As we all know that the receive of the flex is marginal at best below 1.8 mhz. The images and birdies would make it difficult at best to use the flex down there. Flex Radio does not even supply sensitivity specifications for the receiver at those frequencies. As I have an intense desire to use the Flex at VLF and LF, I have been researching band pass filters and would love to see someone design a variable preselector for Vlf/Lf that can make the Flex a respectful receiver at those frequencies. My only thought is to use a transverter that outputs at 4 mhz.
I would like to hear how you geared up as I would love to experiment with my flex on the lowfer(160-190 khz) band. 73, Robert KB6QXM "Ham Radio Open Conversation" Yahoo group owner/moderator ----- Reply message ----- From: "Lloyd Berg N9LB" <lloydb...@charter.net> To: <flexradio@flex-radio.biz> Subject: [Flexradio] The new 472-479 kHz band - Technical Info Date: Thu, Feb 16, 2012 10:32 am All, While the 1 watt to 5 watt power seems small, it really isn't because the specification is Effective Radiated Power. An efficient dipole antenna at this frequency would be about 1000 feet long, a 1/4 wave vertical would be over 500 feet tall. If you are running a 60 foot vertical ( requiring a huge matching network ), your efficiency would only be a few percent, therefore your transmitter power output would be somewhere around 100 watts. That is still very low communications power, but quite suitable for CW and some digital modes over 100's of miles - maybe more. I plan to gear up for it and be ready to go on the first day operation becomes legal. Yes I'll be using my FLEX-5000. Transmitting will probably require some form of low frequency transverter. Receiving might just require filtering and possibly a pre-amp. I'm looking forward to exploring a whole new band! 73 Lloyd - N9LB Message: 3 Date: Wed, 15 Feb 2012 12:55:14 -0800 From: " Robert Costa, KB6QXM " <kb6...@yahoo.com> To: " Stephen Victor " <victo...@yahoo.com>, " flexradio@flex-radio.biz " <flexradio@flex-radio.biz> Subject: Re: [Flexradio] The new 472-479 kHz band Message-ID: <648839.89845...@smtp217.mail.gq1.yahoo.com> Content-Type: text/plain; charset=utf-8 1 watt maximum EIRP. Big deal. Not too exciting news. I am glad to hear that we have some Medium Frequency spectrum, but 1 watt output and the size of the antenna is almost not worth the effort. The requirements remind me of the lowfer band (160-190 khz) limitations. This is almost part 15 output. How about giving back the lower portion of the 220 band. 73, Robert KB6QXM "Ham Radio Open Conversation" Yahoo group owner/moderator _______________________________________________ FlexRadio Systems Mailing List FlexRadio@flex-radio.biz http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz Archives: http://www.mail-archive.com/flexradio%40flex-radio.biz/ Knowledge Base: http://kc.flexradio.com/ Homepage: http://www.flexradio.com/ _______________________________________________ FlexRadio Systems Mailing List FlexRadio@flex-radio.biz http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz Archives: http://www.mail-archive.com/flexradio%40flex-radio.biz/ Knowledge Base: http://kc.flexradio.com/ Homepage: http://www.flexradio.com/
