[TowerTalk] Re: Yagi's

[art unwin]

WHOOPS..............I made an error(s)
Please up date as follows:

Gain is dbi,(not db). Real ground translates  to approx 13 dbd.
When comparing to Force 12 data  ie 'net gain' reduce by 5.5db

F/B should read worst case FRONT TO REAR (F/R )

 This takes on meaning at around 28.4 Mhz where
the F/B recedes (beyond 60 db )below the worst case lobes. 
Rear lobes tend to remain faily constant in magnitude
across the band (great front to side)with the thin lobe
exactly to the rear being the main change in overall
pattern with respect to frequency change

Sorry about that!!
Fortunately the corrections make the antenna look
better and more informative


>Yagi, < 1 WL boom,13 elements 3 of which are reflectors at 65 feet.
>
>FREQ (Mhz)     GAIN (dbi)     WORST CASE LOBE FRONT TO REAR (DB)        
  28.0              15.56       25.60
> 28.1              15.67       31.69
> 28.2              15.75       37.31
> 28.3              15.82       42.54       This antenna provides a natural
50 ohm 
> 28.4              15.87       47.07       impedance and allows good SWR
across 
> 28.5              15.92       48.18       the band. 
> 28.6              15.93       35.28       Feed line is placed in a metal
tube
> 28.7              16.0        44.34       parallel AND GROUNDED to the
boom to                                             > 28.8
16.03       39.46       prevent near field  distortions
> 28.9              16.07       35.81


>
>Best Regards
>Art Unwin KB9MZ
>



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