[600MRG] VNA S11 measurements, el cheapo junk box jewel...

[Dave Riley]

Always looking for a value in the junk piles around here by picking out 
some old dusty item to get some of em back in service as something new 
but even useful...

I guess we have all made some inroads as to MF antenna theory, feed 
lines, and equipment etc...

Then saw a nice old clean Protek sweeper on e-bay that goes up to 2 
mhz., then picked up a home brew swr bridge for re-issue, thence to 
closest USB port for a fancy SWR look see about this litz loop transmit 
antenna on 630 meters, sure tunes sharp...

This is how it looks >>  Protek sweeper is centered on 475 khz. and 
sweeping out each way till about 10khz wide, then dump this in to a 
standard SWR bridge port along with the UNKNOWN loop which is a 630 
meter litz loop on the other side of the bridge.. Then that output is 
sent to the SDR receiver to see SWR ( return loss ) spectrum...
Using old sdr-iq receiver as a pan adapter scope and made them all go 
like this;     plug and play

http://www.radiocom.net/600M/VNA1.png

Is noise floor of receiver tuned the 475 khz center

http://www.radiocom.net/600M/VNA2.png

Calibration open/short

http://www.radiocom.net/600M/VNA3.png

50 ohm calibrated load

http://www.radiocom.net/600M/VNA4.png

Loop antenna feed point  @ center of scan with return loss across the 
band, 10 khz. active window
Indicates about -32 db return loss = about 1.05 SWR @475.670 khz.,  AA1A 
WSPR

http://www.radiocom.net/600M/VNAsetup.jpg

Another junk box jewel...  ( test equipment division )   What's in your 
junk pile??

Have fun!! 73s de DaveR aa1a