Hi all,
I'm considering to upgrade my receiver ICOM R75 with narrow CW filters. My
main interest is NDB listening in the LW band.
There are 2 possiblities:
a) ICOM FL101 (CW narrow 9mHz IF, 250Hz) + ICOM FL53A (CW narrow 455kHz,
250Hz)
b) INRAD 121 (CW narrow 9010.6kHz, 250Hz) + INRAD 122 (CW narrow 455kHz,
250Hz)
Which combination is the better one in terms of quality and efficiency.
Price does'nt matter.
Any advice is welcome!
Thanks in advance

D. Kremp
France

D.K. wrote:
I'm considering to upgrade my receiver ICOM R75 with narrow CW filters. My
main interest is NDB listening in the LW band.
There are 2 possiblities:
a) ICOM FL101 (CW narrow 9mHz IF, 250Hz) + ICOM FL53A (CW narrow 455kHz,
250Hz)
b) INRAD 121 (CW narrow 9010.6kHz, 250Hz) + INRAD 122 (CW narrow 455kHz,
250Hz)
Which combination is the better one in terms of quality and efficiency.
Price does'nt matter.
Any advice is welcome!

Why? Do you hear more than one signal from adjacent frequencies? Or do you
hear broad spectrum noise?

250Hz CW filters are designed to be used by ham radio operators in
crowded bands. They often make listening difficult due to "ringing"
(noise).

They won't filter out broad spectrum noise because it covers the same
frequencies as the signal you want.

You might find that a DSP audio processor will give you better results. It's
easy to test, there are lots of DSP audio programs around for PC's, you
just record some signals and try it.

You could also ask around the local ham community and see if you can find
someone with a similar filter in a receiver that covers the LF bands.

Geoff.

--
Geoffrey S. Mendelson, Jerusalem, Israel N3OWJ/4X1GM

On May 5, 12:13 pm, "D.K." wrote:
Hi all,
I'm considering to upgrade my receiver ICOM R75 with narrow CW filters. My
main interest is NDB listening in the LW band.
There are 2 possiblities:
a) ICOM FL101 (CW narrow 9mHz IF, 250Hz) + ICOM FL53A (CW narrow 455kHz,
250Hz)
b) INRAD 121 (CW narrow 9010.6kHz, 250Hz) + INRAD 122 (CW narrow 455kHz,
250Hz)
Which combination is the better one in terms of quality and efficiency.
Price does'nt matter.
Any advice is welcome!
Thanks in advance

D. Kremp
France


You may want to try using a Timewave DSP Filter. The DSP-59+ can be
had for about $150 US or less and the DSP-599zx for about $300 US. I
had the 599zx for a long time and wish I still had had it. It was a
very good filter.

Rick KR4EY

Greetings D. Kremp..

Typically, for very narrow CW work, 250 Hz IF filters are a reasonable
choice. Many prefer 500 Hz however, if you frequent very crowded band
conditions, you may have little alternative but to narrow up the IF as
much as possible. Now days, this narrowing has somewhat been
alleviated by Digital Signal Processing (DSP) within the IF. Through
IF DSP, you [typically] have options to narrow the IF to whatever you
desire. Short of DSP technology, IF filtering by way of a crystal
filtering elements is the desired choice. An outboard DSP unit
connected to your speaker output will not be as effective however,
they are great at reducing heterodynes and general band noise. I
relate this from using DSP units since their introduction to the
amateur services.

A side note..

Regarding:
"a) ICOM FL101 (CW narrow 9mHz IF, 250Hz)"

Somehow, I doubt that they have a 9 millihertz IF. If you're just
cutting and pasting this from another source, then be aware of:

Megahertz is defined as MHz, kilohertz as kHz and hertz as Hz. It is,
in fact, ALWAYS a capital "H" to pay homage to Mr. Heinrich Hertz.
Consider: http://www.ideafinder.com/history/inventors/hertz.htm or,
http://searchnetworking.techtarget.c...214263,00.html
or, http://tf.nist.gov/timefreq/general/glossary.htm (click on "M" or
"J-K" - these folks should know the difference)



Further proof? Take a look at www.fcc.gov and note their frequency
references. In addition, simply take a look at a stereo dial, clock
radio or even your transistor radio and notice how the manufacturers
abbreviate frequency.


