Sound equipment question

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tdenfuny

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Hello. I am a complete noob when it comes to electronics. Recently I got a shortwave radio with plug for headphones. I have had fun with trying to find various international stations (I think this is called DXing) and other sounds. The radio is pretty simple and the sound isn't great. I find a station and I can hear what is being said, but there is a lot of noise. I know that this is just how it is with shortwave radios, and so I am not complaining.

Anyway, I was wondering is it is possible to get some cheapish equipment that would take the sound from the head phone plug and be able to reduce the noise. Some kind of thing where one might be able to cut of certain high faudio frequencies or something while preserving other other elements in the sound. I don't know the technical term for this. I was thinking it is a mixer or a filter, but I don't think that is true.

Any help/suggestions?
 

kb5udf

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Idea

Hi there,

You might try feeding the audio into your pc running a copy of SDR# and using the
noise reduction features.
 

ko6jw_2

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There are external speaker/amplifiers that have DSP built in. You also might try to find headphones intended for radio monitoring. Stereo headphones have high end response that is not needed or desirable for shortwave listening. Using PC software is also a good suggestion. Probably cheaper than an external speaker.
 

n5ims

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Often the speakers in radios are not the best quality and using an external speaker can make things sound better. It also could be that unlike your typical FM broadcast station, a SW station compresses the signal and has limited audio bandwidth to maximize the signal coverage at the cost of audio quality. Also, radios designed for communication, not for broadcasting, have very limited audio bandwidth and include circuits to maximize voice frequencies and minimize the highs and lows. This helps reduce static and other noises while improving the voice signals, but would make music or other signals with a wide audio frequency range sound quite dull and flat.
 

tdenfuny

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Thanks for the responses. How would one go about using the PC? Do I just take the output (for the headphones) and somehow plug that into the mic input on the computer?
 

krokus

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Thanks for the responses. How would one go about using the PC? Do I just take the output (for the headphones) and somehow plug that into the mic input on the computer?
A line input would be better than a microphone input. A simple cable from the headphone jack to the line in jack would do the job.

Another option for getting rid of some of the static noise is to use a DSP speaker. They are more expensive than the other options mentioned, but do work well.

Sent via Tapatalk
 

majoco

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Are you using the whip antenna on the the radio? An outdoor wire antenna will perform much better.
 

tdenfuny

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I can see that a DSP speaker is too expensive for me. I wouldn't want to spend more than I spent on the radio. So maybe using my computer is the best option. I had hoped that one could find some kind of cheap filter to run the sound through that would help a bit. I can often easily hear what is being said, but it gets a bit annoying listening for long with the noise.

Krokos: I looked around online, and it seems like some are saying that just passing the headphone output to the mic input in general isn't a good idea. Is that true?

majoco: Yes, I have just been using the whip antenna indoors. I can hear that it gets better is I go outdoors. But I should maybe try to get some wire and clip this onto the antenna and hang this outdoor somehow.
 

k9rzz

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Why can't you use the mic input? It's amplified, don't over drive it.

Install some form of real time audio filter: DSP - Software: DSP

I used to use "SR5" but not sure if that's still available (freeware)

Then, pump the audio out into your stereo. I always had some sort of thrift store set up.

The limits are only in your imagination. :^]
 

majoco

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Depends. What SW radio did you get? Some radios are designed and tuned to use the whip antenna - hanging another bit of wire onto it may de-tune the radio and there is also a risk of blowing a special transistor at the whip input. If there is an external antenna socket it will be better to use that.
 

tdenfuny

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majoco: I got the Tecsun PL600. It did come with a separate wire antenna that works better than the whip. But I am still interested in how to reduce the noise.
 

majoco

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Are you sure the noise is being generated inside the radio? There is a circuit inside the radio that reduces the noise as the signal increases, which is why I suggested a better antenna. But a lot of noise these days come from within your own house and your neighbours. Take your radio around your house and try switching things off one at a time - power supplies, small chargers for cellphones, laptops and notebooks, TV of course, aircon, flourescent lights and their compact brothers, motors - all may make a lot of noise on your radio.
The Tecsun PL600 is actually a pretty good little radio and has had good write-ups - don't condemn it yet.
You'll find a pair of headphones or earbuds will improve the sound quality.
 

majoco

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Quote from a "Eham" contributor about the PL600...

One final thing. The power transformer was made for 240 volts, so the wall wart provided is also a stepdown 240-120 transformer. At least on my sample, this wall wart was the cause of a lot of line noise, making the radio almost unusable on some frequencies. Running the 600 on batteries is the answer. It's a very quiet radio on batteries and is more resistant to things like dimmer noise than most portables.
 

Boombox

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Ditto what Majoco just said. Sounds like you may have an RFI problem.

Plus, to cut treble you can try a different set of headphones.
 
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