[Amps] 10 DB increase

R.Measures r at somis.org
Sat Feb 5 06:39:00 EST 2005


On Feb 4, 2005, at 4:03 PM, Radioal wrote:

> A 10 dB increase in power will be propagated as a 10 dB increase - 
> regardless of the state of the ionosphere, antennas, locations, etc.

I used to think that this was the case until I sold the original 
Plywood Box/8170 amplifier.  Even though I had measured the amplifier's 
voltage-gain as x10 with an oscilloscope (20db power-gain), but on the 
air,  I measured 20 - 23db with my calibrated S-meter.  Other people 
with calibrated S-meters reported the same crazy thing.  Others who saw 
the 23db change said that Stanford (University) Research Institute had 
observed something similar during their ionospheric heating research 
project

> Instantaneous or rapid cyclical changes in propagation (QSB) can 
> account for some A--->B and B--->A (amplifier/barefoot) differences, 
> but repetitive A to B changes will average out the differences.  A 
> difference of 10 dB is unaffected by other factors, except the 
> cyclical changes noted above, inaccurate S-meters or just plain 
> prevarication.

I have heard this sort of thing and my impression was that it was a 
form of sceptre-kissing.
>
> An increasingly common factor in this distortion of fact is the guy 
> who tells you he is increasing power from 100 watts to 1000 watts - 
> and you see a 15 dB or greater increase.  It becomes obvious that his 
> "very linear" tube-with-handles amplifier has somehow broken the 100% 
> efficiency barrier!!
>
> A rose is a rose, and 10 dB is 10dB.
>
> Al - K8EUR
> ----- Original Message ----- From: "Ian White, G3SEK" 
> <G3SEK at ifwtech.co.uk>
> To: <amps at contesting.com>
> Sent: Friday, February 04, 2005 5:27 AM
> Subject: Re: [Amps] 10 DB increase
>
>
>> kenw2dtc wrote:
>>> Many times when someone adds 10db to the transmit side, in an A/B 
>>> test, almost no one on the receiver side shows a 10 db 'S' meter 
>>> increase, many times the receiver readings show a 20 or 25 db 
>>> increase.  Is the major reason due to liberal non-linear metering
>>
>> Libertarian non-linear metering, more like  :-)
>>
>>> or are other factors such as antenna, location of both stations, 
>>> propagation etc, the greater of the factors?
>>
>> Yup.
>>
>>
>> -- 
>> 73 from Ian G3SEK
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>
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Richard L. Measures, AG6K, 805.386.3734.  www.somis.org



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