Re: Topband: "Thinking out loud"
I've spent some time using the MFJ-1026 noise canceler. It took some effort to get it to work, I had to come up with a much better noise antenna. I bought one of those 8' crappie poles from local big chain and spiral wrapped about 50' of wire on it. I mounted it in the clear as close to my neighbors houses. It takes some practice to null noise out but it's really worth the effort. I'm on the west coast outside of San Diego and during 2015 WPX CW contest, I worked D4C on 160. Granted that station is in the elite status but my IC-7410 with 100 watts into a 36' vertical and a 40M loop as a caphat, I was able to log the contact. I'm on a small lot with the longest dimension about 80'. I've been able to put down 2 ~200' radials that go around the perimeter of my property. Definitely though, SNR is king. I keep the AF gain at max and ride the RF gain. The sensitivity of modern rigs is rather amazing but that also means more noise is also received. 73! Mark KA6WKE 4NEC2 The Definitive Guide <https://leanpub.com/4nec2definitiveguide> Website: http://www.ka6wke.net On Fri, Dec 23, 2016 at 1:12 AM, vk3io wrote: > Hi all. Very interesting "thinking out loud" topic. > > With regards to the 403 crystal front end unit system (it seems not yet > available), it will obviously be quiet expensive, even much more than the > Yaesu uTune system. > > With 15 or 30, 1 Khz bandwidth segments or 15 or 30, 3Khz bandwidth > segments and it seems with relatively low insertion loss, I can see it's > performance would be much better than the uTune units, in some > circumstances. > > Firstly I presume you would want two units, one for cw and one for ssb? > > Secondly, being CAT controlled, I presume they will handle split frequency > operation? > > Thirdly, these units seem to mostly only desirable by contest operations. > Probably essential when running multi-multi mode. These multi-multi contest > operations are most likely big radio clubs and so would be happy to pay for > such a device, regardless of the expense, as they do for their antenna > farms. > > When chasing a rare dx stations who are working wide splits, it would be > my luck I did'nt have the 1Khz or 3Khz segment I need. > > As for me, I have never experienced my FTdx3000 being overloaded by strong > in-band signals at my QTH in Australia, (not even with my previous FT950) > and I don't have any nearby broadcast stations, so is it reasonable to say, > I would not benefit from such a device or the Yaesu uTune system? > > 73's, from Ron. vk3io. > > > > On 23/12/2016 6:16 PM, Mirosław Paczocha wrote: > >> Hi, >> >> In my opinion, a high selectivity device at the front end will help >> regarding noise and QRM only in case of relatively poor IM3 receiver. >> >> 73, Mirek >> SP5ENA >> >> -Original Message- >> From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Matt >> Murphy >> Sent: Thursday, December 22, 2016 11:19 PM >> To: k...@myfairpoint.net >> Cc: Topband >> Subject: Re: Topband: "Thinking out loud" >> >> This appears to be the 4O3A unit. I hadn't realized these existed, so I'm >> glad you posted the question: >> >> http://www.4o3a.com/index.php/products/ham-radio-gear/crysta >> l-front-end-unit >> / >> >> On Thu, Dec 22, 2016 at 3:47 PM, K1FZ-Bruce wrote: >> >> Thanks Mirko, >>> >>> >>> Very Good information. What is needed is to reduce noise more (lower) >>> than signals. >>> 73 >>> Bruce-k1fz >>> >>> >>> On Thu, 22 Dec 2016 22:36:30 +0100, S57AD wrote: >>> >>>As far as I recall, Inrad sells front-end xtal filters. Some 25 >>> years ago when I lived in Belgrade, at YU1EXY we had two six-pole >>> filters for SSB part of 40M band but I can't recall and difference >>> with or without those filters. Beside those two xtal filters we used 8 >>> pole Cohn LC filter with 4-gang variable capacitor and with very step >>> curve (I think it was 600 or >>> 800 Hz at -6 dB), which drastically reduced noise and QRM. We could >>> hear 3rd or even 4th layer of callers in 40m pile-ups. >>> >>> As for xtal front end filters, I think 4O3A produces such a filters to >>> be used at in-band stations, but didn't have chance to try & use them... >>> >>> 73, Mirko, S57AD >>> >>> 2016-12-22 21:57 GMT+01:00 K1FZ-Bruce : >>> >>> Tim, >>>> >>>> My single crystal was in the 1950's. >>>> A
Re: Topband: "Thinking out loud"
