Nuts & Volts - September 2004

Tech Forum

so I bought a $50.00, AC/DC, 5 inch, B&W TV from RadioShack and brought the AGC voltage to a jack in the rear. It goes up the ladder just fine and runs on batteries if you don't want to sling a 50 foot extension cord up on the roof. My DVM shows me when I'm aimed right, and the picture helps me see if I have ghosts. It's better than any expensive field strength meter, and the frequency is continuously, manually, tunable.

C. L. Larson Largo, FL

#2 In order to build a suitable UHF field strength meter, you'd be looking at a sizeable outlay to get the sensitivity required. An easier way is to borrow a pair of FRS radios, station one with a viewer at the TV set while you orient the antenna on the desired channel. Moving the antenna back and forth until an average mid point results in best reception. The FRS radios serve as communication between you and the TV observer.

This method is suitable for any frequency range of interest.

Ralph Cameron Ottawa, Ontario, Canada

[6044 - June 2004]

If I were to take two 500,000 volt stun guns and connect both positive outputs together and both negative outputs together, would I have 1,000,000 volts? I’m planning an experiment which uses high voltage.

#1 NO. In the first place, the output should be connected in series, plus to minus. But the outputs are not DC and not the same frequency, so they don't necessarily add. However, I would expect the voltage to be more than one alone.

Russ Kincaid Milford, NH

#2 Such a simple question — but one for which a technically accurate answer is horrendously complicated.

As for the proposed experimentation — DON'T TRY IT!!!

The insulation on those devices — while good enough for the voltage they produce — is NOT adequate to contain double that voltage, nor anything even close to double it. Not to mention the difficulty you will have in finding something with adequate insulation, to use to tie them together.

If you try this experiment, it is virtually guaranteed that you'll have some form of catastrophic failure, with destruction of the gear, and serious hazard to life and limb.

The semi-safe way to experiment with 'very high' voltages is with static electricity. Search the Internet for 'Wimhurst static machine' or 'Van de Graaf generator' for some starting points. (Also check out Gerard Fonte’s four-part Enigma Machine project, beginning in the June 2004 issue of Nuts & Volts. — Editor Dan)