Measuring filter shape factor
Amongst all these political propaganda posts, I wonder if there is a
little room for a technical question related to radio please? If so, here goes: How does one measure the IF filter shape factor in a shortwave radio? I am technically minded and do have a signal generator, etc., but I am not sure of the exact procedure. Do I get the audio level at the peak frequency, then detune both sides off the peak for -3dB of the demodulated audio, note down the width between these points, then detune to obtain for -50dB of the demodulated audio, get the width at these points, and then the ratio of the two widths is the filter shape factor? I would appreciate a link to the exact procedure if there is one (don't seem to be able to find this in Google) or an expert advice please. I would also appreciate advice as to what actual values of filter shape are considered poor, good, excellent, etc... Thanks in advance, Michael |
Measuring filter shape factor
Networksciences (original filter supplier for Drake) has a very
elaborate website on this subject. Try them first. |
Measuring filter shape factor
"Michael Thorpe" wrote in message news:43c4e407.4277000@news-server... Amongst all these political propaganda posts, I wonder if there is a little room for a technical question related to radio please? If so, here goes: How does one measure the IF filter shape factor in a shortwave radio? I am technically minded and do have a signal generator, etc., but I am not sure of the exact procedure. Do I get the audio level at the peak frequency, then detune both sides off the peak for -3dB of the demodulated audio, note down the width between these points, then detune to obtain for -50dB of the demodulated audio, get the width at these points, and then the ratio of the two widths is the filter shape factor? I would appreciate a link to the exact procedure if there is one (don't seem to be able to find this in Google) or an expert advice please. I would also appreciate advice as to what actual values of filter shape are considered poor, good, excellent, etc... Thanks in advance, Michael Hi Michael, Although I have never given it much thought, I don't believe one can fully characterize a filter while it is installed in the receiver- certainly, parameters such as insertion loss would not be easily measurable. Perhaps programs like Spectran may give some rough insight. My method is classic- the filter is removed, properly terminated and connected as the DUT on a scalar network analyzer. If you have a vector network analyzer available you could also observe group delay- an important factor in narrow filters. See Paul Kiciak's (N2PK) site for his clever VNA- ideally suited for filters. Dale W4OP |
Measuring filter shape factor
On Wed, 11 Jan 2006 21:23:09 GMT, "Dale Parfitt"
wrote: "Michael Thorpe" wrote in message news:43c4e407.4277000@news-server... Amongst all these political propaganda posts, I wonder if there is a little room for a technical question related to radio please? If so, here goes: How does one measure the IF filter shape factor in a shortwave radio? I am technically minded and do have a signal generator, etc., but I am not sure of the exact procedure. Do I get the audio level at the peak frequency, then detune both sides off the peak for -3dB of the demodulated audio, note down the width between these points, then detune to obtain for -50dB of the demodulated audio, get the width at these points, and then the ratio of the two widths is the filter shape factor? I would appreciate a link to the exact procedure if there is one (don't seem to be able to find this in Google) or an expert advice please. I would also appreciate advice as to what actual values of filter shape are considered poor, good, excellent, etc... Thanks in advance, Michael Hi Michael, Although I have never given it much thought, I don't believe one can fully characterize a filter while it is installed in the receiver- certainly, parameters such as insertion loss would not be easily measurable. Perhaps programs like Spectran may give some rough insight. My method is classic- the filter is removed, properly terminated and connected as the DUT on a scalar network analyzer. If you have a vector network analyzer available you could also observe group delay- an important factor in narrow filters. See Paul Kiciak's (N2PK) site for his clever VNA- ideally suited for filters. Dale W4OP Look at the interstation atmospheric noise with a spectrum analyzer? |
Measuring filter shape factor
http://www.lazygranch.com/images/radio/cwfilter.gif
I did this test as follows: 1) radio in AM 2) AGC turned off 3) RF generator connector to antenna input 4) distortion analyzer connected to earphone output Pick a frequency. I used 10Mhz. Set the RF generator and radio to that frequency. Leave the radio dial alone. Sweep the RF generator manually and measure the audio level from the distortion analyser. Plot the results. This was a crystal filter, so you will need a RF generator with 1Hz steps. This is an in-situ measurement, i.e. this is not the same as just testing the IF filter by itself. You need the distortion analyzer to get the audio signal level independent from the noise. All that said, Bush should be impeached. Michael Thorpe wrote: Amongst all these political propaganda posts, I wonder if there is a little room for a technical question related to radio please? If so, here goes: How does one measure the IF filter shape factor in a shortwave radio? I am technically minded and do have a signal generator, etc., but I am not sure of the exact procedure. Do I get the audio level at the peak frequency, then detune both sides off the peak for -3dB of the demodulated audio, note down the width between these points, then detune to obtain for -50dB of the demodulated audio, get the width at these points, and then the ratio of the two widths is the filter shape factor? I would appreciate a link to the exact procedure if there is one (don't seem to be able to find this in Google) or an expert advice please. I would also appreciate advice as to what actual values of filter shape are considered poor, good, excellent, etc... Thanks in advance, Michael |
Measuring filter shape factor
On 11 Jan 2006 14:14:01 -0800, wrote:
http://www.lazygranch.com/images/radio/cwfilter.gif I did this test as follows: 1) radio in AM 2) AGC turned off 3) RF generator connector to antenna input 4) distortion analyzer connected to earphone output Pick a frequency. I used 10Mhz. Set the RF generator and radio to that frequency. Leave the radio dial alone. Sweep the RF generator manually and measure the audio level from the distortion analyser. Plot the results. This was a crystal filter, so you will need a RF generator with 1Hz steps. This is an in-situ measurement, i.e. this is not the same as just testing the IF filter by itself. You need the distortion analyzer to get the audio signal level independent from the noise. All that said, Bush should be impeached. Can't you just use the random pink noise between stations, rather than a sweep generator? |
