Re: [time-nuts] Active LORAN antenna
Gentlemen, I would like to thank you all for your help in this affair. In the meantime we have both built the antenna according Stan's circuit and it seems to perform well. It seems however that the antenna needs to be put a bit away from the receiver itself because otherwise some kind of self-oscillation is observed. While 1 k and 100 k are indeed far away from each other: I tried the circuit with 0 k (!) and with 100 k without seeing a difference in performance. BTW: Since a few of you have the antenna circuit, do you have perhaps the scchematics of the receiver itself too? Best regrads Ulrich Bangert -Ursprungliche Nachricht- Von: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] Im Auftrag von George Dubovsky Gesendet: Montag, 29. August 2011 17:22 An: Discussion of precise time and frequency measurement Betreff: Re: [time-nuts] Active LORAN antenna Ulrich, I have the SRS active antenna schematic FS700-14, Revision B, and it is identical to Stan's schematic except that my R3 is 1k and his is 100k. Don't know which is the newer schematic. 73, geo - n4ua On Fri, Aug 26, 2011 at 9:02 AM, Stan, W1LE stanw...@verizon.net wrote: Hello UL, My SRS active antenna is internally potted in resin, so tracing the circuit is difficult. I was able to chip away the PVC white housing and some of the black potting material to get at the antenna input terminal. Then I repackaged it with a new CB antenna. Living on Cape Cod, quite near to the former Nantucket Loran station, I can only rarely receive some of the European stations. The schematic in the manual shows a switch or a jumper for the gain reduction. So, the schematic is probably an old version, and all bets are off as to what the production models, we have, consist of. I did buy the manual form SRS and the active antenna schematic shows a 2N5951, not the 2N5991 you mention. My schematic is a rev B, Document Number FS700-14 This document in not dated. The frequency selective L-C filter network is different, see attachment. If the attachment does not get thru, please send your direct e-mail address. Stan, W1LE Cape CodFN41sr On 8/26/2011 6:00 AM, Ulrich Bangert wrote: Gentlemen, my friend Frank and I both miss the matching actice antenna for our Standford Research FS700 Loran frequency standards. We also do not have a schematic of it. Nevertheless we have tried to re-engineer the circut from the part's list and the circuit description in the FS700 manual. Our result is shown in the accompanying schematic.pdf. The generator in the left in conjunction with the 10 k resistor represents the expected high footpoint impedance of the very short (3 m) antenna. The VDD in the right in conjunction with the 100 ohms resistor represents what it believed to be inside the FS700. Not shown here is a 100 k resistor that may be included between the filter output and the 7 k resistor to form a 30 dB divider together with it. Also not shown is a 390 micro henry inductance which's impact is not to be found in the circuit descripion. Also not shown is a small neon bulb for overvoltage protection. The ac analysis shows that the overall filter function is well around 100 kHz. But it seems as if the fet (a 2N5991 in the original) would not have enough gain to counteract the overall damping included in the front end let alone to deliver some additional gain for the receiver's front end. We both feed the receiver currently with dipoles for 80 m ham radio and a resistor that makes the receiver think the active antenna is connected. The receiver has a possible total of 130 dB gain and my receiver says it uses 94 dB gain while Franks receiver says it uses 102 dB gain. The noise margin is also a bit better on my location. However, if one looks at the manual f.e. at page 17 one could get the impression as if a receiver gain of 75 dB may be considered much more normal as our values. Instead of improving the reception everything gets even worse if the active antenna is connected. I should also note that my qth is only 200 km away from SYLT (our German Loran station) while Frank is even 70 km nearer to it. Questions: 1) Anyone an idea what we are possibly doing wrong? 2) Anyone an idea for the 390 micro henry inductor? 3) Anyone own the original schematic? TIA for your help Ulrich Bangert www.ulrich-bangert.de Ortholzer Weg 1 27243 Gross Ippener __**_ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/** mailman/listinfo/time-nutshttps://www.febo.com/cgi-bin/mailman/listi nfo/time-nuts and follow the instructions there. ___ time-nuts
Re: [time-nuts] Active LORAN antenna
Hello Ulrich, There are 13 each, double pages of schematics for the FS700. Most of my pages are marked up. When I got the manual, before I had the hardware, I read it thru and I highlighted each adjustment in the circuit to get a better understanding. Not much of a plot, but a pretty good story. If you need a specific page, I can scan each 1/2 page and you can paste together on receipt. All I have is a simple A size Cannon scanner, but I can scan to high resolution. The other alternative is to get a new manual from Stanford Research Systems for ~ 35$ Shipping may be a killer. Please advise. Stan, W1LE Cape CodFN41sr On 8/31/2011 6:53 AM, Ulrich Bangert wrote: Gentlemen, I would like to thank you all for your help in this affair. In the meantime we have both built the antenna according Stan's circuit and it seems to perform well. It seems however that the antenna needs to be put a bit away from the receiver itself because otherwise some kind of self-oscillation is observed. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Active LORAN antenna
Stan, in the long term it may be interesting to have them all but I am currently most interested in the power supply schematic since my device seems to have problems with it. , unexpected resets, sometimes all led and display off and things like that. 73s and my best regards Ulrich, DF6JB Am 31.08.2011 um 14:37 schrieb Stan, W1LE: Hello Ulrich, There are 13 each, double pages of schematics for the FS700. Most of my pages are marked up. When I got the manual, before I had the hardware, I read it thru and I highlighted each adjustment in the circuit to get a better understanding. Not much of a plot, but a pretty good story. If you need a specific page, I can scan each 1/2 page and you can paste together on receipt. All I have is a simple A size Cannon scanner, but I can scan to high resolution. The other alternative is to get a new manual from Stanford Research Systems for ~ 35$ Shipping may be a killer. Please advise. Stan, W1LE Cape CodFN41sr On 8/31/2011 6:53 AM, Ulrich Bangert wrote: Gentlemen, I would like to thank you all for your help in this affair. In the meantime we have both built the antenna according Stan's circuit and it seems to perform well. It seems however that the antenna needs to be put a bit away from the receiver itself because otherwise some kind of self-oscillation is observed. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. Ulrich Bangert Ortholzer Weg1 27243 Gross Ippener Deutschland Tel +49 (0)4224 95071 Fax +49 (0)4224 95072 Mob +49 (0)172 8006546 www.ulrich-bangert.de ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Active LORAN antenna
