In article ,
Fred McKenzie wrote:
In article ,
"Mike Andrews" wrote:

Some friends and I have been looking into making antennas for 70 cm.
and higher frequencies, but we don't have an MFJ-269; my MFJ-259 tops
out at 175 MHz. I _do_, however, have an SWR meter that supposedly
works up to 500 MHz( and maybe higher), and an HP 8640B that is good
to about 1.2 GHz.

If the SWR meter is sensitive enough, could I get at least ballpark
SWR values using the 8640B as a source, running the signal through
the SWR meter to the antenna? Or am I way off in left field?

Mike-

You have to try it to find out.

One problem is that your SWR meter's diode output is non-linear for very
low voltages, resulting in SWR being higher than indicated for low
values of SWR. You may be able to get around this with a
hand-calibrated dial on the meter, or a calibration correction chart.

Fred
K4DII


Analog devices makes RF-log amp/detector chips which are good to microwave
frequencies (basically RF in, 10mv per dBm out, from -80dBm to 0dBm).
Replace the SWR meter's detector with one of these.

--
/* AB1GO */ /* Joseph H. Allen */
int a[1817];main(z,p,q,r){for(p=80;q+p-80;p-=2*a[p])for(z=9;z--q=3&(r=time(0)
+r*57)/7,q=q?q-1?q-2?1-p%79?-1:0%79-77?1:01659?79:0158?-79:0,q?!a[p+q*2
]?a[p+=a[p+=q]=q]=q:0:0;for(;q++-1817printf(q%79?"%c":"%c\n"," #"[!a[q-1]]);}