Brad, If you use an LED with a dropping resistor across the coil to monitor relay status, then you must use a fly-back diode. The coil of the type you're using will produce substantial EMF as power i
A single-component option with the benefits of the combo diode/Zener that Jim described is a Transorb device. The link below opens an application note that discusses various forms of coil transient s
No doubt some ops are using WebSDR on receive, but in this case, I am skeptical of the skepticism. Here's why: I routinely work VU2GSM on 40m GL-LP in the early morning hours on a 210-degree bearing
Steve, Thanks. Word wrap prevented me from opening the file with your e-mail messages but I copied the full URL into my browser and it did open. Possibly he is using WebSDR more on 160m-80m, but from
Dan and all... I am in the middle of constructing 4-squares for 160m and 80m. One element of each array is up and operating. A decision must be made concerning the layout of Teflon-insulated radial w
always involved strapping radials to a copper strap running along the line of radial intersection, clipping off the radial wire that runs past the strap." Unless there's modeled or measured data, th
When over-resonating with a long T-top, the maximum current point moves away from the ground and up toward the center of the vertical radiator -- another benefit. Unless there's a deliberate need to
Tony, Instead of a wire, consider using a short 1/2" wide copper strap from the radial plate up to the coaxial input connection on your box. I think you made the right choice in using a separate box
in order to make sure they have not encountered a major Several options: (1) CHU is still operating on several HF frequencies that reasonably cover North America; (2) In the U.S., AM broadcast stati
"NIST will discontinue the dissemination of the U.S. time and frequency via the NIST radio stations in Hawaii and Ft. Collins, CO. These radio stations transmit signals that are used to synchronize c
Seems like a great opportunity to spin-off WWV/WWVB to one of Colorado's state universities; WWVH to a Hawaii university. Let a university run it as a STEM project under the auspices of their dept.
Jim, Just my 2-cents. Here goes... First, NEC 4.2 160m "T" modeling shows very little advantage of having 4 top-hat wires instead of just two. The azimuth radiation pattern is almost a circle in the
I ran the same model in 4Nec2 as below but changed the hat from the traditional two wires to four, spaced 90 degs. Complex base Z is near 16+j0. Even though two symmetrical top-hat wires produce litt
Google isn't my friend today... I am looking for an isolated "F" barrel connector, commonly known as the F81. I am designing an aluminum interface plate for use with a Hi-Z 8-circle receive array. Th
Thanks for all the replies. I failed to mention that the plate is being designed in Front Panel Express (FPE) software. I didnt think FPE offered non-metallic panels. However, I just took another loo
Although I've decided to create a Hi-Z interface panel with Perspex, I did discover an insulated F81 barrel from L-Com. See the link below if there's an interest in saving the information for future
I think the primary flaw of the PL-259/UHF connector is that shield connectivity is strictly a function of thread tightness. There's no inner sleeve to maintain good electrical contact of the shield
problematic because its difficult to install the center pin with proper depth and axial alignment." Lived it. To support myself during college, I was chief engineer at an AM/FM station in Dekalb, Il
the SWR curve should narrow as ground losses are reduced; since the effect of ground loss resistance swamping the results lessens." The base resistance, not the radiation resistance is lowered by ad
radial field..uhhh, really Wes? I agree with Wes' assessment -- as well as him questioning why Rr would increase with an increased number of radials. If Rr is changing significantly with the increas