Ulrich, I have the SRS active antenna schematic FS700-14, Revision B, and it is identical to Stan's schematic except that my R3 is 1k and his is 100k. Don't know which is the newer schematic. 73, geo - n4ua On Fri, Aug 26, 2011 at 9:02 AM, Stan, W1LE stanw...@verizon.net wrote: Hello UL, My SRS active antenna is internally potted in resin, so tracing the circuit is difficult. I was able to chip away the PVC white housing and some of the black potting material to get at the antenna input terminal. Then I repackaged it with a new CB antenna. Living on Cape Cod, quite near to the former Nantucket Loran station, I can only rarely receive some of the European stations. The schematic in the manual shows a switch or a jumper for the gain reduction. So, the schematic is probably an old version, and all bets are off as to what the production models, we have, consist of. I did buy the manual form SRS and the active antenna schematic shows a 2N5951, not the 2N5991 you mention. My schematic is a rev B, Document Number FS700-14 This document in not dated. The frequency selective L-C filter network is different, see attachment. If the attachment does not get thru, please send your direct e-mail address. Stan, W1LE Cape CodFN41sr On 8/26/2011 6:00 AM, Ulrich Bangert wrote: Gentlemen, my friend Frank and I both miss the matching actice antenna for our Standford Research FS700 Loran frequency standards. We also do not have a schematic of it. Nevertheless we have tried to re-engineer the circut from the part's list and the circuit description in the FS700 manual. Our result is shown in the accompanying schematic.pdf. The generator in the left in conjunction with the 10 k resistor represents the expected high footpoint impedance of the very short (3 m) antenna. The VDD in the right in conjunction with the 100 ohms resistor represents what it believed to be inside the FS700. Not shown here is a 100 k resistor that may be included between the filter output and the 7 k resistor to form a 30 dB divider together with it. Also not shown is a 390 micro henry inductance which's impact is not to be found in the circuit descripion. Also not shown is a small neon bulb for overvoltage protection. The ac analysis shows that the overall filter function is well around 100 kHz. But it seems as if the fet (a 2N5991 in the original) would not have enough gain to counteract the overall damping included in the front end let alone to deliver some additional gain for the receiver's front end. We both feed the receiver currently with dipoles for 80 m ham radio and a resistor that makes the receiver think the active antenna is connected. The receiver has a possible total of 130 dB gain and my receiver says it uses 94 dB gain while Franks receiver says it uses 102 dB gain. The noise margin is also a bit better on my location. However, if one looks at the manual f.e. at page 17 one could get the impression as if a receiver gain of 75 dB may be considered much more normal as our values. Instead of improving the reception everything gets even worse if the active antenna is connected. I should also note that my qth is only 200 km away from SYLT (our German Loran station) while Frank is even 70 km nearer to it. Questions: 1) Anyone an idea what we are possibly doing wrong? 2) Anyone an idea for the 390 micro henry inductor? 3) Anyone own the original schematic? TIA for your help Ulrich Bangert www.ulrich-bangert.de Ortholzer Weg 1 27243 Gross Ippener __**_ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/** mailman/listinfo/time-nutshttps://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
[time-nuts] Active LORAN antenna
Gentlemen, my friend Frank and I both miss the matching actice antenna for our Standford Research FS700 Loran frequency standards. We also do not have a schematic of it. Nevertheless we have tried to re-engineer the circut from the part's list and the circuit description in the FS700 manual. Our result is shown in the accompanying schematic.pdf. The generator in the left in conjunction with the 10 k resistor represents the expected high footpoint impedance of the very short (3 m) antenna. The VDD in the right in conjunction with the 100 ohms resistor represents what it believed to be inside the FS700. Not shown here is a 100 k resistor that may be included between the filter output and the 7 k resistor to form a 30 dB divider together with it. Also not shown is a 390 micro henry inductance which's impact is not to be found in the circuit descripion. Also not shown is a small neon bulb for overvoltage protection. The ac analysis shows that the overall filter function is well around 100 kHz. But it seems as if the fet (a 2N5991 in the original) would not have enough gain to counteract the overall damping included in the front end let alone to deliver some additional gain for the receiver's front end. We both feed the receiver currently with dipoles for 80 m ham radio and a resistor that makes the receiver think the active antenna is connected. The receiver has a possible total of 130 dB gain and my receiver says it uses 94 dB gain while Franks receiver says it uses 102 dB gain. The noise margin is also a bit better on my location. However, if one looks at the manual f.e. at page 17 one could get the impression as if a receiver gain of 75 dB may be considered much more normal as our values. Instead of improving the reception everything gets even worse if the active antenna is connected. I should also note that my qth is only 200 km away from SYLT (our German Loran station) while Frank is even 70 km nearer to it. Questions: 1) Anyone an idea what we are possibly doing wrong? 2) Anyone an idea for the 390 micro henry inductor? 3) Anyone own the original schematic? TIA for your help Ulrich Bangert www.ulrich-bangert.de Ortholzer Weg 1 27243 Gross Ippener Schematic.pdf Description: Adobe PDF document ACAnalysis.pdf Description: Adobe PDF document ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Active LORAN antenna
I have the schematic of the active antenna, but I will not be able to get to it until Monday. 73, geo - n4ua On Fri, Aug 26, 2011 at 6:00 AM, Ulrich Bangert df...@ulrich-bangert.dewrote: Gentlemen, my friend Frank and I both miss the matching actice antenna for our Standford Research FS700 Loran frequency standards. We also do not have a schematic of it. Nevertheless we have tried to re-engineer the circut from the part's list and the circuit description in the FS700 manual. Our result is shown in the accompanying schematic.pdf. The generator in the left in conjunction with the 10 k resistor represents the expected high footpoint impedance of the very short (3 m) antenna. The VDD in the right in conjunction with the 100 ohms resistor represents what it believed to be inside the FS700. Not shown here is a 100 k resistor that may be included between the filter output and the 7 k resistor to form a 30 dB divider together with it. Also not shown is a 390 micro henry inductance which's impact is not to be found in the circuit descripion. Also not shown is a small neon bulb for overvoltage protection. The ac analysis shows that the overall filter function is well around 100 kHz. But it seems as if the fet (a 2N5991 in the original) would not have enough gain to counteract the overall damping included in the front end let alone to deliver some additional gain for the receiver's front end. We both feed the receiver currently with dipoles for 80 m ham radio and a resistor that makes the receiver think the active antenna is connected. The receiver has a possible total of 130 dB gain and my receiver says it uses 94 dB gain while Franks receiver says it uses 102 dB gain. The noise margin is also a bit better on my location. However, if one looks at the manual f.e. at page 17 one could get the impression as if a receiver gain of 75 dB may be considered much more normal as our values. Instead of improving the reception everything gets even worse if the active antenna is connected. I should also note that my qth is only 200 km away from SYLT (our German Loran station) while Frank is even 70 km nearer to it. Questions: 1) Anyone an idea what we are possibly doing wrong? 2) Anyone an idea for the 390 micro henry inductor? 3) Anyone own the original schematic? TIA for your help Ulrich Bangert www.ulrich-bangert.de Ortholzer Weg 1 27243 Gross Ippener ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Active LORAN antenna
