On 28/05/17 04:35, 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 have two of those. I bought the second because I thought I'd
broken the first, it performed so badly. They're as bad as each
other.
If you have a strong and stable signal, it can work ok, but
the input design is poor. The HF and the pre-scaler both
have dual-gate mosfets, but there's no gain control (automatic
or otherwise) and the inputs are paralleled. I've disconnected
the two inputs by cutting a track and soldered on a little bit
of RG-158 to an SMA connector for the high range.
I'd love it if Mike is willing to share some of his counter
front-end wisdom.