Hi all. Very interesting "thinking out loud" topic. With regards to the 403 crystal front end unit system (it seems not yet available), it will obviously be quiet expensive, even much more than the Yaesu uTune system. With 15 or 30, 1 Khz bandwidth segments or 15 or 30, 3Khz bandwidth segments and it seems with relatively low insertion loss, I can see it's performance would be much better than the uTune units, in some circumstances. Firstly I presume you would want two units, one for cw and one for ssb? Secondly, being CAT controlled, I presume they will handle split frequency operation? Thirdly, these units seem to mostly only desirable by contest operations. Probably essential when running multi-multi mode. These multi-multi contest operations are most likely big radio clubs and so would be happy to pay for such a device, regardless of the expense, as they do for their antenna farms. When chasing a rare dx stations who are working wide splits, it would be my luck I did'nt have the 1Khz or 3Khz segment I need. As for me, I have never experienced my FTdx3000 being overloaded by strong in-band signals at my QTH in Australia, (not even with my previous FT950) and I don't have any nearby broadcast stations, so is it reasonable to say, I would not benefit from such a device or the Yaesu uTune system? 73's, from Ron. vk3io. On 23/12/2016 6:16 PM, Mirosław Paczocha wrote: Hi, In my opinion, a high selectivity device at the front end will help regarding noise and QRM only in case of relatively poor IM3 receiver. 73, Mirek SP5ENA -Original Message- From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Matt Murphy Sent: Thursday, December 22, 2016 11:19 PM To: k...@myfairpoint.net Cc: Topband Subject: Re: Topband: "Thinking out loud" This appears to be the 4O3A unit. I hadn't realized these existed, so I'm glad you posted the question: http://www.4o3a.com/index.php/products/ham-radio-gear/crystal-front-end-unit / On Thu, Dec 22, 2016 at 3:47 PM, K1FZ-Bruce wrote: Thanks Mirko, Very Good information. What is needed is to reduce noise more (lower) than signals. 73 Bruce-k1fz On Thu, 22 Dec 2016 22:36:30 +0100, S57AD wrote: As far as I recall, Inrad sells front-end xtal filters. Some 25 years ago when I lived in Belgrade, at YU1EXY we had two six-pole filters for SSB part of 40M band but I can't recall and difference with or without those filters. Beside those two xtal filters we used 8 pole Cohn LC filter with 4-gang variable capacitor and with very step curve (I think it was 600 or 800 Hz at -6 dB), which drastically reduced noise and QRM. We could hear 3rd or even 4th layer of callers in 40m pile-ups. As for xtal front end filters, I think 4O3A produces such a filters to be used at in-band stations, but didn't have chance to try & use them... 73, Mirko, S57AD 2016-12-22 21:57 GMT+01:00 K1FZ-Bruce : Tim, My single crystal was in the 1950's. A crystal lattice could take in much of the 160 meter band and be pratical. Thanks for your input. 73 Bruce On Thu, 22 Dec 2016 15:49:12 -0500, Tim Shoppa wrote: Bruce - It has long been rumored that the big EU multi-multis have a crystal filter at their run frequency receivers. e.g. if they are running on 7003.4, they have a crystal filter in front of their receiver for 7003.4. have never observed that in my visits but maybe in decades past, when receivers had less damage range, it would've made sense. Also a good reason to put up a fight for ownership of YOUR run frequency HI HI I believe EMRFD has a schematic for a single-frequency receiver, maybe not exactly like you described but similar in principle. Let me see if I can dig it up. Tim N3QE On Thu, Dec 22, 2016 at 3:41 PM, K1FZ-Bruce wrote: We know that limiting the noise pick up from more directions of an antenna we can usually hear better. We also know if we limit the noise from a receiver IF we can hear less noise, and better yet, if we have a roofing filter earlier in the receiver we can eliminate even more noise in relationship to the wanted signals. What if we take it a step further, could we limit the band-with of the antenna signal with a crystal lattice for 160 meters before the receiver. Years ago I played around with a single crystal at the input of an old tube type receiver. It was remarkable what I could hear on 40 meters, on what seemed to be one frequency. 73 Bruce-k1fz http://www.qsl.net/k1fz/beverage_antenna.html _ Topband Reflector Archives - http://www.contesting.com/_topband - End forwarded message - _ Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: "Thinking out loud"
