RadioBanter - MW Receiver

RadioBanter (https://www.radiobanter.com/)

- Shortwave (https://www.radiobanter.com/shortwave/)

- - MW Receiver (https://www.radiobanter.com/shortwave/39387-mw-receiver.html)

Let me know what you are looking for, folks!

Pete

(Hi Pete-Just a repeat of an earlier post. Keep us up to date, this
is exciting...Russ)

Please, no slider controls for anything!

Also, please consider a mechanical on/off switch like the Sony 2010.
This enables one to keep in "on" state and turn it on/off via digital
timer and make unattended recordings and be able to vary the # of
recordings and length of them.

For battery power, please consider C or D cells for longer life. It
will also help add weight to the radio to prevent the slide around
problem.

In article , RHF wrote:
Pete and Russ,

Here is my Two-Cents-Worth on the 'topic' of "Power Sources":

1. Standard 120VAC Power.

Not everyone on this list has that. My outlets give me 230VAC 50Hz. And BTW,
AM broadcast stations are 9kHz apart. :-)

Geoff.
--
Geoffrey S. Mendelson 972-54-608-069
Icq/AIM Uin: 2661079 MSN IM: (Not for email)

PCAD 2000...........it's in the 6K range.

Pete

Geoffrey S. Mendelson wrote in message
...
In article ,
Pete KE9OA wrote:
I just do a quick layout with a CAD program, and print out the artwork
on a

Would you please tell us which one?

Thanks in advance, and 73,

Geoff.

--
Geoffrey S. Mendelson 972-54-608-069
Icq/AIM Uin: 2661079 MSN IM: (Not for
email)

I am not sure how this will work out..............the main thing is that you
need a hard limited signal at the LO input of the detector. It may require a
crystal filter.......I am not sure yet. As it stands right now, even input
noise with not antenna connected will provide that hard limited signal, so I
don't think that weak signal reception will be a problem. Since this is a
quasi-sync detector, there is no lock problem. I should know in the next
couple of days.

Pete

RFCOMMSYS wrote in message
...
said:

I have never used the sync detect mode. I don't even use it on my
SW8 or my AOR7030. I know that many folks like this function, so it is a
worthwhile thing to design into the receiver.
I am not sure how well this circuit will lock, so it may just be a first
pass at most. Still, signals won't be fading into the noise floor of the
system; the atmospherics will be the determining factor.

In my opinion, a synch detector that keeps losing lock on problem signals
is
useless. Like another poster in this thread said, if you can't design a
good
synch detector (apparently it's not easy to do considering that ICOM can't
seem
to do it), I would rather have manual ECSS ability (SSB mode with an
extremely
fine tuning (preferably analog) knob)).

I like the feel of that tuning knob............keypads don't do anything for
me. I've done a quick board layout for a VCO.........this way, I can see
what the detector sounds like with continous tuning. If it doesn' hang on to
a .1uV signal, I will move on to another design. Interesting thing I learned
in my Internet research.................sync detectors supposedly exhibit
capture effect, where the strongest signal on the channel will capture the
system, while homodyne detectors do not. This will be an interesting week.
Too bad that the radio manufacturers have made lifetime buys on the
available chips, thus capturing the market on these items. That's
ok.....................I will come up with my own design, eliminating the
need for those specialty chips.
I had considered that Analog Devices AD607, but that chip has got to be the
most unfriendly chip to implement. They have even eliminated the AGC
function in newer iterations of the '607. Even if they hadn't done that, it
is still inexcusable to have a modern day chip that requires external
resistive biasing networks. This goes back to the days of the MC1496.

Pete

Stinger wrote in message
...
I don't know if I would exactly call it useless -- synch detectors can
speed
up the process of tuning. However I agree that nothing beats the
fine-tuning knob (not a button!) / human ear combination for really
nailing
down a signal.

-- Stinger
--
"RFCOMMSYS" wrote in message
...
In my opinion, a synch detector that keeps losing lock on problem
signals
is
useless. Like another poster in this thread said, if you can't design a
good
synch detector (apparently it's not easy to do considering that ICOM
can't
seem
to do it), I would rather have manual ECSS ability (SSB mode with an
extremely
fine tuning (preferably analog) knob)).

On Sun, 7 Dec 2003 23:52:00 -0600, Geoffrey S. Mendelson wrote
(in message ):

In article , RHF wrote:
Pete and Russ,

Here is my Two-Cents-Worth on the 'topic' of "Power Sources":

1. Standard 120VAC Power.

Not everyone on this list has that. My outlets give me 230VAC 50Hz.

You would have appreciated two of us walking down the hallway in an US Army
barracks in Germany and tried to yell to a "new guy" as he plugged his
AM/FM/Cassette unit into the wall (he had a "prong-to-DIN" adapter but no
transformer).

The cassette went very quickly for about two/three seconds.

And BTW,
AM broadcast stations are 9kHz apart. :-)

My CCradio has 1 kHz tuning and five memories per band - looks good, lasts a
long time.

Geoff.

Gray Shockley
-----------------------
DX-392 DX-398
RX-320 DX-399
CCradio w/RS Loop
Torus Tuner (3-13 MHz)
Select-A-Tenna
-----------------------
Vicksburg, MS US

"Pete KE9OA" wrote in
:

I like the feel of that tuning knob.

Tuning knobs are great, as long as they don't jump in 1 kHz increments and
"chuff" when they do.

That's why nothing will ever replace a true L/C combo for me.

