How to find the location of an pirate radio studio

[peterpan73]

Hello,

I stumbled into this thread while I was searching for ham radio audio topics on this forum. I am a Ham Radio operator from India with Callsign VU3PAT. The problem as I can see here is simple. If you want to do it the Fox Hunting way as someone mentioned earlier, you will need to make or buy Radio Direction Finding (RDF) equipment which in its basic form consists of a receiver with an S-meter and a loop antenna.

As in this case the freq is around 103 Mhz on VHF it is simple. First construct the antenna. you can check up www.dxzone.com and www.qrz.com or even www.arrl.org for the details and schematics to some of these antennas and receivers. As this is VHF, a Yagi antenna would work best, for greater directivity use more elements and greater boom length according to the formulas laid down in the resources you will find in the above mentioned sites.
Keep in mind that a long boom though highly directional (and unwieldy) should be mechanically stable and light to mount on your vehicle or motrocycle. Certainly you will not want a fellow motorist or pedestrian taking you to task when an innocent piece of metal tubing smacks him on his face and into oblivion. At best, a 5 element yagi for this purpose is good enough and may have a fwd gain gain of 13 to 15dbi with an F/B of 28 or more db depending on the design.

When tracking the transmitter, turn the Yagi ant. 360 degrees and mark the direction of the ant. around which your receiver's S-meter reading is Max. Note this direction down and move towards the direction of the first director element of your antenna. Keep going until your S-meter reading peaks no more. Then look around for Yagi antennas like the one you have in hand or for Verticals scanning the rooftops around the vicinity all the time with your eyes. MOve closer around the suspect antenna locations and you could 'bingo' any moment, besides you could land yourself a plum job at your local Radio monitoring station. The basic assumption in this process is that you have this pirate station on the air all the time eklse this won't work. other rdf methods involve trigonometry.. but thats a different story altogether. keep us posted on your developments and when you've found your fox.. ... on your booty!


BTW it would be a good idea if you could inform this to your radio monitoring authorities for necessary action as this is a grave offence.

Good luck and good fox hunting.

73ees
peterpan73

[Rahul]

Hi!
Very interesting to note Fox hunting here at DIY. In practice a 3 element Yagi for 100Mhz should do the trick. One point overlooked is that as you get nearer to the transmitter the readings would become consistant . Reason being the signal strength becoming stronger and added to it the gain of your Yagi.
Now what you will need is an attenuator between the antenna and receiver to reduce the signal. With greater attenuation you will soon find youself directly on top of the pirate.
Say Hi to the fox from my side too.