Re: [Flexradio] The new 472-479 kHz band - REAL DX
On Mon, Feb 20, 2012 at 10:56 AM, Carol F. Milazzo, KP4MD/W6 kp...@cfmilazzo.com wrote: Here is a description of a simple low pass filter with a 510 kHz cutoff frequency I built for my FLEX-3000 http://www.qsl.net/kp4md/lpfilter.htm I still think that a tunable preselector makes more sense than a low-pass filter. The band is so narrow that a couple of relatively high-Q LC networks ganged together would do a better job of rejecting cruft both above and below this band. -- 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] The new 472-479 kHz band - REAL DX
On Mon, Feb 20, 2012 at 9:04 PM, Ralph W5JGV w5...@w5jgv.com wrote: Don't get me wrong; I LOVE this rig, but I'm going to keep some of my old manually operated stuff as a backup, just in case. The problem is that PowerSDR makes assumptions about how you want to use the radio rather than just providing knobs to set things up the way you want them. I understand this because it would be very annoying and error-prone to have knobs and switches for every switch, relay, input, and parameter. But the problem is, when we think of doing something new, there is no way to get around PowerSDR, knows what we want to do better than we do ourselves. Solving this problem would be easy if we could command the software to, connect RX1 to input X and bypass the input filtering. We know that the hardware is capable but that is not a preprogrammed mode for the radio. This points up why the underlying operation of the radio needs to be decoupled from the user interface. Hint: think 'macros'. (The hacker types know what I am talking about.) -- 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] The new 472-479 kHz band - REAL DX
I agree a bandpass filter makes sense for just 472-479 kHz. My low-pass filter was intended for receiving the entire LF range. Carol, KP4MD/W6 On Tue, Feb 21, 2012 at 8:25 AM, Brian Lloyd brian-wb6...@lloyd.com wrote: On Mon, Feb 20, 2012 at 10:56 AM, Carol F. Milazzo, KP4MD/W6 kp...@cfmilazzo.com wrote: Here is a description of a simple low pass filter with a 510 kHz cutoff frequency I built for my FLEX-3000 http://www.qsl.net/kp4md/lpfilter.htm I still think that a tunable preselector makes more sense than a low-pass filter. The band is so narrow that a couple of relatively high-Q LC networks ganged together would do a better job of rejecting cruft both above and below this band. -- 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] The new 472-479 kHz band - REAL DX
What I want to see is someone design a tuneable preselector with many adjustable parameters. Anyone up to the task. I will even build your website to market it. 73, Robert KB6QXM Ham Radio Open Conversation Yahoo group owner/moderator - Reply message - From: Carol F. Milazzo, KP4MD/W6 kp...@cfmilazzo.com To: Brian Lloyd brian-wb6...@lloyd.com Cc: flexradio@flex-radio.biz Subject: [Flexradio] The new 472-479 kHz band - REAL DX Date: Tue, Feb 21, 2012 8:39 am I agree a bandpass filter makes sense for just 472-479 kHz. My low-pass filter was intended for receiving the entire LF range. Carol, KP4MD/W6 On Tue, Feb 21, 2012 at 8:25 AM, Brian Lloyd brian-wb6...@lloyd.com wrote: On Mon, Feb 20, 2012 at 10:56 AM, Carol F. Milazzo, KP4MD/W6 kp...@cfmilazzo.com wrote: Here is a description of a simple low pass filter with a 510 kHz cutoff frequency I built for my FLEX-3000 http://www.qsl.net/kp4md/lpfilter.htm I still think that a tunable preselector makes more sense than a low-pass filter. The band is so narrow that a couple of relatively high-Q LC networks ganged together would do a better job of rejecting cruft both above and below this band. -- 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/ ___ 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] The new 472-479 kHz band - REAL DX
On Tue, Feb 21, 2012 at 8:47 AM, Robert Costa, KB6QXM kb6...@yahoo.comwrote: What I want to see is someone design a tuneable preselector with many adjustable parameters. Anyone up to the task. I will even build your website to market it. Signal levels tend to be pretty strong unless using a small loop antenna, and then you need a preamp. No reason that the small, multi-turn, receiving loop antenna cannot itself be made tunable, followed by a preamp and a second tuned stage that is gang-tuned with the loop. (If Q is low enough the loop can be tuned with lumped constants.) But if one wants the preselector to be independent of the loop, I would use a link or tapped input to the first LC network, loosely-coupled to a FET gain stage, followed by a second, identical LC network, followed by a FET buffer to match a 50-ohm feedline to the RX. Just thinking aloud here. -- 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] The new 472-479 kHz band - REAL DX
Brian, Yes I agree about your assessment on the preselector, but who is going to take the time to design, test and market the preselector. We could talk all day what it should be in theory, but until someone takes the time to take their theory and make it a viable product all we have is what if 73, Robert KB6QXM Ham Radio Open Conversation Yahoo group owner/moderator - Reply message - From: Brian Lloyd brian-wb6...@lloyd.com To: Robert Costa, KB6QXM kb6...@yahoo.com Cc: Carol F. Milazzo, KP4MD/W6 kp...@cfmilazzo.com, flexradio@flex-radio.biz Subject: [Flexradio] The new 472-479 kHz band - REAL DX Date: Tue, Feb 21, 2012 9:35 am On Tue, Feb 21, 2012 at 8:47 AM, Robert Costa, KB6QXM kb6...@yahoo.com wrote: What I want to see is someone design a tuneable preselector with many adjustable parameters. Anyone up to the task. I will even build your website to market it. Signal levels tend to be pretty strong unless using a small loop antenna, and then you need a preamp. No reason that the small, multi-turn, receiving loop antenna cannot itself be made tunable, followed by a preamp and a second tuned stage that is gang-tuned with the loop. (If Q is low enough the loop can be tuned with lumped constants.) But if one wants the preselector to be independent of the loop, I would use a link or tapped input to the first LC network, loosely-coupled to a FET gain stage, followed by a second, identical LC network, followed by a FET buffer to match a 50-ohm feedline to the RX. Just thinking aloud here. -- 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] The new 472-479 kHz band - REAL DX
