On 5/23/2021 7:29 AM, VE6WZ_Steve wrote:
I have received a few direct email questions about this thread…..
Just to be clear, the reason for inductor switching at the Yagi elements is NOT only to get
a “good, low SWR" match at the driver.
The “SWR” and “matching” at the feedpoint is really NOT the issue.
The real issue is tuning the REFLECTOR across the band. That is what
determines the gain and F/B performance.
The PARASITIC element needs to be incremented across the band to maintain
maximum gain and F/B performance.
Yagi SWR has very little to do with performance.
Steve, ve6wz
Another great posting from Steve. It seems like this point
has to be constantly repeated on TT to counteract marketing
hype and wishful thinking. When I first got my MonstIR,
I did some experiments where I set the tuning for 40 CW
and then QSY'ed to 40 phone, without retuning the MonstIR.
Of course the SWR went way up. I then used the custom
tuning feature to tweak just the driven element for SWR.
This did improve the VSWR somewhat, but the gain and F/B
were still lousy. SWR bandwidth doesn't equal pattern
bandwidth. And the MonstIR is a full size 3 element
design (yes, 70 foot elements), so it will tend to do
better than a shortened 2 element.
Rick N6RK
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