Hello,

I'm mainly a sw listener, Sr. Citizen now, and frankly not very
knowledgeable about radio theory.

Have a new WinRadio receiver that I'm enjoying very much.

But I realize there are several optional settings that I really don't
understand, and don't have a handle on.

I do listening from about 1 MHz up thru the vhf/uhf scanner freq's,
including MIL and Maritime stuff on SSB.

Regarding the IF Bandwidth options:

Might someone please give me a short discourse on what this does, and
what it effects.

And, some suggested (Default) settings that I could get started with for:

AM
NFM
LSB
USB

Also the effect of slow, medium and fast for what I think is
the the AF Filter

Thank you very much; appreciate the help,
Bob

Bob wrote:
Hello,

I'm mainly a sw listener, Sr. Citizen now, and frankly not very
knowledgeable about radio theory.

Have a new WinRadio receiver that I'm enjoying very much.

But I realize there are several optional settings that I really don't
understand, and don't have a handle on.

I do listening from about 1 MHz up thru the vhf/uhf scanner freq's,
including MIL and Maritime stuff on SSB.

Regarding the IF Bandwidth options:

Might someone please give me a short discourse on what this does, and
what it effects.

And, some suggested (Default) settings that I could get started with for:

AM
4 KHz or wider
NFM
use for 2-way radios, cops, etc. Use WFM for entertainment radio and
analog TV audio.
LSB
3 KHz or less for HF phone (mainly hams below 10 MHz)
USB
3 KHz or less for most HF phone (other than hams below 10 MHz)

Also the effect of slow, medium and fast for what I think is
the the AF Filter

AGC rates. Fast for knob-tuning. Medium for SSB. Slow for AM program
listening.

Thank you very much; appreciate the help,
Bob

dave wrote:


And, some suggested (Default) settings that I could get started with for:

AM
4 KHz or wider
Medium Wave and HF broadcast. VHF Aero. UHF Aero.
NFM
use for 2-way radios, cops, etc. Use WFM for entertainment radio and
analog TV audio.
LSB
3 KHz or less for HF phone (mainly hams below 10 MHz)
USB
3 KHz or less for most HF phone (other than hams below 10 MHz)

Also the effect of slow, medium and fast for what I think is
the the AF Filter

AGC rates. Fast for knob-tuning. Medium for SSB. Slow for AM program
listening.

Thank you very much; appreciate the help,
Bob

Bob wrote:


Might someone please give me a short discourse on what this does, and
what it effects.

The IF bandwidth is how wide (in frequency) a signal you want to receive.
Filters have shapes, or more acurately, if you plotted the response of the
filter, it's going to be better at one frequency (the center) and as you go
away from it (up or down) the response curve will have a shape.

Narrow filters look like an upside down letter U, with a sharp cutoff,
wide filters have a long curve of the sides. Narrow filters are more expensive
and have other characteristics.

Then there is the bandwidth of the filter. Those terms only really work in
context, for example a wide filter for AM is 6khz "wide", for SSB 3kHz and
for CW 1kHz.

For example, if you were listening to an AM shortwave station with little
noise and no nearby stations, you would want a 6kHz filter with a wide
response. As the band gets more crowded, you would want one with a narrower
frequency response, though at around 3kHz it starts to become difficult to
understand them (like an old digital cell phone) and by 2 almost impossible.

The narrower a filter is, the more sounds become odd going through it,
a phenomenon known as "ringing". So if you have a choice or adjustment,
you want the widest filter bandwidth with the widest response curve that
blocks out enough interference and noise to understand the station.

Got that? Read it over a few times, it's difficult to understand, and
I'm not a great teacher.

The same principal applies to SSB (single side band), except that SSB
only has have of the wave, (top or bottom) and you can filter out the
side you don't want. So a 3kHz SSB filter is like a 6kHz AM filter.
Generally SSB filters start at 2.4kHz and become narrower.

CW is just a switched carrier, on and off, so a narrow filter (250Hz) is fine.
Since at that narrow a filter you get lots of ringing, and other effects,
it becomes difficult to listen to. To make listening easier, you want as wide
a filter as possible.

