I have several multimeters with a rather useless frequency counter option. Has anyone built an interface to boost it's sensitivity so it could be used with a signal generator. I for one cannot justify the expense of purchasing a frequency counter. Especially at this time in my life when a down size is just around the corner.
Regards Jimb.

There are apparently some Chinese counter modules around for a pittance. I have one kitset widget under $10 that can measure, Ohms. Inductance, Capacitance, Test transistors ... Blow up if you use a charged cap. Fantastic & really handy.

Have not tried the counter in the 2 Jaycar meters I have that are supposed to measure freq. The calibration here is a semi permanent couple of a Counter, Generator, & Oscilloscope via a box designed to couple them & attenuate OP as well as DC block.

What I note is that SG-11 has a cap in the OP which is signal reducing. But it still has an attenuator. The TE-20D clone has no cap.

I calibrate, tone off, full power; that's the best way. I note that if the attenuator is wound down, your problem manifests. My counter is a Fluke ex Army.

This is a cheap Chinese frequency counter that I am using, fitted a BNC connector to the input side.
There are several variations of this module.
This is a cheap component tester.
Will get Brad to add links.

https://www.ebay.com.au/itm/123585287899

https://www.ebay.com.au/itm/122940799562

LCR-T4 is the one for transistors etc. Its in a demountable type clear plastic box (coloured plastic is likely dearer)?

Thanks Marcc and Normf.

What can be done using the same frequency and one they can all actually read, is to use the oscilloscope to measure the minimum PP voltage that they will work at.

That is a good idea Marcc

The point is that there are traps in measuring & calibrating. Often modern test equipment cannot handle the voltages nor mixed RF & DC. The RF can cause a flashover of be added to the DC reading. DVM's are fairly hopeless at presenting an accurate reading with dirty or fluctuating input.

With the SG-11 whilst drift may be of concern as there is absolutely no heater & B regulation. Once it is calibrated having the frequency meter drop out is not such an issue. The reality is that in most cases you have to have the Modulation / Tone off. AS soon as you turn the tone on The reading goes haywire anyway.

That will not change even if you add a dedicated plug to bypass the attenuator.

Links added.

Quote: https://www.ebay.com.au/itm/123585287899

I wish they would make cheap Debt-Counter-Displays (would require wi-fi)
- so that we could check, at a glance, how close doomsday is:
http://www.usdebtclock.org/world-debt-clock.html

Thank you all for your contributions and thank you Brad for the upload.