Well, I guess I didn't really learn as much as I thought I did. I took your advice and modeled a 450 MHz dipole instead and got a curious result. I split the dipole into 31 wires each 2mm thick and
I just posted the following update to the QRZ.com forum, which includes a picture of the dipole and dielectric sleeves: Dave AB7E ** As best I can tell, NEC2 and NEC4 simply produce errors for part
I fully agree. I don't understand the point of swaging when an inside coupler is an extremely nice fit, leaves a uniform outside diameter, and for the same amount of strength has no additional weigh
"A more interesting question is why are you seeing the stickiness." Yes indeed. My guess is that unless the relays are truly hermetic (which I doubt), some amount of moisture has penetrated the casi
All true. The only Prosistel rotator I know of that uses a Hall Effect digital sensor is the big one ... the PST-110D-Pro. As far as I know all others use a potentiometer, which is DC at low curren
I wonder what happened to it. K9LTN is an expired callsign. Dave AB7E John KK9A Too bad, that DB-42 is a lotta $$. $13.5K, plus shipping, all in with various options. One fellow emailed me, who ha
It would be interesting to know what the failure rate of Steppir yagis is over a ten year period. Everyone I know of that has one has had one or more failures, but then again we probably don't hear
Somebody with more cents than sense. John KK9A _______________________________________________ _______________________________________________ TowerTalk mailing list TowerTalk@contesting.com http://l
That's not actually true. Stacked yagis are only optimized at one frequency, but they are pretty tolerant of that spacing. LOTS of hams have stacked multi-band tribanders and they do have worthwhil
I've used that stuff quite a lot, although I usually put a layer of teflon plumbing tape over the connector itself first in order to make sure I can remove everything in the future. Hot glue isn't a
If your looking for a mostly foolproof construction for a homebrew 435 MHz satellite antenna and have access to a 3D printer, you might check this out. It's a weak choice for general 70 cm terrestri
Type 31 is fine throughout the HF bands. K9YC's Cookbook has specs and test data for chokes built with it ... not just opinion. Dave AB7E On 6/25/2025 11:40 AM, Kirk Kleinschmidt via TowerTalk wro
A few months ago I did some experiments with variable dielectric loading on a 100 MHz dipole, but I just recently got around to putting the results in a YouTube video. The idea was to be able to tun
My suggestion would be the Chamelion SS25 25' extendable whip together with this mount clamped to the side of the tongue of your trailer. Put a ground screw in the tongue if it's painted. If your t
Because whatever current is left after the loss in the tuner still makes it to the antenna but doesn't have a major portion of it compressed inside the coil where it matches and also suffers loss but
The loss is the same (probably), but the current profile at the antenna is different (definitely). Dave AB7E Wes N7WS Because whatever current is left after the loss in the tuner still makes it to t
Use the "Currents" data from EZNEC to plot the current profile of a base loaded vertical and compare that to the "Currents" profile of a non-loaded vertical of the same length. Calculate the loss in
"A load placed anywhere on the radiator other than the feedpoint is a different story." And base loaded vertical antennas don't have their loading coils at the feedpoint ... the loading coil is ABOVE
Wes isn't modeling inductive loading ... he's modeling a series resistor in the feed. It's a matching network, not a loading coil in the element. He's comparing apples and walnuts. Dave AB7E All g
Here's a video I made showing how you can 3D print your own boom-to-element brackets for a yagi or similar antenna, using whatever diameter boom or elements you prefer. It probably is most applicabl