[TowerTalk] OptiBeam OB2-40M

[Richard (Rick) Karlquist]

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