SWLing Post Message Board

first of all, at the moment I'm busy helping some relatives picking olives from trees, so please forgive me if I delay my replies; also, as you can guess. I've no way to run NEC simulations here :D (note: did you know that ezNEC is now free ? https://www.eznec.com/ ) ... anyhow, your simulations are...

forgot, (yes, still ferreting around <sigh>); try the following: load the CTL model, remove the cap/resistor from the outer loop and replace the cap in the inner loop with a resistor (530 Ohms like the SULA will do), now run the NEC model, done so, change the inner loop size and check the result, do...

I'm in a hurry, so I'll keep this short; first, that loop and dipoles setup somewhat recalls at large a yagi (dipoles), did you try changing the size/spacing of the dipoles ? Then, about the CTL, I started wondering if it may be used as a TX antenna, in such a case it would be interesting for lower ...

Thank you, ran the model and it behaves as expected, I just changed the "GN" card to put the antenna over real ground and not in free space ("GN 2 0 0 0 13 0.005") the results are pretty good, but the impedance is around 2 Ohm which means that, to couple the antenna to a receiver...

as for the directional lobe, check out the currents and phase of the CTL, that should tell us something, I believe

Secondly, at 1.8 MHz, maybe you need to significantly increase the both (1) the load inductance of the outer loop and (2) the intrinsic inductance of the inner loop. The CTL article says that for (2) you should use additional wire turns on the inner loop to increase the inductance, but that is a ve...

Thanks for the warm welcome. :) Well, I've been "following" you for some time and it's a pleasure to see you here ! Excellent to hear! Did you ever actually get around to building one? I have only simulated, but not yet actually built, the CTL. No, I just played with some NEC models but t...

spent a (short) bit of time playing with C1, C2 and RL but probably I'm missing something, I mean, I followed the directions in the comments, that is 1. Adjust C2 (outer loop capacitance) to be very large (e.g. 1000 pF), so that the outer loop is far away from resonance. 2. Use 4nec2 optimizer to ad...

First of all, welcome to the forum !! As for the CTL, I've played with it while designing the SULA and it's for sure an interesting design, I've just tried your NEC model and slightly changed it inserting the parameters for the ground CM Model of Coplanar Twin Loop antenna. CM Created by qrp-gaijin@...

I will check those out. let me know... as a note, a good combo for your QTH could be a LoG for the lower frequencies (lower SW, MW and below) and a SULA for SW and up to VHF, such a setup would give you an extensive bands coverage with just two antennas :) ! Also, your preamp/preselector may work p...