Hi, In my opinion, a high selectivity device at the front end will help regarding noise and QRM only in case of relatively poor IM3 receiver. 73, Mirek SP5ENA -Original Message- From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Matt Murphy Sent: Thursday, December 22, 2016 11:19 PM To: k...@myfairpoint.net Cc: Topband Subject: Re: Topband: "Thinking out loud" This appears to be the 4O3A unit. I hadn't realized these existed, so I'm glad you posted the question: http://www.4o3a.com/index.php/products/ham-radio-gear/crystal-front-end-unit / On Thu, Dec 22, 2016 at 3:47 PM, K1FZ-Bruce wrote: > > Thanks Mirko, > > > Very Good information. What is needed is to reduce noise more (lower) > than signals. > 73 > Bruce-k1fz > > > On Thu, 22 Dec 2016 22:36:30 +0100, S57AD wrote: > > As far as I recall, Inrad sells front-end xtal filters. Some 25 > years ago when I lived in Belgrade, at YU1EXY we had two six-pole > filters for SSB part of 40M band but I can't recall and difference > with or without those filters. Beside those two xtal filters we used 8 > pole Cohn LC filter with 4-gang variable capacitor and with very step > curve (I think it was 600 or > 800 Hz at -6 dB), which drastically reduced noise and QRM. We could > hear 3rd or even 4th layer of callers in 40m pile-ups. > > As for xtal front end filters, I think 4O3A produces such a filters to > be used at in-band stations, but didn't have chance to try & use them... > > 73, Mirko, S57AD > > 2016-12-22 21:57 GMT+01:00 K1FZ-Bruce : > > > Tim, > > > > My single crystal was in the 1950's. > > A crystal lattice could take in much of the 160 meter band and be > > pratical. > > Thanks for your input. > > 73 > > Bruce > > > > On Thu, 22 Dec 2016 15:49:12 -0500, Tim Shoppa wrote: > > > > Bruce - It has long been rumored that the big EU multi-multis have a > > crystal filter at their run frequency receivers. e.g. if they are > running > > on 7003.4, they have a crystal filter in front of their receiver for > > 7003.4. have never observed that in my visits but maybe in decades > > past, when receivers had less damage range, it would've made sense. > > Also a good reason to put up a fight for ownership of YOUR run > > frequency HI HI > > > > I believe EMRFD has a schematic for a single-frequency receiver, > > maybe not exactly like you described but similar in principle. Let > > me see if I can dig it up. > > Tim N3QE > > > > > > On Thu, Dec 22, 2016 at 3:41 PM, K1FZ-Bruce wrote: > > > > > > We know that limiting the noise pick up from more directions of an > antenna > > we can usually hear better. We also know if we limit the noise from > > a receiver IF we can hear less noise, and better yet, if we have a > > roofing filter earlier in the receiver we can eliminate even more > > noise in relationship to the wanted signals. > > What if we take it a step further, could we limit the band-with of > > the antenna signal with a crystal lattice for 160 meters before the receiver. > > Years ago I played around with a single crystal at the input of an > > old tube type receiver. It was remarkable what I could hear on 40 > > meters, on what seemed to be one frequency. > > 73 > > Bruce-k1fz > > http://www.qsl.net/k1fz/beverage_antenna.html > _ > Topband Reflector Archives - http://www.contesting.com/_topband > > > > - End forwarded message - > > _ > Topband Reflector Archives - http://www.contesting.com/_topband > _ Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: "Thinking out loud"
Thanks for the information Stew. Originally I tried it at my parents QTH on 40 meters when I was teenager. Was licensed in 1950 as W1TJQ. Ideas get lost and time goes by. In the 1920 Hugo Ginsburg ( not sure of his last name spelling) in a book at the Belfast Library said silicon looked promising as a rectifier. It took to early 1950/ late 1940's for it to be re-discovered. Thanks again. 73 Bruce-k1fz On Fri, 23 Dec 2016 01:51:50 + (UTC), GALE STEWARD via Topband wrote: Years ago at the W3GM M/M station, Gerry had several crystal filters (50 ohm Z input & output) in the 40M RX path. As I recall, these were about 20-30 khz wide (each) and were of slightly different center frequencies so that most of the 40M CW band could be covered. I DO remember that they worked very well. I never saw one for 160. 73, Stew K3ND From: K1FZ-Bruce To: Topband Sent: Thursday, December 22, 2016 3:41 PM Subject: Topband: "Thinking out loud" We know that limiting the noise pick up from more directions of an antenna we can usually hear better. We also know if we limit the noise from a receiver IF we can hear less noise, and better yet, if we have a roofing filter earlier in the receiver we can eliminate even more noise in relationship to the wanted signals. What if we take it a step further, could we limit the band-with of the antenna signal with a crystal lattice for 160 meters before the receiver. Years ago I played around with a single crystal at the input of an old tube type receiver. It was remarkable what I could hear on 40 meters, on what seemed to be one frequency. 73 Bruce-k1fz http://www.qsl.net/k1fz/beverage_antenna.html _ Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: "Thinking out loud"