Hams and commerical radio operators before WWII were trained to copy with wide
filters and to be able to pick out the one signal in may nearby ones intended
for them. As good IF filtering became available during WWII it became less
of a technological requirement, but until the turn of the century when digital
signal processing at the IF became reasonably available, many hams did without
it.

Many hams still use relatively wide (2-3kHz) filtering for CW because
they are used to it, or it's cheap and simple.


And, some suggested (Default) settings that I could get started with for:

AM

AM (amplitude modulation) is the traditional way of adding voice to a signal.
The AM broadcast band in the US is 530kHz to 1750kHz, and scattered through
out the shortwave broadcast bands are mostly AM stations. There are a handful
transmitting in USB or digital radio, but almost everything you will hear
is AM.

Sort range (air/ground to tower, etc) avation is on 108-130(?) mHz and is AM.

NFM

Narrow band FM. Wide band FM is used for broadcasts, such as the US
FM band (88-108 mHz) and analog TV (which is almost dead in the US).

NBFM is (aka NFM) is used for communications. You won't hear any below
26 mHz.

There you may hear remote to studio links for radio stations, illegal
"freebanders", CB operators (FM is illegal in the US on CB) and from
29.5 to 29.7 mHz FM is used by hams.

Over 30 mHz, there are commercial, millitary, government and hams using
FM. Ham bands to listen for are 50-54, 144-148, 223-225,430-450 mHz and so
on.

Short range boats use a band around 165 mHz, there are also weather
forecasts near there.

LSB
USB

Upper and lower sideband. This is used for longer range communications
than AM can provide. Everyone uses USB, ships, airplanes, hams, commercial,
millitary and government etc on HF. Hams and military aircraft use it
on VHF and UHF.

LSB (lower side band) is pretty much only used by hams and only below 10mHz.

Either when not tuned in properly gives you that quacking sound like the
attack scene in star wars.

Note that hams are not required to use either USB or LSB on an particular
band (except for the 5mHz band in the US). It's more convention than
anything else. Occasionaly you will hear a ham using a military or marine
(boat) radio that is only USB below 10mHz.




Also the effect of slow, medium and fast for what I think is
the the AF Filter

No, it's the AGC (automatic gain control) time. The AGC adjusts how loud
the signal sounds, although it usually works in the IF. In the IF it
adjusts how well it is received in relation to the internal noise of the
receiver. Stronger signals can be received with less gain, so the receiver
generates less internal noise. Weaker ones require more gain, which means
more noise.

Fast medium and slow determine how quickly it "resets". For voice you
don't need much of a delay, so a fast delay is desireable. Morse code has
lots of gaps in it, so a slow agc is prefered. Until you get used to it,
leaving it on medium is a good start.

Geoff.

--
Geoffrey S. Mendelson, Jerusalem, Israel N3OWJ/4X1GM
New word I coined 12/13/09, "Sub-Wikipedia" adj, describing knowledge or
understanding, as in he has a sub-wikipedia understanding of the situation.
i.e possessing less facts or information than can be found in the Wikipedia.

On Mar 17, 1:51*pm, Bob wrote:
Hello,

I'm mainly a sw listener, Sr. Citizen now, and frankly not very
knowledgeable about radio theory.

Have a new WinRadio receiver that I'm enjoying very much.

But I realize there are several optional settings that I really don't
understand, and don't have a handle on.

I do listening from about 1 MHz up thru the vhf/uhf scanner freq's,
including MIL and Maritime stuff on SSB.

Regarding the IF Bandwidth options:

Might someone please give me a short discourse on what this does, and
what it effects.

And, some suggested (Default) settings that I could get started with for:

AM
NFM
LSB
USB

Also the effect of slow, medium and fast for what I think is
the the AF Filter

Thank you very much; appreciate the help,
Bob

Hi, Bob -

In terms of IF, Bandwidth describes the width of the slice of the
frequency spectrum that gets through to your final RF stage, and also
affects the width of the audio slice that reaches your speaker. It
serves to determine both the audio quality (how much the of high freqs
get cut off) and the amount of adjacent channel information is allowed
to get through.

