http://www.shakti-innovations.com/audiovideo.htm
--
Tony Sayer

"tony sayer" wrote in message
...

http://www.shakti-innovations.com/audiovideo.htm
--
Tony Sayer





A very expensive lump of ferrite perhaps??

"tony sayer" wrote in message
...

http://www.shakti-innovations.com/audiovideo.htm
--


Never mind that nonsense, Tony - I'm still waiting to hear if an FM
signal strength of '55 dBf' as per:

http://www.apah69.dsl.pipex.com/show/Signal.JPG


Is reckoned to be 'good' (or 'good enough')...???

(Certainly sounds OK!!)

"Keith G" wrote in message
...

"tony sayer" wrote in message
...

http://www.shakti-innovations.com/audiovideo.htm
--


Never mind that nonsense, Tony - I'm still waiting to hear if an FM signal
strength of '55 dBf' as per:

http://www.apah69.dsl.pipex.com/show/Signal.JPG


Is reckoned to be 'good' (or 'good enough')...???

(Certainly sounds OK!!)
Keith:-

If I haven't pressed any wrong tits on my calculator,

55dBf means 55dB above 1 femtowatt, or 10^12 watts
55dB is a power ratio of 3.16 x 10^5
so 55dBf is a power level of 0.316 microwatts.

Assuming a standard 75 ohm antenna, that translates to 4.87 mV, so I'd say
that was a pretty good signal.

S.

--
http://audiopages.googlepages.com

In article , Serge Auckland
writes


"Keith G" wrote in message
...

"tony sayer" wrote in message
...

http://www.shakti-innovations.com/audiovideo.htm
--


Never mind that nonsense, Tony - I'm still waiting to hear if an FM signal
strength of '55 dBf' as per:

http://www.apah69.dsl.pipex.com/show/Signal.JPG


Is reckoned to be 'good' (or 'good enough')...???

(Certainly sounds OK!!)
Keith:-

If I haven't pressed any wrong tits on my calculator,

55dBf means 55dB above 1 femtowatt, or 10^12 watts
55dB is a power ratio of 3.16 x 10^5
so 55dBf is a power level of 0.316 microwatts.

Assuming a standard 75 ohm antenna, that translates to 4.87 mV, so I'd say
that was a pretty good signal.

S.

That tuner uses a common place audio demod chip just to drive the sig
and deviation meters!. They use a totally separate pulse count
discriminator for the audio .. and excellent it is too)
--
Tony Sayer

"tony sayer" wrote


That tuner uses a common place audio demod chip just to drive the sig
and deviation meters!. They use a totally separate pulse count
discriminator for the audio .. and excellent it is too)


Here's the plan, if you fancied running one up:

http://www.fmtunerinfo.com/KT-917schematic.pdf

:-)

"Serge Auckland" wrote in message
news


"Keith G" wrote in message
...

"tony sayer" wrote in message
...

http://www.shakti-innovations.com/audiovideo.htm
--


Never mind that nonsense, Tony - I'm still waiting to hear if an FM
signal strength of '55 dBf' as per:

http://www.apah69.dsl.pipex.com/show/Signal.JPG


Is reckoned to be 'good' (or 'good enough')...???

(Certainly sounds OK!!)
Keith:-

If I haven't pressed any wrong tits on my calculator,

55dBf means 55dB above 1 femtowatt, or 10^12 watts
55dB is a power ratio of 3.16 x 10^5
so 55dBf is a power level of 0.316 microwatts.

Assuming a standard 75 ohm antenna, that translates to 4.87 mV, so I'd
say that was a pretty good signal.


OK, good. Thanks for slogging that out Serge - I had wondered once or
twice if I'd got 'enough' aerial as a wee bit of hiss can creep in if
the signal drops as low as 40 dBf, which it can do occasionally.

"Serge Auckland" wrote in message
news


"Keith G" wrote

http://www.apah69.dsl.pipex.com/show/Signal.JPG


Is reckoned to be 'good' (or 'good enough')...???

(Certainly sounds OK!!)
Keith:-

If I haven't pressed any wrong tits on my calculator,

55dBf means 55dB above 1 femtowatt, or 10^12 watts
55dB is a power ratio of 3.16 x 10^5
so 55dBf is a power level of 0.316 microwatts.

Assuming a standard 75 ohm antenna, that translates to 4.87 mV, so I'd
say that was a pretty good signal.


Hi Serge - I found this in the manual a little earlier:

http://www.apah69.dsl.pipex.com/show/Voltages.JPG

(RTFM was never my strong suit!! ;-)

How does it sit with your figuring? There's a bit of a discrepancy - is
it easily explained?

(Just out of interest and FYI only - no bother whatsoever to me! :-)

"Keith G" wrote in message
...

"Serge Auckland" wrote in message
news


"Keith G" wrote

http://www.apah69.dsl.pipex.com/show/Signal.JPG


Is reckoned to be 'good' (or 'good enough')...???

(Certainly sounds OK!!)
Keith:-

If I haven't pressed any wrong tits on my calculator,

55dBf means 55dB above 1 femtowatt, or 10^12 watts
55dB is a power ratio of 3.16 x 10^5
so 55dBf is a power level of 0.316 microwatts.

Assuming a standard 75 ohm antenna, that translates to 4.87 mV, so I'd
say that was a pretty good signal.


Hi Serge - I found this in the manual a little earlier:

http://www.apah69.dsl.pipex.com/show/Voltages.JPG

(RTFM was never my strong suit!! ;-)

How does it sit with your figuring? There's a bit of a discrepancy - is it
easily explained?

(Just out of interest and FYI only - no bother whatsoever to me! :-)


No, not easily explained.
Take the example of 50dBf = 86.5uV 75 ohm
86.5 uV into 75 ohms is a power level of 99.76 femtowatts, call it 100
femtowatts.
That would be 20dBf in my book *if* dBf means dBs relative to 1 femtowatt.

1 femtowatt is 10^-12 AFAIAC

Consequently, their dBf is not relative to 1 femtowatt, or their femtowatt
is not mine.

According to their figures, you would need a signal strength of better than
80 to get completely (audibly) noise-free audio.

Working back, 86.5uV /75 ohm is 50dB relative to 1 attowatt or 10^-15 watt

S.

--
http://audiopages.googlepages.com

1 femtowatt is 10^-12 AFAIAC

"femto" is the prefix for 10^-15.


Martin
--
M.A.Poyser Tel.: 07967 110890
Manchester, U.K. http://www.livejournal.com/userinfo.bml?user=fleetie