On 11/18/22 6:51 AM, Lux, Jim wrote: On 11/17/22 9:51 PM, KD7JYK DM09 wrote: On 11/17/2022 18:33, Hans Hammarquist via TowerTalk wrote: I used the same type as the utility companies. They are a lot c
About ten years ago, I did the experiment of modeling a pair of radials cut to a free-space resonance, starting with them as close as NEC2 would allow it, and raising them in small increments to sev
Newer SWR meters are much more resistant, but still can be overloaded. The alternative is to try 5 to 10w transmit, whatever makes the radio swr or external meter read reliably and sweep the band. Or
John KK9A It's as simple or complex as you want to make it. You don't even have to do the calibration if you don't want to, and you're happy with moderate accuracy measuring S11. What's useful about
how can you measure that a radial system is still good over the years? Maybe the cable is degraded, or is cutted in some points if animals are around. Is any easy way to determine that the radial sys
And if you have an inexpensive VNA - you can run TDR function and probably get some idea of where the problem is. You can certainly tell if coax has been damaged mid run. ___________________________
On the other hand, some really loud stations n 160m, say 5-10 db above the crowd, use a massive amount of radials. This is for inland stations, far away from salt water. I think this describes my sta
In addition, one could start with a reference - say 4 radials take a set of measurements, add four more and take a set of measurements, add eight more and take a set of measurements, etc. until one s
On 12/2/22 2:41 PM, Jim Brown wrote: On 12/2/2022 10:46 AM, Jeff Blaine wrote: At Dayton/Xenia antenna forum this year 2022, N9NB had a pretty interesting talk on low band verticals. The key take-awa
Only for Horizontal Polarization. For vertical pol, it's a lot more influenced by the soil properties, more to the point, the phase angle of the reflection varies with soil properties and angle, a lo
I have a number of SMA connectors in areas of my station like my RBN SDR and my N1MM Spectrum Display. It seems like every few weeks I start running into problems, and have to go through and retight
73, Pete N4ZR Check out the new Reverse Beacon Network web server at<https://reversebeacon.net>. For spots, please use your favorite "retail" DX cluster. Not on the threads, but on the nut and either
It also occurs to me that that you are NOT depending on the threads for conductivity on a SMA connector. The shield connection is at the face of the threaded part of the jack, and a corresponding fac
Nail polish is viscous and readily available, and easily removed with a solvent if needed. It's also not too brittle, so it won't crack with small loads. Also because it's solvent based, it tends to
Mike is part of the team that put our rovers on Mars, and Jim Lux is part of the same organization. I know he's done some pretty impressive stuff too. Yeah, but I've also had SMA connectors come loos
On 12/11/22 9:18 AM, Grant Saviers wrote: A thought experiment is to consider what happens as the guys are separated by even more than 120 degrees. As 180 degrees is approached the tension needed in
On 12/19/22 8:28 AM, Stan Stockton wrote: 350 feet is about 5 quarter wavelengths at 3.8 MHz. Quarter wavelength is about 65 feet or so. If that thing is really 350 feet long you should see resonance
On 12/19/22 12:57 AM, w5jmw@towerfarm.net wrote: Hello all.I have a t antenna.50ft vertical and roughly 300 ft ntip to tip horizontal.I get a nice drop and resonance at abt 3.8 mhz.Is this weird reso
73, Máximo EA1DDO www.EA1DDO.es There's a nice application note from Copper Mountain that looks at uncertainty in S11 vs S21 measurements of impedance. As one might expect it varies with the magnitu
I made S21 measurements using a test jig quite similar to Steve's. His measurement technique seemed quite good. The (major) shortcoming of his work is that he measured only chokes on only a few cores