Two thoughts: I can't find the reference just now, but I recall an awful years-ago tower accident in which a ham was injured and trapped on his tower when the thrust bearing bolts broke and the loade
I've had the same differential expansion problem on a long run of bigger coax with HN connectors. It would fail only at a certain time of day, and I traced it with a TDR to a taped all-black junction
Imitate or use something like this: https://www.dbspectra.com/products/antenna-clamp-regular-dsh3v3r/ or https://zcg.com.au/product/galvanised-steel-heavy-duty-parallel-extra-large-mount-clamp-boom-5
My own experience is that, once there's a breach in the plastic sheathing, water leaches up and down the entire braid, eventually rendering the coax useless. I've taped some up and it still seems to
When we were operating our M/M HC8N in the Galapagos Is., we noticed that the thimbles, turnbuckles and anchors of power pole guy wires in town were buried underground. We had the impression this was
Modeling of the HyGain element clamp is derived in Chapter 9 of my 1992 book, "Physical Design of Yagi Antennas," https://www.dropbox.com/s/hmhkeofz0igrg1e/Physical%20Design%20Of%20Yagi%20Antennas%20
Here's the model from the 1990s that I've used in YO for the 204BA, with the tip dimensions for CW: Hy-Gain 204BA 14.000 14.175 14.350 MHz 4 elements, inches 2.1448 1.2500 1.1250 0.8750 0.6250 0.4375
Yep Stan, you have that derivation right. As you note, for a clamp around the boom, the clamp electrical half-length includes 0.3 x the boom radius, while the physical length to determine the exposed
Many years ago, Dave Pruett, K8CC (SK) was working for Chrysler-Jeep, and he mentioned to me that auto manufacturers specified a minimum current to maintain the contacts in every switch, relay or con
I think the limited DC arc is the cleaning mechanism, but it would be good to give AC a try. A typical rig relay failure point is the RX side of the TX-RX relay, which is often available from the ext
I have the same issue, some 400' to towers sited for ground slope advantage. I use a pair of remote 24VDC relays for each rotator, with power supplied by Romex from the house and the relay coils and
Agree for most situations, but we're also a commercial tower site here with literally hundreds of VHF/UHF/microwave transmitters going in licensed and unlicensed bands. So outdoor WiFi links aren't a