The SNR is set at the antenna. There is a persistent desire to move the selectivity closer to the antenna, however With modern "bullet-proof" front ends, filtering can be delayed and done at i-f. In fact, with H-mode mixer front ends, the IMD in the following filter can be more of a limit on signal handling than the mixer. See: http://martein.home.xs4all.nl/pa3ake/hmode/roofer_intro.html Imagine trying to build a multiplicity of such filters to cover the 160-meter band. Wes N7WS On 12/22/2016 2:44 PM, K1FZ-Bruce wrote: Thanks Mirko, Very Good information. What is needed is to reduce noise lower than signals. 73 Bruce-k1fz _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: "Thinking out loud"
One must remember that the purpose of these filters is to reduce the total energy presented to circuitry that would otherwise be overloaded by it, or create crud at any level because of the poor IMD characteristics of the radio circuits. I did something of the sort at W4BVV in the 1960's with tuned circuits in front of the 40 meter RX to get rid of all the carrier energy at 7100 and up. These days with a K3 I can tune right under a 30 over 9 BC carrier and listen to the way-down 60 Hz energy in their audio. Are we back with these filters being used to provide a crutch for inferior RX? Isn't a roofing filter the same thing, but effectively tuneable, except for the first conversion stage. Isn't this high level bleed measured in the standard tests you find on the Sherwood Engineering site? The advantages being touted for the filters seem to be the same thing I finally got when I bought a K3. Limiting on frequency noise coming from the antenna with RX antenna pattern is another thing altogether. 73, Guy K2AV On Thu, Dec 22, 2016 at 8:51 PM, GALE STEWARD via Topband < topband@contesting.com> wrote: > Years ago at the W3GM M/M station, Gerry had several crystal filters (50 > ohm Z input & output) in the 40M RX path. As I recall, these were about > 20-30 khz wide (each) and were of slightly different center frequencies so > that most of the 40M CW band could be covered. > I DO remember that they worked very well. I never saw one for 160. > 73, Stew K3ND > > From: K1FZ-Bruce > To: Topband > Sent: Thursday, December 22, 2016 3:41 PM > Subject: Topband: "Thinking out loud" > > > > We know that limiting the noise pick up from more directions of an antenna > we can usually hear better. We also know if we limit the noise from a > receiver IF we can hear less noise, and better yet, if we > have a roofing filter earlier in the receiver we can eliminate even more > noise in relationship to the wanted signals. > > What if we take it a step further, could we limit the band-with of the > antenna signal with a crystal lattice for 160 meters before the receiver. > Years ago I played around with a single crystal at the input of an old > tube type receiver. It was remarkable what I could hear on 40 meters, > on what seemed to be one frequency. > > 73 > Bruce-k1fz > http://www.qsl.net/k1fz/beverage_antenna.html > > > _ > Topband Reflector Archives - http://www.contesting.com/_topband > > > _ > Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: "Thinking out loud"
Years ago at the W3GM M/M station, Gerry had several crystal filters (50 ohm Z input & output) in the 40M RX path. As I recall, these were about 20-30 khz wide (each) and were of slightly different center frequencies so that most of the 40M CW band could be covered. I DO remember that they worked very well. I never saw one for 160. 73, Stew K3ND From: K1FZ-Bruce To: Topband Sent: Thursday, December 22, 2016 3:41 PM Subject: Topband: "Thinking out loud" We know that limiting the noise pick up from more directions of an antenna we can usually hear better. We also know if we limit the noise from a receiver IF we can hear less noise, and better yet, if we have a roofing filter earlier in the receiver we can eliminate even more noise in relationship to the wanted signals. What if we take it a step further, could we limit the band-with of the antenna signal with a crystal lattice for 160 meters before the receiver. Years ago I played around with a single crystal at the input of an old tube type receiver. It was remarkable what I could hear on 40 meters, on what seemed to be one frequency. 73 Bruce-k1fz http://www.qsl.net/k1fz/beverage_antenna.html _ Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: "Thinking out loud"
