[Flexradio] Heros VLF Converter
Please folks, the Heros VLF converter is vastly more sophisticated than the lower priced units with limited filtering from Palomar (which I own) or Jackson Harbor or the others. The Heros is very fairly priced. Still, most of us will NOT benefit from the Heros unless we're in an area of very high RF density. My $89 Palomar works great with my 5000. Here are details on the impressive Heros VLF converter: http://herostechnology.co.uk/pdf/VLF_LF_Converter_brochure_web.pdf Regarding the Heros preselector: that's another waste for almost all U.S. hams. But maybe a nice addition if you live in rf-noisy downtown London. Jeff K0OD ___ 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/
Re: [Flexradio] Heros VLF Converter
Jeff, Don't you believe that the Heros pre-selector would be advantagous to SWL listeners? Considering that there is no filtering on the Flex outside of the ham bands, wouldn't the pre-selector help with selectivity issues on the general coverage of the Flex? 73, Robert KB6QXM Ham Radio Open Conversation Yahoo group owner/moderator - Reply message - From: Jeff Singer jsin...@i1.net To: flexradio@flex-radio.biz Subject: [Flexradio] Heros VLF Converter Date: Mon, Jan 14, 2013 10:37 am Please folks, the Heros VLF converter is vastly more sophisticated than the lower priced units with limited filtering from Palomar (which I own) or Jackson Harbor or the others. The Heros is very fairly priced. Still, most of us will NOT benefit from the Heros unless we're in an area of very high RF density. My $89 Palomar works great with my 5000. Here are details on the impressive Heros VLF converter: http://herostechnology.co.uk/pdf/VLF_LF_Converter_brochure_web.pdf Regarding the Heros preselector: that's another waste for almost all U.S. hams. But maybe a nice addition if you live in rf-noisy downtown London. Jeff K0OD ___ 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/
Re: [Flexradio] Heros VLF Converter
A preselector is an improvement, especially ouside of the Ham Bands 73...VE6ZT - Original Message - From: Jeff Singer jsin...@i1.net To: flexradio@flex-radio.biz Sent: Monday, January 14, 2013 11:37 AM Subject: [Flexradio] Heros VLF Converter Please folks, the Heros VLF converter is vastly more sophisticated than the lower priced units with limited filtering from Palomar (which I own) or Jackson Harbor or the others. The Heros is very fairly priced. Still, most of us will NOT benefit from the Heros unless we're in an area of very high RF density. My $89 Palomar works great with my 5000. Here are details on the impressive Heros VLF converter: http://herostechnology.co.uk/pdf/VLF_LF_Converter_brochure_web.pdf Regarding the Heros preselector: that's another waste for almost all U.S. hams. But maybe a nice addition if you live in rf-noisy downtown London. Jeff K0OD ___ 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/
Re: [Flexradio] Heros VLF Converter
A preselector is necessary for any serious use of my Flex5K anywhere outside of the ham bands below ~ 20Mhz, and it can and does help at times even above that. The input impedance of the Rx section is rarely 50 ohms, even in the ham bands in many cases. 73Jordan VE6ZT - Original Message - From: Robert Costa, KB6QXM kb6...@yahoo.com To: Jeff Singer jsin...@i1.net; flexradio@flex-radio.biz Sent: Monday, January 14, 2013 11:52 AM Subject: Re: [Flexradio] Heros VLF Converter Jeff, Don't you believe that the Heros pre-selector would be advantagous to SWL listeners? Considering that there is no filtering on the Flex outside of the ham bands, wouldn't the pre-selector help with selectivity issues on the general coverage of the Flex? 73, Robert KB6QXM Ham Radio Open Conversation Yahoo group owner/moderator - Reply message - From: Jeff Singer jsin...@i1.net To: flexradio@flex-radio.biz Subject: [Flexradio] Heros VLF Converter Date: Mon, Jan 14, 2013 10:37 am Please folks, the Heros VLF converter is vastly more sophisticated than the lower priced units with limited filtering from Palomar (which I own) or Jackson Harbor or the others. The Heros is very fairly priced. Still, most of us will NOT benefit from the Heros unless we're in an area of very high RF density. My $89 Palomar works great with my 5000. Here are details on the impressive Heros VLF converter: http://herostechnology.co.uk/pdf/VLF_LF_Converter_brochure_web.pdf Regarding the Heros preselector: that's another waste for almost all U.S. hams. But maybe a nice addition if you live in rf-noisy downtown London. Jeff K0OD ___ 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/ ___ 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/
Re: [Flexradio] Heros VLF Converter
wouldn't the pre-selector help with selectivity issues on the general coverage of the Flex? What problem are you having that you think a preselector will help with? Lots of hams read about a preselector's gain and think DX will be 20 dB more copyable. THAT's certainly not going to happen. As long as you can hear band noise drop when you disconnect the antenna you have plenty of sensitivity. And just about every receiver made since the 1960s has tons of sensitivity even on the highest bands. 20 dB improvement could also be achieved by turning the audio gain all the way to the right or by sticking your head into the speaker. You know that's not going to help. Yes, if you're next door to a VOA transmitter additional front end selectivity might be useful but only if the VOA is causing a problem. Jeff K0OD ___ 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/
Re: [Flexradio] Heros VLF Converter
