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Old 9th Apr 2018, 8:20 pm   #1
G6Tanuki
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Join Date: Apr 2012
Location: Wiltshire, UK.
Posts: 14,007
Default Quick-and-dirty 1MHz test oscillator.

Like most of you, I've got a few decent crystal-controlled 1MHz oscillators whose harmonics I can trim to zero-beat with WWV and the like - but recently came across a 'packaged' solution which rather more easily fits the bill of a quick-and-dirty oscillator I can take around with me which provides 1MHz-harmonics for general purpose testing of amateur-radio stuff, car-radios, FM tuners etc.

The RS 478-5749 being the heart of it.

https://uk.rs-online.com/web/p/cryst...ators/4785749/

Way cheaper than a traditional 1MHz rock, and it's got the necessary drive-circuitry included. Feed it 5V and get your 1MHz 5V pk-pk squarewave a couple of pins further down.

OK, it's got no way of 'trimming' the frequency so you can't zero it with WWV but for £3.23 it's a lot of value in a small package. Mine I've fitted on a square-inch of Veroboard along with four 1.2V AA-size Nicads of questionable age/chargeability: even running from these two-decades-old cells I can hear harmonics of this little beastie up to 175MHz.
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