Cheers,
Mr. Mentor



"D.K." wrote in message
...
| Hi all,
| I'm considering to upgrade my receiver ICOM R75 with narrow CW
filters. My
| main interest is NDB listening in the LW band.
| There are 2 possiblities:
| a) ICOM FL101 (CW narrow 9mHz IF, 250Hz) + ICOM FL53A (CW narrow
455kHz,
| 250Hz)
| b) INRAD 121 (CW narrow 9010.6kHz, 250Hz) + INRAD 122 (CW narrow
455kHz,
| 250Hz)
| Which combination is the better one in terms of quality and
efficiency.
| Price does'nt matter.
| Any advice is welcome!
| Thanks in advance
|
| D. Kremp
| France
|
|

On May 5, 12:13*pm, "D.K." wrote:
Hi all,
I'm considering to upgrade my receiver ICOM R75 with narrow CW filters. My
main interest is NDB listening in the LW band.
There are 2 possiblities:
a) ICOM FL101 (CW narrow 9mHz IF, 250Hz) + ICOM FL53A (CW narrow 455kHz,
250Hz)
b) INRAD 121 (CW narrow 9010.6kHz, 250Hz) + INRAD 122 (CW narrow 455kHz,
250Hz)
Which combination is the better one *in terms of quality and efficiency.
Price does'nt matter.
Any advice is welcome!
Thanks in advance

You mention NDB's... note that NDB's are not the usual CW (carrier
interrupted), but are instead AM stations broadcasting the tones of
400 or 1020 Hz. To receive these in AM mode, you'd need bandwidths of
800 Hz and 2040 Hz respectively.

If you're really interested in NDB's and "true" LW activity, a PC
sound card and a waterfall-type graphical program will set you
furthest ahead.

N3QE

Tim Shoppa wrote:
On May 5, 12:13 pm, "D.K." wrote:

Hi all,
I'm considering to upgrade my receiver ICOM R75 with narrow CW filters. My
main interest is NDB listening in the LW band.
There are 2 possiblities:
a) ICOM FL101 (CW narrow 9mHz IF, 250Hz) + ICOM FL53A (CW narrow 455kHz,
250Hz)
b) INRAD 121 (CW narrow 9010.6kHz, 250Hz) + INRAD 122 (CW narrow 455kHz,
250Hz)
Which combination is the better one in terms of quality and efficiency.
Price does'nt matter.
Any advice is welcome!
Thanks in advance


You mention NDB's... note that NDB's are not the usual CW (carrier
interrupted), but are instead AM stations broadcasting the tones of
400 or 1020 Hz. To receive these in AM mode, you'd need bandwidths of
800 Hz and 2040 Hz respectively.

If you're really interested in NDB's and "true" LW activity, a PC
sound card and a waterfall-type graphical program will set you
furthest ahead.

N3QE

You're correct about all US domestic NDBs.

There still are NDBs elsewhere that transmit a unmodulated carrier most
of the time and then switch to on/off keyed morse ident periodically.

Such systems require a BFO to hear the morse ident.

Even 'modern' airborne ADFs still have a BFO mode... some things never die.

Bob

Megahertz is defined as MHz, kilohertz as kHz and hertz as Hz. It is,
in fact, ALWAYS a capital "H" to pay homage to Mr. Heinrich Hertz.
Consider: http://www.ideafinder.com/history/inventors/hertz.htm or,
http://searchnetworking.techtarget.c...214263,00.html
or, http://tf.nist.gov/timefreq/general/glossary.htm (click on "M" or
"J-K" - these folks should know the difference)

I have a different understanding. Hz is written with a capital H not to pay
homage to Mr. Heinrich Hertz, but more simply because all measurement units
begin with a capital letter.

Homage was instead paid to Mr Kelvin when they decided that the capital K is
assigned to the temperature measurement unit (kelvin degree) instead than to the
1000 multiplier. This explains why kilohertz is written with a small k, an
exception to the general rule that all multipliers have a capital lettere (kHz,
MHz, GHz, THz).

73

Tony I0JX.

