I have a 1 meter diameter loop antenna with a pic-controlled tuning device to tune the loop to resonance. Using this method, the loop can cover from about 1MHz to 20MHz. The tuning device is several capacitors switched in and out with RF signal relays plus some varactor diodes driven with filtered PWM from the PIC. The frequency setting is controlled by two pots, one coarse tuning and the other fine tuning. You can see photos here: http://www.cheapgalvis.com/overall_setup.jpg This is the tuned loop along with the smaller pickup loop to couple the receiver to the large loop. http://www.cheapgalvis.com/remote_tuning_unit.jpg This box contains the capacitors and varactors http://www.cheapgalvis.com/rx_and_tuning_control.jpg Below is a homebrew HF general coverage receiver (uses two PICs) and the box on top is the control for the loop tuning. The original idea was based on this guy's work: http://www.kr1st.com/swlloop.htm with additional help from http://brneurosci.org/loopantenna.html Sean On Sun, Aug 15, 2010 at 8:42 PM, YES NOPE9 wrote: >> >> On Aug 15, 2010, at 5:58 AM, Olin Lathrop wrote: >> >> Sean Breheny wrote: >>> In Lexington, MA I also find that CHU is stronger than WWV, although >>> on 5MHz I can usually get both WWV and WWVH (Hawaii - albeit faintly >>> in the background). >> >> Here in Littleton (three towns north, 2000 miles from Boulder) the >> WWVB >> clocks only pick up the signal at night. =A0I don't know how good the >> receivers in these clocks are, but of the three I know of around >> here none >> of them gets the signal during the day and all of them get it reliably >> overnight. =A0According to the NIST WWVB coverage map, we're right on >> the >> edge. >> >> > What kind of antennas are being used ? > Gus > -- > http://www.piclist.com PIC/SX FAQ & list archive > View/change your membership options at > http://mailman.mit.edu/mailman/listinfo/piclist > --=20 http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .