Being on a city lot, not much bigger than 60'x120', I plan to install an HF2V ground mounted in the middle of the back yard, unfortunately with an unavoidably limited radial field. But the soil is go
A question for the group: How does one go about guaranteeing a good RF ground between a rotating mast and the tower proper? I'm assuming that a thrust bearing isn't adequate, even a Rohn TB-3, but I'
Well, the only contact between the mast and the tower is through the point contacts across the balls, or rollers, in the bearing, which doesn't seem like a low impedance path. Sure, that's the plan,
the I across OK, thanks for that, had no idea if these bearings are ball, roller, tapered roller, or bronze bushing. The problem with anything other than a bronze bushing is that the point contact of
Ah, thanks for that. You wouldn't happen to remember what thrust bearings you measured, do you? I figure it couldn't hurt either, and it's cheap. Thanks very much, Pete, AD5HD
at have Yeah, wondered about that as well. Unless the antenna is a log periodic with a stub shorting the booms, there's no path from a yagi to the feedline other than via the driven element. But then
I figured the impedance would be high enough to create a heck of a potential which would flash over to the tower itself. Yeah, it would at that. the Ah, thanks for that, very helpful bit of informati
to Been over that, very cool idea. Makes sense, thanks for that. Capacitively coupling from the tower to the wires would be in series with their intrinsic capacitance to ground so the arrangement mus
weight OK, that's good to know. That makes the mast have two discharge ground paths to the tower, one at the rotator and one at the thrust bearing. The more the merrier, I figure. 7 at ground creates
DOH! Yep, F12 on the brain. A hairpin match tied to the boom at its centerpoint doesn't effect matching or the driven element operation and provides a dc ground, and yeah, many yagis have reflectors
stroke Yes, got that from the Polyphaser book. It's interesting that regardless of the peak current, the slew rate is still around 10A/ns, or so. Having designed power supplies that had to deal with
Oooh, close but no cigar, sorry...:-) Degree in Engineering Physics back in <mumble>, administered by Engineering, not Physics Dept., and currently working as a EE in electro-optics for a telecom com
Not being much of a fan of MOVs in the first place, I figured there had to be some series type protectors out there somewhere but I'm not finding them at all. Design is relatively easy but extremely
Why May be, lightning does very strange things I've noticed. I would of course use MOVs at the rotators themselves and again at the base of the tower but at the master ground bar at the service entra
Had thought of that, tricky thing to do given the voltage slew rate though since even a tiny bit of end-to-end capacitance would couple the transient across. Figuring all eight lines, for example, as
A question to the list. needs to be routed roughly 10' along the adjacent sloping roof surface to a ridge where it needs to run about 20' to the gable peak where it can run down an unrelated fibergla
Being in the midst of beginning a project along the lines N3RR details on his site, I wandered over to the JetLube site and found that they state the following wrt SS-30: "Where U.L. listing is neede
Good point, hadn't thought about that, was more worried about the roof. But you're right, the coax would be damaged long before the roof will be. I believe it, and another good point. Wouldn't take m