I am not a listener only, I am one that talks! grin

Despite supposed international conventions about how one says their
callsigns they are often peppered with strange nuances and abnormal
phonetics.

Callsigns are often also rushed or abbreviated if those talking know
each other and talk often. I have found this makes things very
difficult. Of course its easy if you can ask them to slow down!

I find the best way is to record (on a PC) then play it back a few times
to work out what is being said.

It might be worthwhile trying to tackle your noise problem too. Care to
elaborate? Rememeber that the brain is a very effective filter. You just
have to keep at it.

Cheers Bob W5/VK2YQA

weatherall wrote:

Lately I use my Sony ICF SW7600GR for ssb reception. I can clarify the
signal quite well, but the noise level affects the clarity.

Are there any others in this newsgroup that are strictly listeners?
What have your experiences been like?

Thanks for your reply. I have recorded from my shortwave radio before but never thought about recording ham conversations for deciphering. I should do that. Also I should point out that I am referring to voice communications rather than morse code.

During the warmer seasons, I prefer to take my radio outside and listen while walking around. This lets me get far away from interference sources. While indoors, I am getting adequate reception from international broadcasters with some noise. Last night while listening to some ham radio operators, I was able to clearly hear a nearby person (in San Jose) but some others were faint.

I posted a few weeks ago in rec.radio.shortwave asking for some interference reduction advice. I'm on the top floor of an apartment building. There are dimmer switches in my apartment, and I turn them off when listening. I have a DE31 active loop antenna, but it typically doesn't improve the reception vs. the whip on my SW7600GR. My whip antenna is right by my window. Recently I've been placing the whip antenna horizontal, which I've heard can reduce some interference. I always run my radios with rechargeable NiMH batteries.

I've only been involved in shortwave radio for several months, so I'd be glad to hear any additional advice regarding interference.

thanks!

I personally have some major power line interference nearby that even
makes noise on 144MHz. One day I'll go and track it down! (Not that the
power company will do anything!)

- You'll generally find that a horizontally polarised antenna will
receive less local noise than a vertical. Note I am not talking about
close noises sources (say less than 100 yards) but those up to a ground
wave distances away. Also keep in mind that the receiver you are using
may have some of its antenna "internal" in the form of a ferrite etc bar
that might alse be responding to other polarisations. (ie also try
rotating the radio)

- Many noise reduction techniques come out of specialized receiver
design. This of course doesnt help you!. DSP techiques for example
sampling much more than the usual AM/SSB bandwidths to apply digital
filters make a huge difference nowadays.

- It is also conceivable that what you perceive as noise may even be
fundamental overload of the receiver front end with strong signals. ie
the radios selectivity isnt good. There are various ways to combat that.
If the active loop antenna has a tuning adjustment this can make a huge
difference. The main help will be a directive antenna of some variety.

- I should point out that I have heard anecdotal evidence that a magloop
antenna receives less noise but I have never found out why. I dont know
if your active loop antenna is one of these. They would normally have a
manual adjustment for frequency - that I dont see...

- You can use phase addition/subtraction techniques to suppress
interference/noise from a single source. Probably not helpful in your
case but still worth mentioning.

- The active antenna may be helpful if it has a reception/radiation
pattern nulls that can be positioned to point at the noise source.

- Noise blanker and noise limiter circuits are useful if the receiver
has them. If I was into SWL nowadays I'd be using a DSP filter, possibly
by using a PC soundcard.

- If you run a remote antenna (eg an outside dipole) ensure that the
currents in the feedline are balanced. (Use a balun etc) This makes
errant signal pickup along the feedline length less of a problem. (Or
coax transmitting RF if it is connected to a transmitter)

- An RF ground is important for noise reduction. Given your top floor
location though this may be difficult. Not a good idea to use the
power/utility ground as that will be full of noise. Note that a balanced
antenna system removes the need for RF earthing as one side of it "works
against the other" rather than against a ground counterpoise.

- The best noise solution is to tackle the sources.

- Ham radio ops will generally be much weaker than broadcast stations.
An antenna (or 3) tuned for the job may even be a good investment.

Probably not all that helpful, sorry.

Cheers Bob


weatherall wrote:


I've only been involved in shortwave radio for several months, so I'd
be glad to hear any additional advice regarding interference.

Oh, I didn't realize that part. I assumed this was to address the closest noise sources.

I agree there. In some cases I can use the antenna trimmer on the SW7600GR to improve the signal.

I guess I'm not sure if there are any differences between a magloop and an active loop antenna. Most of what I know about active loop antennas is from this antenna review:
http://www.radiointel.com/review-degende31.htm

I definitely appreciate the response! It encourages me to keep trying.