Measuring filter shape factor
Michael Thorpe wrote: Amongst all these political propaganda posts, I wonder if there is a little room for a technical question related to radio please? If so, here goes: How does one measure the IF filter shape factor in a shortwave radio? I am technically minded and do have a signal generator, etc., but I am not sure of the exact procedure. Do I get the audio level at the peak frequency, then detune both sides off the peak for -3dB of the demodulated audio, note down the width between these points, then detune to obtain for -50dB of the demodulated audio, get the width at these points, and then the ratio of the two widths is the filter shape factor? I would appreciate a link to the exact procedure if there is one (don't seem to be able to find this in Google) or an expert advice please. I would also appreciate advice as to what actual values of filter shape are considered poor, good, excellent, etc... Thanks in advance, Michael You need to generate a swept frequency response of the IF filter Take a look at the following article on filter selectivity: http://www.radio-electronics.com/inf...electivity.php The shape factor is traditionally defined as BW(-60dB) SF =--------------- BW(-6dB) (see the third figure in the article illustrating a typical filter response and the meaning of the two bandwidths) For an ideal filter (see second figure), this bandwidth ratio would be equal to ONE (1.0). The closer the shape factor is to 1.0, the sharper the selectivity. For example, if you look at the specs for the Eton E1 on the following link (Monitoring Times review) http://www.monitoringtimes.com/html/...k-etone1xm.pdf the shape factor for the 7 KHz filter would be: SF = 12 KHz/7 KHz = 1.71 (not a very sharp filter, but not bad for a radio of this type) The other two filters have even worse shape factors. With DSP receivers, these filters can be made extremely tight and shape factors can be very close to 1.0. Hope this is helpful. Perhaps Pete can chime in with a detailed measurement procedure. RK |
Measuring filter shape factor
Sine-wave measurements are more precise. My test is very close to real
life since it is testing the entire signal path, i.e. from antenna input to audio output. I couldn't find the connector I made that taps the line output, so I used the earphone output. I have audio test gear that uses random noise with FFT analysis, in addition to a swept sine. You always get more accurate results with a swept sine. FFT analysis is only used when you need speed. As you will notice from the graphical output, the noise floor is quite high. I may do the test again BTW, you need a decent distortion analyser for David wrote: On 11 Jan 2006 14:14:01 -0800, wrote: http://www.lazygranch.com/images/radio/cwfilter.gif I did this test as follows: 1) radio in AM 2) AGC turned off 3) RF generator connector to antenna input 4) distortion analyzer connected to earphone output Pick a frequency. I used 10Mhz. Set the RF generator and radio to that frequency. Leave the radio dial alone. Sweep the RF generator manually and measure the audio level from the distortion analyser. Plot the results. This was a crystal filter, so you will need a RF generator with 1Hz steps. This is an in-situ measurement, i.e. this is not the same as just testing the IF filter by itself. You need the distortion analyzer to get the audio signal level independent from the noise. All that said, Bush should be impeached. Can't you just use the random pink noise between stations, rather than a sweep generator? |
Measuring filter shape factor
At the time I did my test, I had a "hole" in my generators. The audio
gear went as high as 100k, and the RF gear went as low at 1Mhz, but the IF was 455Khz. Hence I tested the whole audio path. The impedances in the radio itself will effect the performance of the filter, so there is something to be said for in-situ measurements. Oh yeah, note that Abramoff didn't donate any money to the Democrats. rkhalona wrote: Michael Thorpe wrote: Amongst all these political propaganda posts, I wonder if there is a little room for a technical question related to radio please? If so, here goes: How does one measure the IF filter shape factor in a shortwave radio? I am technically minded and do have a signal generator, etc., but I am not sure of the exact procedure. Do I get the audio level at the peak frequency, then detune both sides off the peak for -3dB of the demodulated audio, note down the width between these points, then detune to obtain for -50dB of the demodulated audio, get the width at these points, and then the ratio of the two widths is the filter shape factor? I would appreciate a link to the exact procedure if there is one (don't seem to be able to find this in Google) or an expert advice please. I would also appreciate advice as to what actual values of filter shape are considered poor, good, excellent, etc... Thanks in advance, Michael You need to generate a swept frequency response of the IF filter Take a look at the following article on filter selectivity: http://www.radio-electronics.com/inf...electivity.php The shape factor is traditionally defined as BW(-60dB) SF =--------------- BW(-6dB) (see the third figure in the article illustrating a typical filter response and the meaning of the two bandwidths) For an ideal filter (see second figure), this bandwidth ratio would be equal to ONE (1.0). The closer the shape factor is to 1.0, the sharper the selectivity. For example, if you look at the specs for the Eton E1 on the following link (Monitoring Times review) http://www.monitoringtimes.com/html/...k-etone1xm.pdf the shape factor for the 7 KHz filter would be: SF = 12 KHz/7 KHz = 1.71 (not a very sharp filter, but not bad for a radio of this type) The other two filters have even worse shape factors. With DSP receivers, these filters can be made extremely tight and shape factors can be very close to 1.0. Hope this is helpful. Perhaps Pete can chime in with a detailed measurement procedure. RK |
Measuring filter shape factor
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Measuring filter shape factor
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Measuring filter shape factor
Michael Thorpe wrote:
Amongst all these political propaganda posts, I wonder if there is a little room for a technical question related to radio please? If so, here goes: How does one measure the IF filter shape factor in a shortwave radio? I am technically minded and do have a signal generator, etc., but I am not sure of the exact procedure. Do I get the audio level at the peak frequency, then detune both sides off the peak for -3dB of the demodulated audio, note down the width between these points, then detune to obtain for -50dB of the demodulated audio, get the width at these points, and then the ratio of the two widths is the filter shape factor? I would appreciate a link to the exact procedure if there is one (don't seem to be able to find this in Google) or an expert advice please. I would also appreciate advice as to what actual values of filter shape are considered poor, good, excellent, etc... Thanks in advance, Michael Michael: If you don't have a spectrum analyzer, you can use an oscope (setup for x-y) while driving the filter (and x ) with a sweep function generator. Remember that if you look at the IF output prior to the detector, you will get a curve going positive and negative. If you look at the response after the detector, it will look more like the IF filter shape that you expect. -- Brian Denley http://home.comcast.net/~b.denley/index.html |