Hi All, I'm not sure what kind of parameters you'd like to be able to adjust Brian. I think that if you put a good filter at the antenna jack and get rid of the AM broadcasters then your Flex can easily do the rest. I have already built a lowpass filter that cleans the longwave band of any AM broadcast interference. A bandpass filter is more difficult to do; it's not as forgiving of variations in component values so trimmer capacitors would have to be added to get it set up correctly, which makes it more expensive to build. It seems to me one only benefits from a bandpass filter if one lives in parts of the world where Loran-C is still operating, or where the longwave broadcast band is still active, i.e., not North America. Otherwise, the lowpass filter lets you hear EVERYTHING below 500 kHz. Anyway, I'm building a few lowpass filters as soon as I get the rest of the components I need; one for me and one for a list member I've been corresponding with who is going to give me some feedback. I'll be glad to make more if they work out well. The bandpass filter too, but that'll take a little longer. 73 - Ken, VE3HLS From: Robert Costa, KB6QXM kb6...@yahoo.com To: Brian Lloyd brian-wb6...@lloyd.com Cc: Carol F. Milazzo, KP4MD/W6 kp...@cfmilazzo.com; flexradio@flex-radio.biz Sent: Tuesday, February 21, 2012 12:48:24 PM Subject: Re: [Flexradio] The new 472-479 kHz band - REAL DX Brian, Yes I agree about your assessment on the preselector, but who is going to take the time to design, test and market the preselector. We could talk all day what it should be in theory, but until someone takes the time to take their theory and make it a viable product all we have is what if 73, Robert KB6QXM Ham Radio Open Conversation Yahoo group owner/moderator - Reply message - From: Brian Lloyd brian-wb6...@lloyd.com To: Robert Costa, KB6QXM kb6...@yahoo.com Cc: Carol F. Milazzo, KP4MD/W6 kp...@cfmilazzo.com, flexradio@flex-radio.biz Subject: [Flexradio] The new 472-479 kHz band - REAL DX Date: Tue, Feb 21, 2012 9:35 am On Tue, Feb 21, 2012 at 8:47 AM, Robert Costa, KB6QXM kb6...@yahoo.com wrote: What I want to see is someone design a tuneable preselector with many adjustable parameters. Anyone up to the task. I will even build your website to market it. Signal levels tend to be pretty strong unless using a small loop antenna, and then you need a preamp. No reason that the small, multi-turn, receiving loop antenna cannot itself be made tunable, followed by a preamp and a second tuned stage that is gang-tuned with the loop. (If Q is low enough the loop can be tuned with lumped constants.) But if one wants the preselector to be independent of the loop, I would use a link or tapped input to the first LC network, loosely-coupled to a FET gain stage, followed by a second, identical LC network, followed by a FET buffer to match a 50-ohm feedline to the RX. Just thinking aloud here. -- 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/ ___ 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] The new 472-479 kHz band - REAL DX
Ken, I will give you extensive feedback if you build one for me. :-) 73, Robert KB6QXM Ham Radio Open Conversation Yahoo group owner/moderator - Reply message - From: Ken Alexander k.alexan...@rogers.com To: Robert Costa, KB6QXM kb6...@yahoo.com, Brian Lloyd brian-wb6...@lloyd.com Cc: Carol F. Milazzo, KP4MD/W6 kp...@cfmilazzo.com, flexradio@flex-radio.biz flexradio@flex-radio.biz Subject: [Flexradio] The new 472-479 kHz band - REAL DX Date: Tue, Feb 21, 2012 10:33 am Hi All, I'm not sure what kind of parameters you'd like to be able to adjust Brian. I think that if you put a good filter at the antenna jack and get rid of the AM broadcasters then your Flex can easily do the rest. I have already built a lowpass filter that cleans the longwave band of any AM broadcast interference. A bandpass filter is more difficult to do; it's not as forgiving of variations in component values so trimmer capacitors would have to be added to get it set up correctly, which makes it more expensive to build. It seems to me one only benefits from a bandpass filter if one lives in parts of the world where Loran-C is still operating, or where the longwave broadcast band is still active, i.e., not North America. Otherwise, the lowpass filter lets you hear EVERYTHING below 500 kHz. Anyway, I'm building a few lowpass filters as soon as I get the rest of the components I need; one for me and one for a list member I've been corresponding with who is going to give me some feedback. I'll be glad to make more if they work out well. The bandpass filter too, but that'll take a little longer. 73 - Ken, VE3HLS From: Robert Costa, KB6QXM kb6...@yahoo.com To: Brian Lloyd brian-wb6...@lloyd.com Cc: Carol F. Milazzo, KP4MD/W6 kp...@cfmilazzo.com; flexradio@flex-radio.biz Sent: Tuesday, February 21, 2012 12:48:24 PM Subject: Re: [Flexradio] The new 472-479 kHz band - REAL DX Brian, Yes I agree about your assessment on the preselector, but who is going to take the time to design, test and market the preselector. We could talk all day what it should be in theory, but until someone takes the time to take their theory and make it a viable product all we have is what if 73, Robert KB6QXM Ham Radio Open Conversation Yahoo group owner/moderator - Reply message - From: Brian Lloyd brian-wb6...@lloyd.com To: Robert Costa, KB6QXM kb6...@yahoo.com Cc: Carol F. Milazzo, KP4MD/W6 kp...@cfmilazzo.com, flexradio@flex-radio.biz Subject: [Flexradio] The new 472-479 kHz band - REAL DX Date: Tue, Feb 21, 2012 9:35 am On Tue, Feb 21, 2012 at 8:47 AM, Robert Costa, KB6QXM kb6...@yahoo.com wrote: What I want to see is someone design a tuneable preselector with many adjustable parameters. Anyone up to the task. I will even build your website to market it. Signal levels tend to be pretty strong unless using a small loop antenna, and then you need a preamp. No reason that the small, multi-turn, receiving loop antenna cannot itself be made tunable, followed by a preamp and a second tuned stage that is gang-tuned with the loop. (If Q is low enough the loop can be tuned with lumped constants.) But if one wants the preselector to be independent of the loop, I would use a link or tapped input to the first LC network, loosely-coupled to a FET gain stage, followed by a second, identical LC network, followed by a FET buffer to match a 50-ohm feedline to the RX. Just thinking aloud here. -- 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/ ___ 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] The new 472-479 kHz band - REAL DX
My mistake, I directed my comment about parameters to Brian, when I should have directed them to Robert. Sorry for any confusion. 73 - Ken From: Ken Alexander k.alexan...@rogers.com To: Robert Costa, KB6QXM kb6...@yahoo.com; Brian Lloyd brian-wb6...@lloyd.com Cc: Carol F. Milazzo, KP4MD/W6 kp...@cfmilazzo.com; flexradio@flex-radio.biz flexradio@flex-radio.biz Sent: Tuesday, February 21, 2012 1:33:35 PM Subject: Re: [Flexradio] The new 472-479 kHz band - REAL DX Hi All, I'm not sure what kind of parameters you'd like to be able to adjust Brian. I think that if you put a good filter at the antenna jack and get rid of the AM broadcasters then your Flex can easily do the rest. I have already built a lowpass filter that cleans the longwave band of any AM broadcast interference. A bandpass filter is more difficult to do; it's not as forgiving of variations in component values so trimmer capacitors would have to be added to get it set up correctly, which makes it more expensive to build. It seems to me one only benefits from a bandpass filter if one lives in parts of the world where Loran-C is still operating, or where the longwave broadcast band is still active, i.e., not North America. Otherwise, the lowpass filter lets you hear EVERYTHING below 500 kHz. Anyway, I'm building a few lowpass filters as soon as I get the rest of the components I need; one for me and one for a list member I've been corresponding with who is going to give me some feedback. I'll be glad to make more if they work out well. The bandpass filter too, but that'll take a little longer. 73 - Ken, VE3HLS From: Robert Costa, KB6QXM kb6...@yahoo.com To: Brian Lloyd brian-wb6...@lloyd.com Cc: Carol F. Milazzo, KP4MD/W6 kp...@cfmilazzo.com; flexradio@flex-radio.biz Sent: Tuesday, February 21, 2012 12:48:24 PM Subject: Re: [Flexradio] The new 472-479 kHz band - REAL DX Brian, Yes I agree about your assessment on the preselector, but who is going to take the time to design, test and market the preselector. We could talk all day what it should be in theory, but until someone takes the time to take their theory and make it a viable product all we have is what if 73, Robert KB6QXM Ham Radio Open Conversation Yahoo group owner/moderator - Reply message - From: Brian Lloyd brian-wb6...@lloyd.com To: Robert Costa, KB6QXM kb6...@yahoo.com Cc: Carol F. Milazzo, KP4MD/W6 kp...@cfmilazzo.com, flexradio@flex-radio.biz Subject: [Flexradio] The new 472-479 kHz band - REAL DX Date: Tue, Feb 21, 2012 9:35 am On Tue, Feb 21, 2012 at 8:47 AM, Robert Costa, KB6QXM kb6...@yahoo.com wrote: What I want to see is someone design a tuneable preselector with many adjustable parameters. Anyone up to the task. I will even build your website to market it. Signal levels tend to be pretty strong unless using a small loop antenna, and then you need a preamp. No reason that the small, multi-turn, receiving loop antenna cannot itself be made tunable, followed by a preamp and a second tuned stage that is gang-tuned with the loop. (If Q is low enough the loop can be tuned with lumped constants.) But if one wants the preselector to be independent of the loop, I would use a link or tapped input to the first LC network, loosely-coupled to a FET gain stage, followed by a second, identical LC network, followed by a FET buffer to match a 50-ohm feedline to the RX. Just thinking aloud here. -- 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/ ___ 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] The new 472-479 kHz band - REAL DX
On Tue, Feb 21, 2012 at 10:33 AM, Ken Alexander k.alexan...@rogers.comwrote: Hi All, I'm not sure what kind of parameters you'd like to be able to adjust Brian. I don't think there are any besides frequency (tuning) and possibly preamp gain. I think that if you put a good filter at the antenna jack and get rid of the AM broadcasters then your Flex can easily do the rest. The Flex has its own filters that get in the way. If you bypass the front-end filters and feed the signal directly to the QSD you need to provide the functionality of the front end filtering externally. Oh, and you need a way to command the radio to bypass the built-in front-end filters. I have already built a lowpass filter that cleans the longwave band of any AM broadcast interference. A bandpass filter is more difficult to do; it's not as forgiving of variations in component values so trimmer capacitors would have to be added to get it set up correctly, which makes it more expensive to build. It seems to me one only benefits from a bandpass filter if one lives in parts of the world where Loran-C is still operating, or where the longwave broadcast band is still active, i.e., not North America. Otherwise, the lowpass filter lets you hear EVERYTHING below 500 kHz. Anyway, I'm building a few lowpass filters as soon as I get the rest of the components I need; one for me and one for a list member I've been corresponding with who is going to give me some feedback. I'll be glad to make more if they work out well. The bandpass filter too, but that'll take a little longer. Sometimes old technology suffices. Think tunable RF receivers that predated superhets. Lastly, since I have no real interest in operating in the 600m band, most of this discussion is moot for me. I was just thinking that it might be easy to spider-web wind a coil and use a two-gang 365pF variable to tune it and use that as your preselector with suitable loose coupling so as not to kill the Q of the resulting LC circuit. (One can get amazing Q out of a spider-web wound coil of Litz wire tuned with an air-variable.) And if you need more Q, make a second, identical stage. Heck, you can use mutual coupling between the two coils for coupling the stages. Makes me think of the old wave couplers used back in the spark days with early crystal detectors. What's old is new again. :-) -- 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] The new 472-479 kHz band - REAL DX
Hi All, What I want to see is someone design a tuneable preselector with many adjustable parameters. At these frequencies and with a load impedance of 50 ohms you can come a long way with a good 1 mH inductor and a tuneable capacitor in series with the antenna. The 1 mH inductor is in the order of 3 k ohm at 500 kHz in series with about 100 pF it will resonate at the desired frequency. Q should be about 60 for a 3 dB bandwidth of about 8 kHz. With just a single (air-dielectric) capacitor to tune this solution is pretty efficient but it is necessary that the output impedance of the antenna is low. Otherwise it will not work. Use a source or emitter follower for example. For narrower bandwidth, use a bigger inductor and a smaller capacitor. The tuning range becomes fairly big and you can easily investigate whether any false signals are present. Connect the normally grounded side of the capacitor to the low impedance point of your antenna. (The output of your small loop amplifier or small wire source follower.) The impedance at the junction between the inductor and the capacitor becomes vey high. It probably needs screening to not pick up all the switch power and computer noise in your schack. 73 Leif / SM5BSZ ___ 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] The new 472-479 kHz band - REAL DX
Hi I am a newbe to flex but looking at your screenshot it looks like the preamp for RX1 is on and the preamp for RX2 is off. Could that be messing things up? HANFORD R. WRIGHT WA4LZC CRA # 1515 CCA# AC11-12590 -Original Message- From: flexradio-boun...@flex-radio.biz [mailto:flexradio-boun...@flex-radio.biz] On Behalf Of Ralph W5JGV Sent: Monday, February 20, 2012 01:45 To: flexradio@flex-radio.biz Subject: Re: [Flexradio] The new 472-479 kHz band - REAL DX Surprised at your observation, I checked my 5000a and noticed that if RX1 preamp is off, I get same results on both RXes at 485 KHz, but if RX1 preamp is on, the baselines are different and I see an apparent difference of 30-something dB. Are you using the same settings on both receivers? Hello Jerry, Yes, I am. See this screen shot: http://w5jgv.com/special/RX1-RX2.jpg (177 kB) It shows that both RX's are set for USB reception, with a 2.7 KHz bandwidth. A 50 Ohm dummy load is connected to the ANT1. The signal on the screen is my PSK31 200 watt transmitter while it is on the air. The antenna connections are: RX1 to ANT1 connector RX2 to ANT1 TAP You can see the signal level difference between the RX's. The gain of RX2 is about the same as both of my Yaesu FT-747GX's. I therefore conclude that RX1 is deaf. As for the preamps, in my F5K, the preamps on both RX's are grayed out and not available at frequencies at or below 2.000 MHz. 73, Ralph W5JGV - WD2XSH/7 ___ 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] The new 472-479 kHz band - REAL DX
