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In a bridge, as used in the NanoVNA there is an internal 50 ohm resistor. You have no control of it and you probably can't actually measure it. The bridge will only be in balance when the external

No the return loss of open and short is theoretically 12dB. The RLB has a voltage factor of 8 and the transmission has a factor of 2 .?Sent from my Samsung Galaxy smartphone.

You are correct. In theory, a 6 dB attenuator will give a 12 dB return loss, which another way to test accuracy of the instrument. Stuart K6YAZ

I'm probably missing something here, but shouldn't opens and shorts give 0 dB of return loss, not 12? After all, their Gamma ought to be equal to 1. - Jeff, k6jca

As has been stated before, the importance of SWR or return loss for most practical users is not how little power is reflected (within reason) but at what frequency is the antenna actually resonant.

Tuck I am not sure if you are misunderstanding (I don't think so) or simply miss-stating the concept. A load, any load, does not have an inherent return loss. It only has a return loss as measured

An antenna without a counterpoise (ground or ground-plane) is just a piece of wire. If you are testing a "rubber duckie" I would recommend mounting it onto a piece of metal; even a piece of aluminum

Yes Warren, what you say is exactly what is done on any return loss bridge. You measure an open load, you measure a shorted load both of which should give 12dB return loss but in practice they differ

You can try a short coax loaded with low freq ferrites that fit tight on the coax. It helps (somewhat). Cal at the end of the coax

I saw similar effects myself when testing the antenna from a handheld transceiver. As Peter says it is to be expected as, in its intended use, the human operator together with the conductive part of

And, just to ground this discussion a bit, for practical purposes in the professional RF and video worlds any return loss in excess of 30 dB is considered excellent. A return loss of 30 dB for example

Hi Tuck(?) Whether a load shows a return loss of 50 dB, 30 dB or 70 dB depends upon what load was used to calibrate the VNA. As you can see from the chart, all three loads exhibited better than 70 dB

This seems like taking an arbitrary resistor from the bin and calibrating your ohmmeter to it. From that point you only know how other resistors compare. This also reminds me of some of the time-nuts

It should be much better in the field on a proper HF antenna, both because of the counterpoise and also the lower frequencies involved. Well at least your HF antenna should have a proper counterpoise,

Hello Peter, On the device itself. So I will elaborate a little more, as I would like to use one nanovna at the field, as a simple SWR measurement tool, and of course operate it handheld. Maybe it

Thank you Warren. This is no argument over a pin head. Do you believe any of your loads are 50dB or better or even 38dB or better. How do these figures degrade with Frequency?Sent from my Samsung

Are you seeing the effects of your hand on the instrument or on the antenna? Remember also that those antennas are dependent on a counterpoise, usually the HT and your body, so you will see

I don't? think this vna calibration just arbitrarily sets the 50ohm dummy to the noise floor. If it is based on a 3 load measurement then it must use Thomas Baier' s DG8SAQ procedure which is to find

Hello team, While I was measuring an handheld VU antenna, I noticed that the nanovna was suffering of "Hand capacitance" influence. My unit is an original one, shielded. What can I do to improve it?

Just a slight correction -- actually, I should have said that the load's resistive "deviation from 50 ohms" must be less than 0.032 ohms. Sorry about that! - Jeff