tag:blogger.com,1999:blog-1126984176108779019.post7040575963694596771..comments2024-03-03T21:39:37.833ZComments on Arctic DX: When You Need To Get Rid Of That NoiseBjarne Mjeldehttp://www.blogger.com/profile/03405758708145585467noreply@blogger.comBlogger8125tag:blogger.com,1999:blog-1126984176108779019.post-38759811620691917632012-07-29T17:11:46.020Z2012-07-29T17:11:46.020ZKevin: I bought a low pass filter from CliftonLabs...Kevin: I bought a low pass filter from CliftonLabs to reduce SW interference to MW. I already have a 100 kHz notch (or bandstop) filter, which is combined with a 500 kHz high pass filter to reduce LW interference to MW. Requirements will vary with location. I live in a very low-level signal area, with some important exceptions: A very strong station on 5930 kHz, a Loran C station on 100 kHz and a strong broadcasting station on 153 kHz.Bjarne Mjeldehttps://www.blogger.com/profile/03405758708145585467noreply@blogger.comtag:blogger.com,1999:blog-1126984176108779019.post-9658638627059281042012-07-29T17:04:19.061Z2012-07-29T17:04:19.061ZBjarne - what specifically did you buy for use wit...Bjarne - what specifically did you buy for use with the AFEDRI? I just oprdered one today, and need to order filters also, to control the signals getting through. Also do you have a recomendation for an inexpensive antenna aerial? I like plug and play solutions as much as possible. Kevin N1KCGKevinhttps://www.blogger.com/profile/13540366107857952203noreply@blogger.comtag:blogger.com,1999:blog-1126984176108779019.post-54860387967927274512012-07-15T16:27:59.774Z2012-07-15T16:27:59.774ZFor use with my Afedri SDR-Net, I am looking at ht...For use with my Afedri SDR-Net, I am looking at http://www.dmcstore.com/filters.html for their compact passive high-pass and low-pass filters with SMA connecters on each end, for only US $26 each.<br /><br />For shortwave listeners with an Afedri SDR-Net, it would be simple to screw together a high-pass and a low-pass filter to get a pass band focused on a specific broadcast band.<br /><br />The above webstore lists high-pass and low-pass filters with values<br /><br />5Mhz<br />7Mhz<br />9Mhz<br />12Mhz<br />16Mhz<br />21MhzRobertnoreply@blogger.comtag:blogger.com,1999:blog-1126984176108779019.post-12942383521823125302012-07-11T22:18:26.882Z2012-07-11T22:18:26.882ZBjarne:
I use AADE filter design software, and th...Bjarne:<br /><br />I use AADE filter design software, and there other programs such as the mentioned Elsie software.<br /><br />However, obtaining performance that matches the computer design requires significant attention to detail. <br /><br />For example, all inductors are adjusted for +/- 0.5% of theoretical value using an HP 4192A LF Impedance bridge, with the measurement being made at the inductor's design frequency. Capacitors are measured and selected with a similar objective of 0.5% using a General Radio 1658 DigiBridge. Fortunately capacitors show little shift in value from 1000 Hz measurements to frequencies in the low MHz range.<br /><br />It's also necessary to pay close attention to the filter's physical layout to reduce coupling between inductors and also unintended coupling due to common impedance in the ground returns. <br /><br />It's simple to build a filter with 60 dB ultimate rejection; it's far more difficult to build the same filter and obtain 80 or 90 dB ultimate rejection.<br /><br />Jack K8ZOA<br />www.cliftonlaboratories.comJackOfVAhttps://www.blogger.com/profile/09908627282128491170noreply@blogger.comtag:blogger.com,1999:blog-1126984176108779019.post-6062299729487609052012-07-11T00:13:23.454Z2012-07-11T00:13:23.454ZSVC Filter designer from http://www.tonnesoftware....SVC Filter designer from http://www.tonnesoftware.com/ is handy for designing 3rd-to-7th order highpass and lowpass LC filters or various types. Plots ideal filter response as well as the response using standard-value parts. I used it to design a couple of elliptical filters that perform very well. Best of all, it's free.Bill McFaddennoreply@blogger.comtag:blogger.com,1999:blog-1126984176108779019.post-27857445875468673352012-07-09T20:11:28.659Z2012-07-09T20:11:28.659ZHi Bjarne. Regarding other filter designs or DIY&#...Hi Bjarne. Regarding other filter designs or DIY's: <br />I suppose your'e aware of Arne Nilsson's experiments, in this case a HP filter @500kHz? Described in SWB 1749. I tested the mentioned Elsie program and "reversed engineered" Cliftons MW HP filter. All figures matches :-). Probably I will try out something myself...Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-1126984176108779019.post-65494400242404020422012-07-09T07:11:47.919Z2012-07-09T07:11:47.919ZStill cool though ;-)Still cool though ;-)Bjarne Mjeldehttps://www.blogger.com/profile/03405758708145585467noreply@blogger.comtag:blogger.com,1999:blog-1126984176108779019.post-46511817120017027322012-07-09T06:20:56.147Z2012-07-09T06:20:56.147ZHPSDR - Alex RF Bandpass Filters
can be found here...HPSDR - Alex RF Bandpass Filters<br />can be found here<br /><br />http://tapr.org/kits_alex.html<br /><br />Perhaps a little bit overkill?<br /><br />/Fredrik DourénAnonymousnoreply@blogger.com