need a unique circuit

[chinsoon]

hey there..

there is a competition going on around my area. it sounds something like this

there will be a transmitter hidden in a college, and participants are to build receivers that can lead them to the location of the transmitter.

therefore, a receiver with a pointer is good, but is that possible? or else, a receiver that can show the signal strength in proportion with the distance from the transmitter.

any idea?

 

[dknguyen]

Have you ever seen a bear tracker? THe guys walk around a forest holding a giant directional antenna that beeps faster with a stronger signal.

 

[Nigel Goodwin]

Try searching for "DF hunt" - it's a common radio amateur pastime!.

 

[dch222]

If the transmitter frequency is in the AM radio band a simple AM radio makes a good direction finder. Just twiddle it around until the signal disappears at a few different locations and do some triangulation.

 

[Nigel Goodwin]

If the transmitter frequency is in the AM radio band a simple AM radio makes a good direction finder. Just twiddle it around until the signal disappears at a few different locations and do some triangulation.

Various bands are used, we used to use a specific frequency in the 2m band - if I remember correctly (it was a LONG time ago), the hidden station used to transmit for 1 minute every 10 or 15 minutes?.

There were basically two different techniques:

1) Use a directional aerial and try and get two reading to triangulate on the map (we used a specific 2 inch to the mile map, I think it was called SK36?, but now I'm really pushing my memory!). I used to ride a motorbike at the time, and built myself a collapseable yagi using wooden dowels, which I could stick down the front of my coat!.

2) Just use the aerial on the car, and take signal strength readings from different places.

To be honest, both methods seemed to be as successful as each other.

 

[Sceadwian]

Directional antennas are useful if it's a constant broadcast, or high frequency as they're more manageable.

 

[Gaston]

in the usa amature radio calls that a fox hunt. so you might be able to find some info on that also