Hi George, I appreciate your help a lot and the next week is surely early enough. 73s de Ulrich, DF6JB Am 26.08.2011 um 14:15 schrieb George Dubovsky: I have the schematic of the active antenna, but I will not be able to get to it until Monday. 73, geo - n4ua On Fri, Aug 26, 2011 at 6:00 AM, Ulrich Bangert df...@ulrich-bangert.dewrote: Gentlemen, my friend Frank and I both miss the matching actice antenna for our Standford Research FS700 Loran frequency standards. We also do not have a schematic of it. Nevertheless we have tried to re-engineer the circut from the part's list and the circuit description in the FS700 manual. Our result is shown in the accompanying schematic.pdf. The generator in the left in conjunction with the 10 k resistor represents the expected high footpoint impedance of the very short (3 m) antenna. The VDD in the right in conjunction with the 100 ohms resistor represents what it believed to be inside the FS700. Not shown here is a 100 k resistor that may be included between the filter output and the 7 k resistor to form a 30 dB divider together with it. Also not shown is a 390 micro henry inductance which's impact is not to be found in the circuit descripion. Also not shown is a small neon bulb for overvoltage protection. The ac analysis shows that the overall filter function is well around 100 kHz. But it seems as if the fet (a 2N5991 in the original) would not have enough gain to counteract the overall damping included in the front end let alone to deliver some additional gain for the receiver's front end. We both feed the receiver currently with dipoles for 80 m ham radio and a resistor that makes the receiver think the active antenna is connected. The receiver has a possible total of 130 dB gain and my receiver says it uses 94 dB gain while Franks receiver says it uses 102 dB gain. The noise margin is also a bit better on my location. However, if one looks at the manual f.e. at page 17 one could get the impression as if a receiver gain of 75 dB may be considered much more normal as our values. Instead of improving the reception everything gets even worse if the active antenna is connected. I should also note that my qth is only 200 km away from SYLT (our German Loran station) while Frank is even 70 km nearer to it. Questions: 1) Anyone an idea what we are possibly doing wrong? 2) Anyone an idea for the 390 micro henry inductor? 3) Anyone own the original schematic? TIA for your help Ulrich Bangert www.ulrich-bangert.de Ortholzer Weg 1 27243 Gross Ippener ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. Ulrich Bangert Ortholzer Weg1 27243 Gross Ippener Deutschland Tel +49 (0)4224 95071 Fax +49 (0)4224 95072 Mob +49 (0)172 8006546 www.ulrich-bangert.de ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Active LORAN antenna
Hello UL, My SRS active antenna is internally potted in resin, so tracing the circuit is difficult. I was able to chip away the PVC white housing and some of the black potting material to get at the antenna input terminal. Then I repackaged it with a new CB antenna. Living on Cape Cod, quite near to the former Nantucket Loran station, I can only rarely receive some of the European stations. The schematic in the manual shows a switch or a jumper for the gain reduction. So, the schematic is probably an old version, and all bets are off as to what the production models, we have, consist of. I did buy the manual form SRS and the active antenna schematic shows a 2N5951, not the 2N5991 you mention. My schematic is a rev B, Document Number FS700-14 This document in not dated. The frequency selective L-C filter network is different, see attachment. If the attachment does not get thru, please send your direct e-mail address. Stan, W1LE Cape CodFN41sr On 8/26/2011 6:00 AM, Ulrich Bangert wrote: Gentlemen, my friend Frank and I both miss the matching actice antenna for our Standford Research FS700 Loran frequency standards. We also do not have a schematic of it. Nevertheless we have tried to re-engineer the circut from the part's list and the circuit description in the FS700 manual. Our result is shown in the accompanying schematic.pdf. The generator in the left in conjunction with the 10 k resistor represents the expected high footpoint impedance of the very short (3 m) antenna. The VDD in the right in conjunction with the 100 ohms resistor represents what it believed to be inside the FS700. Not shown here is a 100 k resistor that may be included between the filter output and the 7 k resistor to form a 30 dB divider together with it. Also not shown is a 390 micro henry inductance which's impact is not to be found in the circuit descripion. Also not shown is a small neon bulb for overvoltage protection. The ac analysis shows that the overall filter function is well around 100 kHz. But it seems as if the fet (a 2N5991 in the original) would not have enough gain to counteract the overall damping included in the front end let alone to deliver some additional gain for the receiver's front end. We both feed the receiver currently with dipoles for 80 m ham radio and a resistor that makes the receiver think the active antenna is connected. The receiver has a possible total of 130 dB gain and my receiver says it uses 94 dB gain while Franks receiver says it uses 102 dB gain. The noise margin is also a bit better on my location. However, if one looks at the manual f.e. at page 17 one could get the impression as if a receiver gain of 75 dB may be considered much more normal as our values. Instead of improving the reception everything gets even worse if the active antenna is connected. I should also note that my qth is only 200 km away from SYLT (our German Loran station) while Frank is even 70 km nearer to it. Questions: 1) Anyone an idea what we are possibly doing wrong? 2) Anyone an idea for the 390 micro henry inductor? 3) Anyone own the original schematic? TIA for your help Ulrich Bangert www.ulrich-bangert.de Ortholzer Weg 1 27243 Gross Ippener ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. attachment: FS700 Active Antenna0050.jpg___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Active LORAN antenna
Stan you beat me to it. This is the schematic I also have. When LORAN C was active I was at 53 DB using a whip antenna 8' in length. But I wound 24 guage wire on a 8 ft fiberglass pole hundreds of turns as a single layer. This feeds a loran c preamp that used to be common. Nothing magic about it. The 99600 chain station was 90 miles from my location. Very clearly the filter on the frontend helps. Paul WB8TSL On Fri, Aug 26, 2011 at 9:02 AM, Stan, W1LE stanw...@verizon.net wrote: Hello UL, My SRS active antenna is internally potted in resin, so tracing the circuit is difficult. I was able to chip away the PVC white housing and some of the black potting material to get at the antenna input terminal. Then I repackaged it with a new CB antenna. Living on Cape Cod, quite near to the former Nantucket Loran station, I can only rarely receive some of the European stations. The schematic in the manual shows a switch or a jumper for the gain reduction. So, the schematic is probably an old version, and all bets are off as to what the production models, we have, consist of. I did buy the manual form SRS and the active antenna schematic shows a 2N5951, not the 2N5991 you mention. My schematic is a rev B, Document Number FS700-14 This document in not dated. The frequency selective L-C filter network is different, see attachment. If the attachment does not get thru, please send your direct e-mail address. Stan, W1LE Cape CodFN41sr On 8/26/2011 6:00 AM, Ulrich Bangert wrote: Gentlemen, my friend Frank and I both miss the matching actice antenna for our Standford Research FS700 Loran frequency standards. We also do not have a schematic of it. Nevertheless we have tried to re-engineer the circut from the part's list and the circuit description in the FS700 