The reason for the "chuff" is because the receiver is probably muted for the
relatively long settling time of the synthesizer. For a 1kHz tuning step,
and a value of N of 11,000, for instance, you need to have the Omega_d of
the loop filter to be set at approximately 15Hz in order to have adequate
reference sideband suppression.
The settling time will be about 100mSec, with a 50 degree phase margin.
This settling time would be unacceptable.
The workaround in this situation is to use a DAC to pretune the VCO to the
required frequency; this way, the loop filter doesn't have to deal with a
very large step response (and a long settling time). If the settling time
could be set at 5 to 10mSec, the tuning would feel instantaneous.

Pete

donutbandit wrote in message
...
"Pete KE9OA" wrote in
:

I like the feel of that tuning knob.

Tuning knobs are great, as long as they don't jump in 1 kHz increments and
"chuff" when they do.

That's why nothing will ever replace a true L/C combo for me.

"Pete KE9OA" wrote in message ...
I know...........it seems that the more you learn, the more you realize how
much you just don't know.
On another note..................I am working on a quasi-sync detector, so I
should be able to build the prototype unit up this Monday. Basically, it
consists of a limiting amplifier (MC1350) feeding the squared up I.F. signal
into the LO input of an NE602. The unconditioned I.F. signal it fed both to
the input of the limiting amplifier and to the RF input of the NE602. It
should be interesting.
I've been meaning to get around to these things for the past couple of
years..........I'm glad that this radio project came along.

Pete

Do you actually need two ICs? The MC1496 datasheet talks of using
it as a "synchronous detector" but even mentions that an external
limiter is not needed so long as the signal level is sufficient.
I don't suppose that can work out with the 602?

For that matter, the variable gain stage in the MC1350 is
a "Gilbert cell" and it can be used as a mixer, albeit one
with a gain stage between it and the output pins. Could it
be better suited for a self-limiting "synchronous detector"?

I don't suppose the MC1330 which is the same scheme intended
for detector use in TV sets, is still available and suitable?

Michael

I completely agree..................I have a multitude of vias on all of my
boards, especially around the RF components. When a system has 80dB gain at
one frequency, it is just to easy to have things fly, otherwise.
On another note, I have completed the first pass of my quasi-synchronous
detector. Audio is very crisp, and since no PLL is involved, there is no
lock to lose. Basically, it consists of splitting the I.F. signal into to
paths...........one path feeds the input port of a Gilbert Cell mixer, while
the other path feeds the input of a high gain limiter. The clipped output of
the limiter feeds the LO port of the mixer, and the audio is taken from the
I.F. port of that same mixer.
It is interesting, when I compare it to the envelope detector output of the
receiver. While the envelope detector output exhibits distortion from the
selective fading mechanism, the quasi-sync detector output remains very
clean, all the way down to the .1uV lower system limit.
My next iteration will use a Philips SA637.................if this circuit
work out the way I expect it to, I will have a single chip solution for this
function. I just need to check the parameters of the LO input, low frequency
limit of the mixer, etc.

Pete

Telamon wrote in message
...
In article , starman
wrote:

Pete KE9OA wrote:

I usually go for less than one tenth of a wavelength for maximum
spacing
between vias. I never lay out the vias on a grid. This is one of the
things
I learned at one of the EMI/EMC classes I took at when I was working
at
Rockwell-Collins. I understand that different folks have different
approaches to board design, and these different approaches do work
well, my
approach has been ok, with boards I have been designing well up to
5GHz. I
do need to state that I am not the foremost expert in this field; I am
just
a simple soul that is scratching the surface of the RF realm!

Given that the highest HF frequency is 30-Mhz, then 1/10 wavelength
would be about 1-meter. This is much larger than the circuit boards in a
radio like the R8, so how important would it be to adhere to the 1/10
wavelength rule for grounding an HF board?

We were discussing what had to be done to prevent board features from
becoming resonant structures on the board and yes at 3 to 30 MHz it's
much less likely due to propagational effects alone but still possible.
If a trace on the board is not closely associated with a ground plane
then its impedance is high and can look more like a lumped inductor than
a transmission line. If the following input to the next device or
circuit has enough capacitance it could resonate anywhere in the HF
spectrum. There are other reasons for via spacing like tying ground
planes together so they look unified electrically. One goal dictating
via density in board design is to make the RF return current path for a
device on the board as small as possible.

--
Telamon
Ventura, California

Hi Michael,
I finished the prototype this morning, and it does work
pretty well on low to medium level signals. On very strong signals, there is
a little bit of edginess on the modulation peaks.
As far as the NE602, you can feed the limited I.F. signal into pin 6, and
this works out pretty well.
My next iteration of this circuit will be one that uses a Philips SA637.

Pete

Michael Black wrote in message
om...
"Pete KE9OA" wrote in message
...
I know...........it seems that the more you learn, the more you realize
how
much you just don't know.
On another note..................I am working on a quasi-sync detector,
so I
should be able to build the prototype unit up this Monday. Basically, it
consists of a limiting amplifier (MC1350) feeding the squared up I.F.
signal
into the LO input of an NE602. The unconditioned I.F. signal it fed both
to
the input of the limiting amplifier and to the RF input of the NE602. It
should be interesting.
I've been meaning to get around to these things for the past couple of
years..........I'm glad that this radio project came along.

Pete

Do you actually need two ICs? The MC1496 datasheet talks of using
it as a "synchronous detector" but even mentions that an external
limiter is not needed so long as the signal level is sufficient.
I don't suppose that can work out with the 602?

For that matter, the variable gain stage in the MC1350 is
a "Gilbert cell" and it can be used as a mixer, albeit one
with a gain stage between it and the output pins. Could it
be better suited for a self-limiting "synchronous detector"?

I don't suppose the MC1330 which is the same scheme intended
for detector use in TV sets, is still available and suitable?

Michael