2018-02-12 Loading coil for short multiband vertical 10m-80m

Building my new multiband shortwave vertical for WFF (Worldwide Flora Fauna) operations.

Inspired by N1LO shortened mobile vertical:  http://www.qsl.net/n1lo/mobilhf.pdf

Learned that very critical for efficiency is loading coil - must be airgap construction in order to reduce stray capacitacne and dielectrical losses. The coil shold not be “narrow and high”in order to maintain high Q.

1. Designing and printing the coil support on 3D printer, material is PET. Consists of top, bottom part and 4x comb sticks. All plastic parts are assembled together and form one piece.

2. Preparing Cu wire, diameter is 1.7mm, wound on plastic pipe of 10cm diameter and taken down from the pipe.


3. Cu spirale is easily wound on coil support. Wire pressed/clicked into openings on perimeter and fixed at both ends. All goes smoothly, I’m missing only a few last windings so now the antenna resonates at 4.3 MHz. After adding missing windings it should be OK also for 80m.

Next version of support will need to be stronger as middle of the coil is now slightly shrinked by pressure caused by windings.

2018-02-11 SOTA OM/TT-002

Marhat (OM/TT-002), closest SOTA summit to my home, only 2 points. However in winter time there are additional 3 bonus points counted as the elevation is 748m asl. Good reason to start trip on sunny Sunday afternoon.

Pictures were taken by iPhone equipped with Circular Polarization Lens attached to it with clip. Bought on eBay.

Tower on the summit. I was transmitting from bottom as the wind was rather fresh

Sun is setting down. Picture taken from top of tower, my hands were freezing

2018-02-08 SOTA OK/LI-010 Jested

Jested is the highest mountain peak of the Ještěd-Kozákov Ridge near Liberec in the north of the Czech Republic. From the summit there are views into Germany and Poland.

On the summit is located spectacular tower in hyperboloid shape, architectural treasure of Czech Rpublic designed by Karel Hubacek.

Unfortunately it was fog on summit and freezing, fortunately there is restaurant and bufet with warm meals and drinks.

Tower

Linked dipole for 7MHz

Alien statue (left)