Hi A question about wire ... I have constructed a 3/8 for 160 meter. I use the tower to support the antenna. It runs 22 meter vertically and then (horisontal for 24,5 meters (i.e. total 46.5 meter).
Flam, I modeled this with EZNEC (without the tower) and assumed the 1.5 mm diameter stainless steel wire has a resistivity of 7.2 e-7 ohm-m and relative permeability of 1.02. I estimated about 20 ohm
Your 3/8 wave 160 Inv L should be more like 58m in length. Then your series feeding capacitor would be more like 225mmf. Try to find a variable capacitor to adjust the Inv L to freq of choice. de Joe
Using 2.5 mm vs. 1.5 mm diameter copper only increases the gain by about 0.1 dB. The feedpoint R is about 1 ohm lower, and the bandwidth increases by about 4 kHz. The resonance moves up by 13 kHz to
Flam, Based on your description and measurements, I am certain that proximity to the tower is affecting the impedance matching. I was able to obtain similar results modeling the tower about 30m tall.
Hi Terry ok, 0.1 db thats not worth it ... especially when i already have 100m Cu 1.5mm lying around ... I hope not to have to change the Cap, since this part of the project is already done, with mec
Hi Gary Yes the distance to the tower has influenced the matching a lot ... besides the 22.5 tower theres also two 80 meter sloopers and 1 inverted V 160 meter dipole - altogether making the antenna
Yes, Flam's 46.5m wire is only about 0.29 wl. However, making it longer would raise the feedpoint Z even higher. There might be a slight improvement in efficiency, but usually most of the extra signa
Hi Terry It would be better to have the antenna at resonans around 1830 (CW portion of the band), rather than 1860 where it is now , but this is where it endend up with the fixed capacitors. So if i
Dr OM Flam, Not only does the tower affect your INV L, now you have let us know of the 80m slopers and another 160m antenna. These wire antennas have drastically more influence on your INV L than you
Hi Joe Yes, i know, there are many odds againt it beeing a perfect antenna. But that how it is with this super limited space. But what im going for is some vertical radiation, to get some low angale
Hi Just a follow up on the question about replacing the steel wire with copper wire. Today we replaced the steel wire with copper wire. Also, a 100pF in the cap box was replaced with a 150pF adding 5