Hi Bruce "We know that limiting the noise pick up from more directions of an antenna we can usually hear better" Agree, actually the directivity of the receiving antenna is the only place you can increase signal to noise ratio. More RDF means more directivity (3D) resulting better signal to noise ratio. All electronic devices add noise at output. No amplifier is perfect. Passive devices ahead of the preamplifier add noise impacting directly on the Noise Figure of the system. 2 db cable loss, 1.5 db filter insertion loss add up to 3.5 db on the total Noise Figure. Whatever you do adjusting the radio you are reducing degradation of the signal noise from the signal coming from the antenna, including adjusting the bandwidth of the receiver. Reducing RF gain reduce the degradation and the signal to noise ratio at the speaker is improved. The issue with RDF or directivity is that we have many antennas on 160. The one we know, our TX antenna, and sometimes six or twelve other antennas fort 160m that we don’t know about it. All these antennas interact with you receiving antenna and your ground at the station near the receiver. 2 wave length on 160m is over 500ft. AM broadcast station detune cell phone towers miles away for the same reason. Just because you can’t measure the deterioration of the patter of you beverage or any fixed receiving antenna, does not mean it is a working as it shows on the paper. EZNEC can simulate the interaction, you just need to all "all your 160m antennas". Antennas you don’t know you have for 160m. 1- That 120 ft of coax for your 6m Yagi 2- The triband feed line 3- Rotor cable 150ft with not a single ground, connected to your control box and right into the ground of your station combining from the AC line 4- The wiring in you r house. 5 -\,,, 6 ... and on and on and on. 7- elevated radials, ... 8- low dipoles with no choke!! ... Any 100Ft of wire is a very good vertical for 160m. If you live near a city the level of energy captured by this "antenna" is huge, and what we do with that? , we connected it to our station ground with a #14 wire ... at the station. Right next to the radio!!! All these "antennas" as well the TX antenna must be detuned for 160, believe or not, it is the true for any vertical receiving antenna. For vertical receiving antennas the reduction in noise is 12 to 24 db, for horizontal receiving antennas, it is 6 or 8 db. Narrow filter, like the one I use ahead of my preamplifier, 0.2db insertion loss and 40KHz BW does help to reduce reciprocal noise and unload the radio from the energy from outside the band. I visited several station during 2016, I found signals above +10 dBm coming from the TX antenna, and leaking everywhere into the radio. That's a lot of RF energy. 10 mW.. of garbage.. Agree again with you about the narrow filter front end. Happy Holidays! 73 JC N4IS This concept is very important -Original Message- From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of K1FZ-Bruce Sent: Thursday, December 22, 2016 3:42 PM To: Topband Subject: Topband: "Thinking out loud" We know that limiting the noise pick up from more directions of an antenna we can usually hear better. We also know if we limit the noise from a receiver IF we can hear less noise, and better yet, if we have a roofing filter earlier in the receiver we can eliminate even more noise in relationship to the wanted signals. What if we take it a step further, could we limit the band-with of the antenna signal with a crystal lattice for 160 meters before the receiver. Years ago I played around with a single crystal at the input of an old tube type receiver. It was remarkable what I could hear on 40 meters, on what seemed to be one frequency. 73 Bruce-k1fz http://www.qsl.net/k1fz/beverage_antenna.html _ Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: "Thinking out loud"
Hi, I wonder if you could cover the whole band or just the part that interest *you*. I have a radio now that uses an xtal filter with about a 7 kHz bandwidth on the 20 meter band. Probably those filters can be made wider with perhaps less filtering action - tradeoffs ya know. The idea isn't new and it works! Merry Christmas and... 73, Bill KU8H On 12/22/2016 05:56 PM, K1FZ-Bruce wrote: Thanks Mirko and Matt, This is not on the market yet, but should do a lot for noise on 160 meters. Bet a tube transmitter had naysayers. Need a spark to transmit. hi. 73 Bruce-k1fz On Thu, 22 Dec 2016 16:18:56 -0600, Matt Murphy wrote: This appears to be the 4O3A unit. I hadn't realized these existed, so I'm glad you posted the question: http://www.4o3a.com/index.php/products/ham-radio-gear/crystal-front-end-unit/ On Thu, Dec 22, 2016 at 3:47 PM, K1FZ-Bruce wrote: Thanks Mirko, Very Good information. What is needed is to reduce noise more (lower) than signals. 