90 comments posted · 1 followers · following 0

14 weeks ago @ Ham Radio . me - Improving the Super-J · 1 reply · +1 points

The propagation is "altered" by the inductance of the coiling such that one needs more actual wire for a given electrical phase length when coil turns move closer to each other. That's one reason I made figure 6 to highlight this interesting find. It's another good reason to use NEC, if you can, to model the coil along with the antenna as it does a good job.

46 weeks ago @ Ham Radio . me - Diamond NR770HBNMO vs.... · 1 reply · +1 points

I haven't done a test, but I did recently simulate the same sort of thing here...


Key takeaway is the EFHW appears to be fine with a grounded transformer. Real tests are the best, but I'm reasonably confident the simulations give us a pretty good idea the mag mount approach will probably work fine.

53 weeks ago @ Ham Radio . me - The 43 foot vertical -... · 0 replies · +1 points

Antenna tuner is still a necessity I'm afraid, but if you hit upon a certain length of feedline, there is likely at least one point where it might tune up just right.

53 weeks ago @ Ham Radio . me - Electrically isolated ... · 0 replies · +1 points

Your hypothesis is worthy of testing by way of repeating the same tests at much higher elevation. I have all the gear, but need volunteers to perform the testing in a valid way. I'm presenting the details to my local ARC in August and will hopefully stir up the troops to provide some manpower. Stay tuned.

As for "something to push against" keep in mind you can do so against an open end as well as short. That's what many people miss.

55 weeks ago @ Ham Radio . me - EFHW transformer two ways · 0 replies · +1 points

I've seen those and they are indeed prevalent, but they serve to hone in on a particular frequency by tuning C against L. The ones above, especially the HF one, are very broadband suggesting another purpose. Thanks for the comment regardless as it is a good observation.

55 weeks ago @ Ham Radio . me - Electrically isolated ... · 0 replies · +1 points

Thank you.

58 weeks ago @ Ham Radio . me - Electrically isolated ... · 0 replies · +1 points

60 weeks ago @ Ham Radio . me - Not all mobile antenna... · 0 replies · +1 points

If you dig deep enough the truth is in there, but they sure don't make it easy. Vendors of Laird often add to the confusion with their own confusing specifications. On a positive not, I did test both antennas in their end-fed dipole configuration this weekend with success.

60 weeks ago @ Ham Radio . me - Electrically isolated ... · 0 replies · +1 points

"dipole vs EFHW"

Just for clarity of definitions, both of the above are dipoles.

60 weeks ago @ Ham Radio . me - Electrically isolated ... · 0 replies · +1 points

"Ok, I see. I thought your intention was to compare an effectiveness of a dipole vs EFHW. IMHO there is little use of conclusion that the EFHW with a LNR transformer functions. There is little doubt in that and you could just make a few QSOs using both antennas and make the same conclusion. No need in measuring field strength or anything."

You must understand there are many people who don't think the EFHW can work without some sort of extra wires attached. I set out to prove it one way or the other with good measurements that avoid subjective ability to make a QSO or two. I'm thrilled you are among those who don't need such evidence, but many others do.