Can someone recomend a good BC band filter?

[W2NBC]

Excellent info on various BC traps, high pass, and notch filtering

http://www.dxing.com/tnotes/tnote06.pdf

[ke7trp]

Thanks fred.  I am going to just go to the doctor/clinic tomorrow.  Someone mentioned something called a Z pack that the doctor gave them and in days they where normal. 

C

[Jim WB5WPA]

Carr's "Figure 3" (pg 6) High-Pass filter looks pretty good.

He says it has a cut-off frequency between 1700 and 3000 KHz and blocks some some AM BCB signals while passing all the shortwave frequencies.

" Figure 3 shows a design used for many decades. It is easily built because the capacitor values are 0.001 μF and 0.002 μF (which some people make byparallelling two 0.001 μF capacitors). "

Figure 3 below:



http://i39.tinypic.com/fxb9s1.png

[ke7trp]

W7TFO knocked on the Door today and handed me a JW miller 812-bc1 wave trap.  This looks like an IF can.  It has an adjustment to fine tune the trap.  I clip leaded the filter inline to the antenna ahead of the SDR and BINGO!  Problem solved. I can no longer here the Disney station anywhere on on the spectrum. I have attached Screen shots of the Primary signal with and without the Wave trap installed inline and of 75 meters with and without the filter.  As you can see 75 meters was not usable without the wave trap. 

BIG thanks to Dennis for this little Gem.  I need to mount it to a box with connectors now!

C

[ke7trp]

These shots show 75 meters with and without the wave trap.

[flintstone mop]

W7TFO wins the "Victory Over Disney Award"

Clark, Now the fun begins.

I bet you're close to heaven now.

Fred

[ke7trp]

I sure am. The SDR works great now Fred.  The ECSS, is really cool.  I can use the AM mode, Choose the Sideband I want and the software tracks the carrier back and forth auto!

C

[ke7trp]

I put a Galvanic isolator on the sound card input.  This is a simple 1 to 1 600 ohm stereo transformer.  This took the peak out seen in the plots.  The LO of the SDR shows up there without the isolator.  This Dropped the noise level of the radio down 2 full SU.  Its now very nice to use on SSB and AM.  Not bad for a $100 radio. 

C

[W7TFO]

Friggin' old tech, saves bacon every day!

73DG

[ke7trp]

Sure does.  It really worked perfectly Dennis. 

The SDR is alot of fun now with out that LO signal in your way and with the BC station out of its ears.  One I learned how to adjust the AGC threashold, The noise disapeared and the stations came up.

Now I need a TR switch with 100DB pad so i can have this thing inline all the time.

C