A couple of options here. Not knowing your actual need for accuracy etc
makes it hard to guess!

From my standpoint I'd probably just adjust an antenna for max field
strength but if I wanted actual VSWR meaurement or minimizing same I'd
probably use a directioinal coupler and a sensitive voltmeter.

A DC is essentially the active component of a power/VSWR measuring
device. AT 1GHz I have seen PCB designs with SMA connectors that you
just put in circuit, measure the volts, reverse its direction, measure
the volts again and calculate the VSWR. Pretty simple and cheap stuff.
The biggest problem is preserving the impedance across the DC device
itself. You can use teflon PC board for example to help out on this. You
will also need to think about the calibration of the thing because the
diode is not a linear device and needs some volts to get over the
forward drop. You can also DC bias it but those components will affect
accuracy over temperature change etc.

Still a good general purpose tool though. You can even make loads that
would look like known impedances to calibrate the thing.

Have a look around for these. You'll be impressed by the low price. They
are after all just a lump of PCB, two connectors, a microwave diode and
a filter cap! You'll have to supply your own voltmeter!

Cheers Bob VK2YQA

wrote:
I did find Electrorents. $700 for a month... I didn't think it would
be that much. It's mainly just for basic stuff, like SWR. I'm not a
ham. Seems like anything that goes past 500 MHz is really expensive.