[TowerTalk] dx blaster antenna

Richard (Rick) Karlquist richard at karlquist.com
Thu Mar 5 08:38:49 PST 2009



Dan Zimmerman N3OX wrote:
>> Anyway Im curious as to db gain vs s-unit. As I understant one S unit =
>> aproximately 6 db however on my local repeater one gentleman is adimant that
>> it's 3 db = 1 sunit. Im 95% sure it is 6=1s unit but when in slight doubt I
>> confer with the wizards on tower talk.  :--}
> 
> 
> There is no standard conversion from dB to S-unit.
> 
> On my FT-857D, I measured with a step attenuator and signal generator and
> found something like this:
> 
> barely audible to S1 : lots of dB, don't remember how many, but way more
> than 6dB
> S1 - S2: 1dB
> S2 - S3: 1dB
> S3 - S4: 2dB
> S4 - S5: 3dB
> S5 - S6: 4dB
> S6 - S7: 5dB
> S7 - S8: 6dB
> S8 - S9: 6dB
> S9 - +10: actually 10dB, same for +20 and +30

I have found most rigs tend to be like this.  Certainly my FT-1000
is.  I made up a chart showing actual S units (per 50 uV and 6 dB)
vs displayed S units.  I then give signal reports based on the chart.
A signal that just moves the S meter is actually about S4 IIRC.

Rick N6RK


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