Measuring filter shape factor
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Measuring filter shape factor
check this page out:
http://www.radio-electronics.com/inf...electivity.php "Michael Thorpe" wrote in message news:43c4e407.4277000@news-server... Amongst all these political propaganda posts, I wonder if there is a little room for a technical question related to radio please? If so, here goes: How does one measure the IF filter shape factor in a shortwave radio? I am technically minded and do have a signal generator, etc., but I am not sure of the exact procedure. Do I get the audio level at the peak frequency, then detune both sides off the peak for -3dB of the demodulated audio, note down the width between these points, then detune to obtain for -50dB of the demodulated audio, get the width at these points, and then the ratio of the two widths is the filter shape factor? I would appreciate a link to the exact procedure if there is one (don't seem to be able to find this in Google) or an expert advice please. I would also appreciate advice as to what actual values of filter shape are considered poor, good, excellent, etc... Thanks in advance, Michael |
Measuring filter shape factor
Good web page.....................I throw them on a network analyzer when I
want to measure them, but there are some pretty good ideas here. Pete "mike maghakian" wrote in message ... check this page out: http://www.radio-electronics.com/inf...electivity.php "Michael Thorpe" wrote in message news:43c4e407.4277000@news-server... Amongst all these political propaganda posts, I wonder if there is a little room for a technical question related to radio please? If so, here goes: How does one measure the IF filter shape factor in a shortwave radio? I am technically minded and do have a signal generator, etc., but I am not sure of the exact procedure. Do I get the audio level at the peak frequency, then detune both sides off the peak for -3dB of the demodulated audio, note down the width between these points, then detune to obtain for -50dB of the demodulated audio, get the width at these points, and then the ratio of the two widths is the filter shape factor? I would appreciate a link to the exact procedure if there is one (don't seem to be able to find this in Google) or an expert advice please. I would also appreciate advice as to what actual values of filter shape are considered poor, good, excellent, etc... Thanks in advance, Michael |
Measuring filter shape factor
I'm a National Review subscriber. Really. However, I don't read the
on-line version as it is routinely disinformation, i.e. articles that don't make it to the magazine. If you subscribe to the magazine, they will print retractions of what appears online. I will say at NR is the only conservative mag worth reading. They never stooped to the level of say the Spectator. David wrote: On 11 Jan 2006 17:23:37 -0800, wrote: At the time I did my test, I had a "hole" in my generators. The audio gear went as high as 100k, and the RF gear went as low at 1Mhz, but the IF was 455Khz. Hence I tested the whole audio path. The impedances in the radio itself will effect the performance of the filter, so there is something to be said for in-situ measurements. Oh yeah, note that Abramoff didn't donate any money to the Democrats. Read Rich Lowrie's latest editorial at National Review Online. |
Measuring filter shape factor
On Wed, 11 Jan 2006 21:23:09 GMT, "Dale Parfitt"
wrote: "Michael Thorpe" wrote in message news:43c4e407.4277000@news-server... Amongst all these political propaganda posts, I wonder if there is a little room for a technical question related to radio please? If so, here goes: How does one measure the IF filter shape factor in a shortwave radio? I am technically minded and do have a signal generator, etc., but I am not sure of the exact procedure. Do I get the audio level at the peak frequency, then detune both sides off the peak for -3dB of the demodulated audio, note down the width between these points, then detune to obtain for -50dB of the demodulated audio, get the width at these points, and then the ratio of the two widths is the filter shape factor? I would appreciate a link to the exact procedure if there is one (don't seem to be able to find this in Google) or an expert advice please. I would also appreciate advice as to what actual values of filter shape are considered poor, good, excellent, etc... Thanks in advance, Michael Hi Michael, Although I have never given it much thought, I don't believe one can fully characterize a filter while it is installed in the receiver- certainly, parameters such as insertion loss would not be easily measurable. Perhaps programs like Spectran may give some rough insight. My method is classic- the filter is removed, properly terminated and connected as the DUT on a scalar network analyzer. If you have a vector network analyzer available you could also observe group delay- an important factor in narrow filters. See Paul Kiciak's (N2PK) site for his clever VNA- ideally suited for filters. Dale W4OP Thanks, Dale, for your input. I would have no problems measuring filters when taken out of a receiver. But this is not always possible, for example with modern DSP software-defined receivers. There you have no choice, the filter is no longer just a component you can desolder, so you do need to measure the entire receiver. Parameters such as insertion loss is immaterial in such cases - all that matters is the filter shape. Michael |
Measuring filter shape factor
On 11 Jan 2006 14:14:01 -0800, wrote:
http://www.lazygranch.com/images/radio/cwfilter.gif I did this test as follows: 1) radio in AM 2) AGC turned off 3) RF generator connector to antenna input 4) distortion analyzer connected to earphone output Pick a frequency. I used 10Mhz. Set the RF generator and radio to that frequency. Leave the radio dial alone. Sweep the RF generator manually and measure the audio level from the distortion analyser. Plot the results. This was a crystal filter, so you will need a RF generator with 1Hz steps. This is an in-situ measurement, i.e. this is not the same as just testing the IF filter by itself. You need the distortion analyzer to get the audio signal level independent from the noise. Many thanks, this is interesting. What I am still unsure about is how you determine the -6dB and -60dB points using the distortion analyzer: When you say "measure the audio level", what exactly do you measure, the audio signal fundamental (i.e. filtered at the modulation frequency)? So in fact you are only using the distortion analyzer to filter the audio and to measure the level? I don't have a distortion analyzer, but I guess I could simply use an oscilloscope or an audio spectrum analyzer (PC sound card based). Michael |