manual. Our result is shown in the accompanying schematic.pdf. The generator in the left in conjunction with the 10 k resistor represents the expected high footpoint impedance of the very short (3 m) antenna. The VDD in the right in conjunction with the 100 ohms resistor represents what it believed to be inside the FS700. Not shown here is a 100 k resistor that may be included between the filter output and the 7 k resistor to form a 30 dB divider together with it. Also not shown is a 390 micro henry inductance which's impact is not to be found in the circuit descripion. Also not shown is a small neon bulb for overvoltage protection. The ac analysis shows that the overall filter function is well around 100 kHz. But it seems as if the fet (a 2N5991 in the original) would not have enough gain to counteract the overall damping included in the front end let alone to deliver some additional gain for the receiver's front end. We both feed the receiver currently with dipoles for 80 m ham radio and a resistor that makes the receiver think the active antenna is connected. The receiver has a possible total of 130 dB gain and my receiver says it uses 94 dB gain while Franks receiver says it uses 102 dB gain. The noise margin is also a bit better on my location. However, if one looks at the manual f.e. at page 17 one could get the impression as if a receiver gain of 75 dB may be considered much more normal as our values. Instead of improving the reception everything gets even worse if the active antenna is connected. I should also note that my qth is only 200 km away from SYLT (our German Loran station) while Frank is even 70 km nearer to it. Questions: 1) Anyone an idea what we are possibly doing wrong? 2) Anyone an idea for the 390 micro henry inductor? 3) Anyone own the original schematic? TIA for your help Ulrich Bangert www.ulrich-bangert.de Ortholzer Weg 1 27243 Gross Ippener __**_ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/** mailman/listinfo/time-nutshttps://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Active LORAN antenna
Hi Ulrich: You might consider the AMRAD active antenna that they designed for the 136 kHz ham band. http://www.prc68.com/I/LF-Ant.shtml or the McKay Dymec DA-100 active whip. http://www.prc68.com/I/DR33.shtml#DA100 Have Fun, Brooke Clarke http://www.PRC68.com http://www.End2PartyGovernment.com/ Ulrich Bangert wrote: Gentlemen, my friend Frank and I both miss the matching actice antenna for our Standford Research FS700 Loran frequency standards. We also do not have a schematic of it. Nevertheless we have tried to re-engineer the circut from the part's list and the circuit description in the FS700 manual. Our result is shown in the accompanying schematic.pdf. The generator in the left in conjunction with the 10 k resistor represents the expected high footpoint impedance of the very short (3 m) antenna. The VDD in the right in conjunction with the 100 ohms resistor represents what it believed to be inside the FS700. Not shown here is a 100 k resistor that may be included between the filter output and the 7 k resistor to form a 30 dB divider together with it. Also not shown is a 390 micro henry inductance which's impact is not to be found in the circuit descripion. Also not shown is a small neon bulb for overvoltage protection. The ac analysis shows that the overall filter function is well around 100 kHz. But it seems as if the fet (a 2N5991 in the original) would not have enough gain to counteract the overall damping included in the front end let alone to deliver some additional gain for the receiver's front end. We both feed the receiver currently with dipoles for 80 m ham radio and a resistor that makes the receiver think the active antenna is connected. The receiver has a possible total of 130 dB gain and my receiver says it uses 94 dB gain while Franks receiver says it uses 102 dB gain. The noise margin is also a bit better on my location. However, if one looks at the manual f.e. at page 17 one could get the impression as if a receiver gain of 75 dB may be considered much more normal as our values. Instead of improving the reception everything gets even worse if the active antenna is connected. I should also note that my qth is only 200 km away from SYLT (our German Loran station) while Frank is even 70 km nearer to it. Questions: 1) Anyone an idea what we are possibly doing wrong? 2) Anyone an idea for the 390 micro henry inductor? 3) Anyone own the original schematic? TIA for your help Ulrich Bangert www.ulrich-bangert.de Ortholzer Weg 1 27243 Gross Ippener ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Active LORAN antenna
In message 4e57cbee.3000...@pacific.net, Brooke Clarke writes: You might consider the AMRAD active antenna that they designed for the 136 kHz ham band. If you want to build an active monopole, Chris Trasks secret design is far better and far more manageable than the AMRAD: http://www.home.earthlink.net/~christrask/Paper007.html I built this one with BFQ19+BQ149+J174+J310 all in SMD parts. (J270 is a better choice than J174 which tends to forward bias) With my primitive measurement methods, it was flat to 100 MHz and tapered off just short of 800MHz. In the other end it reliably pulls out the Russian ELF (OMEGA like) navigation system down around 10kHz. Chris mentioned that a kit might be underway, but I havn't seen any sign of it anywhere... -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 p...@freebsd.org | TCP/IP since RFC 956 FreeBSD committer | BSD since 4.3-tahoe Never attribute to malice what can adequately be explained by incompetence. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Active LORAN antenna
Hey Brooke, How are you doing? Are you still using that AMRAD antenna preamp I made for you several years ago? It's been several years since we emailed each other and I have lost contact with you until now. Last time I heard from you, your wife had run over the coax with the lawn mower and cut it into! Just curious if that thing was still working. 73's. Doug, k4cle. Connected by DROID on Verizon Wireless -Original message- From: Brooke Clarke bro...@pacific.net To: Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Fri, Aug 26, 2011 16:39:01 GMT+00:00 Subject: Re: [time-nuts] Active LORAN antenna Hi Ulrich: You might consider the AMRAD active antenna that they designed for the 136 kHz ham band. http://www.prc68.com/I/LF-Ant.shtml or the McKay Dymec DA-100 active whip. http://www.prc68.com/I/DR33.shtml#DA100 Have Fun, Brooke Clarke http://www.PRC68.com http://www.End2PartyGovernment.com/ Ulrich Bangert wrote: Gentlemen, my friend Frank and I both miss the matching actice antenna for our Standford Research FS700 Loran frequency standards. We also do not have a schematic of it. Nevertheless we have tried to re-engineer the circut from the part's list and the circuit description in the FS700 manual. Our result is shown in the accompanying schematic.pdf. The generator in the left in conjunction with the 10 k resistor represents the expected high footpoint impedance of the very short (3 m) antenna. The VDD in the right in conjunction with the 100 ohms resistor represents what it believed to be inside the FS700. Not shown here is a 100 k resistor that may be included between the filter output and the 7 k resistor to form a 30 dB divider together with it. Also not shown is a 390 micro henry inductance which's impact is not to be found in the circuit descripion. Also not shown is a small neon bulb for overvoltage protection. The ac analysis shows that the overall filter function is well around 100 kHz. But it seems as if the fet (a 2N5991 in the original) would not have enough gain to counteract the overall damping included in the front end let alone to deliver some additional gain for the receiver's front end. We both feed the receiver currently with dipoles for 80 m ham radio and a resistor that makes the receiver think the active antenna is connected. The receiver has a possible total of 130 dB gain and my receiver says it uses 94 dB gain while Franks receiver says it uses 102 dB gain. The noise margin is also a bit better on my location. However, if one looks at the manual f.e. at page 17 one could get the impression as if a receiver gain of 75 dB may be considered much more normal as our values. Instead of improving the reception everything gets even worse if the active antenna is connected. I should also note that my qth is only 200 km away from SYLT (our German Loran station) while Frank is even 70 km nearer to it. Questions: 1) Anyone an idea what we are possibly doing wrong? 2) Anyone an idea for the 390 micro henry inductor? 3) Anyone own the original schematic? TIA for your help Ulrich Bangert www.ulrich-bangert.de Ortholzer Weg 1 27243 Gross Ippener ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Active LORAN antenna
