Using a 450Mhz band antenna tester at 900Mhz

[VintageTekFan]

Question for ask the HAMs out there: I'm heading into the field today with a MFJ269Pro antenna tester to test some 900Mhz antennas.

I know it only covers up to 450Mhz, but I've got very little choice.   What  difference can I expect to see between the the measurements?  I well have a known good setup to compare to.

I would love to learn the theory, but time is short for now.   Thanks!

[Fraser]

900Mhz antenna is half the length of that used for 450Mhz as you likely know. A 900MHz antennas is unlikely to resonate in any meaningful way in terms of making any measurements for return loss etc. If the SWR analyser is really poor quality and produces a large harmonic of its tuned fundamental you MAY see some readings but the bridge is not optimised for such a high frequency so don't get your hopes up.

You need a suitable tool for this job, a 450Mhz unit isn't up to the task.

Aurora

[tggzzz]

You will probably be able to see gross abnormalities, but not be able to determine whether something is in or out of spec.

By analogy, you will find it as easy as using a 500MHz scope to see a 1GHz signal. You will see something, but it won't show the high frequency detail.