Editor:
I disagree with the letter regarding the unsuitability of Heathkit (vacuum) tube radios for EMP protection. Let me elaborate:
- Lethal voltages: While you really don’t want to tangle with +700 VDC, the most lethal voltage in any radio is that which comes from the wall outlet: 120 VAC. AC fibrillates hearts (we use it for that purpose in cardiac surgery); DC defibrillates hearts (done that many times).
- Requires 120 Volts AC: Unless you get the 12 volt power supply (I have two). Or solar power / inverters.…right?
- No cooling fan: Well, they rarely need it! My primary rig is more than 40 years old and going strong! Digital modes do indeed have high duty cycle (though actually not 100%), so turn down that mic gain appropriately. Watch the specs on solid state rigs also; they may not be spec’d for high duty cycle either! Tubes show a nice cherry color; transistors may just quit.
- No easy way to turn down the power: It is possible if you know how to run the rig. For example, on the HW-101, see pp. 140-141 of the manual. If you adjust that mic/cw level control, you can pick any power you want!
- Yes, Heathkits are old. Yes, they may fail. Usually the same electrolytics that will eventually fail in your solid state rigs also. It is cheap to buy replacements on DigiKey. Tubes may be physically fragile, but electrically they’re far tougher than transistors or FETS. Try exceeding the max collector-base voltage and watch what happens! SWR can kill transistors! Tubes are often easy to find, whereas getting a replacement transistor can be a problem too, as there are so many of them. Costs? I own lots of both, so I know the prices. A new ICOM-718 is around $600, and then you have to buy the power supply; that money alone would purchase TWO complete Heathkit SB’s including power supplies. Vacuum tube rigs are actually inexpensive by comparison. A set of replacement tubes might run you about $120. Try buying replacements for your proprietary and single-run semiconductors!
I own probably four or five Heathkits and use two on a regular basis. I’ve already refurbished at least six, which are in service. I also own four wonderful ICOM HF rigs. Both types have their purposes. The writer missed a really important point though: when would it ever be safe to pull your EMP-fragile solid state rig out of its protective Faraday Cage? The unfortunate answer: never. There could always be another attack. Are you going to be willing to risk it? By comparison, long after my solid state rigs are fried, my vacuum tube rigs will soldier on, proven in EMP testing and published in QST. Both have their uses, but if EMP is your concern, vacuum tubes are your friend. – PrepperDoc