Hi Doug: It turns out that the fuses AMRAD specified were way too high in current to keep the transformer from being smoked. The only fuses that work are self resetting types. I've added them on the primary and secondary side of the transformer but have not yet reinstalled the antenna. I get requests every now and then for someone to build that AMRAD antenna. Are you still making them? Just sent an email to Chris Trask asking about his push pull design. My interest in active antennas is for the low frequency area where quarter wave wire antennas are not practical. For HF you can't beat wire antennas. Active antennas, either whip or loop do not work as well as wire. http://www.prc68.com/I/WireAntenna.shtml Have Fun, Brooke Clarke http://www.PRC68.com http://www.End2PartyGovernment.com/ k4...@aol.com wrote: Hey Brooke,How are you doing? Are you still using that AMRAD antenna preamp I made for you several years ago? It's been several years since we emailed each other and I have lost contact with you until now. Last time I heard from you, your wife had run over the coax with the lawn mower and cut it into! Just curious if that thing was still working. 73's. Doug, k4cle. Connected by DROID on Verizon Wireless -Original message- From: Brooke Clarke bro...@pacific.net To: Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Fri, Aug 26, 2011 16:39:01 GMT+00:00 Subject: Re: [time-nuts] Active LORAN antenna Hi Ulrich: You might consider the AMRAD active antenna that they designed for the136 kHz ham band. http://www.prc68.com/I/LF-Ant.shtml or the McKay Dymec DA-100 active whip. http://www.prc68.com/I/DR33.shtml#DA100 Have Fun, Brooke Clarke http://www.PRC68.com http://www.End2PartyGovernment.com/ Ulrich Bangert wrote: Gentlemen, my friend Frank and I both miss the matching actice antenna for our Standford Research FS700 Loran frequency standards. We also do not have a schematic of it. Nevertheless we have tried to re-engineer the circut from the part's list and the circuit description in the FS700 manual. Our result is shown in the accompanying schematic.pdf. The generator in the left in conjunction with the 10 k resistor represents the expected high footpoint impedance of the very short (3 m) antenna. The VDD in the right in conjunction with the 100 ohms resistor represents what it believed to be inside the FS700. Not shown here is a 100 k resistor that may be included between the filter output and the 7 k resistor to form a 30 dB divider together with it. Also not shown is a 390 micro henry inductance which's impact is not to be found in the circuit descripion. Also not shown is a small neon bulb for overvoltage protection. The ac analysis shows that the overall filter function is well around 100 kHz. But it seems as if the fet (a 2N5991 in the original) would not have enough gain to counteract the overall damping included in the front end let alone to deliver some additional gain for the receiver's front end. We both feed the receiver currently with dipoles for 80 m ham radio and a resistor that makes the receiver think the active antenna is connected. The receiver has a possible total of 130 dB gain and my receiver says it uses 94 dB gain while Franks receiver says it uses 102 dB gain. The noise margin is also a bit better on my location. However, if one looks at the manual f.e. at page 17 one could get the impression as if a receiver gain of 75 dB may be considered much more normal as our values. Instead of improving the reception everything gets even worse if the active antenna is connected. I should also note that my qth is only 200 km away from SYLT (our German Loran station) while Frank is even 70 km nearer to it. Questions: 1) Anyone an idea what we are possibly doing wrong? 2) Anyone an idea for the 390 micro henry inductor? 3) Anyone own the original schematic? TIA for your help Ulrich Bangert www.ulrich-bangert.de Ortholzer Weg 1 27243 Gross Ippener ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Active LORAN antenna
In message 4e5803cd.5020...@pacific.net, Brooke Clarke writes: My interest in active antennas is for the low frequency area where quarter wave wire antennas are not practical. That's why I built it: Loran-C, DCF77, Rugby and HBG. For HF you can't beat wire antennas. Active antennas, either whip or loop do not work as well as wire. Well, strictly specking he same is true for low frequency, there are terms in Maxwells equations which means that size matter. Poul-henning PS: Danish blog-post w/ pictures of my build of Chris Trasks antenna: http://ing.dk/artikel/96239-min-stakkels-revisor -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 p...@freebsd.org | TCP/IP since RFC 956 FreeBSD committer | BSD since 4.3-tahoe Never attribute to malice what can adequately be explained by incompetence. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Active LORAN antenna
Hi ESD is also an issue with outdoor active antennas. Even if you don't get a lightning hit, anything sticking up into the air can get a pretty good charge on it as the clouds go over. The blocking cap on the input to the Trask amp really isn't needed with a monopole. It's also unlikely to survive the summer. The real question is weather if fails open or as a short... Bob -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Brooke Clarke Sent: Friday, August 26, 2011 4:36 PM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Active LORAN antenna Hi Doug: It turns out that the fuses AMRAD specified were way too high in current to keep the transformer from being smoked. The only fuses that work are self resetting types. I've added them on the primary and secondary side of the transformer but have not yet reinstalled the antenna. I get requests every now and then for someone to build that AMRAD antenna. Are you still making them? Just sent an email to Chris Trask asking about his push pull design. My interest in active antennas is for the low frequency area where quarter wave wire antennas are not practical. For HF you can't beat wire antennas. Active antennas, either whip or loop do not work as well as wire. http://www.prc68.com/I/WireAntenna.shtml Have Fun, Brooke Clarke http://www.PRC68.com http://www.End2PartyGovernment.com/ k4...@aol.com wrote: Hey Brooke,How are you doing? Are you still using that AMRAD antenna preamp I made for you several years ago? It's been several years since we emailed each other and I have lost contact with you until now. Last time I heard from you, your wife had run over the coax with the lawn mower and cut it into! Just curious if that thing was still working. 73's. Doug, k4cle. Connected by DROID on Verizon Wireless -Original message- From: Brooke Clarke bro...