These spreadsheets show the results of workshops/picnics where amateur microwave
stations were compared on a unique test range for both transmitting and receiving
performance. The test setup was developed by Kerry Banke, N6IZW and has been used
by the San Diego Microwave Group and during joint Picnics held the past few years
by the SDMG and the San Bernardino Microwave Society. The test setup consists
of a remote Tx/Rx transmitter/sensor unit installed on a pole about 15 ft. high
at a distance of approximately 220 ft. from the stations being tested. The remote
transmitter produces a stable signal on the operating frequency, such as 10368
MHz. Operators tune this in with their rigs and peak their antennas. The signal
is then reduced in level until barely discernible (MDS). That level is logged.
The operator then transmits with maximum cw power and the Rx sensor power level
is logged. The spreadsheet is used with the logged data and with data on each
rigs claimed antenna size and transmit power to allow comparison of measured versus
expected performance.
The results have been useful, not from an absolute
basis, but by allowing operators to compare their rig's results against other
amateur's rigs having similar Tx, Rx, and antenna characteristics. Any major differences
between performance can help to focus on unsuspected problems that can be solved
before upcoming contest events. In past events, operators have discovered problems
with relays, cables, connectors, and even non-functioning power supplies.
The
spreadsheets are provided in Adobe Acrobat (.pdf) format. You will need an Adobe
Acrobat Reader program to view or download the spreadsheets.
What you should
look for: Your receiving performance is shown in the column marked "MDS Gen
dBm". You want the largest negative value compared to other stations having
the same size or performance antenna on that frequency band. In the last column
marked "Meas-Calc" your transmit ERP performance is shown. A zero means
that your ERP came out exactly as expected given the claimed transmitter power
and antenna gain. If you have a positive number, then your ERP is better than
expected by that many dB. If you have a negative number then your system measures
worse than expected. Good Luck!
July
16, 2007 SDMG Workshop at N6IZW QTH in La Mesa, CA Also N6IZW provided a Microsoft
Excel Worksheet allowing you to select tabs at the bottom of the worksheet to
view current and prior year's results. If you have Microsoft Excel installed in
your computer you can download and run this Excel Worksheet.