On Sat, 27 May 2017, Jeff Liebermann wrote:
On Sat, 27 May 2017 12:55:02 -0400, wrote:
Look for something that has a built in prescaler. Something like
this:
http://www.ebay.com/itm/Blue-RF-Signal-Frequency-Counter-Cymometer-Tester-0-1-60MHz-20MHz-2400MHZ/172396798620
The basic counter goes from 100KHz to 60MHz. The other ranges use a
prescaler to divide down the input frequency so that it ends up at
less than 60MHz and can be counted.
I"m assuming those really cheap portable counters are using prescalers,
since they only start counting at 50MHz or something. INtended for two
way radio checking I assume, so you don't need the lower frequencies, and
a whip or rubber duckie antenna will pick up the output power fine.
I've certainly thought about buying one of those cheap ones, hoping I
could bypass the prescaler, though I suspect another issue, the prescaler
isn't a decade counter. Back when Heathkit came out with a frequency
counter, circa 1971, the prescalers were decade counters, and things got
better as they improved, and the frequency counters had higher limits.
But that sort of IC seems out of fashion now, so the prescalers are meant
for other things, and offer a binary division, so bypassing it in the
counter (and maybe adding an input stage) means the clock for the counter
is "wrong".
Michael