73 Bruce-k1fz On Thu, 22 Dec 2016 22:36:30 +0100, S57AD wrote: As far as I recall, Inrad sells front-end xtal filters. Some 25 years ago when I lived in Belgrade, at YU1EXY we had two six-pole filters for SSB part of 40M band but I can't recall and difference with or without those filters. Beside those two xtal filters we used 8 pole Cohn LC filter with 4-gang variable capacitor and with very step curve (I think it was 600 or 800 Hz at -6 dB), which drastically reduced noise and QRM. We could hear 3rd or even 4th layer of callers in 40m pile-ups. As for xtal front end filters, I think 4O3A produces such a filters to be used at in-band stations, but didn't have chance to try & use them... 73, Mirko, S57AD 2016-12-22 21:57 GMT+01:00 K1FZ-Bruce : > Tim, > > My single crystal was in the 1950's. > A crystal lattice could take in much of the 160 meter band and be > pratical. > Thanks for your input. > 73 > Bruce > > On Thu, 22 Dec 2016 15:49:12 -0500, Tim Shoppa wrote: > > Bruce - It has long been rumored that the big EU multi-multis have > a crystal filter at their run frequency receivers. e.g. if they are running > on 7003.4, they have a crystal filter in front of their receiver for > 7003.4. have never observed that in my visits but maybe in decades past, > when receivers had less damage range, it would've made sense. Also a good > reason to put up a fight for ownership of YOUR run frequency HI HI > > I believe EMRFD has a schematic for a single-frequency receiver, maybe > not exactly like you described but similar in principle. Let me see if I > can dig it up. > Tim N3QE > > > On Thu, Dec 22, 2016 at 3:41 PM, K1FZ-Bruce wrote: > > > We know that limiting the noise pick up from more directions of an antenna > we can usually hear better. We also know if we limit the noise from a > receiver IF we can hear less noise, and better yet, if we > have a roofing filter earlier in the receiver we can eliminate even more > noise in relationship to the wanted signals. > What if we take it a step further, could we limit the band-with of the > antenna signal with a crystal lattice for 160 meters before the receiver. > Years ago I played around with a single crystal at the input of an old > tube type receiver. It was remarkable what I could hear on 40 meters, > on what seemed to be one frequency. > 73 > Bruce-k1fz > http://www.qsl.net/k1fz/beverage_antenna.html _ Topband Reflector Archives - http://www.contesting.com/_topband - End forwarded message - _ Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband -- bark less - wag more _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: "Thinking out loud"
This appears to be the 4O3A unit. I hadn't realized these existed, so I'm glad you posted the question: http://www.4o3a.com/index.php/products/ham-radio-gear/crystal-front-end-unit/ On Thu, Dec 22, 2016 at 3:47 PM, K1FZ-Bruce wrote: > > Thanks Mirko, > > > Very Good information. What is needed is to reduce noise more (lower) > than signals. > 73 > Bruce-k1fz > > > On Thu, 22 Dec 2016 22:36:30 +0100, S57AD wrote: > > As far as I recall, Inrad sells front-end xtal filters. Some 25 > years ago > when I lived in Belgrade, at YU1EXY we had two six-pole filters for SSB > part of 40M band but I can't recall and difference with or without those > filters. Beside those two xtal filters we used 8 pole Cohn LC filter with > 4-gang variable capacitor and with very step curve (I think it was 600 or > 800 Hz at -6 dB), which drastically reduced noise and QRM. We could hear > 3rd or even 4th layer of callers in 40m pile-ups. > > As for xtal front end filters, I think 4O3A produces such a filters to be > used at in-band stations, but didn't have chance to try & use them... > > 73, Mirko, S57AD > > 2016-12-22 21:57 GMT+01:00 K1FZ-Bruce : > > > Tim, > > > > My single crystal was in the 1950's. > > A crystal lattice could take in much of the 160 meter band and be > > pratical. > > Thanks for your input. > > 73 > > Bruce > > > > On Thu, 22 Dec 2016 15:49:12 -0500, Tim Shoppa wrote: > > > > Bruce - It has long been rumored that the big EU multi-multis have > > a crystal filter at their run frequency receivers. e.g. if they are > running > > on 7003.4, they have a crystal filter in front of their receiver for > > 7003.4. have never observed that in my visits but maybe in decades past, > > when receivers had less damage range, it would've made sense. Also a good > > reason to put up a fight for ownership of YOUR run frequency HI HI > > > > I believe EMRFD has a schematic for a single-frequency receiver, maybe > > not exactly like you described but similar in principle. Let me see if I > > can dig it up. > > Tim N3QE > > > > > > On Thu, Dec 22, 2016 at 3:41 PM, K1FZ-Bruce wrote: > > > > > > We know that limiting the noise pick up from more directions of an > antenna > > we can usually hear better. We also know if we limit the noise from a > > receiver IF we can hear less noise, and better yet, if we > > have a roofing filter earlier in the receiver we can eliminate even more > > noise in relationship to the wanted signals. > > What if we take it a step further, could we limit the band-with of the > > antenna signal with a crystal lattice for 160 meters before the receiver. > > Years ago I played around with a single crystal at the input of an old > > tube type receiver. It was remarkable what I could hear on 40 meters, > > on what seemed to be one frequency. > > 73 > > Bruce-k1fz > > http://www.qsl.net/k1fz/beverage_antenna.html > _ > Topband Reflector Archives - http://www.contesting.com/_topband > > > > - End forwarded message - > > _ > Topband Reflector Archives - http://www.contesting.com/_topband > _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: "Thinking out loud"
