Frequency counter question

Why don’t frequency counters measure the power of the signal too? Is there an easy way to do this (easily measure frequency and power)? I have built much electronics before - so maybe I’m missing the whole point and there are other toolds for doing this… Thanks.

I’ve never seen one that did that. Usually the last thing you want to do to a frequency counter is to plug in a high power signal. That tends to fry the front end. The usual setup is to run a high power RF signal through an inline power meter to a dummy load and to connect the frequency counter to a low power test point.

If you were analyzing a cell phone for example, then wouldn’t you want to know its power output in addition to its frequency?

I’d probably use a spectrum analyzer if I wanted to check the transmitter output, since I would want to check for spurious outputs and other possible problems. A frequency counter would just tell me that the master oscillator was on frequency. For any transmitter, I would use a dummy load and connect the test equipment to a monitoring port.

Not really. You would measure the output power at the output of the amplifier stage while you would measure the frequency of the PLL oscillator. Differents things at different places with different instruments. I can see no advantage to combining them into one and many disadvantages.

There are instruments that do this and a lot else besides. I knew them as communications analysers, but they are also known as service monitors. This is an example. Quite complex and quite expensive.

Everything I find that gives a power reading in addition to frequency is so much more expensive than a frequency counter - why? (Frequency counters can be had for less than $10 by the way.)

Also, I think it would be cost effective to have some sort of PC interface like this: http://www.picotech.com/oscilloscope.html

But like a frequency counter, I would like to tune in on any frequency between, say, 1mhz and 1ghz - and also have reasonably good power sensitivity.

Measuring RF power is easy if you’re measuring a signal of relatively high power (at least 0 dBm) and/or you do not need good accuracy. It becomes a pricy proposition when you want to measure low power levels or if you need low uncertainty.

We have an old HP 436A at work. Bought it used a few years ago for (I think) $1000. But that’s just for the unit itself. The real money is tied up in the sensor heads. They run about $800 used and $1600 new. My most coveted power head is an HP 8481D. It can measure down to -70 dBm.

FYI, our co-op students are not allowed to touch the RF power heads until they are subjected to a training session that entails excruciating physical pain and countless death threats.

I use frequency counters in a variety of industrial situations and have never yet measured a signal that was going to or coming from an antenna. Often my signals are in the frequency range that people think of as RF, but they’ll be TTL pulse trains or sensor outputs or something, not “radio”, not for radiating. human_extinction, I take it from context that this is the kind of signal you want to measure?

Ditto others about the expense and convenience and so forth. I don’t happen to remember a time when I wanted both a frequency and a power measurement on the same signal.

Yes, measuring the power and frequency of a cell phone from various distances - is the functionality I’m looking for (on a wider range of frequencies).