The seller sets the price and the buyer sets the value.
Saturday, August 29, 2020
Friday, August 21, 2020
- High efficiency
- Ease of construction
- Low cost
- Small physical size Since it doubles as a filter it helps reduces inter-station interferenceNetwork can be dynamically altered to suit 3 or more yagis in the stack
- It is too narrow band to be used on more than one band
- Coils and capacitors must be chosen and properly used to achieve the desired efficiency, stability and power handling
- The network must be tuned (L and C) for the stack parallel impedance and frequency range
Saturday, August 15, 2020
Longtime 6 meter enthusiasts are, of course, not young. For many the transition to digital modes has been difficult or unwelcome. We all do it for one simple reason: it delivers the goods. The advantages of FT8 far outweigh its perceived negatives on 6 meters. What was once difficult to impossible is, well, not routine but doable. Previously unknown marginal paths are being discovered and exploited to make QSOs.
That is why FT8 has not only been accepted on the magic band but, over time, enthusiastically embraced. I don't see that changing.
Despite excellent DX results this year I am running into the limits of my station capabily. Sporadic E on the longest DX paths are brief and signals are very weak. Every decibel counts. At the very least I need more power. This year my plan was to have a kilowatt and lower loss
transmission line it was delayed (again) by tower, antenna and equipment
projects for HF.
Wednesday, August 5, 2020
Sunday, August 2, 2020
Note: For shifts greater than 2% or so it is better to use a ratio rather than an absolute (linear) frequency offset as an accurate scaling factor. Yagi parasitic elements are almost always offset more than that relative to the design (centre) frequency.
Trials, measurements and implications
In total we did 6 lifts of the antenna to gather the required data. That should be enough to confidently interpolate and extrapolate the dimensions of the 3 yagi elements using EZNEC without benefit of SDC.
- Length of the inner (largest) diameter section, which also shifted the position of the capacitance hats
- Length of the outer (smallest) diameter section (element tips)
- Length of the capacitance hat arms
- Test approximate dimensions for director and reflector elements
|Heading down after a job well done