My weekend hack:
I have been living with a MFJ 281 ClearTone(yea right) http://www.mfjenterprises.com/Product.php?productid=MFJ-281 speaker on my 857D since day one. With the bands so bad and the noise floor so high it drives me crazy to have to have the volume so high just to try to hear a faint QSO. The constant hiss was maddening even when using the DSP controls on the Yaesu 857D.
I started looking into Noise Canceling Speakers but the high price and me just starting back to work after 7 months of unemployment, I could not bear to spend the money on one.
The 857D has some “good” DNR functions, but they just don’t cut it with the dinky Cleartone and my ears.
I have several Onkyo speakers from a retired Surround Sound system and a 100 watt 12 volt car audio amplifier and started to think on hacking this into something usable.
I picked up a Behringer MINIFBQ800 9 band Graphic Equalizer from Amazon for $70 and after a few hours ended up with this.
It actually works quite well and the difference is amazing between this and the Cleartone. This photo is the “bread board” version to be sure it works. All of the wiring will be cleaned up into a nice clean package at the end of the project.
I could have saved some money by buying a cheaper model EQ knowing what bands need to be suppressed, but this one had the best S/N ratio of 95 dB vs some that were in the 60dB range.
The quality of the audio coming out of the radio does not warrant this level of EQ, but more is better right? I ordered this before getting the O Scope program http://www.zeitnitz.eu/scope_en or I would have know that 90% of all the noise is coming in at 2kHz..
Now just looking for the bands to clear and see how this thing works when it opens up.
Here are the parts I used in the system:
The Behringer MINIFBQ FBQ800 9 Channel Equalizer from Amazon $70
The Behringer MINIFBQ FBQ800 9 Channel Equalizer from Amazon $70 one minor issue with this unit is it runs off of 9 volt wall wart. I could probably get it to run off of the radio power supply like the amp does, but….. oh well.
There are several other EQs that are less expensive like
BOSS Audio EQ1208 4 Band Amplified Equalizer with Subwoofer Control
Or the GRAVITY 7 Band Graphic Equalizer GR-EQ9 $34.99 that will run off of your 12 volt power supply
Gravity 7 Band EQ
Power Acoustik PWM-16 Pre-Amp Equalizer| $32.90
Power Acoustik PWM-16
SSL S7EQ 7 Band Pre-Amp Equalizer with Subwoofer Control $28.99
Now as always YMMV(your mileage may vary) meaning I am not saying the these will work with your system. That is up to you to determine. No Warranties expressed or implied.
Since the audio out of any Ham radio is mono/1 channel you can get by with a mono amp, but they are a little harder to find. There are kits you can find to build mono amps or you can buy one already built and be done with it. The amp listed below is exactly the same as I had on hand, but branded under another brand.
Boss Two Channel 100 Watt Power Amp
Boss 2 Channel 100 Watt Power AMP
This amp has both “Line Level” inputs meaning non amplified and “High Level inputs” meaning with power.
Now according to the specs, my Yaesu 857D has 2.5 watts @ 4 ohms which is considered high level, but the volume control can drop this down so that you can use this as a Line Level input, which is what I did.
I bought a 1/8 inch mini mono to RCA adapter cord from Amazon but could not find one shorter than 6 feet. You can buy the end connectors and make you own if you wish. This cable is the output from the radio to the FBQ800 EQ
1/8 inch mini mono to RCA coard
I also bought a RCA cable to split for the mono channel output from the EQ to the Amp.
So we have the audio out of the Yaesu 857D with the mono 1/8 inch mini to RCA male into the Behringer Equalizer. Out of the EQ with a RAC Male to RCA Male cable to the Amp. Out of the Amp with the supplied speaker wire((s) this is a stereo amp but I am only using one channel)) to the Onkyo Speaker.
A quick video showing how this works will be post shortly.
If you have questions post them. Remember I am a Mechanical Engineer, so anything electrical should be taken with a grain of salt.
Disclaimer: I do have a Affiliate account at Amazon. Any link you click on and buy from Amazon, I may get some compensation from Amazon. This does not cost you anymore money and you are obviously free to shop around to find a better price.