If your local RF environment is not challenging, then this may be a good low cost solution for $14 plus shipping:
http://www.wb9kzy.com/lfconv.htm I built one several years ago setup with the 10 MHz IF crystal. Performs very well at my location with just a 40/80M parallel dipole. It completely outperforms the Flex-5K natively below the AM BCB. And it actually rivals my HPSDR Mercury and Hermes for what it can hear below the AM BCB on that same antenna as well. It may not be a good solution though if you have some high powered AM BCB transmitters close by. Though I have never run into any overload problems with mine. It is built around the SA612 mixer, so it will ultimately be limited performance wise by that. Duane N9DG -------------------------------------------- On Wed, 11/19/14, Chuck ONeal <cdon...@comcast.net> wrote: Subject: Re: [Flexradio] Better broadcast band and longwave reception To: ke...@3950.net, "FlexRadio@flex-radio.biz" <flexradio@flex-radio.biz> Date: Wednesday, November 19, 2014, 7:54 PM Hi Folks, To get complete BC band reception I had Clifton Labs build a custom 800 KHz low pass filter which I switch in when I tune below 800 KHz. Here is a link to his web page with a BC band reject filter. I believe he still does special filters. BTW, I bought the BC band reject filter and it cleans up my Flex 5000A on 160M. http://www.cliftonlaboratories.com/z10020_am_medium_wave_band_reject_filter.htm For below the BC band I use this: http://www.herostechnology.co.uk/pages/VLF_LF_Converter.html When I run the 800 KHz low pass filter and the BC band reject filter in series, the 5000A work very well down to about 350 KHz. Then the images start showing up. Either switch in the LF converter or buy a couple more low pass filters, depending on how low you want to receive. Chuck K1KW ----- Original Message ----- From: <ke...@3950.net> To: "FlexRadio@flex-radio.biz" <flexradio@flex-radio.biz> Sent: Wednesday, November 19, 2014 8:35 PM Subject: [Flexradio] Better broadcast band and longwave reception > Both the SDR-1000 and the Flex 5000 suffer from poor AM broadcast and > longwave reception, with images of BC stations breaking through in many > inappropriate places, especially below 1 MHz. > > I have been wondering what others have done to remedy this. > > I have considered 1) a preselector/antenna tuner to greatly narrow the > spectrum bandwidth seen by the front end, using my existing inverted L > antenna; 2) a tunable narrow loop antenna; or 3) an upconverter to tune > longwave and AM broadcast at, say, 4 MHz. > > I wonder if anyone on the reflector has any wisdom to impart on this > subject. > > Thanks, > > Kevin. > _______________________________________________ FlexRadio Systems Mailing List FlexRadio@flex-radio.biz To opt out of the Reflector: http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz
