52 dB any good?
 

My new/old Technics tuner advises me my FM signal strength is 52 dB - is
that good, bad or just plain ugly, given the palaver with the aerial
installation a while back?

TIA

(Also posted to the vinyl group in error!)

52 dB any good?
 

"Keith G" wrote in message
...

My new/old Technics tuner advises me my FM signal strength is 52 dB - is
that good, bad or just plain ugly, given the palaver with the aerial
installation a while back?

TIA

(Also posted to the vinyl group in error!)
Keith,

Without knowing what the 0dB reference is, it's difficult to know *what*
they mean.

If the signal strength is -52dBm into 75 ohms, then that's a voltage level
of 687uV which is a bit low. Knowing where you're located and how far from
Peterborough, I would have expected some 2mV at the tuner, but maybe you
have some high ground between you and the TX. If the tuner doesn't hiss on
Radio 3 in the evenings when the processing is turned off, then you should
be OK even on the signal you have. Most tuners achieve 50dB S/N ratio with
under 100uV, but don't reach their maximum S/N ratio until nearer 1mV.

S.

52 dB any good?
 

"Serge Auckland" wrote in message
...

"Keith G" wrote in message
...

My new/old Technics tuner advises me my FM signal strength is 52 dB - is
that good, bad or just plain ugly, given the palaver with the aerial
installation a while back?

TIA

(Also posted to the vinyl group in error!)
Keith,

Without knowing what the 0dB reference is, it's difficult to know *what*
they mean.


I never know what they mean!! :-)



If the signal strength is -52dBm into 75 ohms, then that's a voltage level
of 687uV which is a bit low. Knowing where you're located and how far from
Peterborough, I would have expected some 2mV at the tuner, but maybe you
have some high ground between you and the TX. If the tuner doesn't hiss on
Radio 3 in the evenings when the processing is turned off, then you should
be OK even on the signal you have. Most tuners achieve 50dB S/N ratio with
under 100uV, but don't reach their maximum S/N ratio until nearer 1mV.


OK Serge, thanks for that

Ordinarily, the signal/sound quality seems to be very good. I have only
noticed a bit of R3 hiss on the odd occasion in the evenings.....

52 dB any good?
 

On Thu, 27 Apr 2006 13:44:00 +0100, "Serge Auckland"
wrote:

If the signal strength is -52dBm into 75 ohms, then that's a voltage level
of 687uV which is a bit low.

My Sony ST-S311 tuner gives the signal strength in dBf, which I
believe is relative to one femtowatt (10E-15W). If my calculations are
correct, then 52dBf would equate to 109uV, which is not very good at
all.

The OP's manual should hopefully define the measurement units used.

--
Chris Isbell
Southampton, UK

52 dB any good?
 

one femtowatt (10E-15W).

No. 1E-15 W.

10E-15 W == 1E-14 W == 10^-14 W.

1 fW = 10^-15 W


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

52 dB any good?
 

"Serge Auckland" wrote in message
...

"Keith G" wrote in message
...

My new/old Technics tuner advises me my FM signal strength is 52 dB - is
that good, bad or just plain ugly, given the palaver with the aerial
installation a while back?

TIA

(Also posted to the vinyl group in error!)
Keith,

Without knowing what the 0dB reference is, it's difficult to know *what*
they mean.

If the signal strength is -52dBm into 75 ohms, then that's a voltage level
of 687uV which is a bit low. Knowing where you're located and how far from
Peterborough, I would have expected some 2mV at the tuner, but maybe you
have some high ground between you and the TX. If the tuner doesn't hiss on
Radio 3 in the evenings when the processing is turned off, then you should
be OK even on the signal you have. Most tuners achieve 50dB S/N ratio with
under 100uV, but don't reach their maximum S/N ratio until nearer 1mV.

S.




Keith

Didn't the mast at Peterborough fall down a while back, after the
transmitter building at the bottom caught fire ? Left them with temporary
transmitters, and a rather shorter than normal mast ? Might be wrong -
probably somewhere completely different ... I wouldn't expect a Technics
tuner to declare an accurate value for received signal level anyway - after
all, it's not designed as a signal strength meter. I should think that it's
one of those flim-flam feel good indications based loosely on how much AGC
is being produced. Keeps the technophiles happy ...

Arfa

52 dB any good?
 

On Thu, 27 Apr 2006 18:54:28 +0100, "Fleetie"
wrote:

one femtowatt (10E-15W).

No. 1E-15 W.


Correct. I meant 10^-15W, which is, as you say, 1E-15.

To err is human....

--
Chris Isbell
Southampton, UK

52 dB any good?
 

On Thu, 27 Apr 2006 17:49:12 +0100, Chris Isbell
wrote:

On Thu, 27 Apr 2006 13:44:00 +0100, "Serge Auckland"
wrote:

If the signal strength is -52dBm into 75 ohms, then that's a voltage level
of 687uV which is a bit low.

My Sony ST-S311 tuner gives the signal strength in dBf, which I
believe is relative to one femtowatt (10E-15W). If my calculations are
correct, then 52dBf would equate to 109uV, which is not very good at
all.

The OP's manual should hopefully define the measurement units used.

The trouble here of course is that Keith is obsessed with
measurements. What really matters is how the signal *sounds*! Is it
clean, with no multipath distortion and no noticeable hiss? Then you
have enough signal strength. :-)

--

Stewart Pinkerton | Music is Art - Audio is Engineering

52 dB any good?
 

"Keith G" wrote in message
...

My new/old Technics tuner advises me my FM signal strength is 52 dB - is
that good, bad or just plain ugly, given the palaver with the aerial
installation a while back?


Keith, I don't believe that Technics ever made a decent FM tuner!

I would say that Kenwood, Pioneer, Sansui and Yamaha are all better bets...

52 dB any good?
 

On Fri, 28 Apr 2006 06:32:16 +0100, Stewart Pinkerton
wrote:

The trouble here of course is that Keith is obsessed with
measurements. What really matters is how the signal *sounds*! Is it
clean, with no multipath distortion and no noticeable hiss? Then you
have enough signal strength. :-)

Yes, up to a point.

I noticed a matterable improvement going from an adequate to a very
good aerial signal. This observation was not validated using a
double-blind level matched test, so it may be a consequence of the
effort expended optimising the aerial, or possibly down to reducing
multipath. ;-)

It would be interesting to hear from those who know about RF whether
there might be an engineering basis for this observation.

--
Chris Isbell
Southampton, UK