After my post yesterday about the accuracy of the Heath "Cantenna" dummy load being found to be "off value", I started wondering about the original specifications and did a little search.
Heath spec'd the Cantenna as having a VSWR of "<1.5:1" across the HF range. Now, if the reactance is negligible over that range (the Cantenna is rated for frequencies as high as 900 MHz so the reactance should be very low below 30 MHz), then a perfectly "in spec" Cantenna might show as little as 35 ohms or as much as 75 ohms and still meet "factory specifications". That's something to consider whenever working with older gear. Modern manufacturing techniques have spoiled most of us with cheap and highly accurate devices and parts that would have been simply unavailable or incredibly expensive only a few years ago. A dummy load with an SWR >1.5:1 is a fine dummy load for most purposes, but when doing things like critical power measurements, etc., it's good to realize that the actual value may not be as close to the desired value as one hopes. Ron AC7AC _______________________________________________ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