@pacific.net To: Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Fri, Aug 26, 2011 16:39:01 GMT+00:00 Subject: Re: [time-nuts] Active LORAN antenna Hi Ulrich: You might consider the AMRAD active antenna that they designed for the136 kHz ham band. http://www.prc68.com/I/LF-Ant.shtml or the McKay Dymec DA-100 active whip. http://www.prc68.com/I/DR33.shtml#DA100 Have Fun, Brooke Clarke http://www.PRC68.com http://www.End2PartyGovernment.com/ Ulrich Bangert wrote: Gentlemen, my friend Frank and I both miss the matching actice antenna for our Standford Research FS700 Loran frequency standards. We also do not have a schematic of it. Nevertheless we have tried to re-engineer the circut from the part's list and the circuit description in the FS700 manual. Our result is shown in the accompanying schematic.pdf. The generator in the left in conjunction with the 10 k resistor represents the expected high footpoint impedance of the very short (3 m) antenna. The VDD in the right in conjunction with the 100 ohms resistor represents what it believed to be inside the FS700. Not shown here is a 100 k resistor that may be included between the filter output and the 7 k resistor to form a 30 dB divider together with it. Also not shown is a 390 micro henry inductance which's impact is not to be found in the circuit descripion. Also not shown is a small neon bulb for overvoltage protection. The ac analysis shows that the overall filter function is well around 100 kHz. But it seems as if the fet (a 2N5991 in the original) would not have enough gain to counteract the overall damping included in the front end let alone to deliver some additional gain for the receiver's front end. We both feed the receiver currently with dipoles for 80 m ham radio and a resistor that makes the receiver think the active antenna is connected. The receiver has a possible total of 130 dB gain and my receiver says it uses 94 dB gain while Franks receiver says it uses 102 dB gain. The noise margin is also a bit better on my location. However, if one looks at the manual f.e. at page 17 one could get the impression as if a receiver gain of 75 dB may be considered much more normal as our values. Instead of improving the reception everything gets even worse if the active antenna is connected. I should also note that my qth is only 200 km away from SYLT (our German Loran station) while Frank is even 70 km nearer to it. Questions: 1) Anyone an idea what we are possibly doing wrong? 2) Anyone an idea for the 390 micro henry inductor? 3) Anyone own the original schematic? TIA for your help Ulrich Bangert www.ulrich-bangert.de Ortholzer Weg 1 27243 Gross Ippener ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions
Re: [time-nuts] Active LORAN antenna
Hi Poul: It looks like the noise floor is maybe 10 dB higher than the AMRAD http://www.prc68.com/I/Images/AMRAD_BT.GIF or 30 dB higher than the McKay Dymec active antenna. http://www.prc68.com/I/Images/Da100nf.GIF Have Fun, Brooke Clarke http://www.PRC68.com http://www.End2PartyGovernment.com/ Poul-Henning Kamp wrote: In message4e5803cd.5020...@pacific.net, Brooke Clarke writes: My interest in active antennas is for the low frequency area where quarter wave wire antennas are not practical. That's why I built it: Loran-C, DCF77, Rugby and HBG. For HF you can't beat wire antennas. Active antennas, either whip or loop do not work as well as wire. Well, strictly specking he same is true for low frequency, there are terms in Maxwells equations which means that size matter. Poul-henning PS: Danish blog-post w/ pictures of my build of Chris Trasks antenna: http://ing.dk/artikel/96239-min-stakkels-revisor ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Active LORAN antenna
Hi Bob: My problem was the lawnmower cutting the coax between the antenna and it's DC power supply. The short on the output of the DC supply blew the very special transformer. Have Fun, Brooke Clarke http://www.PRC68.com http://www.End2PartyGovernment.com/ Bob Camp wrote: Hi ESD is also an issue with outdoor active antennas. Even if you don't get a lightning hit, anything sticking up into the air can get a pretty good charge on it as the clouds go over. The blocking cap on the input to the Trask amp really isn't needed with a monopole. It's also unlikely to survive the summer. The real question is weather if fails open or as a short... Bob -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Brooke Clarke Sent: Friday, August 26, 2011 4:36 PM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Active LORAN antenna Hi Doug: It turns out that the fuses AMRAD specified were way too high in current to keep the transformer from being smoked. The only fuses that work are self resetting types. I've added them on the primary and secondary side of the transformer but have not yet reinstalled the antenna. I get requests every now and then for someone to build that AMRAD antenna. Are you still making them? Just sent an email to Chris Trask asking about his push pull design. My interest in active antennas is for the low frequency area where quarter wave wire antennas are not practical. For HF you can't beat wire antennas. Active antennas, either whip or loop do not work as well as wire. http://www.prc68.com/I/WireAntenna.shtml Have Fun, Brooke Clarke http://www.PRC68.com http://www.End2PartyGovernment.com/ k4...@aol.com wrote: Hey Brooke,How are you doing? Are you still using that AMRAD antenna preamp I made for you several years ago? It's been several years since we emailed each other and I have lost contact with you until now. Last time I heard from you, your wife had run over the coax with the lawn mower and cut it into! Just curious if that thing was still working. 73's. Doug, k4cle. Connected by DROID on Verizon Wireless -Original message- From: Brooke Clarkebro...@pacific.net To: Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Fri, Aug 26, 2011 16:39:01 GMT+00:00 Subject: Re: [time-nuts] Active LORAN antenna Hi Ulrich: You might consider the AMRAD active antenna that they designed for the136 kHz ham band. http://www.prc68.com/I/LF-Ant.shtml or the McKay Dymec DA-100 active whip. http://www.prc68.com/I/DR33.shtml#DA100 Have Fun, Brooke Clarke http://www.PRC68.com http://www.End2PartyGovernment.com/ Ulrich Bangert wrote: Gentlemen, my friend Frank and I both miss the matching actice antenna for our Standford Research FS700 Loran frequency standards. We also do not have a schematic of it. Nevertheless we have tried to re-engineer the circut from the part's list and the circuit description in the FS700 manual. Our result is shown in the accompanying schematic.pdf. The generator in the left in conjunction with the 10 k resistor represents the expected high footpoint impedance of the very short (3 m) antenna. The VDD in the right in conjunction with the 100 ohms resistor represents what it believed to be inside the FS700. Not shown here is a 100 k resistor that may be included between the filter output and the 7 k resistor to form a 30 dB divider together with it. Also not shown is a 390 micro henry inductance which's impact is not to be found in the circuit descripion. Also not shown is a small neon bulb for overvoltage protection. The ac analysis shows that the overall filter function is well around 100 kHz. But it seems as if the fet (a 2N5991 in the original) would not have enough gain to counteract the overall damping included in the front end let alone to deliver some additional gain for the receiver's front end. We both feed the receiver currently with dipoles for 80 m ham radio and a resistor that makes the receiver think the active antenna is connected. The receiver has a possible total of 130 dB gain and my receiver says it uses 94 dB gain while Franks receiver says it uses 102 dB gain. The noise margin is also a bit better on my location. However, if one looks at the manual f.e. at page 17 one could get the impression as if a receiver gain of 75 dB may be considered much more normal as our values. Instead of improving the reception everything gets even worse if the active antenna is connected. I should also note that my qth is only 200 km away from SYLT (our German Loran station) while Frank is even 70 km nearer to it. Questions: 1) Anyone an idea what we are possibly doing wrong? 2) Anyone an idea for the 390 micro henry inductor? 3) Anyone own the original schematic? TIA for your help Ulrich Bangert
