Helvetia Contest 2021

Like every every the last weekend of April is the date for Helvetia contest. This year the weather was nice so that was a pleasure to stay outside in my mobile shack.

Finally I finished with around 240 qso on CW and SSB. 

Antennas used: Windom and Superantenna YP-3, power up to 250w.

New antennas for satellites

 My little "arrow like" antenna works only for strong satellites and with limited effeciency. 

Therefore I decided to build some new 2m and 70cm yagi antennas. Additionally I want "cross yagis" with polarisation switches - allowing working all types of polarisations.

I have chosen the GTV 2-6 described in:

http://dg7ybn.de/144MHz/144_GTV2_6m.htm

This is fantastic site created by Hartmut DG7YBN devoted to various aspects of the yagi antennas building.

These antennas seem to be optimized for 144.1MHz when I need around 145.800MHz (satellites band). Also antennas described by Hartmut DG7YBN have elements going thru the boom when in my case I need antenna which will be highly portable/mobile with elements attached to the boom when needed.

I have designed a mount where element can be quickly mounted on the boom and fixed by a screw. 

I have designed additional elements for the drivers and the N socket.

Ok, next it is time to prepare the elements. The basic dimensions are here.

However I need slightly different freq (145.8) so loaded the data into the MMANA-GAL and tried to optimize.

The remaining is Boom Correction - the element sizes calculated in MMANA-GAL should be corrected depending on boom type and the type of the mount of elements (isolated from boom, non isolated, thru boom or above, element type etc),

This is the current stage. 

3 March 2021

Stub Symmetrising Device

According to 

http://dg7ybn.de/Symmetrising/Symmetrising.htm#Classic_Style_Sleeve

for 144MHz and vc=0.7 the length of coax = 369mm

for my 145.8MHz and vc=0.83 the length = 442.9mm

calculating from classic equotation:

v/f = lambda = 299792458/145800000=2.056

lambda/4 = 0.5140 multiplied by vc=0.83 = 426mm

lets say.. 430mm

15 March 2021

Raining... 

Can I tune the antenna in the garage?

If the garage is big enough... :)

This is not google car... ;)

 

After a few attempts to modify the size of elements the result is so far like this:

Update 14.05.2021

..will be continued..