RFI Locating Activity
RFI Locating activity 08-20-2009
Materials:
Radar Engineers Model 239 RFI Locator
12 volt 7 amp-hours gel cell.
BNC 50 Ohm feed line.
headset with .25 inch plug.
Arrow dual band (2M/70CM) handheld antenna.
Steps:
1. hook feed line to antenna.
2. hook feed line to model 239.
3. plug headset in model 239.
4. Cross 3rd Street to the south curb.
5. Turn on Model 239 using the On/Volume knob and set to about 9 Oclock position.
6. set band knob to 100 MHz and use the Frequency know to tune to 147 MHz. Note that the unit only indicates MHz which is usually sufficient to locate noise.
7. Turn the RF gain up until you can hear noise. Rotate the antenna in the azmuth while watching the meter.
8 Turn down the RF gain until you only get a reading in one direction.
9. See if you can duplicate the results at 142 MHz. What does that tell you about the type of noise source?
10. Try rotating the antenna about its long axis. What does that tell you about the noise source?
11. Now set the Band select to 200 MHz and tune to 435 MHz. Try steps 7 and 8 at this frequency. Is this the same noise source?
Now let others try to duplicate your work.