Measuring filter shape factor
On 11 Jan 2006 21:06:53 -0800, wrote:
I'm a National Review subscriber. Really. However, I don't read the on-line version as it is routinely disinformation, i.e. articles that don't make it to the magazine. If you subscribe to the magazine, they will print retractions of what appears online. I will say at NR is the only conservative mag worth reading. They never stooped to the level of say the Spectator. David wrote: On 11 Jan 2006 17:23:37 -0800, wrote: At the time I did my test, I had a "hole" in my generators. The audio gear went as high as 100k, and the RF gear went as low at 1Mhz, but the IF was 455Khz. Hence I tested the whole audio path. The impedances in the radio itself will effect the performance of the filter, so there is something to be said for in-situ measurements. Oh yeah, note that Abramoff didn't donate any money to the Democrats. Read Rich Lowrie's latest editorial at National Review Online. He says the Abramoff scandal is 100% Republicans. |
Measuring filter shape factor
In article 43c63d58.6926500@news-server,
Michael Thorpe wrote: On Wed, 11 Jan 2006 21:23:09 GMT, "Dale Parfitt" wrote: "Michael Thorpe" wrote in message news:43c4e407.4277000@news-server... Amongst all these political propaganda posts, I wonder if there is a little room for a technical question related to radio please? If so, here goes: How does one measure the IF filter shape factor in a shortwave radio? I am technically minded and do have a signal generator, etc., but I am not sure of the exact procedure. Do I get the audio level at the peak frequency, then detune both sides off the peak for -3dB of the demodulated audio, note down the width between these points, then detune to obtain for -50dB of the demodulated audio, get the width at these points, and then the ratio of the two widths is the filter shape factor? I would appreciate a link to the exact procedure if there is one (don't seem to be able to find this in Google) or an expert advice please. I would also appreciate advice as to what actual values of filter shape are considered poor, good, excellent, etc... Although I have never given it much thought, I don't believe one can fully characterize a filter while it is installed in the receiver- certainly, parameters such as insertion loss would not be easily measurable. Perhaps programs like Spectran may give some rough insight. My method is classic- the filter is removed, properly terminated and connected as the DUT on a scalar network analyzer. If you have a vector network analyzer available you could also observe group delay- an important factor in narrow filters. See Paul Kiciak's (N2PK) site for his clever VNA- ideally suited for filters. Thanks, Dale, for your input. I would have no problems measuring filters when taken out of a receiver. But this is not always possible, for example with modern DSP software-defined receivers. There you have no choice, the filter is no longer just a component you can desolder, so you do need to measure the entire receiver. Parameters such as insertion loss is immaterial in such cases - all that matters is the filter shape. But when the whole system is put together, it's no longer "filter shape factor", it's some other parameter, "adjacent signal rejection" or something like that. Mark Zenier Googleproofaddress(account:mzenier provider:eskimo domain:com) |
Measuring filter shape factor
David wrote:
On 11 Jan 2006 21:06:53 -0800, wrote: Read Rich Lowrie's latest editorial at National Review Online. He says the Abramoff scandal is 100% Republicans. Then he's stupid, or ignorant, or lying. 40 out of 45 Senate Democrats got money from Abramoff. Senator John Kerry (D-MA) received at least $98,550 in Abramoff-linked cash. Senator Harry Reid (D-NV) received at least $68,941 in Abramoff-linked cash. Senator Tom Harkin (D-IA) received at least $45,750 in Abramoff-linked cash. Senator Hillary Clinton (D-NY) received at least $12,950 in Abramoff-linked cash. Senator Patty Murray (D-WA) received at least $78,991 in Abramoff-linked cash. Senator Chuck Schumer (D-NY) received at least $29,550 in Abramoff-linked cash. Senator Debbie Stabenow (D-MI) received at least $6,250 in Abramoff-linked cash. Senator Max Baucus (D-MT) received at least $22,500 in Abramoff-linked cash. Senator Evan Bayh (D-IN) received at least $6,500 in Abramoff-linked cash. Senator Joseph Biden (D-DE) received at least $1,250 in Abramoff-linked cash. Senator Jeff Bingaman (D-NM) received at least $2,000 in Abramoff-linked cash. Senator Barbara Boxer (D-CA) received at least $20,250 in Abramoff-linked cash. Senator Maria Cantwell (D-WA) received at least $21,765 in Abramoff-linked cash. Senator Tom Carper (D-DE) received at least $7,500 in Abramoff-linked cash. Senator Kent Conrad (D-ND) received at least $8,000 in Abramoff-linked cash. Senator Jon Corzine (D-NJ) received at least $7,500 in Abramoff-linked cash. Senator Chris Dodd (D-CT) received at least $14,792 in Abramoff-linked cash. Senator Byron Dorgan (D-ND) received at least $79,300 in Abramoff-linked cash. Senator Dick Durbin (D-IL) received at least $14,000 in Abramoff-linked cash. Senator Dianne Feinstein (D-CA) received at least $2,000 in Abramoff-linked cash. Senator Russ Feingold (D-WI) received at least $1,250 in Abramoff-linked cash. Senator Daniel Inouye (D-HI) received at least $9,000 in Abramoff-linked cash. Senator Jim Jeffords (I-VT) received at least $2,000 in Abramoff-linked cash. Senator Tim Johnson (D-SD) received at least $14,250 in Abramoff-linked cash. Senator Ted Kennedy (D-MA) received at least $3,300 in Abramoff-linked cash. Senator Mary Landrieu (D-LA) received at least $28,000 in Abramoff-linked cash. Senator Pat Leahy (D-VT) received at least $4,000 in Abramoff-linked cash. Senator Carl Levin (D-MI) received at least $6,000 in Abramoff-linked cash. Senator Joe Lieberman (D-CT) received at least $29,830 in Abramoff-linked cash. Senator Blanche Lincoln (D-AR) Received At Least $14,891 in Abramoff-linked cash. Senator Barbara Mikulski (D-MD) received at least $10,550 in Abramoff-linked cash. Senator Bill Nelson (D-FL) received at least $20,168 in Abramoff-linked cash. Senator Ben Nelson (D-NE) Received At Least $5,200 in Abramoff-linked cash. Senator Barack Obama (D-IL) received at least $7,500 in Abramoff-linked cash. Senator Mark Pryor (D-AR) received at least $2,300 in Abramoff-linked cash. Senator Jack Reed (D-RI) received at least $3,500 in Abramoff-linked cash. Senator John Rockefeller (D-WV) received at least $4,000 in Abramoff-linked cash. Senator Ken Salazar (D-CO) received at least $4,500 in Abramoff-linked cash. Senator Paul Sarbanes (D-MD) received at least $4,300 in Abramoff-linked cash. Senator Ron Wyden (D-OR) received at least $6,250 in Abramoff-linked cash. -- If John McCain gets the 2008 Republican Presidential nomination, my vote for President will be a write-in for Jiang Zemin. |
