toggle quoted messageShow quoted text
Hi all - I have been using one of Kent's Log Periodic antennas as feed for a 13+9 cm dish for some years now. As I run power on both bands (240W on 13cm and 80W on 9 cm, unfortunately only half at the feed) burnout of the PCB elements was a concern. I modified the antenna - a 2.1-5 GHz design - by soldering thicker wires on top of all the PCB tracks. This reduces the ohmic losses in the elements and the central feed structure (and improves cooling). To keep with the idea of the logarithmic antenna, I have used different diameter wires. See picture.
Adding the wires had the effect of raising the low frequency limit, so matching on 13 cm was compromised. I extended the rear 2 elements on each side by abt. 10 mm, until I had a reasonable return loss. This was done after the photo had been taken.
73 Ole OZ2OE
Den 13. maj 2018 kl. 19.00.21 +02.00, skrev 'jewell@...' jewell@... [ukmicrowaves] :