As an example - For SWL on AM, most stations are spaced about 5 kHz
apart. That means one on 9,555, one on 9,560, one on 9,565 and so
forth. If you want to listen to a station on 9,560 and you don't want
adjacent interference from those other freqs, the slice you take
should be narrow enough to reject those adjacent signals but wide
enough to provide a pleasing audio regime. In this case, a 6 kHz IF
filter width (typical for a wide AM with good midrange tones) would be
adequate, cutting off everything more than 3 kHz away on either side
and leaving you with a clear channel. You would hear everything from
0 to 3,000 Hz audio, an adequate range for comfortable hearing and
understanding.

If you run across a station closer than 5 kHz, you may want to narrow
your filter a bit. If an offending station is on 9,558, you would
have to take a narrower slice, and maybe use a filter that cuts off at
4 kHz width. You again get a clean signal, but the trade-off is that
you lose some high audio frequencies. The desired signal gets a
*little* bit harder to understand.

Lots of things can affect this, of course. If your filter has steep
"skirts", meaning a good solid cutoff at each end, then they should
work very well. If your filter has gentle skirts, they may not work
as well as their bandwidth rating would suggest, allowing in some
adjacent interference. I am not sure about the WinRadios, but if they
have continuously variable bandwidths, you should be able to adjust
the filter width so that the skirt quality will be slightly less
important. Also, if the adjacent signal is very strong and your
desired signal is weaker, even a decent filter may have a harder time
rejecting the adjacent interference. In this case, a passband / IF
shift adjustment can be handy - it can take the whole desired signal
and essentially shove it away from the offending adjavcent
interference. Again, I don't know if the WinRadios have this feature.

For AM SWL, good bandwidths are something nice and wide for strong
signals on clear channels (6 kHz or more), a 6 kHz filter for general
listening on a modestly crowded band, and a 3 - 4.5 KHz bandwidth for
the modest signal next to the stornger station. If you get much
narrower, you may lose a lot of audio and the sound becomes very
muddy.

This is where SSB - USB - LSB can help. If you get interference from
a station a few kHz away and the AM filter won't cut if out, a switch
to the sideband farther away from the offending signal can make a big
difference. In fact, using sideband for AM listening can help with a
number of problems ranging from noise to fading. For USB / LSB, you
can have narrower bandwidths, say 1.5 - 3 kHz, and still enjoy decent
audio, because the slice you take is only half the incoming signal,
and it can include everything from 0 up to the desired higher
frequency.

The passband / IF shift can also help on USB / LSB, sliding your
signal away from the interference. You will probably hear some
variation in the sound of the SB signal, though, so it must be used
judiciously.

Finally, if you have a REALLY close signal but you can use SSB, you
can switch to that sideband farther from the offending signal and
switch in a narrow filter. Howeve, you may still get a whistling
heterodyne from the nearby station - in that case, switch in a Notch
filter to cut it out, and adjust it is possible to achieve the desired
level of whistle removal.

Does that help?

73,
Bruce

On Mar 17, 1:51*pm, Bob wrote:
Hello,

I'm mainly a sw listener, Sr. Citizen now, and frankly not very
knowledgeable about radio theory.

Have a new WinRadio receiver that I'm enjoying very much.

But I realize there are several optional settings that I really don't
understand, and don't have a handle on.

I do listening from about 1 MHz up thru the vhf/uhf scanner freq's,
including MIL and Maritime stuff on SSB.

Regarding the IF Bandwidth options:

Might someone please give me a short discourse on what this does, and
what it effects.

And, some suggested (Default) settings that I could get started with for:

AM
NFM
LSB
USB

Also the effect of slow, medium and fast for what I think is
the the AF Filter

Thank you very much; appreciate the help,
Bob

BTW, slow/medium/fast is probably for the AGC (automatic gain
control). This helps to make listening comfortable when you switch
between tuning and listening, or with varying degrees of fading. Fast
AGC for tuning and slow for listening usually works well; and if the
fading is strong or rapid, your ability to adjust the AGC may help.
AGC often works well in conjunction with the RF Gain control - at
times of fading, pulling back the RF gain with AGC properly adjusted
can reduce the effects noticeably. In fact, without the AGC the
fluttering of the signal might drive you nuts! :-) Experiment and see
what works best for you.

Bruce