Measuring filter shape factor
There is a difference between getting money from tribes, and getting
money from Abramoff. You should switch from kool-aid to beer. clifto wrote: David wrote: On 11 Jan 2006 21:06:53 -0800, wrote: Read Rich Lowrie's latest editorial at National Review Online. He says the Abramoff scandal is 100% Republicans. Then he's stupid, or ignorant, or lying. 40 out of 45 Senate Democrats got money from Abramoff. Senator John Kerry (D-MA) received at least $98,550 in Abramoff-linked cash. Senator Harry Reid (D-NV) received at least $68,941 in Abramoff-linked cash. Senator Tom Harkin (D-IA) received at least $45,750 in Abramoff-linked cash. Senator Hillary Clinton (D-NY) received at least $12,950 in Abramoff-linked cash. Senator Patty Murray (D-WA) received at least $78,991 in Abramoff-linked cash. Senator Chuck Schumer (D-NY) received at least $29,550 in Abramoff-linked cash. Senator Debbie Stabenow (D-MI) received at least $6,250 in Abramoff-linked cash. Senator Max Baucus (D-MT) received at least $22,500 in Abramoff-linked cash. Senator Evan Bayh (D-IN) received at least $6,500 in Abramoff-linked cash. Senator Joseph Biden (D-DE) received at least $1,250 in Abramoff-linked cash. Senator Jeff Bingaman (D-NM) received at least $2,000 in Abramoff-linked cash. Senator Barbara Boxer (D-CA) received at least $20,250 in Abramoff-linked cash. Senator Maria Cantwell (D-WA) received at least $21,765 in Abramoff-linked cash. Senator Tom Carper (D-DE) received at least $7,500 in Abramoff-linked cash. Senator Kent Conrad (D-ND) received at least $8,000 in Abramoff-linked cash. Senator Jon Corzine (D-NJ) received at least $7,500 in Abramoff-linked cash. Senator Chris Dodd (D-CT) received at least $14,792 in Abramoff-linked cash. Senator Byron Dorgan (D-ND) received at least $79,300 in Abramoff-linked cash. Senator Dick Durbin (D-IL) received at least $14,000 in Abramoff-linked cash. Senator Dianne Feinstein (D-CA) received at least $2,000 in Abramoff-linked cash. Senator Russ Feingold (D-WI) received at least $1,250 in Abramoff-linked cash. Senator Daniel Inouye (D-HI) received at least $9,000 in Abramoff-linked cash. Senator Jim Jeffords (I-VT) received at least $2,000 in Abramoff-linked cash. Senator Tim Johnson (D-SD) received at least $14,250 in Abramoff-linked cash. Senator Ted Kennedy (D-MA) received at least $3,300 in Abramoff-linked cash. Senator Mary Landrieu (D-LA) received at least $28,000 in Abramoff-linked cash. Senator Pat Leahy (D-VT) received at least $4,000 in Abramoff-linked cash. Senator Carl Levin (D-MI) received at least $6,000 in Abramoff-linked cash. Senator Joe Lieberman (D-CT) received at least $29,830 in Abramoff-linked cash. Senator Blanche Lincoln (D-AR) Received At Least $14,891 in Abramoff-linked cash. Senator Barbara Mikulski (D-MD) received at least $10,550 in Abramoff-linked cash. Senator Bill Nelson (D-FL) received at least $20,168 in Abramoff-linked cash. Senator Ben Nelson (D-NE) Received At Least $5,200 in Abramoff-linked cash. Senator Barack Obama (D-IL) received at least $7,500 in Abramoff-linked cash. Senator Mark Pryor (D-AR) received at least $2,300 in Abramoff-linked cash. Senator Jack Reed (D-RI) received at least $3,500 in Abramoff-linked cash. Senator John Rockefeller (D-WV) received at least $4,000 in Abramoff-linked cash. Senator Ken Salazar (D-CO) received at least $4,500 in Abramoff-linked cash. Senator Paul Sarbanes (D-MD) received at least $4,300 in Abramoff-linked cash. Senator Ron Wyden (D-OR) received at least $6,250 in Abramoff-linked cash. -- If John McCain gets the 2008 Republican Presidential nomination, my vote for President will be a write-in for Jiang Zemin. |
Measuring filter shape factor
The distortion analyzer has a tracking bandpass filter. I'm using the
HP8903E, but for this purpose, even the 334B would do the trick. You can use the analyzer to display the signal level of the sine wave inpedentent of noise to the degree the bandpass filter can remove it. [The 8903E reads amplitude, distortion, and frequency.] I never reached the -60db point, because the signal was lost in the noise. But you have to ask yourself, if the signal is in the noise, you do care about the rejection? In the dark ages, I was designing switched capacitor filters for modem products. When you sold the chip as a Bell standard filter, you had to implement that exact filter. However, the reality was the noise floor and THD totally negated the effectiveness of the filter. [Power supply rejection is a factor too.] So yeah, I could attenuate the alternate (out of band) channel, but the filter noise was more significant than what I was attenuating. Once the product became integrated, nobody could see the filter implementation. The amount of filtering was reduced to a level where the alternate channel (out of band) signal level was minimum by picking a compromise between the number of poles of filtering and the noise level of the amplifiers. Less poles of filtering meant fewer all passes were required. Now I'm not happy the noise floor of the radio crapped out at around -45db. I don't know if measuring at the line outputs would have been better. I need to do the measurement again. It is quite possible that you can use your sound card to measure the amplitude of the signal independent of the noise. BTW, I should have mentioned I turned on the 1khz modulation on the RF signal generator. My goal was to test a crystal filter I picked up at the flea market and installed in my radio. [A good deal at $10.] One thing I learned is the coupling capacitors make a difference in terms of the signal level. I'd have to open the radio to see what I used, but I recall if the caps were too small, the signal level was attenuated. Michael Thorpe wrote: On 11 Jan 2006 14:14:01 -0800, wrote: http://www.lazygranch.com/images/radio/cwfilter.gif I did this test as follows: 1) radio in AM 2) AGC turned off 3) RF generator connector to antenna input 4) distortion analyzer connected to earphone output Pick a frequency. I used 10Mhz. Set the RF generator and radio to that frequency. Leave the radio dial alone. Sweep the RF generator manually and measure the audio level from the distortion analyser. Plot the results. This was a crystal filter, so you will need a RF generator with 1Hz steps. This is an in-situ measurement, i.e. this is not the same as just testing the IF filter by itself. You need the distortion analyzer to get the audio signal level independent from the noise. Many thanks, this is interesting. What I am still unsure about is how you determine the -6dB and -60dB points using the distortion analyzer: When you say "measure the audio level", what exactly do you measure, the audio signal fundamental (i.e. filtered at the modulation frequency)? So in fact you are only using the distortion analyzer to filter the audio and to measure the level? I don't have a distortion analyzer, but I guess I could simply use an oscilloscope or an audio spectrum analyzer (PC sound card based). Michael |
Measuring filter shape factor
How exactly does one see 60db down?
