Yes. One of the respondents, Ed Lethert, a respected Minneapolis-based consultant, recommended SurgeX products. I strongly second that recommendation. They make series-mode suppressors for branch cir
Yes on both counts. But to the extent that the performance is accurately described by a lumped parameter model (< 3 miles at 3 kHz, a half mile at 20 kHz), the impedance (50-100 ohms typical) of the
They go way back before the 70's, but they are LUMPED elements, and they are compensating in a LUMPED model. What's the old line -- "if you remember the 70's you weren't there?" I haven't worked in t
When thinking about it, remember that the energy in lightning is NOT at dc, it is around 1 MHz. The impedance of that path is primarily INDUCTIVE REACTANCE, not resistance. Resistance (greatly increa
Yes. That's the modern equivalent of the passive equalizers both in the line driver and line receiver. But the modem MUST be doing its best to match the Z of the line -- the closer it gets to that id
The 1 MHz number I bandied about is from vintage IEEE statistical data that showed a broad peak of the energy in a typical strike somewhere around 1 MHz. Don't ask me exactly where I saw it, how old
Yes. A week or so ago, someone posted a wonderful treatise on something as simple, yet complex, as how to drive a vertical stack of antennas on some band. The issues were as varied as the distance to
might What you describe sounds a lot like a diversity receiving system if you assume two receivers at each end. But one really big caveat is that you must account for the arrival time and polarity di
The inherent Z of a free space dipole at resonance is closer to 75 ohms than 50 ohms. Put that dipole close to ground and the Z is going to be closer to 50 ohms. My rule of thumb is to use 50 ohm coa
You must not have been in the right place in the store. Every Home Depot I've been in (Chicago area and central California around Sacramento) carries large and small spools of plain ordinary insulate
At the frequencies involved in lightning (IEEE says the energy in lightning is broadly centered around 1 MHz), the impedance of the earth connection is, for all practical purposes, entirely dominated
I bought two packages of DX Engineering's "non-inductive"470 ohm 2 watt resistors with the intent of using them to terminate Beverages, calibrate/test some bridges, and build some dummy loads. Yester
Thanks, Tom Jim _______________________________________________ See: http://www.mscomputer.com for "Self Supporting Towers", "Wireless Weather Stations", and lot's more. Call Toll Free, 1-800-333-904
I belong to nearly a dozen email lists, less than half of which are related to ham radio. My "default" signature lists my name and company affilliation. When I'm on a ham list, I usually sign with my
Burghardt Radio. I have found them wonderful to deal with. Great attitude, very good service, good prices. http://www.burghardt-amateur.com By contrast, I found Texas Towers, who also sells Philystra
You didn't say what frequencies or what power level. Jim K9YC _______________________________________________ See: http://www.mscomputer.com for "Self Supporting Towers", "Wireless Weather Stations",
Aw cummon -- cut the acronyms -- what the heck is HFTA? If people understood your question you might get more and better answers. :) That's kind of like going after a gnat with an elephant gun! There
I found a Bird 4311 in very nice shape at a hamfest, and need batteries for it. TR-169 and TR-164R are specified, but they appear to be discontinued, and I can't seem to find any sort of cross refere
My friends who claim to be educated in matters of GPS say that because of the manner in which the system is modulated for security reasons, consumer units are limited to accuracy on the order of seve
Huh? I said "several meters" in plan and you said "a few meters" in plan. Jim _______________________________________________ See: http://www.mscomputer.com for "Self Supporting Towers", "Wireless We