Re: [time-nuts] Active LORAN antenna
In message a0d4b11cb4c04f7dbf296e3494e78...@vectron.com, Bob Camp writes: The blocking cap on the input to the Trask amp really isn't needed with a monopole. It's also unlikely to survive the summer. The real question is weather if fails open or as a short... I put mine up two years ago, and it still works fine... -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 p...@freebsd.org | TCP/IP since RFC 956 FreeBSD committer | BSD since 4.3-tahoe Never attribute to malice what can adequately be explained by incompetence. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Active LORAN antenna
In message 4e580972.6080...@pacific.net, Brooke Clarke writes: It looks like the noise floor is maybe 10 dB higher than the AMRAD http://www.prc68.com/I/Images/AMRAD_BT.GIF or 30 dB higher than the McKay Dymec active antenna. http://www.prc68.com/I/Images/Da100nf.GIF If you are basing that claim on the SA plot in my blog-post, you instantly win the inappropriate apple-oranges comparison price of the year First there is nothing even remotely close to a natural noise-floor in the LW broadcast band in the middle of a city here in Denmark, there is far too much EMI from switchmodes etc etc. Second, there is a significant impedance mismatch between the antenna and my SA in that plot. I backhaul the signal over a balanced twinax cable (78Z I belive) and crank it up for the LORAN-C receiver in the matching balun, so the feed impedance is way higher than 50Z Mind you, I don't dispute that you may be right, I just don't think you have data to back up your claim... -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 p...@freebsd.org | TCP/IP since RFC 956 FreeBSD committer | BSD since 4.3-tahoe Never attribute to malice what can adequately be explained by incompetence. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Active LORAN antenna
Hi Poul: You're correct. The noise floor for the AMRAD unit is caused by line conducted noise, not the background noise coming from the whip. The DA-100 seems to have filtered out the line noise so you do see the background. I live in a jungle (forrest?) so there's not as much noise as in a city. Have Fun, Brooke Clarke http://www.PRC68.com http://www.End2PartyGovernment.com/ Poul-Henning Kamp wrote: In message4e580972.6080...@pacific.net, Brooke Clarke writes: It looks like the noise floor is maybe 10 dB higher than the AMRAD http://www.prc68.com/I/Images/AMRAD_BT.GIF or 30 dB higher than the McKay Dymec active antenna. http://www.prc68.com/I/Images/Da100nf.GIF If you are basing that claim on the SA plot in my blog-post, you instantly win the inappropriate apple-oranges comparison price of the year First there is nothing even remotely close to a natural noise-floor in the LW broadcast band in the middle of a city here in Denmark, there is far too much EMI from switchmodes etc etc. Second, there is a significant impedance mismatch between the antenna and my SA in that plot. I backhaul the signal over a balanced twinax cable (78Z I belive) and crank it up for the LORAN-C receiver in the matching balun, so the feed impedance is way higher than 50Z Mind you, I don't dispute that you may be right, I just don't think you have data to back up your claim... ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Active LORAN antenna
Try to get a DA-100 with a socket for the FET along with some spare FETs. The FETs are very hard to get but a sub will work if strong local signals are absent. On 08/26/2011 02:46 PM, Brooke Clarke wrote: Hi Poul: You're correct. The noise floor for the AMRAD unit is caused by line conducted noise, not the background noise coming from the whip. The DA-100 seems to have filtered out the line noise so you do see the background. I live in a jungle (forrest?) so there's not as much noise as in a city. Have Fun, Brooke Clarke http://www.PRC68.com http://www.End2PartyGovernment.com/ Poul-Henning Kamp wrote: In message4e580972.6080...@pacific.net, Brooke Clarke writes: It looks like the noise floor is maybe 10 dB higher than the AMRAD http://www.prc68.com/I/Images/AMRAD_BT.GIF or 30 dB higher than the McKay Dymec active antenna. http://www.prc68.com/I/Images/Da100nf.GIF If you are basing that claim on the SA plot in my blog-post, you instantly win the inappropriate apple-oranges comparison price of the year First there is nothing even remotely close to a natural noise-floor in the LW broadcast band in the middle of a city here in Denmark, there is far too much EMI from switchmodes etc etc. Second, there is a significant impedance mismatch between the antenna and my SA in that plot. I backhaul the signal over a balanced twinax cable (78Z I belive) and crank it up for the LORAN-C receiver in the matching balun, so the feed impedance is way higher than 50Z Mind you, I don't dispute that you may be right, I just don't think you have data to back up your claim... ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. -- Chuck Forsberg WA7KGX N2469R c...@omen.com www.omen.com Developer of Industrial ZMODEM(Tm) for Embedded Applications Omen Technology Inc The High Reliability Software 10255 NW Old Cornelius Pass Portland OR 97231 503-614-0430 ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Active LORAN antenna
Brooke, no I am not making the AMRAD units any longer. I made several of them for various folks, but had to stop making them due to some health issues I had a few years ago. 73's, Doug... Connected by DROID on Verizon Wireless -Original message- From: Brooke Clarke bro...@pacific.net To: Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Fri, Aug 26, 2011 20:37:43 GMT+00:00 Subject: Re: [time-nuts] Active LORAN antenna Hi Doug: It turns out that the fuses AMRAD specified were way too high in current to keep the transformer from being smoked. The only fuses that work are self resetting types. I've added them on the primary and secondary side of the transformer but have not yet reinstalled the antenna. I get requests every now and then for someone to build that AMRAD antenna. Are you still making them? Just sent an email to Chris Trask asking about his push pull design. My interest in active antennas is for the low frequency area where quarter wave wire antennas are not practical. For HF you can't beat wire antennas. Active antennas, either whip or loop do not work as well as wire. http://www.prc68.com/I/WireAntenna.shtml Have Fun, Brooke Clarke http://www.PRC68.com http://www.End2PartyGovernment.com/ k4...@aol.com wrote: Hey Brooke,How are you doing? Are you still using that AMRAD antenna preamp I made for you several years ago? It's been several years since we emailed each other and I have lost contact with you until now. Last time I heard from you, your wife had run over the coax with the lawn mower and cut it into! Just curious if that thing was still working. 73's. Doug, k4cle. Connected by DROID on Verizon Wireless -Original message- From: Brooke Clarke bro...