Brian Denley wrote: Michael Thorpe wrote: Amongst all these political propaganda posts, I wonder if there is a little room for a technical question related to radio please? If so, here goes: How does one measure the IF filter shape factor in a shortwave radio? I am technically minded and do have a signal generator, etc., but I am not sure of the exact procedure. Do I get the audio level at the peak frequency, then detune both sides off the peak for -3dB of the demodulated audio, note down the width between these points, then detune to obtain for -50dB of the demodulated audio, get the width at these points, and then the ratio of the two widths is the filter shape factor? I would appreciate a link to the exact procedure if there is one (don't seem to be able to find this in Google) or an expert advice please. I would also appreciate advice as to what actual values of filter shape are considered poor, good, excellent, etc... Thanks in advance, Michael Michael: If you don't have a spectrum analyzer, you can use an oscope (setup for x-y) while driving the filter (and x ) with a sweep function generator. Remember that if you look at the IF output prior to the detector, you will get a curve going positive and negative. If you look at the response after the detector, it will look more like the IF filter shape that you expect. -- Brian Denley http://home.comcast.net/~b.denley/index.html |
[OT] Measuring filter shape factor
wrote:
clifto wrote: David wrote: On 11 Jan 2006 21:06:53 -0800, wrote: Read Rich Lowrie's latest editorial at National Review Online. He says the Abramoff scandal is 100% Republicans. Then he's stupid, or ignorant, or lying. 40 out of 45 Senate Democrats got money from Abramoff. There is a difference between getting money from tribes, and getting money from Abramoff. You should switch from kool-aid to beer. It took me all of 120 seconds to find this in the liberal Chicago Tribune: http://www.chicagotribune.com/news/local/southsouthwest/chi-0601110210jan11,1,5780990.story?coll=chi-newslocalssouthwest-hed "Kennedy on Tuesday also explained why Weller used $1,640 of his own money to reimburse a lobbying firm where Abramoff once worked for a 1999 trip to two Indian reservations in Louisiana and Mississippi. "He visited those reservations at the request of former U.S. Rep. David Funderburk (R-N.C.), and THOUGHT THE TRIBES HAD PAID FOR THE TRIP [emphasis by clifto], Kennedy said. As soon as he confirmed otherwise, he repaid the money from his own pocket, he said." Here's one from liberal rag UnionLeader.com: http://www.theunionleader.com/article.aspx?headline=Sullivan+defends+Democrats+k eeping+lobbyist%E2%80%99s+money&articleId=c0963d8c-692b-47e6-b316-f42c8053aeef "Top Democrats received donations from scandal-plagued Washington lobbyist Jack Abramoff?s Indian tribe clients for legitimate reasons and are right to refuse to give up the money, the state?s Democratic chairman says." I bet if I took the time to search further, which I'm not going to bother doing, I could find *tribal* money going to Democrats via Abramoff in mass quantities. Note that unlike most of the Republicans involved, Kennedy and Reid have no intention of giving the money back or giving it to charity. They're keeping it. -- If John McCain gets the 2008 Republican Presidential nomination, my vote for President will be a write-in for Jiang Zemin. |
[OT] Measuring filter shape factor
On Thu, 12 Jan 2006 16:00:51 -0600, clifto wrote:
wrote: clifto wrote: David wrote: On 11 Jan 2006 21:06:53 -0800, wrote: Read Rich Lowrie's latest editorial at National Review Online. He says the Abramoff scandal is 100% Republicans. Then he's stupid, or ignorant, or lying. 40 out of 45 Senate Democrats got money from Abramoff. There is a difference between getting money from tribes, and getting money from Abramoff. You should switch from kool-aid to beer. It took me all of 120 seconds to find this in the liberal Chicago Tribune: http://www.chicagotribune.com/news/local/southsouthwest/chi-0601110210jan11,1,5780990.story?coll=chi-newslocalssouthwest-hed But the Indians didn't work for Abramoff. |
Measuring filter shape factor
|
Measuring filter shape factor
In article 43c63f8a.7487750@news-server,
(Michael Thorpe) wrote: On 11 Jan 2006 14:14:01 -0800, wrote: http://www.lazygranch.com/images/radio/cwfilter.gif I did this test as follows: 1) radio in AM 2) AGC turned off 3) RF generator connector to antenna input 4) distortion analyzer connected to earphone output Pick a frequency. I used 10Mhz. Set the RF generator and radio to that frequency. Leave the radio dial alone. Sweep the RF generator manually and measure the audio level from the distortion analyser. Plot the results. This was a crystal filter, so you will need a RF generator with 1Hz steps. This is an in-situ measurement, i.e. this is not the same as just testing the IF filter by itself. You need the distortion analyzer to get the audio signal level independent from the noise. Many thanks, this is interesting. What I am still unsure about is how you determine the -6dB and -60dB points using the distortion analyzer: When you say "measure the audio level", what exactly do you measure, the audio signal fundamental (i.e. filtered at the modulation frequency)? So in fact you are only using the distortion analyzer to filter the audio and to measure the level? I don't have a distortion analyzer, but I guess I could simply use an oscilloscope or an audio spectrum analyzer (PC sound card based). rkhalona gave you the right definition of shape factor and a web page that explains it. BW(-60dB) SF =--------------- BW(-6dB) http://www.radio-electronics.com/inf...ty/selectivity. php The audio passband is often but not always defined at the IF stage with a IF passband filter. The -6dB and -60dB is referenced to the filter center IF frequency of 0dB. The filter is usually symmetrical and the SF number refers to how fast the slope changes. Steeper is better. The -6dB down point is usually considered the bandwidth of the filter. With what you have the easiest thing to do would be to use the PC audio spectrum analyzer. On a strong signal playing music use a max hold function on the analyzer software and the passband of the filter should become apparent. Look at where the high end response rolls off 6dB down relative to what looks like a flat audio spectrum from low to middle audio frequencies. Where the high frequencies roll of 6dB down from the flat audio response range will be 1/2 the filter bandwidth. For this to work the station you have are receiving must be have a wider modulation bandwidth then you are using for an audio bandwidth filter so this may only work for narrow filters. If this does not work well enough then you will need an RF generator that you can modulate at a frequency higher than the largest filter you want to measure and use the PC analyzer as described above. -- Telamon Ventura, California |
Measuring filter shape factor
In article ,
"Brian Denley" wrote: wrote: How exactly does one see 60db down? Very carefully! Things start getting pretty dark after 40dB down so be very careful! -- Telamon Ventura, California |
Measuring filter shape factor
On Fri, 13 Jan 2006 04:47:07 GMT, Telamon
