Re: 415E's

Robin Szemeti - G1YFG

Noted, mine is pretty well sorted out and in spotless condition.  I only have diode detectors, a couple of coaxial ones and a WG16 one, which work well and are quite sensitive, the point about adding an attenuator is understood.  On my WG16 tests I used a Sanders 20dB coupler, and a good quality lab grade load on the "through" port, and the WG16 detector on the coupled port.

On Thu, 16 Jun 2022 at 18:12, KENT BRITAIN <WA5VJB@...> wrote:

One last set of comments on 415's

I have owned about a dozen of them.   I highly suggest getting a spray can of contact cleaner and giving the range switch a good cleaning.  And hit the pots while you are at it.

The 60+ dB of dynamic range is with a theromister head, not a diode detector.

Avoid the 50-60 range when you can, usually you have a lot of noise on the signal.

Don't have the signal so strong that you drive the meter into the 20 scale.  The diode is no longer 'Square Law'.

And if using a diode detetor, be sure to put a 6 to 10 dB attenuator on it.   This gives the antenna a good 50 Ohm load, gives the diode a DC return path.     (Yes you can go 75 if you like)  Gets easy after a while!   Cheers  Kent


Robin Szemeti - G1YFG

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