@pacific.net To: Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Fri, Aug 26, 2011 16:39:01 GMT+00:00 Subject: Re: [time-nuts] Active LORAN antenna Hi Ulrich: You might consider the AMRAD active antenna that they designed for the136 kHz ham band. http://www.prc68.com/I/LF-Ant.shtml or the McKay Dymec DA-100 active whip. http://www.prc68.com/I/DR33.shtml#DA100 Have Fun, Brooke Clarke http://www.PRC68.com http://www.End2PartyGovernment.com/ Ulrich Bangert wrote: Gentlemen, my friend Frank and I both miss the matching actice antenna for our Standford Research FS700 Loran frequency standards. We also do not have a schematic of it. Nevertheless we have tried to re-engineer the circut from the part's list and the circuit description in the FS700 manual. Our result is shown in the accompanying schematic.pdf. The generator in the left in conjunction with the 10 k resistor represents the expected high footpoint impedance of the very short (3 m) antenna. The VDD in the right in conjunction with the 100 ohms resistor represents what it believed to be inside the FS700. Not shown here is a 100 k resistor that may be included between the filter output and the 7 k resistor to form a 30 dB divider together with it. Also not shown is a 390 micro henry inductance which's impact is not to be found in the circuit descripion. Also not shown is a small neon bulb for overvoltage protection. The ac analysis shows that the overall filter function is well around 100 kHz. But it seems as if the fet (a 2N5991 in the original) would not have enough gain to counteract the overall damping included in the front end let alone to deliver some additional gain for the receiver's front end. We both feed the receiver currently with dipoles for 80 m ham radio and a resistor that makes the receiver think the active antenna is connected. The receiver has a possible total of 130 dB gain and my receiver says it uses 94 dB gain while Franks receiver says it uses 102 dB gain. The noise margin is also a bit better on my location. However, if one looks at the manual f.e. at page 17 one could get the impression as if a receiver gain of 75 dB may be considered much more normal as our values. Instead of improving the reception everything gets even worse if the active antenna is connected. I should also note that my qth is only 200 km away from SYLT (our German Loran station) while Frank is even 70 km nearer to it. Questions: 1) Anyone an idea what we are possibly doing wrong? 2) Anyone an idea for the 390 micro henry inductor? 3) Anyone own the original schematic? TIA for your help Ulrich Bangert www.ulrich-bangert.de Ortholzer Weg 1 27243 Gross Ippener ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time
Re: [time-nuts] Active LORAN antenna
Thanks for the link. Just ordered parts. Talk about cheap! Mouser electronics had all of the TO92 parts. Regards Paul. On Fri, Aug 26, 2011 at 3:27 PM, Poul-Henning Kamp p...@phk.freebsd.dkwrote: In message 4e57cbee.3000...@pacific.net, Brooke Clarke writes: You might consider the AMRAD active antenna that they designed for the 136 kHz ham band. If you want to build an active monopole, Chris Trasks secret design is far better and far more manageable than the AMRAD: http://www.home.earthlink.net/~christrask/Paper007.html I built this one with BFQ19+BQ149+J174+J310 all in SMD parts. (J270 is a better choice than J174 which tends to forward bias) With my primitive measurement methods, it was flat to 100 MHz and tapered off just short of 800MHz. In the other end it reliably pulls out the Russian ELF (OMEGA like) navigation system down around 10kHz. Chris mentioned that a kit might be underway, but I havn't seen any sign of it anywhere... -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 p...@freebsd.org | TCP/IP since RFC 956 FreeBSD committer | BSD since 4.3-tahoe Never attribute to malice what can adequately be explained by incompetence. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Active LORAN antenna
A Wellbrook ALA-100 will kick arse over most wire antennas. I used this unit with various sized loops up to about 50ft. I've used my loop down to about 24kHz. -Original Message- From: Brooke Clarke bro...@pacific.net Sender: time-nuts-boun...@febo.com Date: Fri, 26 Aug 2011 13:36:29 To: Discussion of precise time and frequency measurementtime-nuts@febo.com Reply-To: Discussion of precise time and frequency measurement time-nuts@febo.com Subject: Re: [time-nuts] Active LORAN antenna Hi Doug: It turns out that the fuses AMRAD specified were way too high in current to keep the transformer from being smoked. The only fuses that work are self resetting types. I've added them on the primary and secondary side of the transformer but have not yet reinstalled the antenna. I get requests every now and then for someone to build that AMRAD antenna. Are you still making them? Just sent an email to Chris Trask asking about his push pull design. My interest in active antennas is for the low frequency area where quarter wave wire antennas are not practical. For HF you can't beat wire antennas. Active antennas, either whip or loop do not work as well as wire. http://www.prc68.com/I/WireAntenna.shtml Have Fun, Brooke Clarke http://www.PRC68.com http://www.End2PartyGovernment.com/ k4...@aol.com wrote: Hey Brooke,How are you doing? Are you still using that AMRAD antenna preamp I made for you several years ago? It's been several years since we emailed each other and I have lost contact with you until now. Last time I heard from you, your wife had run over the coax with the lawn mower and cut it into! Just curious if that thing was still working. 73's. Doug, k4cle. Connected by DROID on Verizon Wireless -Original message- From: Brooke Clarke bro...@pacific.net To: Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Fri, Aug 26, 2011 16:39:01 GMT+00:00 Subject: Re: [time-nuts] Active LORAN antenna Hi Ulrich: You might consider the AMRAD active antenna that they designed for the136 kHz ham band. http://www.prc68.com/I/LF-Ant.shtml or the McKay Dymec DA-100 active whip. http://www.prc68.com/I/DR33.shtml#DA100 Have Fun, Brooke Clarke http://www.PRC68.com http://www.End2PartyGovernment.com/ Ulrich Bangert wrote: Gentlemen, my friend Frank and I both miss the matching actice antenna for our Standford Research FS700 Loran frequency standards. We also do not have a schematic of it. Nevertheless we have tried to re-engineer the circut from the part's list and the circuit description in the FS700 manual. Our result is shown in the accompanying schematic.pdf. The generator in the left in conjunction with the 10 k resistor represents the expected high footpoint impedance of the very short (3 m) antenna. The VDD in the right in conjunction with the 100 ohms resistor represents what it believed to be inside the FS700. Not shown here is a 100 k resistor that may be included between the filter output and the 7 k resistor to form a 30 dB divider together with it. Also not shown is a 390 micro henry inductance which's impact is not to be found in the circuit descripion. Also not shown is a small neon bulb for overvoltage protection. The ac analysis shows that the overall filter function is well around 100 kHz. But it seems as if the fet (a 2N5991 in the original) would not have enough gain to counteract the overall damping included in the front end let alone to deliver some additional gain for the receiver's front end. We both feed the receiver currently with dipoles for 80 m ham radio and a resistor that makes the receiver think the active antenna is connected. The receiver has a possible total of 130 dB gain and my receiver says it uses 94 dB gain while Franks receiver says it uses 102 dB gain. The noise margin is also a bit better on my location. However, if one looks at the manual f.e. at page 17 one could get the impression as if a receiver gain of 75 dB may be considered much more normal as our values. Instead of improving the reception everything gets even worse if the active antenna is connected. I should also note that my qth is only 200 km away from SYLT (our German Loran station) while Frank is even 70 km nearer to it. Questions: 1) Anyone an idea what we are possibly doing wrong? 2) Anyone an idea for the 390 micro henry inductor? 3) Anyone own the original schematic? TIA for your help Ulrich Bangert www.ulrich-bangert.de Ortholzer Weg 1 27243 Gross Ippener ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman
