The images on this web page had been taken during this more moderen repair, after the unit had been in steady service for 12-13 years. Click on small pictures for bigger view in separate browser/tab. Drill two holes holes via the diameter of the PVC pipe to help the small loop in the proper orientation. At the underside of the loop was welded a small plate of steel as may be seen close to the left facet in the underside image of Figure 1. This plate was welded in the midst of the loop, reverse the gap at the top and such that when the plate was bolted to the side of the utility field, it held the loop upright. Working with him, I sketched out the design for a shielded loop and the result was that visible in Figure 1. Since he was handy with a welder and had plenty of pieces around it was a natural to make it out of scrap pieces of 1/2" electrical conduit and utilizing a conduit bender he customary a "sq. loop" that was about 18" (45cm) on a facet as shown in the image. When the loop was made with a conduit bender, the two ends of the loop had been introduced shut together, however not touching, and this hole is lined by the black tape/tubing seen at the top of the loop in the image!
To ensure that this to work however, there must be a hole in the shield or else it will merely "quick out" the impinging magnetic field from the specified sign and for reasons mechanical, electrical and symmetrical, it's best that this hole be right in the course of the loop. Note that an attic set up is not going to work properly you probably have aluminum-skinned insulation on the underside of the roof (or a metal roof). For receive-only APRS monitoring or igate obligation, the smaller version will work as nicely because the larger one. By adjusting the resonant frequencies of the loops, there's also no purpose why it could not even be used for the Japanese forty kHz JJY or the German 77.5 kHz DFC77 signal as well! The reply is a bit tough as any system involving probably involving radio frequencies is subject to FCC guidelines. For personal use, one would take care to keep away from doing one thing that could cause interference and considering the frequencies concerned, one could fairly be assured that a system like this can be usually incapable of doing so - even when it had been to malfunction in some bizarre means!
Being that this was a trendy constructing of steel and bolstered concrete building, and since it was stuffed with electronic devices resembling computers, fluorescent lights, and so forth. neither of these receivers ever managed to get a ok sign to synchronize themselves to the 60 kHz time sign being transmitted from Fort Collins, Colorado by the NIST station, WWVB though the signal from that station here within the Salt Lake space is kind of strong. I've occasionally been asked "Where can I get a system like this"? Were a system like this to be actively marketed and offered then it could be incumbent on the manufacturer/seller to guarantee correct FCC compliance - a course of that can be both costly and arduous! In circumstances like this the X-3.0 is the better Cable. This may increasingly just not do for actually lengthy Cables (just like the 5m I will need in the future for the hyperlink from my Pre to my Mono-block Amp's (beneath development). I didn't want the antenna to be tunable since it is going to operate on a single spot frequency (10.149 MHz) permanently. Top: The rooftop-mounted 60 kHz shielded loop antenna. A loop antenna has a "figure 8" pattern and thus has two nulls and a degree of directionality.
The 10-foot piece of pipe is reduce into two items after which rejoined with a pipe cross-tee, permitting the antenna to be disassembled to suit into the trunk of a automobile. I've now setteled down to 2 primary Versions of this Cable. The calculator referred to above is now downloadable from this web site. I calculated the required capacitance required to resonate the loop at 10.15 MHz using the calculator referred to above, and set out to create a cheap mounted-worth capacitor with 4-5 KV breakdown voltage. I'm measuring the Cables Capacitance. It isn't very hygienical (don't inform people that really buy those Cables yeah?) however the one dependable stripper I have found are my teeth. Since I have written the final two Interconnect Articles I had both some suggestions from you, the Readers and have made a few more Cables myself. All but one Cable where variations of the XLO Geometry, which I have determined to call X-Cable (as a result of crossing conductors making many, copper conductor meter cable many X's down the length of the Cable). Solder one end to one of many holes within the flange of a coax socket. The number denotes the distance between the begin and finish of 1 full flip across the core.