I’ve been DFing and RFI locating professionally for more than 30 years; and Terry’s method is sound. The commercial DF/RFI Kits have a built in analogue signal strength meter, that helps you determine left or right. The human ear, if in good condition, is far more sensitive to variations than all but the most sophisticated and expensive meters.
Two things could possibly help to refine the method: Loop Antenna, and stubby antenna (1”) for when you get very close. Arrow does make loop antennas in both VHF and UHF. I haven’t tried them yet, but I intend to. As for the stubby; the ones I have used were supplied with commercial DFing Kits. I have yet to identify a commercial source for them. I suppose I could make one easily enough with a BNC connector and a piece of solid wire.. Max From: altusmetrum [mailto:[email protected]] On Behalf Of Terry W7AMI Sent: June 16, 2015 10:56 To: Altus Metrum Subject: Re: [altusmetrum] RDF on the cheap I guess I do DFing differently than most people? I don't use the signal strength meter at all. I open up the squelch and listen to the incoming signal. You can hear a weak signal, even using FM, long before the squelch will open or the signal will show up on the S-Meter. I move the beam antenna around until I find the direction where the signal is the least noisy. When the signal is stronger I switch in attenuation to reduce the signal strength so the signal becomes noisy again. Terry On Mon, Jun 15, 2015 at 10:43 PM, W7AMI <[email protected] <mailto:[email protected]> > wrote: The problem with the Baofeng UV3R that I have is ease of use, or rather lack of. If you want to set it up with a Mobilinkd modem it's good. But for general use it cumbersome. To DF you will want to turn off the squelch. To do that you have to hit the Menu button on the front panel and use the selector knob on the top of the radio to scroll through the functions to the squelch function. Then hit the U/V button to select the squelch feature and then rotate the selector knob on top until the squelch is set to zero. It works. It takes longer to read than to actually do it but it isn't convenient. Even the volume control is primitive. Hit the Vol button and rotate the selector knob to turn the volume up or down. The entire volume range is only 9 steps. I find I only use the first two steps. The big feature is that is is cheap. I mostly use mine to monitor the launch channel on the FRS service while hunting rockets away from the launch area. The launches are almost cooler 1/2 mile away from the pad! That's my experience your mileage may vary. Terry
_______________________________________________ altusmetrum mailing list [email protected] http://lists.gag.com/mailman/listinfo/altusmetrum