On Fri, 16 May 2008 21:48:37 UTC, "Antonio Vernucci"
wrote:

Megahertz is defined as MHz, kilohertz as kHz and hertz as Hz. It is,
in fact, ALWAYS a capital "H" to pay homage to Mr. Heinrich Hertz.
Consider: http://www.ideafinder.com/history/inventors/hertz.htm or,
http://searchnetworking.techtarget.c...214263,00.html
or, http://tf.nist.gov/timefreq/general/glossary.htm (click on "M" or
"J-K" - these folks should know the difference)

I have a different understanding. Hz is written with a capital H not to pay
homage to Mr. Heinrich Hertz, but more simply because all measurement units
begin with a capital letter.

Homage was instead paid to Mr Kelvin when they decided that the capital K is
assigned to the temperature measurement unit (kelvin degree) instead than to the
1000 multiplier. This explains why kilohertz is written with a small k, an
exception to the general rule that all multipliers have a capital lettere (kHz,
MHz, GHz, THz).

73

Tony I0JX.
I still use kilocycles and megacycles, that is because my boatanchors
have the words on the dial faces!

On Fri, 16 May 2008, Count Floyd wrote:

On Fri, 16 May 2008 21:48:37 UTC, "Antonio Vernucci"
wrote:

Megahertz is defined as MHz, kilohertz as kHz and hertz as Hz. It is,
in fact, ALWAYS a capital "H" to pay homage to Mr. Heinrich Hertz.
Consider: http://www.ideafinder.com/history/inventors/hertz.htm or,
http://searchnetworking.techtarget.c...214263,00.html
or, http://tf.nist.gov/timefreq/general/glossary.htm (click on "M" or
"J-K" - these folks should know the difference)

I have a different understanding. Hz is written with a capital H not to pay
homage to Mr. Heinrich Hertz, but more simply because all measurement units
begin with a capital letter.

Homage was instead paid to Mr Kelvin when they decided that the capital K is
assigned to the temperature measurement unit (kelvin degree) instead than to the
1000 multiplier. This explains why kilohertz is written with a small k, an
exception to the general rule that all multipliers have a capital lettere (kHz,
MHz, GHz, THz).

73

Tony I0JX.
I still use kilocycles and megacycles, that is because my boatanchors
have the words on the dial faces!


Of course, if we're nitpicking, there's no such thing as kilocycles and
megacycles. They always needed the "per second" attached to them in order
to have meaning, since otherwise you'd not know what time period the
million or thousand cyles appeared in.

When Hertz was brought in as a replacement, the ambiguity went away
since Hertz mean "cycle per second".

Michael VE2BVW

Antonio Vernucci wrote:
Megahertz is defined as MHz, kilohertz as kHz and hertz as Hz. It is,
in fact, ALWAYS a capital "H" to pay homage to Mr. Heinrich Hertz.
Consider: http://www.ideafinder.com/history/inventors/hertz.htm or,
http://searchnetworking.techtarget.c...214263,00.html

or, http://tf.nist.gov/timefreq/general/glossary.htm (click on "M" or
"J-K" - these folks should know the difference)

I have a different understanding. Hz is written with a capital H not to
pay homage to Mr. Heinrich Hertz, but more simply because all
measurement units begin with a capital letter.

That contradicts units like the gram (g, kg, mg), the meter (m, cm, mm,
km) the liter/litre (l, ml), the second (sec, msec)... or at least how
they are presented in all my science texts, and...

Homage was instead paid to Mr Kelvin when they decided that the capital
K is assigned to the temperature measurement unit (kelvin degree)
instead than to the 1000 multiplier.

....Fahrenheit (F), Rankin (R), Henry (H, mH), Farad (F, pF, nF), Volta
(V), Ampere (A), Gauss (G, mG), Tesla (T), Watt (W, mW, kW, MW)...

This explains why kilohertz is
written with a small k, an exception to the general rule that all
multipliers have a capital lettere (kHz, MHz, GHz, THz).

....deci (d), centi (c), milli (m), nano (n), pico (p), femto (f), atto (a),

Am I missing your sarcasm?

Although, I frequently (almost always) see 'million' prefixed by 'm' by
the news media in headlines, like 'XYZ Liable for $10m' A liability of
ten cents isn't a big news item. In my opinion.


73

Tony I0JX.

- W8LNA