At 01:45 AM 2/20/2012, Ralph W5JGV wrote: Surprised at your observation, I checked my 5000a and noticed that if RX1 preamp is off, I get same results on both RXes at 485 KHz, but if RX1 preamp is on, the baselines are different and I see an apparent difference of 30-something dB. Are you using the same settings on both receivers? Hello Jerry, Yes, I am. See this screen shot: http://w5jgv.com/special/RX1-RX2.jpg (177 kB) It shows that both RX's are set for USB reception, with a 2.7 KHz bandwidth. A 50 Ohm dummy load is connected to the ANT1. The signal on the screen is my PSK31 200 watt transmitter while it is on the air. Looks like rx1 BW is 2.4 and rx2 BW is 2.9 KHz, but that shouldn't make a difference. Also, AGC-T is set differently, but that shouldn't make a difference either. Since some minor difference in internal rx shielding could affect the receivers differently with a local signal, I would compare using a distant signal or no signal at all - just using the noise baseline. When I look at your baseline, I see only a few dB difference - maybe 5-6. The antenna connections are: RX1 to ANT1 connector RX2 to ANT1 TAP You can see the signal level difference between the RX's. The gain of RX2 is about the same as both of my Yaesu FT-747GX's. I therefore conclude that RX1 is deaf. As for the preamps, in my F5K, the preamps on both RX's are grayed out and not available at frequencies at or below 2.000 MHz. My rx1 preamp is available at 485 kHz, and I can turn it on/off. Makes a big difference in the baseline. My rx2 preamp will not turn on at 485 kHz. Your rx1 preamp button is blue - this means it is off? I am not familiar with the skin you are using, but I see that your other function buttons go blue when they are on. You might want to recheck the status of your rx1 preamp. When I look at a distant AM station on 580 KHz, I see an apparent difference in rx sensitivity when I switch rx1 preamp on/off - it looks like rx2 is more sensitive by about 30 dB with rx1 preamp on. They are the same when off. GL Jerry W4UK ___ 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] The new 472-479 kHz band - REAL DX
Here is a description of a simple low pass filter with a 510 kHz cutoff frequency I built for my FLEX-3000 http://www.qsl.net/kp4md/lpfilter.htm Carol, KP4MD/W6 ___ 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] The new 472-479 kHz band - REAL DX
+1 Thanks for the information. On Mon, Feb 20, 2012 at 10:56 AM, Carol F. Milazzo, KP4MD/W6 kp...@cfmilazzo.com wrote: Here is a description of a simple low pass filter with a 510 kHz cutoff frequency I built for my FLEX-3000 http://www.qsl.net/kp4md/lpfilter.htm Carol, KP4MD/W6 ___ 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/ -- Steven L Hess ARS KC6KGE DM05gd22 Skype user flamebait Cell 661 487 0357 (Facetime) Google Voice 661 769 6201 openSUSE Linux 11.4 ___ 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] The new 472-479 kHz band - REAL DX
I am a newbe to flex but looking at your screenshot it looks like the preamp for RX1 is on and the preamp for RX2 is off. Could that be messing things up? Sigh... I suppose this is what software radio is all about - frustration!! G I have NO idea how the preamp appears to be turned on in that picture. I went back out to the shack today, and try as I might, I was never able to get the preamp to be switched on or off with either receiver. They are consistently grayed out below 2.01 MHz. What's even more frustrating, is that it appears that the problem may be related to the antenna switching relay matrix. Depending on what band I start from, I find that I am often unable to actually change the antenna connections for RX1 - it stays stuck physically on ANT1, no matter what the selector form says. I can usually (but not always!) change the input to RX2 to any of the settings, except, of course, to the one that RX1 is actually connected to at the time. Usually I have to shut down PSDR, close the program, and power cycle the F5K to recover control of the relay matrix. After carefully powering everything up from a cold start, I selected ANT1 to RX1, and ANT1 TAP to RX2, selected 160 meters on RX1 and RX2, then manually tuned down to 475 KHz. Amazingly enough, both RX's actually showed the same sensitivity, which is a Good Thing.(tm) However, as soon as I switched the relays a few times, the low sensitivity of RX1 returned. Grr!! Something, somewhere, is getting confused. It's also very scary when the software decides to send the full 100 watts from the F5K to the ALS-1300 amplifier when the correct drive level for the '1300 is only 40 watts. This results in an immediate trip of the overloads in the amplifier. Most often this happens following a QSY to a different band. I have gotten into the habit of looking at the PSDR screen every time just before I key the rig - just in case. I REALLY don't want to blow up the '1300. Again. Don't get me wrong; I LOVE this rig, but I'm going to keep some of my old manually operated stuff as a backup, just in case. 73, Ralph W5JGV - WD2XSH/7 ___ 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] The new 472-479 kHz band - REAL DX
My Flex-5000 is utterly deaf below the U.S. AM broadcast band. Can't even pick up local airport Non-Directional Beacons. But I do some longwave listening with my old Kenwood TS-850/HF vertical and often hear European AM broadcast stations in the 150-200 kHz range even from my QTH in Missouri. Radio France Inter can often be heard from local sunset until sunrise in Europe on 162 kKHz. The BBC station on 198 kHz is almost as loud. It's easy to assume that these signals are spurs from local AM stations but they make the very long trip using immense power, often above a megawatt. Even very low power 600-meter ham beacons around 500 kHz can be heard over most of the U.S. Don't sell longwave short. 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] The new 472-479 kHz band - REAL DX
I'm surprised the Flex-5000 is so deaf. My 1500 receives perfectly well down to about 480 something kilohertz, then the bandpass filter clicks out and all heck breaks loose. Lots of room to hear most of the 600m band. I guess there's something different in the hardware...well, there's a ton different in the hardware! I built a simple lowpass filter that opens the longwave band up right down to 100 kHz. It probably works down further but there's not much down that far that can be decoded with one's own ears. Don't sell longwave short. I see a new bumper sticker in there somewhere! :-) 73, Ken VE3HLS From: Jeff Singer jsin...@i1.net To: flexradio@flex-radio.biz Sent: Sunday, February 19, 2012 10:02:51 AM Subject: [Flexradio] The new 472-479 kHz band - REAL DX My Flex-5000 is utterly deaf below the U.S. AM broadcast band. Can't even pick up local airport Non-Directional Beacons. But I do some longwave listening with my old Kenwood TS-850/HF vertical and often hear European AM broadcast stations in the 150-200 kHz range even from my QTH in Missouri. Radio France Inter can often be heard from local sunset until sunrise in Europe on 162 kKHz. The BBC station on 198 kHz is almost as loud. It's easy to assume that these signals are spurs from local AM stations but they make the very long trip using immense power, often above a megawatt. Even very low power 600-meter ham beacons around 500 kHz can be heard over most of the U.S. Don't sell longwave short. 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] The new 472-479 kHz band - REAL DX