wrote: In article 43c63f8a.7487750@news-server, (Michael Thorpe) wrote: On 11 Jan 2006 14:14:01 -0800, wrote: http://www.lazygranch.com/images/radio/cwfilter.gif I did this test as follows: 1) radio in AM 2) AGC turned off 3) RF generator connector to antenna input 4) distortion analyzer connected to earphone output Pick a frequency. I used 10Mhz. Set the RF generator and radio to that frequency. Leave the radio dial alone. Sweep the RF generator manually and measure the audio level from the distortion analyser. Plot the results. This was a crystal filter, so you will need a RF generator with 1Hz steps. This is an in-situ measurement, i.e. this is not the same as just testing the IF filter by itself. You need the distortion analyzer to get the audio signal level independent from the noise. Many thanks, this is interesting. What I am still unsure about is how you determine the -6dB and -60dB points using the distortion analyzer: When you say "measure the audio level", what exactly do you measure, the audio signal fundamental (i.e. filtered at the modulation frequency)? So in fact you are only using the distortion analyzer to filter the audio and to measure the level? I don't have a distortion analyzer, but I guess I could simply use an oscilloscope or an audio spectrum analyzer (PC sound card based). rkhalona gave you the right definition of shape factor and a web page that explains it. BW(-60dB) SF =--------------- BW(-6dB) http://www.radio-electronics.com/inf...ty/selectivity. php The audio passband is often but not always defined at the IF stage with a IF passband filter. The -6dB and -60dB is referenced to the filter center IF frequency of 0dB. The filter is usually symmetrical and the SF number refers to how fast the slope changes. Steeper is better. The -6dB down point is usually considered the bandwidth of the filter. With what you have the easiest thing to do would be to use the PC audio spectrum analyzer. On a strong signal playing music use a max hold function on the analyzer software and the passband of the filter should become apparent. Look at where the high end response rolls off 6dB down relative to what looks like a flat audio spectrum from low to middle audio frequencies. Where the high frequencies roll of 6dB down from the flat audio response range will be 1/2 the filter bandwidth. For this to work the station you have are receiving must be have a wider modulation bandwidth then you are using for an audio bandwidth filter so this may only work for narrow filters. If this does not work well enough then you will need an RF generator that you can modulate at a frequency higher than the largest filter you want to measure and use the PC analyzer as described above. -- Telamon Ventura, California Yep, that's a very good method, thanks! To refine this, I might use a noise generator modulating a signal generator (instead of using a station music). This should show the passband nicer and more steady, I think. I do have a signal generator, and I guess I could make a noise generator using a Zener diode followed by an amplifier. Let's see... Thanks again. Michael |
Measuring filter shape factor
On 12 Jan 2006 12:00:25 -0800, wrote:
The distortion analyzer has a tracking bandpass filter. I'm using the HP8903E, but for this purpose, even the 334B would do the trick. You can use the analyzer to display the signal level of the sine wave inpedentent of noise to the degree the bandpass filter can remove it. [The 8903E reads amplitude, distortion, and frequency.] I never reached the -60db point, because the signal was lost in the noise. But you have to ask yourself, if the signal is in the noise, you do care about the rejection? Well I agree, but the point it is that I would like to be able to compare my results to the actual manufactures' specifications of the shape factor for various receivers. So if everyone defines the shape factor as BW(-6dB)/BW(-60dB), then somehow I need to be able to measure this. But I think I now have enough input from this group to be able to do this. Thank you very much for your help. In the dark ages, I was designing switched capacitor filters for modem products. When you sold the chip as a Bell standard filter, you had to implement that exact filter. However, the reality was the noise floor and THD totally negated the effectiveness of the filter. [Power supply rejection is a factor too.] So yeah, I could attenuate the alternate (out of band) channel, but the filter noise was more significant than what I was attenuating. Once the product became integrated, nobody could see the filter implementation. The amount of filtering was reduced to a level where the alternate channel (out of band) signal level was minimum by picking a compromise between the number of poles of filtering and the noise level of the amplifiers. Less poles of filtering meant fewer all passes were required. Now I'm not happy the noise floor of the radio crapped out at around -45db. I don't know if measuring at the line outputs would have been better. I need to do the measurement again. It is quite possible that you can use your sound card to measure the amplitude of the signal independent of the noise. BTW, I should have mentioned I turned on the 1khz modulation on the RF signal generator. My goal was to test a crystal filter I picked up at the flea market and installed in my radio. [A good deal at $10.] One thing I learned is the coupling capacitors make a difference in terms of the signal level. I'd have to open the radio to see what I used, but I recall if the caps were too small, the signal level was attenuated. Michael Thorpe wrote: On 11 Jan 2006 14:14:01 -0800, wrote: http://www.lazygranch.com/images/radio/cwfilter.gif I did this test as follows: 1) radio in AM 2) AGC turned off 3) RF generator connector to antenna input 4) distortion analyzer connected to earphone output Pick a frequency. I used 10Mhz. Set the RF generator and radio to that frequency. Leave the radio dial alone. Sweep the RF generator manually and measure the audio level from the distortion analyser. Plot the results. This was a crystal filter, so you will need a RF generator with 1Hz steps. This is an in-situ measurement, i.e. this is not the same as just testing the IF filter by itself. You need the distortion analyzer to get the audio signal level independent from the noise. Many thanks, this is interesting. What I am still unsure about is how you determine the -6dB and -60dB points using the distortion analyzer: When you say "measure the audio level", what exactly do you measure, the audio signal fundamental (i.e. filtered at the modulation frequency)? So in fact you are only using the distortion analyzer to filter the audio and to measure the level? I don't have a distortion analyzer, but I guess I could simply use an oscilloscope or an audio spectrum analyzer (PC sound card based). Michael |
Measuring filter shape factor
On Fri, 13 Jan 2006 05:10:44 GMT, Telamon
wrote: In article , "Brian Denley" wrote: wrote: How exactly does one see 60db down? Very carefully! Things start getting pretty dark after 40dB down so be very careful! -- Telamon Ventura, California Many thanks to everyone who invested their time and effort to help me with my filter shape measurement problem. Your advice has been very valuable to me and I am now back on track as a result. I will report what I'll find. Michael |
Measuring filter shape factor
I'm not sure why the XY display, but seeing 40db is about the limit.