Thanks Mirko, Very Good information. What is needed is to reduce noise lower than signals. 73 Bruce-k1fz On Thu, 22 Dec 2016 22:36:30 +0100, S57AD wrote: As far as I recall, Inrad sells front-end xtal filters. Some 25 years ago when I lived in Belgrade, at YU1EXY we had two six-pole filters for SSB part of 40M band but I can't recall and difference with or without those filters. Beside those two xtal filters we used 8 pole Cohn LC filter with 4-gang variable capacitor and with very step curve (I think it was 600 or 800 Hz at -6 dB), which drastically reduced noise and QRM. We could hear 3rd or even 4th layer of callers in 40m pile-ups. As for xtal front end filters, I think 4O3A produces such a filters to be used at in-band stations, but didn't have chance to try & use them... 73, Mirko, S57AD 2016-12-22 21:57 GMT+01:00 K1FZ-Bruce : Tim, My single crystal was in the 1950's. A crystal lattice could take in much of the 160 meter band and be pratical. Thanks for your input. 73 Bruce On Thu, 22 Dec 2016 15:49:12 -0500, Tim Shoppa wrote: Bruce - It has long been rumored that the big EU multi-multis have a crystal filter at their run frequency receivers. e.g. if they are running on 7003.4, they have a crystal filter in front of their receiver for 7003.4. have never observed that in my visits but maybe in decades past, when receivers had less damage range, it would've made sense. Also a good reason to put up a fight for ownership of YOUR run frequency HI HI I believe EMRFD has a schematic for a single-frequency receiver, maybe not exactly like you described but similar in principle. Let me see if I can dig it up. Tim N3QE On Thu, Dec 22, 2016 at 3:41 PM, K1FZ-Bruce wrote: We know that limiting the noise pick up from more directions of an antenna we can usually hear better. We also know if we limit the noise from a receiver IF we can hear less noise, and better yet, if we have a roofing filter earlier in the receiver we can eliminate even more noise in relationship to the wanted signals. What if we take it a step further, could we limit the band-with of the antenna signal with a crystal lattice for 160 meters before the receiver. Years ago I played around with a single crystal at the input of an old tube type receiver. It was remarkable what I could hear on 40 meters, on what seemed to be one frequency. 73 Bruce-k1fz http://www.qsl.net/k1fz/beverage_antenna.html _ Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband -- Mirko S57AD _ Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: "Thinking out loud"
As far as I recall, Inrad sells front-end xtal filters. Some 25 years ago when I lived in Belgrade, at YU1EXY we had two six-pole filters for SSB part of 40M band but I can't recall and difference with or without those filters. Beside those two xtal filters we used 8 pole Cohn LC filter with 4-gang variable capacitor and with very step curve (I think it was 600 or 800 Hz at -6 dB), which drastically reduced noise and QRM. We could hear 3rd or even 4th layer of callers in 40m pile-ups. As for xtal front end filters, I think 4O3A produces such a filters to be used at in-band stations, but didn't have chance to try & use them... 73, Mirko, S57AD 2016-12-22 21:57 GMT+01:00 K1FZ-Bruce : > Tim, > > My single crystal was in the 1950's. > A crystal lattice could take in much of the 160 meter band and be > pratical. > Thanks for your input. > 73 > Bruce > > On Thu, 22 Dec 2016 15:49:12 -0500, Tim Shoppa wrote: > > Bruce - It has long been rumored that the big EU multi-multis have > a crystal filter at their run frequency receivers. e.g. if they are running > on 7003.4, they have a crystal filter in front of their receiver for > 7003.4. have never observed that in my visits but maybe in decades past, > when receivers had less damage range, it would've made sense. Also a good > reason to put up a fight for ownership of YOUR run frequency HI HI > > I believe EMRFD has a schematic for a single-frequency receiver, maybe > not exactly like you described but similar in principle. Let me see if I > can dig it up. > Tim N3QE > > > On Thu, Dec 22, 2016 at 3:41 PM, K1FZ-Bruce wrote: > > > We know that limiting the noise pick up from more directions of an antenna > we can usually hear better. We also know if we limit the noise from a > receiver IF we can hear less noise, and better yet, if we > have a roofing filter earlier in the receiver we can eliminate even more > noise in relationship to the wanted signals. > What if we take it a step further, could we limit the band-with of the > antenna signal with a crystal lattice for 160 meters before the receiver. > Years ago I played around with a single crystal at the input of an old > tube type receiver. It was remarkable what I could hear on 40 meters, > on what seemed to be one frequency. > 73 > Bruce-k1fz > http://www.qsl.net/k1fz/beverage_antenna.html > > > _ > Topband Reflector Archives - http://www.contesting.com/_topband > > > _ > Topband Reflector Archives - http://www.contesting.com/_topband > -- Mirko S57AD _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: "Thinking out loud"