As I have mentioned, I and many other hams have the desire to listen down at those frequencies with our Flex radios. What I have not heard is an official comment on the specifications are at below 1.8 mhz. From what I have heard it is best just to use an upconverter that will output at a frequency that Flex has designed the radio for. All is quiet on the official word front. Does anyone know when the secondary basis goes into affect? The 1 watt ERP is nothing to write home about. At least there are no antenna restrictions as in the Lowfer hobby. Maybe this new allocation will spark more interest in hams wanting to experiment with the lowfer,medfer and highfer experimental frequencies. If you do not know anything about these non licensed part 15 bands, just go onto the longwave club of America's website. There are some of the same allocations given to other countries. Radio communications is a great hobby, it does bot have to be restricted to the amateur frequencies. 73, Robert KB6QXM Ham Radio Open Conversation Yahoo group owner/moderator - Reply message - From: Ken Alexander k.alexan...@rogers.com To: Jeff Singer jsin...@i1.net, flexradio@flex-radio.biz flexradio@flex-radio.biz Subject: [Flexradio] The new 472-479 kHz band - REAL DX Date: Sun, Feb 19, 2012 7:32 am I'm surprised the Flex-5000 is so deaf. My 1500 receives perfectly well down to about 480 something kilohertz, then the bandpass filter clicks out and all heck breaks loose. Lots of room to hear most of the 600m band. I guess there's something different in the hardware...well, there's a ton different in the hardware! I built a simple lowpass filter that opens the longwave band up right down to 100 kHz. It probably works down further but there's not much down that far that can be decoded with one's own ears. Don't sell longwave short. I see a new bumper sticker in there somewhere! :-) 73, Ken VE3HLS From: Jeff Singer jsin...@i1.net To: flexradio@flex-radio.biz Sent: Sunday, February 19, 2012 10:02:51 AM Subject: [Flexradio] The new 472-479 kHz band - REAL DX My Flex-5000 is utterly deaf below the U.S. AM broadcast band. Can't even pick up local airport Non-Directional Beacons. But I do some longwave listening with my old Kenwood TS-850/HF vertical and often hear European AM broadcast stations in the 150-200 kHz range even from my QTH in Missouri. Radio France Inter can often be heard from local sunset until sunrise in Europe on 162 kKHz. The BBC station on 198 kHz is almost as loud. It's easy to assume that these signals are spurs from local AM stations but they make the very long trip using immense power, often above a megawatt. Even very low power 600-meter ham beacons around 500 kHz can be heard over most of the U.S. Don't sell longwave short. 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] The new 472-479 kHz band - REAL DX
Ken, I was likewise surprised by your statement about successfully using the Flex-1500 to receive 600 meter ham beacons. I've read Flex discussion boards for several years. To the very limited degree that users comment on the lowfer receive performance of Flex radios, posts have always suggested the 3000 and 5000 are worthless below the BCB (and perhaps not great even on the AM BCB). I wonder what's so different about the 1500 in that regard. I agree with KB6QXM that the upcoming allocation should once again Spark [his term] ham interest in lowfer radio so we Don't Sell Longwave Short. Jeff K0OD From: Ken Alexander [mailto:k.alexan...@rogers.com] Sent: Sunday, February 19, 2012 9:32 AM To: Jeff Singer; flexradio@flex-radio.biz Subject: Re: [Flexradio] The new 472-479 kHz band - REAL DX I'm surprised the Flex-5000 is so deaf. My 1500 receives perfectly well down to about 480 something kilohertz, then the bandpass filter clicks out and all heck breaks loose. Lots of room to hear most of the 600m band. I guess there's something different in the hardware...well, there's a ton different in the hardware! I built a simple lowpass filter that opens the longwave band up right down to 100 kHz. It probably works down further but there's not much down that far that can be decoded with one's own ears. Don't sell longwave short. I see a new bumper sticker in there somewhere! :-) 73, Ken VE3HLS _ From: Jeff Singer jsin...@i1.net To: flexradio@flex-radio.biz Sent: Sunday, February 19, 2012 10:02:51 AM Subject: [Flexradio] The new 472-479 kHz band - REAL DX My Flex-5000 is utterly deaf below the U.S. AM broadcast band. Can't even pick up local airport Non-Directional Beacons. But I do some longwave listening with my old Kenwood TS-850/HF vertical and often hear European AM broadcast stations in the 150-200 kHz range even from my QTH in Missouri. Radio France Inter can often be heard from local sunset until sunrise in Europe on 162 kHz. The BBC station on 198 kHz is almost as loud. It's easy to assume that these signals are spurs from local AM stations but they make the very long trip using immense power, often above a megawatt. Even very low power 600-meter ham beacons around 500 kHz can be heard over most of the U.S. Don't sell longwave short. 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] The new 472-479 kHz band - REAL DX
Hi Jeff and all, But I do some longwave listening with my old Kenwood TS-850/HF vertical and often hear European AM broadcast stations in the 150-200 kHz range even from my QTH in Missouri. Radio France Inter can often be heard from local sunset until sunrise in Europe on 162 kHz. The BBC station on 198 kHz is almost as loud. Interesting. This means that your S/N for these stations is somethinh like 3 dB in 5kHz bandwidth or perhaps better. It's easy to assume that these signals are spurs from local AM stations but they make the very long trip using immense power, often above a megawatt. Even very low power 600-meter ham beacons around 500 kHz can be heard over most of the U.S. Your observation that 1 MW will give a reasonable trans- atlantic signal in AM bandwidth means that 1W will give a reasonable signal in 5 mHz (milliHz) bandwidth. We can easily communicate with QRSS if Rx and Tx are frequency stable enough. Have a look at this page: http://sm5bsz.com/linuxdsp/usage/am1030.htm Figure 7 shows AM carriers at a bandwidth of 3 mHz. Look at the signals around 1029.9975 kHz. There is no question that amateur QRSS would be perfectly reliable as a transatlantic communication link. With 3mHz bandwidth each FFT would have to span a time of something like 600 seconds (with a sine squared window) For good QRSS one might need 5 waterfall lines for a Morse code dot. The speed would be one dot in half an hour. One would not be able to transmit more than one or two letters in a whole night. I could transmit a qrss L in 5 hours on a random frequency in the band. Everyone in EU or in the US with any interest could report back my frequency and signal level. Not really a QSO, but simple with existing hardware and software. We can however develop much smarter coding than Morse coded CW:-) Don't sell longwave short. I do not follow the development, but I would guess interesting things already happen on 137 kHz. Now there will be two bands where really narrow bandwidth is possible. 73 Leif / SM5BSZ ___ 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] The new 472-479 kHz band - REAL DX
At 11:41 AM 2/19/2012, Jeff Singer wrote: Ken, I was likewise surprised by your statement about successfully using the Flex-1500 to receive 600 meter ham beacons. I've read Flex discussion boards for several years. To the very limited degree that users comment on the lowfer receive performance of Flex radios, posts have always suggested the 3000 and 5000 are worthless below the BCB (and perhaps not great even on the AM BCB). I wonder what's so different about the 1500 in that regard. Flex has similar frequency coverage specs for all radios, but mentions that additional preselectors or filters are required below 1.8 MHz, even for the 1500. I remember reading that the 5000 has a superior set of filters, so it may appear deader below 1.8 MHz than the other radios. http://www.flexradio.com/Products.aspx?topic=SDR_Feature_Matrix#notes Seems to me this is an opportunity for a third party kitter/manufacturer to supply an outboard preamp+filter product. Jerry W4UK ___ 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] The new 472-479 kHz band - REAL DX
I bet Flex has or, or plans to do, some market research to determine if it is viable to develop an upgrade, accessory, or new product that is capable of 600m. I imagine being first-to-market with a radio that can cover the new band could be good for business. Greg, N2GZ/1 -Original Message- From: flexradio-boun...@flex-radio.biz [mailto:flexradio-boun...@flex-radio.biz] On Behalf Of Jerry Flanders Sent: Sunday, February 19, 2012 12:59 PM To: Jeff Singer; 'Ken Alexander'; flexradio@flex-radio.biz Subject: Re: [Flexradio] The new 472-479 kHz band - REAL DX At 11:41 AM 2/19/2012, Jeff Singer wrote: Ken, I was likewise surprised by your statement about successfully using the Flex-1500 to receive 600 meter ham beacons. I've read Flex discussion boards for several years. To the very limited degree that users comment on the lowfer receive performance of Flex radios, posts have always suggested the 3000 and 5000 are worthless below the BCB (and perhaps not great even on the AM BCB). I wonder what's so different about the 1500 in that regard. Flex has similar frequency coverage specs for all radios, but mentions that additional preselectors or filters are required below 1.8 MHz, even for the 1500. I remember reading that the 5000 has a superior set of filters, so it may appear deader below 1.8 MHz than the other radios. http://www.flexradio.com/Products.aspx?topic=SDR_Feature_Matrix#notes Seems to me this is an opportunity for a third party kitter/manufacturer to supply an outboard preamp+filter product. Jerry W4UK ___ 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] The new 472-479 kHz band - REAL DX
My Flex-5000 is utterly deaf below the U.S. AM broadcast band. Can't even pick up local airport Non-Directional Beacons. My F5K has RX2 installed. I have noticed that the sensitivity of RX1 is 37 dB poorer than RX2. AT 7 MHz, the gain difference between the two receivers is only 1 dB. And yes, an external low pass filter is an absolute must with the F5K for 600 meters. The TX is virtually useless, IMHO. 73, Ralph W5JGV - WD2XSH/7' ___ 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] The new 472-479 kHz band - REAL DX
Hi Jeff, I bought the Flex-1500 to use mainly as a mediumwave DXing receiver. The fact that it transmits is a bonus. Our local ham dealer said he has sold many 1500s to SWLs. As a DXing receiver it's $250 cheaper than the SDR competition and does the job very well. The 3000 and 5000 have even better receiver specs, but then you're paying for a lot more equipment than an SWL needs. I've never heard much in the 137 kHz allocation but have already logged a few stations on 600m, which interests me greatly. I'll be keeping an eye on the band from now on. 73 - Ken From: Jeff Singer jsin...@i1.net To: 'Ken Alexander' k.alexan...@rogers.com; flexradio@flex-radio.biz Sent: Sunday, February 19, 2012 11:41:48 AM Subject: RE: [Flexradio] The new 472-479 kHz band - REAL DX Ken, I was likewise surprised by your statement about successfully using the Flex-1500 to receive 600 meter ham beacons. I’ve read Flex discussion boards for several years. To the very limited degree that users comment on the lowfer receive performance of Flex radios, posts have always suggested the 3000 and 5000 are worthless below the BCB (and perhaps not great even on the AM BCB). I wonder what’s so different about the 1500 in that regard. I agree with KB6QXM that the upcoming allocation should once again “Spark” [his term] ham interest in lowfer radio so we “Don’t Sell Longwave Short.” Jeff K0OD From:Ken Alexander [mailto:k.alexan...@rogers.com] Sent: Sunday, February 19, 2012 9:32 AM To: Jeff Singer; flexradio@flex-radio.biz Subject: Re: [Flexradio] The new 472-479 kHz band - REAL DX I'm surprised the Flex-5000 is so deaf. My 1500 receives perfectly well down to about 480 something kilohertz, then the bandpass filter clicks out and all heck breaks loose. Lots of room to hear most of the 600m band. I guess there's something different in the hardware...well, there's a ton different in the hardware! I built a simple lowpass filter that opens the longwave band up right down to 100 kHz. It probably works down further but there's not much down that far that can be decoded with one's own ears. Don't sell longwave short. I see a new bumper sticker in there somewhere! :-) 73, Ken VE3HLS From:Jeff Singer jsin...@i1.net To: flexradio@flex-radio.biz Sent: Sunday, February 19, 2012 10:02:51 AM Subject: [Flexradio] The new 472-479 kHz band - REAL DX My Flex-5000 is utterly deaf below the U.S. AM broadcast band. Can't even pick uplocal airport Non-Directional Beacons. But I do some longwave listening with my old Kenwood TS-850/HF vertical and often hear European AM broadcast stations in the 150-200 kHz range even from my QTH inMissouri. Radio France Inter can often be heard from local sunset until sunrise in Europe on 162 kHz. The BBC station on 198 kHz is almost as loud. It's easy to assume that these signals are spurs from local AM stations but they make the very long trip using immense power, often above a megawatt. Evenvery low power 600-meter ham beacons around 500 kHz can be heard over most of the U.S. Don't sell longwave short. 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] The new 472-479 kHz band - REAL DX
I just checked on my 1500 and what I notice is that when I change frequency from 481 kHz to 480kHz whatever filter is currently in the front end is removed/bypassed because and the receiver front end is wide open to everything from mediumwave stations to hams participating in the ARRL DX contest this weekend. It becomes a total mess. I designed a lowpass filter that rolls off at 400 kHz. I chose 400 kHz because then there's sufficient attenuation at the lower mediumwave band. If I designed it to roll off at 500 kHz then some strong locals on 530 and 590 would bleed through. One or two people have asked me to share the design I came up with. I'm happy to do that and as soon as I put it in readable form I'll let everybody know and they can roll their own. 73 - Ken From: Jerry Flanders jefland...@comcast.net To: Jeff Singer jsin...@i1.net; 'Ken Alexander' k.alexan...@rogers.com; flexradio@flex-radio.biz Sent: Sunday, February 19, 2012 12:58:40 PM Subject: Re: [Flexradio] The new 472-479 kHz band - REAL DX At 11:41 AM 2/19/2012, Jeff Singer wrote: Ken, I was likewise surprised by your statement about successfully using the Flex-1500 to receive 600 meter ham beacons. I've read Flex discussion boards for several years. To the very limited degree that users comment on the lowfer receive performance of Flex radios, posts have always suggested the 3000 and 5000 are worthless below the BCB (and perhaps not great even on the AM BCB). I wonder what's so different about the 1500 in that regard. Flex has similar frequency coverage specs for all radios, but mentions that additional preselectors or filters are required below 1.8 MHz, even for the 1500. I remember reading that the 5000 has a superior set of filters, so it may appear deader below 1.8 MHz than the other radios. http://www.flexradio.com/Products.aspx?topic=SDR_Feature_Matrix#notes Seems to me this is an opportunity for a third party kitter/manufacturer to supply an outboard preamp+filter product. Jerry W4UK ___ 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] The new 472-479 kHz band - REAL DX
Surprised at your observation, I checked my 5000a and noticed that if RX1 preamp is off, I get same results on both RXes at 485 KHz, but if RX1 preamp is on, the baselines are different and I see an apparent difference of 30-something dB. Are you using the same settings on both receivers? Jerry W4UK At 04:46 PM 2/19/2012, Ralph W5JGV wrote: My Flex-5000 is utterly deaf below the U.S. AM broadcast band. Can't even pick up local airport Non-Directional Beacons. My F5K has RX2 installed. I have noticed that the sensitivity of RX1 is 37 dB poorer than RX2. AT 7 MHz, the gain difference between the two receivers is only 1 dB. And yes, an external low pass filter is an absolute must with the F5K for 600 meters. The TX is virtually useless, IMHO. 73, Ralph W5JGV - WD2XSH/7' ___ 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] The new 472-479 kHz band - REAL DX
On Sun, Feb 19, 2012 at 3:05 PM, Ken Alexander k.alexan...@rogers.comwrote: I just checked on my 1500 and what I notice is that when I change frequency from 481 kHz to 480kHz whatever filter is currently in the front end is removed/bypassed because and the receiver front end is wide open to everything from mediumwave stations to hams participating in the ARRL DX contest this weekend. It becomes a total mess. I designed a lowpass filter that rolls off at 400 kHz. I chose 400 kHz because then there's sufficient attenuation at the lower mediumwave band. If I designed it to roll off at 500 kHz then some strong locals on 530 and 590 would bleed through. One or two people have asked me to share the design I came up with. I'm happy to do that and as soon as I put it in readable form I'll let everybody know and they can roll their own. You might also want to consider a sharp, two stage, tunable, LC bandpass filter. We are only talking about a band that is 7kHz wide. I would think that a lowpass filter would be difficult to make and a simple tunable bandpass preselector would work better. One other thing that would be nice is to have an option to bypass the built-in front-end filters thus allowing selection of an external filter. -- 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] The new 472-479 kHz band - REAL DX
One other thing that would be nice is to have an option to bypass the built-in front-end filters thus allowing selection of an external filter. It's not an option, but that's what my 1500 does right out of the box. The front end filters (appear to) cut out when I tune down from 481 kHz. All is well on 481. It's a total mess on 480 kHz and below. 73 - Ken From: Brian Lloyd brian-wb6...@lloyd.com To: Ken Alexander k.alexan...@rogers.com Cc: Jerry Flanders jefland...@comcast.net; Jeff Singer jsin...@i1.net; flexradio@flex-radio.biz flexradio@flex-radio.biz Sent: Sunday, February 19, 2012 8:03:52 PM Subject: Re: [Flexradio] The new 472-479 kHz band - REAL DX On Sun, Feb 19, 2012 at 3:05 PM, Ken Alexander k.alexan...@rogers.com wrote: I just checked on my 1500 and what I notice is that when I change frequency from 481 kHz to 480kHz whatever filter is currently in the front end is removed/bypassed because and the receiver front end is wide open to everything from mediumwave stations to hams participating in the ARRL DX contest this weekend. It becomes a total mess. I designed a lowpass filter that rolls off at 400 kHz. I chose 400 kHz because then there's sufficient attenuation at the lower mediumwave band. If I designed it to roll off at 500 kHz then some strong locals on 530 and 590 would bleed through. One or two people have asked me to share the design I came up with. I'm happy to do that and as soon as I put it in readable form I'll let everybody know and they can roll their own. You might also want to consider a sharp, two stage, tunable, LC bandpass filter. We are only talking about a band that is 7kHz wide. I would think that a lowpass filter would be difficult to make and a simple tunable bandpass preselector would work better. One other thing that would be nice is to have an option to bypass the built-in front-end filters thus allowing selection of an external filter. -- 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] The new 472-479 kHz band - REAL DX
The FLEX-1500's low frequency hardware band pass filter starts to roll off @ 490 KHz very rapidly. Tim Ellison, W4TME Product Management, Sales Support FlexRadio Systems^(TM) 4616 W Howard Ln, Suite 1-150 Austin, TX 78728 Phone: 512-535-4713 Ext. 223 Email: t...@flexradio.com mailto:t...@flexradio.com Web: www.flexradio.com http://www.flexradio.com logo On 2/19/2012 8:12 PM, Ken Alexander wrote: One other thing that would be nice is to have an option to bypass the built-in front-end filters thus allowing selection of an external filter. It's not an option, but that's what my 1500 does right out of the box. The front end filters (appear to) cut out when I tune down from 481 kHz. All is well on 481. It's a total mess on 480 kHz and below. 73 - Ken From: Brian Lloydbrian-wb6...@lloyd.com To: Ken Alexanderk.alexan...@rogers.com Cc: Jerry Flandersjefland...@comcast.net; Jeff Singerjsin...@i1.net; flexradio@flex-radio.bizflexradio@flex-radio.biz Sent: Sunday, February 19, 2012 8:03:52 PM Subject: Re: [Flexradio] The new 472-479 kHz band - REAL DX On Sun, Feb 19, 2012 at 3:05 PM, Ken Alexanderk.alexan...@rogers.com wrote: I just checked on my 1500 and what I notice is that when I change frequency from 481 kHz to 480kHz whatever filter is currently in the front end is removed/bypassed because and the receiver front end is wide open to everything from mediumwave stations to hams participating in the ARRL DX contest this weekend. It becomes a total mess. I designed a lowpass filter that rolls off at 400 kHz. I chose 400 kHz because then there's sufficient attenuation at the lower mediumwave band. If I designed it to roll off at 500 kHz then some strong locals on 530 and 590 would bleed through. One or two people have asked me to share the design I came up with. I'm happy to do that and as soon as I put it in readable form I'll let everybody know and they can roll their own. You might also want to consider a sharp, two stage, tunable, LC bandpass filter. We are only talking about a band that is 7kHz wide. I would think that a lowpass filter would be difficult to make and a simple tunable bandpass preselector would work better. One other thing that would be nice is to have an option to bypass the built-in front-end filters thus allowing selection of an external filter. ___ 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] The new 472-479 kHz band - REAL DX
Tim, Any comments on the filter rolloff in the 3000 and the 5000a? 73, Robert KB6QXM Ham Radio Open Conversation Yahoo group owner/moderator - Reply message - From: Tim Ellison, W4TME t...@flex-radio.com To: flexradio@flex-radio.biz Subject: [Flexradio] The new 472-479 kHz band - REAL DX Date: Sun, Feb 19, 2012 5:19 pm The FLEX-1500's low frequency hardware band pass filter starts to roll off @ 490 KHz very rapidly. Tim Ellison, W4TME Product Management, Sales Support FlexRadio Systems^(TM) 4616 W Howard Ln, Suite 1-150 Austin, TX 78728 Phone: 512-535-4713 Ext. 223 Email: t...@flexradio.com mailto:t...@flexradio.com Web: www.flexradio.com http://www.flexradio.com logo On 2/19/2012 8:12 PM, Ken Alexander wrote: One other thing that would be nice is to have an option to bypass the built-in front-end filters thus allowing selection of an external filter. It's not an option, but that's what my 1500 does right out of the box. The front end filters (appear to) cut out when I tune down from 481 kHz. All is well on 481. It's a total mess on 480 kHz and below. 73 - Ken From: Brian Lloydbrian-wb6...@lloyd.com To: Ken Alexanderk.alexan...@rogers.com Cc: Jerry Flandersjefland...@comcast.net; Jeff Singerjsin...@i1.net; flexradio@flex-radio.bizflexradio@flex-radio.biz Sent: Sunday, February 19, 2012 8:03:52 PM Subject: Re: [Flexradio] The new 472-479 kHz band - REAL DX On Sun, Feb 19, 2012 at 3:05 PM, Ken Alexanderk.alexan...@rogers.com wrote: I just checked on my 1500 and what I notice is that when I change frequency from 481 kHz to 480kHz whatever filter is currently in the front end is removed/bypassed because and the receiver front end is wide open to everything from mediumwave stations to hams participating in the ARRL DX contest this weekend. It becomes a total mess. I designed a lowpass filter that rolls off at 400 kHz. I chose 400 kHz because then there's sufficient attenuation at the lower mediumwave band. If I designed it to roll off at 500 kHz then some strong locals on 530 and 590 would bleed through. One or two people have asked me to share the design I came up with. I'm happy to do that and as soon as I put it in readable form I'll let everybody know and they can roll their own. You might also want to consider a sharp, two stage, tunable, LC bandpass filter. We are only talking about a band that is 7kHz wide. I would think that a lowpass filter would be difficult to make and a simple tunable bandpass preselector would work better. One other thing that would be nice is to have an option to bypass the built-in front-end filters thus allowing selection of an external filter. ___ 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] The new 472-479 kHz band - REAL DX
All I hear on 472-479 on my Flex 5000 is a bunch of unintelligible broadcast images. -Original Message- From: flexradio-boun...@flex-radio.biz [mailto:flexradio-boun...@flex-radio.biz] On Behalf Of Jerry Flanders Sent: Sunday, February 19, 2012 6:19 PM To: w5...@w5jgv.com; flexradio@flex-radio.biz Subject: Re: [Flexradio] The new 472-479 kHz band - REAL DX Surprised at your observation, I checked my 5000a and noticed that if RX1 preamp is off, I get same results on both RXes at 485 KHz, but if RX1 preamp is on, the baselines are different and I see an apparent difference of 30-something dB. ___ 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] The new 472-479 kHz band - REAL DX
They do not go that low. I'll have to look it up and respond tomorrow. Tim Ellison, W4TME Product Management, Sales Support FlexRadio Systems™ 4616 W Howard Ln, Suite 1-150 Austin, TX 78728 Phone: 512-535-4713 Ext. 223 Email: t...@flexradio.com mailto:t...@flexradio.com Web: www.flexradio.com http://www.flexradio.com logo On 2/19/2012 8:38 PM, Robert Costa, KB6QXM wrote: Tim, Any comments on the filter rolloff in the 3000 and the 5000a? 73, Robert KB6QXM Ham Radio Open Conversation Yahoo group owner/moderator - Reply message - From: Tim Ellison, W4TME t...@flex-radio.com To: flexradio@flex-radio.biz Subject: [Flexradio] The new 472-479 kHz band - REAL DX Date: Sun, Feb 19, 2012 5:19 pm The FLEX-1500's low frequency hardware band pass filter starts to roll off @ 490 KHz very rapidly. Tim Ellison, W4TME Product Management, Sales Support FlexRadio Systems^(TM) 4616 W Howard Ln, Suite 1-150 Austin, TX 78728 Phone: 512-535-4713 Ext. 223 Email: t...@flexradio.com mailto:t...@flexradio.com Web: www.flexradio.com http://www.flexradio.com logo On 2/19/2012 8:12 PM, Ken Alexander wrote: One other thing that would be nice is to have an option to bypass the built-in front-end filters thus allowing selection of an external filter. It's not an option, but that's what my 1500 does right out of the box. The front end filters (appear to) cut out when I tune down from 481 kHz. All is well on 481. It's a total mess on 480 kHz and below. 73 - Ken From: Brian Lloydbrian-wb6...@lloyd.com To: Ken Alexanderk.alexan...@rogers.com Cc: Jerry Flandersjefland...@comcast.net; Jeff Singerjsin...@i1.net; flexradio@flex-radio.bizflexradio@flex-radio.biz Sent: Sunday, February 19, 2012 8:03:52 PM Subject: Re: [Flexradio] The new 472-479 kHz band - REAL DX On Sun, Feb 19, 2012 at 3:05 PM, Ken Alexanderk.alexan...@rogers.com wrote: I just checked on my 1500 and what I notice is that when I change frequency from 481 kHz to 480kHz whatever filter is currently in the front end is removed/bypassed because and the receiver front end is wide open to everything from mediumwave stations to hams participating in the ARRL DX contest this weekend. It becomes a total mess. I designed a lowpass filter that rolls off at 400 kHz. I chose 400 kHz because then there's sufficient attenuation at the lower mediumwave band. If I designed it to roll off at 500 kHz then some strong locals on 530 and 590 would bleed through. One or two people have asked me to share the design I came up with. I'm happy to do that and as soon as I put it in readable form I'll let everybody know and they can roll their own. You might also want to consider a sharp, two stage, tunable, LC bandpass filter. We are only talking about a band that is 7kHz wide. I would think that a lowpass filter would be difficult to make and a simple tunable bandpass preselector would work better. One other thing that would be nice is to have an option to bypass the built-in front-end filters thus allowing selection of an external filter. ___ 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] The new 472-479 kHz band - REAL DX
On Sun, Feb 19, 2012 at 5:12 PM, Ken Alexander k.alexan...@rogers.comwrote: One other thing that would be nice is to have an option to bypass the built-in front-end filters thus allowing selection of an external filter. It's not an option, but that's what my 1500 does right out of the box. The front end filters (appear to) cut out when I tune down from 481 kHz. All is well on 481. It's a total mess on 480 kHz and below. I understand. But I was thinking in terms of the 5000 and 3000 mostly, and also with the option of doing that for other frequencies and not just LF. -- 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] The new 472-479 kHz band - REAL DX
Surprised at your observation, I checked my 5000a and noticed that if RX1 preamp is off, I get same results on both RXes at 485 KHz, but if RX1 preamp is on, the baselines are different and I see an apparent difference of 30-something dB. Are you using the same settings on both receivers? Hello Jerry, Yes, I am. See this screen shot: http://w5jgv.com/special/RX1-RX2.jpg (177 kB) It shows that both RX's are set for USB reception, with a 2.7 KHz bandwidth. A 50 Ohm dummy load is connected to the ANT1. The signal on the screen is my PSK31 200 watt transmitter while it is on the air. The antenna connections are: RX1 to ANT1 connector RX2 to ANT1 TAP You can see the signal level difference between the RX's. The gain of RX2 is about the same as both of my Yaesu FT-747GX's. I therefore conclude that RX1 is deaf. As for the preamps, in my F5K, the preamps on both RX's are grayed out and not available at frequencies at or below 2.000 MHz. 73, Ralph W5JGV - WD2XSH/7 ___ 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/