You really need test equipment to get any meaningful results. Network analysers that cover a few MHz aren't that expensive. You can also just use a RF generator and power meter, which is a cheaper solution since you don't need phase measurements to see attenuation. Telamon wrote: In article , "Brian Denley" wrote: wrote: How exactly does one see 60db down? Very carefully! Things start getting pretty dark after 40dB down so be very careful! -- Telamon Ventura, California |
Measuring filter shape factor
wrote:
I'm not sure why the XY display, but seeing 40db is about the limit. You really need test equipment to get any meaningful results. Network analysers that cover a few MHz aren't that expensive. You can also just use a RF generator and power meter, which is a cheaper solution since you don't need phase measurements to see attenuation. If you DON'T have a spectrum analyzer (most don't) or if you DON'T have expensive test gear, a decent Oscope with x-y and a sweep generator can be used as a poor man's spectrum analyzer. 50 years ago, there was no other way to do it, in fact. If you look at, say, a Hammarlund receiver manual, that's exactly the recommended way to adjust the IF filter response curve. You don't have to go down to 60 db to see a bad shape factor. -- Brian Denley http://home.comcast.net/~b.denley/index.html |
Measuring filter shape factor
In article 43c76b90.3683890@news-server,
(Michael Thorpe) wrote: On Fri, 13 Jan 2006 04:47:07 GMT, Telamon wrote: In article 43c63f8a.7487750@news-server, (Michael Thorpe) wrote: On 11 Jan 2006 14:14:01 -0800, wrote: http://www.lazygranch.com/images/radio/cwfilter.gif I did this test as follows: 1) radio in AM 2) AGC turned off 3) RF generator connector to antenna input 4) distortion analyzer connected to earphone output Pick a frequency. I used 10Mhz. Set the RF generator and radio to that frequency. Leave the radio dial alone. Sweep the RF generator manually and measure the audio level from the distortion analyser. Plot the results. This was a crystal filter, so you will need a RF generator with 1Hz steps. This is an in-situ measurement, i.e. this is not the same as just testing the IF filter by itself. You need the distortion analyzer to get the audio signal level independent from the noise. Many thanks, this is interesting. What I am still unsure about is how you determine the -6dB and -60dB points using the distortion analyzer: When you say "measure the audio level", what exactly do you measure, the audio signal fundamental (i.e. filtered at the modulation frequency)? So in fact you are only using the distortion analyzer to filter the audio and to measure the level? I don't have a distortion analyzer, but I guess I could simply use an oscilloscope or an audio spectrum analyzer (PC sound card based). rkhalona gave you the right definition of shape factor and a web page that explains it. BW(-60dB) SF =--------------- BW(-6dB) http://www.radio-electronics.com/inf...ty/selectivity. php The audio passband is often but not always defined at the IF stage with a IF passband filter. The -6dB and -60dB is referenced to the filter center IF frequency of 0dB. The filter is usually symmetrical and the SF number refers to how fast the slope changes. Steeper is better. The -6dB down point is usually considered the bandwidth of the filter. With what you have the easiest thing to do would be to use the PC audio spectrum analyzer. On a strong signal playing music use a max hold function on the analyzer software and the passband of the filter should become apparent. Look at where the high end response rolls off 6dB down relative to what looks like a flat audio spectrum from low to middle audio frequencies. Where the high frequencies roll of 6dB down from the flat audio response range will be 1/2 the filter bandwidth. For this to work the station you have are receiving must be have a wider modulation bandwidth then you are using for an audio bandwidth filter so this may only work for narrow filters. If this does not work well enough then you will need an RF generator that you can modulate at a frequency higher than the largest filter you want to measure and use the PC analyzer as described above. -- Telamon Ventura, California Yep, that's a very good method, thanks! To refine this, I might use a noise generator modulating a signal generator (instead of using a station music). This should show the passband nicer and more steady, I think. I do have a signal generator, and I guess I could make a noise generator using a Zener diode followed by an amplifier. Let's see... You are welcome. If the PC audio analyzer has a max hold function and you modulate a an RF generator with a diode white noise source you will have the high frequency roll off in seconds. -- Telamon Ventura, California |
Measuring filter shape factor
"Once worked??" Many people have visited Germany, where Hilter once
waged world war. Thus anyone who has been to Germany is a Nazi. You can go to opensecrets.org and trace money given directly by Jack Abramoff. Hopefull this link will do the trick: http://www.opensecrets.org/indivs/search.asp?NumOfThou=0&txtName=abramoff%2C+jack&tx tState=%28all+states%29&txtZip=&txtEmploy=&txtCand =&txt2006=Y&txt2004=Y&txt2002=Y&Order=N I see Tom Delay, Ted Stevens, Elizabeth Dole, Arlen Spector, etc. clifto wrote: wrote: clifto wrote: David wrote: On 11 Jan 2006 21:06:53 -0800, wrote: Read Rich Lowrie's latest editorial at National Review Online. He says the Abramoff scandal is 100% Republicans. Then he's stupid, or ignorant, or lying. 40 out of 45 Senate Democrats got money from Abramoff. There is a difference between getting money from tribes, and getting money from Abramoff. You should switch from kool-aid to beer. It took me all of 120 seconds to find this in the liberal Chicago Tribune: http://www.chicagotribune.com/news/local/southsouthwest/chi-0601110210jan11,1,5780990.story?coll=chi-newslocalssouthwest-hed "Kennedy on Tuesday also explained why Weller used $1,640 of his own money to reimburse a lobbying firm where Abramoff once worked for a 1999 trip to two Indian reservations in Louisiana and Mississippi. "He visited those reservations at the request of former U.S. Rep. David Funderburk (R-N.C.), and THOUGHT THE TRIBES HAD PAID FOR THE TRIP [emphasis by clifto], Kennedy said. As soon as he confirmed otherwise, he repaid the money from his own pocket, he said." Here's one from liberal rag UnionLeader.com: http://www.theunionleader.com/article.aspx?headline=Sullivan+defends+Democrats+k eeping+lobbyist%E2%80%99s+money&articleId=c0963d8c-692b-47e6-b316-f42c8053aeef "Top Democrats received donations from scandal-plagued Washington lobbyist Jack Abramoff?s Indian tribe clients for legitimate reasons and are right to refuse to give up the money, the state?s Democratic chairman says." I bet if I took the time to search further, which I'm not going to bother doing, I could find *tribal* money going to Democrats via Abramoff in mass quantities. Note that unlike most of the Republicans involved, Kennedy and Reid have no intention of giving the money back or giving it to charity. They're keeping it. -- If John McCain gets the 2008 Republican Presidential nomination, my vote for President will be a write-in for Jiang Zemin. |
Measuring filter shape factor
|
Measuring filter shape factor
You need to show a direct connection. Getting money from Indian Tribes
is not illegal. I gather you left your thumb up your ass rather than look at the Open Secrets link. Figures. clifto wrote: wrote: "Once worked??" Many people have visited Germany, where Hilter once waged world war. Thus anyone who has been to Germany is a Nazi. Yeah, exactly. I see you liberals don't like Kennedy's excuse any better than we conservatives do. You can go to opensecrets.org and trace money given directly by Jack Abramoff. Hopefull this link will do the trick: http://www.opensecrets.org/indivs/search.asp?NumOfThou=0&txtName=abramoff%2C+jack&tx tState=%28all+states%29&txtZip=&txtEmploy=&txtCand =&txt2006=Y&txt2004=Y&txt2002=Y&Order=N I see Tom Delay, Ted Stevens, Elizabeth Dole, Arlen Spector, etc. I already posted two liberal rags that named a lot of Democrats involved in the scandal. You can name all the lying liberal rags that don't mention them as many times as you want, and it won't change that 40 out of 45 Senate Democrats received tainted money from Abramoff. -- If John McCain gets the 2008 Republican Presidential nomination, my vote for President will be a write-in for Jiang Zemin. |
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