The fixed-step (10 kHz) tuner is what killed music on AM radio. You
can get a much more pleasant sound by detuning a few 100 Hz. This PLL
crap sounds like ****.

On Sun, 13 Jun 2004 00:36:21 GMT, Jon Noring wrote:

[Following up on a thread dating back to January, similar to one I
started recently. Responding to Patrick Turner's comments.]


Patrick Turner wrote in January 2004:
Jerry Wang wrote:

1. Even it is a single channel [AM] receiver, I would still suggest
the use of one or two intermediate frequency (IF) stages. Because
to achieve good sensitivity you need to have enough gain.

Since you only want one channel, there is no need for a frequency
converter or any IFTs or IF amps, and a TRF with four tuned circuits
in the form of two critically coupled RF trannies will do nicely.

Interesting.

As I noted in a recent message, it is very intriguing to build a
modernized, high-performance AM tube tuner using the "channel"
approach. This takes advantage of the fact that licensed broadcasters
today must broadcast on specific frequencies, every 10 khz in North
America and 9 khz in Europe and elsewhere. So, instead of trying to
be able to continuously tune across the BCB spectrum, we can think
outside the box for the moment and consider the alternative of
building reasonably optimized tuning circuits for each listened-to
frequency.

David wrote:

The fixed-step (10 kHz) tuner is what killed music on AM radio. You
can get a much more pleasant sound by detuning a few 100 Hz. This PLL
crap sounds like ****.

Howcome?

Patrick Turner



On Sun, 13 Jun 2004 00:36:21 GMT, Jon Noring wrote:

[Following up on a thread dating back to January, similar to one I
started recently. Responding to Patrick Turner's comments.]


Patrick Turner wrote in January 2004:
Jerry Wang wrote:

1. Even it is a single channel [AM] receiver, I would still suggest
the use of one or two intermediate frequency (IF) stages. Because
to achieve good sensitivity you need to have enough gain.

Since you only want one channel, there is no need for a frequency
converter or any IFTs or IF amps, and a TRF with four tuned circuits
in the form of two critically coupled RF trannies will do nicely.

Interesting.

As I noted in a recent message, it is very intriguing to build a
modernized, high-performance AM tube tuner using the "channel"
approach. This takes advantage of the fact that licensed broadcasters
today must broadcast on specific frequencies, every 10 khz in North
America and 9 khz in Europe and elsewhere. So, instead of trying to
be able to continuously tune across the BCB spectrum, we can think
outside the box for the moment and consider the alternative of
building reasonably optimized tuning circuits for each listened-to
frequency.

No highs.

On Mon, 14 Jun 2004 01:50:04 +1000, Patrick Turner
wrote:



David wrote:

The fixed-step (10 kHz) tuner is what killed music on AM radio. You
can get a much more pleasant sound by detuning a few 100 Hz. This PLL
crap sounds like ****.

Howcome?

Patrick Turner



On Sun, 13 Jun 2004 00:36:21 GMT, Jon Noring wrote:

[Following up on a thread dating back to January, similar to one I
started recently. Responding to Patrick Turner's comments.]


Patrick Turner wrote in January 2004:
Jerry Wang wrote:

1. Even it is a single channel [AM] receiver, I would still suggest
the use of one or two intermediate frequency (IF) stages. Because
to achieve good sensitivity you need to have enough gain.

Since you only want one channel, there is no need for a frequency
converter or any IFTs or IF amps, and a TRF with four tuned circuits
in the form of two critically coupled RF trannies will do nicely.

Interesting.

As I noted in a recent message, it is very intriguing to build a
modernized, high-performance AM tube tuner using the "channel"
approach. This takes advantage of the fact that licensed broadcasters
today must broadcast on specific frequencies, every 10 khz in North
America and 9 khz in Europe and elsewhere. So, instead of trying to
be able to continuously tune across the BCB spectrum, we can think
outside the box for the moment and consider the alternative of
building reasonably optimized tuning circuits for each listened-to
frequency.

David wrote:

The fixed-step (10 kHz) tuner is what killed music on AM radio. You
can get a much more pleasant sound by detuning a few 100 Hz. This
PLL crap sounds like ****.

Assuming that indeed a more pleasant sound is had by detuning off the
center frequency by a few hundred Hz (Patrick was skeptical), this is
not a problem for the Channel TRF tube tuner design since I believe a
very fine tuning control will be necessary, due to both tuner warmup,
and long-term drift as bandpass component values slowly change over
time between "calibrations".

Only guessing, I think the control should vary the center frequency
for a channel by about +/- 1 khz, enough to cover the several hundred
Hz of deviation for those who think this makes the station sound
better.

Jon Noring

Jon Noring writes:

David wrote:

The fixed-step (10 kHz) tuner is what killed music on AM radio. You
can get a much more pleasant sound by detuning a few 100 Hz. This
PLL crap sounds like ****.

Hmm, and I thought it was a phase noise problem. A lot of these radios
used a 10kHz reference frequency, multiplied up to the LO, giving lots of
close in phase noise. Due to FM/AM conversion, this then showed up in
baseband.

Jon-- are you the originator of this thread?

Steve.

--
Steven D. Swift, , http://www.novatech-instr.com
NOVATECH INSTRUMENTS, INC. P.O. Box 55997
206.301.8986, fax 206.363.4367 Seattle, Washington 98155 USA