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..
