Hello Folks, Was trying to do some ARGO captures last night for the first time. When I checked this morning I found mostly multicolored snow. [...] Paul, this is the second report of such a behavior
-20 points if you ain't awake at the time of capture, John! Who says this stuff isn't competitive! I have been able to see some fragments from G3AQC on 72.4013 kHz in the last hour (0230). Something'
Geri, Great article! I also thought the WWVB propagation plots were very interesting. The amout of day/night increase in signal depends to a great degree on the distance from the transmitter (farthes
Hi Dave, Many thanks for the comeback with you loop parameters. Have a few questions about these: Loop conductor is two runs in parallel of 7/1.5mm aluminium-- your bog standard 11 kV overhead drop-l
Hi Alex, Here goes: L(uh) = .008s((ln(1.414s/2d)+.38) Where s = the length of a side in cm; d = diameter of conductor in cm; ln = natural logarithm This is for a single turn square loop. With the fin
Mal, The only accurate way to measure loop inductance for an installation is to use an inductance meter. Calculations do not take into account the loop environment like trees and other objects in the
Hi Rik, I am trying to find out is how one can calculate the loop inductance of a big transmitting loop (based on the dimensions). I found 2 formulas for the calculation of a 1 turn coil, but both me
Dick, Terman's RADIO ENGINEERS' HANDBOOK (first Edition, Sixth Impression) contains useful information on the proximity effect and the ratio of ac to dc resistance of isolated litz wire: pages 36 and
Cesare, Thank you for your timely proximity equation! I calculate the spacing required to keep the proximity loss at 10% for two #12 ga (2.0 mm) copper conductors to be 0.5 inches. The spacing requir
Hi John, I did a lot of reading about proximity effect in a number of old college text books of mine yesterday (who woulda thunk that this boring stuff would come in handy some day?). The new numbers
Mike, So don't waste your money on #8 wire when the #12 is slightly lossier and a heck of a lot cheaper. Am I right on this Bill??? Well.... It depends on what you are willing to spend to gain 2.2db
All, I get a bit perturbed when I see comparisons of various loop conductors using Rdc values since the 'skin effect' within the conductors causes the Rac to be much higher at the frequencies we use.
Hi Dave I agree with all you have said to this point: Earth losses are immaterial and the loop does NOT need to be kept away from ground or other lossy things. This was my first series of loop tests
Mal, Inductance measured = 173 uH DC resistance of loop wire plus coax feed 1.5 ohms. Your DC resistance is WAY to high! Should be a fraction of an ohm. This is because you have the coax in the circu
Tom. One thing puzzles me Bill, if you are slinging wires over the tops of trees which are close together, how are you adequately insulating the wire from the branches? The main feature of my loop an
Rik, I really appreciate your efforts on the TX loop antenna section. I'll send you a bunch of info from this end. My bet is that these antennas will reach a popularity almost equal to the vertical a
Mal, From Dave G3YMC I notice this series resistance figure was not given in G3KEV's recent mail, it is by far the most important characteristic of a transmitting loop. What's the story, here? The wo
Hi Roy, Don't think a fishing rod would work too well if you were standing in the middle of a forest and had only a small opening in the branches, overhead, to shoot a projectile through. I used to t
Rick, You are absolutely correct with your 3db increase for a doubling of the area. I didn't account for the doubling of the Rac in the conductor. The loss ground loss may increase in proportion to t
Hi Mike For the bottom wire of my 73kHz loop, I used 3-core mains flex at 5ft above ground. My wife used it as a washing line! While transmitting, how long did it take for the closes to dry? <G> Bill