160 meters is above the broadcast band. 3rd order should be above 160, not lower. lattice filters, many near 9 MHZ. for single sideband transceivers, are used successfully. Could take out more noise, than adding. All the arguments against this could also be used against roofing filters. 73 Bruce On Thu, 22 Dec 2016 12:56:21 -0800, "Richard (Rick) Karlquist" wrote: Crystal filters are known to have a 3rd order intercept point. Depending on how many AM BCB stations impinge on your filter, you could get intermods. Switching in an attenuator ahead of the filter should help, if you can stand the increase in noise figure. Rick N6RK On 12/22/2016 12:41 PM, K1FZ-Bruce wrote: We know that limiting the noise pick up from more directions of an antenna we can usually hear better. We also know if we limit the noise from a receiver IF we can hear less noise, and better yet, if we have a roofing filter earlier in the receiver we can eliminate even more noise in relationship to the wanted signals. What if we take it a step further, could we limit the band-with of the antenna signal with a crystal lattice for 160 meters before the receiver. Years ago I played around with a single crystal at the input of an old tube type receiver. It was remarkable what I could hear on 40 meters, on what seemed to be one frequency. 73 Bruce-k1fz http://www.qsl.net/k1fz/beverage_antenna.html _ Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: "Thinking out loud"
Tim, My single crystal was in the 1950's. A crystal lattice could take in much of the 160 meter band and be pratical. Thanks for your input. 73 Bruce On Thu, 22 Dec 2016 15:49:12 -0500, Tim Shoppa wrote: Bruce - It has long been rumored that the big EU multi-multis have a crystal filter at their run frequency receivers. e.g. if they are running on 7003.4, they have a crystal filter in front of their receiver for 7003.4. have never observed that in my visits but maybe in decades past, when receivers had less damage range, it would've made sense. Also a good reason to put up a fight for ownership of YOUR run frequency HI HI I believe EMRFD has a schematic for a single-frequency receiver, maybe not exactly like you described but similar in principle. Let me see if I can dig it up. Tim N3QE On Thu, Dec 22, 2016 at 3:41 PM, K1FZ-Bruce wrote: We know that limiting the noise pick up from more directions of an antenna we can usually hear better. We also know if we limit the noise from a receiver IF we can hear less noise, and better yet, if we have a roofing filter earlier in the receiver we can eliminate even more noise in relationship to the wanted signals. What if we take it a step further, could we limit the band-with of the antenna signal with a crystal lattice for 160 meters before the receiver. Years ago I played around with a single crystal at the input of an old tube type receiver. It was remarkable what I could hear on 40 meters, on what seemed to be one frequency. 73 Bruce-k1fz http://www.qsl.net/k1fz/beverage_antenna.html _ Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: "Thinking out loud"
Crystal filters are known to have a 3rd order intercept point. Depending on how many AM BCB stations impinge on your filter, you could get intermods. Switching in an attenuator ahead of the filter should help, if you can stand the increase in noise figure. Rick N6RK On 12/22/2016 12:41 PM, K1FZ-Bruce wrote: We know that limiting the noise pick up from more directions of an antenna we can usually hear better. We also know if we limit the noise from a receiver IF we can hear less noise, and better yet, if we have a roofing filter earlier in the receiver we can eliminate even more noise in relationship to the wanted signals. What if we take it a step further, could we limit the band-with of the antenna signal with a crystal lattice for 160 meters before the receiver. Years ago I played around with a single crystal at the input of an old tube type receiver. It was remarkable what I could hear on 40 meters, on what seemed to be one frequency. 73 Bruce-k1fz http://www.qsl.net/k1fz/beverage_antenna.html _ Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband
