So, just ballparking. for a few thousand dollars you could have someone with a PE license design and build a UL452 compliant ADU, run the tests, document compliance, etc. If I were doing it, I wo
Could be. I guess my point is that hams put up all sorts of antennas and most might be guided by the code in some way, but not necessarily code compliant. On the other hand, if someones trying to fi
And, of course, those polyphasers arent a listed device. At least not on PP website. They may have a version with the test pedigree and all. Note that the government can waive a host of requirements
This is why the terminated folded dipole is popular in emergency ops. It's inefficient - it could be replaced by a 3-6 dB pad in the feedline to any antenna - but it requires no tuner. In non-ama
I have seen a strategy used in achieving compliance. "Shall use a UL listed device" (and they don't call out a specific standard), then the implementation uses something with a standard that isn't
what'a interesting is that 497 is applied to "communications" line (i.e. phone lines and data interfaces) so it "kind of" fits. For example, you'd use a UL497 listed device for your rotor control lin
That does put a manually operated device somewhere. With respect to patterns, if you use a "short" antenna (relative to wavelength)(e.g. a 10 meter dipole) with an auto tuner, you get the same patte
I use 31 mix up to 30 MHz (and higher) to good effect. The real part of the impedance keeps going up to 1GHz (that's the lossy component) The imaginary part peaks at about 30 MHz, is decent to 10
Yeah, Qty: 10 might be 33k, but so might Qty: 100. Especially if they have to set up tooling. Just imagine if you had to pay $100/hr for an engineer to design and build the coil winding apparatus. T
with N antennas, one can theoretically null N-1 sources, so if the noise isnt sort of generic atmospheric noise distributed in the direction of your desired signal some sort of multichannel coherent
https://www.tefgel.com/contain.php?param=tefgel_infor Seems to be 40% PTFE powder in some sort of carrier This makes me wonder if teflon tape might not be something useful for fasteners? Same sort of
Im not sure the RSPduo actually allows synchronized samples. You can use the same sampling clock, but internally, the ADCs are fed from separate RF front ends, so theres the phase ambiguity in the P
Nice measurements I would guess that the measurement uncertainty (and modeling uncertainty) is sufficiently large that the modeled and measured are the same. Reactance of 22.5 uH at 1.8 MHz is 1480
Noalox and similar "drying out"? According to the website (and the MSDS) it's zinc particles. (and so, it's potentially pyrophoric, which I didn't expect) and hydrophilic fumed silica. Apparently
More to the point, a 2 input phasing box can only null one source. I suppose one could get a whole stack of boxes and connect them. Then the problem becomes "adjusting the knobs", which is a solvab
Yes, if the timing and phase difference is stable (enough), you can adaptively null, and be done with it. I don't own an RSPDuo and I have no commercial association with SDR Play ... although I do
Indeed. Too many people take the "maximum specified loss" or "maximum mismatch" in the data sheet as the value, when in reality, those numbers are more "that's what we can easily measure, with mea
what did you expect to see? What are the impedances you see at the two verticals,without the coax, and with the other antenna "open" Hello all, Let me preface this by saying this - I am NOT a phasi
Rick has a valuable recommendation The Christman scheme was, I think, developed to get some gain from a couple 2m or 70cm band whips. It is *very* sensitive to the mutual Z and the environment of th
The field from the antenna (and from the feedline, if there's any current in the shield, or it's unbalanced) certainly does interact with the soil under the antenna (and houses, trees, etc.). The