amplifying speaker audio out...

[mr_fx]

I have always used old book shelf speakers as radio speakers, usually just narrowing the audio response a bit... seems to work fine...

however, I have recntly been trying to pull signals out fo the mud, and what I have found is that by the time I lower the RF gain to do so that speaker have very little volume...

so I thought... why dont I connect it to my old stereo


however while it is louder there is also a lot of static being amplified as well

any ideas? keep in mind I am not working right now and would rather not spend anything

 

[Beetle]

I have always used old book shelf speakers as radio speakers, usually just narrowing the audio response a bit... seems to work fine...

however, I have recntly been trying to pull signals out fo the mud, and what I have found is that by the time I lower the RF gain to do so that speaker have very little volume...

so I thought... why dont I connect it to my old stereo


however while it is louder there is also a lot of static being amplified as well

any ideas? keep in mind I am not working right now and would rather not spend anything

Anything outside of the 300-3000 Hz spectrum contributes more to noise than it does to voice frequencies. Concentrate on the important part of the transmission. Also, try headphones (not super 20Hz to 25KHz stuff) - ones that are designed for communications.

 

[Captain Kilowatt]

Agree with Beetle. Unless you are listening to strong wide band AM then stereo speakers of even the smaller bookshelf type are not what you want to enhance your ability to pull something out of the mud. You want narrow band audio 300-3000 Hz at the widest and preferably narrower. When DXing on the AM broadcast band I usually tuned my receiver in SSB mode listening for the tell-tale heterodyne of an AM carrier between the regular North American channel assignments every 10 KHz. I did this because the receiver bandwidth is much narrower in SSB mode than in AM mode and it also made it easier to detect a carrier. Once I had detected a carrier I would select either USB or LSB whichever gave the best S/N ratio. From there i would narrow the bandwidth as much as possible in order to filter out as much noise and interference as possible. For weak signals you do not want wideband audio.

BTW using this technique I was able to detect many 1 Kw AM broadcast stations in Central America that were positioned between the regular 10 KHz channels. Also some 10 Kw AM broadcast stations in Europe most notably from Norway on 1314 KHz and even Chah Bahar Iran on 765 KHz........but it was running 1.2 Mega watts at the time.

 

[Moleculo]

Some rigs like the Elecraft K3 or KX3 can take advantage of stereo speakers, using a number of various functions, like putting VFO A on one speaker and VFO B on the other speaker, or even a simulated stereo.

If you want amplified speakers for your rig, try the West Mountain Radio COMspkr. I need just a little more volume out of my rig and am pretty happy with this speaker, which is free from RFI. Rigs that have a RQ EQ will let you tailor the audio response to help deal with the problems that Beetle and CK mentioned.

 

[vkrules]

Bhi dsp speaker ,expensive but worth every penny.