testing the 84 Resistor Loads the IC706 blew the diode in one of my QRP Loads I was comparing with (at QRP levels). Does the IC706 (MK0 what a farce model) put out a spike of full power before the ALC drops it to the set power level. I would not be surprised.