Jeff, I did not say sensitivity, I said selectivity. I want to eliminate or reduce intermods. My Flex is plenty sensitive. As the front end is broadband and there is NO filters outside of the ham bands and I am a SWL, I thought that this would help with the selectivity of receiving short wave broadcasts. The reason I like my Flex is to have 1 platform as a basis for 160-70 cm. Receiving above that is the job of my IC-pcr1500 for my public service monitoring. My interest in radio communications extends from DC-Light. IMHO, there is more to radio communications than just ham radio. 73, Robert KB6QXM Ham Radio Open Conversation Yahoo group owner/moderator - Reply message - From: Jeff Singer jsin...@i1.net To: flexradio@flex-radio.biz Subject: [Flexradio] Heros VLF Converter Date: Mon, Jan 14, 2013 11:33 am wouldn't the pre-selector help with selectivity issues on the general coverage of the Flex? What problem are you having that you think a preselector will help with? Lots of hams read about a preselector's gain and think DX will be 20 dB more copyable. THAT's certainly not going to happen. As long as you can hear band noise drop when you disconnect the antenna you have plenty of sensitivity. And just about every receiver made since the 1960s has tons of sensitivity even on the highest bands. 20 dB improvement could also be achieved by turning the audio gain all the way to the right or by sticking your head into the speaker. You know that's not going to help. Yes, if you're next door to a VOA transmitter additional front end selectivity might be useful but only if the VOA is causing a problem. Jeff K0OD ___ 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/
Re: [Flexradio] Heros VLF Converter
On Mon, Jan 14, 2013 at 11:33 AM, Jeff Singer jsin...@i1.net wrote: wouldn't the pre-selector help with selectivity issues on the general coverage of the Flex? What problem are you having that you think a preselector will help with? Lots of hams read about a preselector's gain and think DX will be 20 dB more copyable. THAT's certainly not going to happen. As long as you can hear band noise drop when you disconnect the antenna you have plenty of sensitivity. The advantage of a preselector is not that it provides more gain, but that it reduces the power of undesired signals at the input of the receiver. Whenever you pass two signals through a nonlinear device, and that would be any amplifying stage, any mixer, any detector, you get intermodulation products. As you pass more of these signals through, they all intermodulate together. In fact, if you have really strong signals, the intermodulation products can themselves intermodulate with signals and other itermodulation products. The result is spurious products all thought the receiver. And even the noise power can be intermodulated up to the receiver's passband resulting in a higher noise floor. The earlier in the receive chain you can reduce or eliminate unwanted signal and/or noise power, the better your receiver will perform. In the olden days, most receivers had decent preselection as a way to eliminate images. Eliminating lots of unwanted signal power was an unlooked-for side effect. Then we got broadbanded receivers that upconverted and didn't need preselection in order to eliminate images. And these receivers even tested well ... on the bench where only a few signals came in the antenna port. But once you plugged in a real antenna, especially one that was relatively broad-banded, and all that cruft came in and intermodulated with everything else, you got crappy receiver performance. Now there seems to be some idea that SDRs suffer more from this problem than do other receivers. This is not the case. In fact, since SDR does conversion to digital early in the receive chain, they are LESS susceptible to this problem. The DDC/DUC (direct conversion) SDRs like the new Flex 6xxx series is going to be even LESS affected by front-end and first-mixer IMD. (In fact, as long as the ADC is not clipping, the DDC/DUC radios should should be darned-near textbook perfect in their response and behavior.) But in the mean time we have radios like the 1500, 3000, and 5000. They will benefit from preselection, to a greater or lesser degree, depending on the amount of unwanted signal power arrives from the antenna. The greater the crap (technical name for unwanted signals) coming down the feedline, the more a preselector will help. -- Brian Lloyd, WB6RQN/J79BPL 3191 Western Dr. Cameron Park, CA 95682 br...@lloyd.com +1.767.617.1365 (Dominica) +1.916.877.5067 (USA) ___ 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/
Re: [Flexradio] Heros VLF Converter
The following link takes you to a review of the Jackson Harbor VLF converter, complete with a discussion of lowpass filtering: http://www.cliftonlaboratories.com/jackson_harbor_press_vlf_converter.htm 73 - Ken From: Jeff Singer jsin...@i1.net To: flexradio@flex-radio.biz Sent: Monday, January 14, 2013 1:37:53 PM Subject: [Flexradio] Heros VLF Converter Please folks, the Heros VLF converter is vastly more sophisticated than the lower priced units with limited filtering from Palomar (which I own) or Jackson Harbor or the others. The Heros is very fairly priced. Still, most of us will NOT benefit from the Heros unless we're in an area of very high RF density. My $89 Palomar works great with my 5000. Here are details on the impressive Heros VLF converter: http://herostechnology.co.uk/pdf/VLF_LF_Converter_brochure_web.pdf Regarding the Heros preselector: that's another waste for almost all U.S. hams. But maybe a nice addition if you live in rf-noisy downtown London. Jeff K0OD ___ 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/
