Re: Topband: FT5ZM
Good morning Garry, Well, all the tea leaves lined up here this AM. He was first discernable at 1348. Heard a good CQ call sign at :50. I started calling at :52. I made it into his log, on the hour, at 1400. He was wall to wall speaker quality for 10 minutes. He faded out at 1425, a full 10 minutes after my sunrise. His signal was audible here in SW NM, DM52lq for a total of 37 minutes. And this morning's op was NOT interleaving VK stations with NA. So the note to the pilot may have helped on that account. Good luck with your situation. 73 de Milt, N5IA -Original Message- From: Garry Shapiro Sent: Monday, February 03, 2014 9:56 PM To: topband@contesting.com Subject: Re: Topband: FT5ZM The west coast depends upon the morning bump and the only window is between their sunset around 14Z and our sunrise around 1515 and shrinking; the actual sunrise bump is, of course, short. Some areas east of the Sierra in the Mountain time zone apparently have no mutual darkness and therefore no opening at all, similar to what happened at VK0IR in 1997. Many west coast stations made good topband Q's over the weekend. Alas, I was plagued with a powerline arc exactly in line with Amsterdam SP and a deer took out my NW/SE Beverage. Now we are about to be clobbered by a CME--the high SFI of the past week heralded its arrival and I join those who are SOL. The prop gods are chortling. Garry, NI6T On 2/3/2014 6:45 PM, Les Kalmus wrote: They were on top band tonight but really weak at best. I heard them better on the inverted L than the beverage which is really weird. They didn't start calling until around 2330Z. The ditter was a pita. 73, Les W2LK On 2/3/2014 6:33 PM, Gary Smith wrote: Well, it's academic for tonight because the only signals on frequency I've heard all night were the buzzards throwing out carriers the occasional dits so to let us know they're there, waiting. Band condx or local issues there keeping them off 160 it seems. Gary, KA1J Gary, I know I worked them on 40 SSB last night, and I do not appear in the log. So, I checked about a dozen other guys in the spots for 40 SSB last night who supposedly worked them after I did. None of them appear in the log either. Methinks there are some bands missing in today's upload! 73, Tony K4QE On Mon, Feb 3, 2014 at 5:18 PM, Gary Smith g...@ka1j.com wrote: Rats, back in the chase, must have been a slim. Just checked clublogs FT5ZM log and the 160M Q didn't show up but my 17M contact an hour a half later did. I know I heard them come back to me so it must have been a slim but geez with the signals like they were, it sure sounded like their signal. Ugh... Gary KA1J Fingers crossed it wasn't a slim I worked. The signals were in out but for 4-5 minutes I could hear them clearly. Time'll tell. If I did get him it was greatly because the kiddies weren't playing so hard today. 73, Gary KA1J --- This email is free from viruses and malware because avast! Antivirus protection is active. http://www.avast.com _ Topband Reflector Archives - http://www.contesting.com/_topband --- This email is free from viruses and malware because avast! Antivirus protection is active. http://www.avast.com _ Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband --- This email is free from viruses and malware because avast! Antivirus protection is active. http://www.avast.com _ Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband - No virus found in this message. Checked by AVG - www.avg.com Version: 2014.0.4259 / Virus Database: 3684/7058 - Release Date: 02/03/14 - No virus found in this message. Checked by AVG - www.avg.com Version: 2014.0.4259 / Virus Database: 3684/7058 - Release Date: 02/03/14 _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: FT5ZM
I just worked him at 1455. He popped up to copiable and a minute later was in the log. I am a happy boy. Still there, still not loud but easy copy. Garry On 2/4/2014 6:55 AM, Milt -- N5IA wrote: Good morning Garry, Well, all the tea leaves lined up here this AM. He was first discernable at 1348. Heard a good CQ call sign at :50. I started calling at :52. I made it into his log, on the hour, at 1400. He was wall to wall speaker quality for 10 minutes. He faded out at 1425, a full 10 minutes after my sunrise. His signal was audible here in SW NM, DM52lq for a total of 37 minutes. And this morning's op was NOT interleaving VK stations with NA. So the note to the pilot may have helped on that account. Good luck with your situation. 73 de Milt, N5IA -Original Message- From: Garry Shapiro Sent: Monday, February 03, 2014 9:56 PM To: topband@contesting.com Subject: Re: Topband: FT5ZM The west coast depends upon the morning bump and the only window is between their sunset around 14Z and our sunrise around 1515 and shrinking; the actual sunrise bump is, of course, short. Some areas east of the Sierra in the Mountain time zone apparently have no mutual darkness and therefore no opening at all, similar to what happened at VK0IR in 1997. Many west coast stations made good topband Q's over the weekend. Alas, I was plagued with a powerline arc exactly in line with Amsterdam SP and a deer took out my NW/SE Beverage. Now we are about to be clobbered by a CME--the high SFI of the past week heralded its arrival and I join those who are SOL. The prop gods are chortling. Garry, NI6T On 2/3/2014 6:45 PM, Les Kalmus wrote: They were on top band tonight but really weak at best. I heard them better on the inverted L than the beverage which is really weird. They didn't start calling until around 2330Z. The ditter was a pita. 73, Les W2LK On 2/3/2014 6:33 PM, Gary Smith wrote: Well, it's academic for tonight because the only signals on frequency I've heard all night were the buzzards throwing out carriers the occasional dits so to let us know they're there, waiting. Band condx or local issues there keeping them off 160 it seems. Gary, KA1J Gary, I know I worked them on 40 SSB last night, and I do not appear in the log. So, I checked about a dozen other guys in the spots for 40 SSB last night who supposedly worked them after I did. None of them appear in the log either. Methinks there are some bands missing in today's upload! 73, Tony K4QE On Mon, Feb 3, 2014 at 5:18 PM, Gary Smith g...@ka1j.com wrote: Rats, back in the chase, must have been a slim. Just checked clublogs FT5ZM log and the 160M Q didn't show up but my 17M contact an hour a half later did. I know I heard them come back to me so it must have been a slim but geez with the signals like they were, it sure sounded like their signal. Ugh... Gary KA1J Fingers crossed it wasn't a slim I worked. The signals were in out but for 4-5 minutes I could hear them clearly. Time'll tell. If I did get him it was greatly because the kiddies weren't playing so hard today. 73, Gary KA1J --- This email is free from viruses and malware because avast! Antivirus protection is active. http://www.avast.com _ Topband Reflector Archives - http://www.contesting.com/_topband --- This email is free from viruses and malware because avast! Antivirus protection is active. http://www.avast.com _ Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband --- This email is free from viruses and malware because avast! Antivirus protection is active. http://www.avast.com _ Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband - No virus found in this message. Checked by AVG - www.avg.com Version: 2014.0.4259 / Virus Database: 3684/7058 - Release Date: 02/03/14 - No virus found in this message. Checked by AVG - www.avg.com Version: 2014.0.4259 / Virus Database: 3684/7058 - Release Date: 02/03/14 _ Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: FT5ZM
Sorry to say no luck in EPA. One positive note, I get to clean up paperwork ; ) Wayne W3EA Sent from my iPad On Feb 4, 2014, at 10:00 AM, Garry Shapiro ga...@ni6t.com wrote: I just worked him at 1455. He popped up to copiable and a minute later was in the log. I am a happy boy. Still there, still not loud but easy copy. Garry On 2/4/2014 6:55 AM, Milt -- N5IA wrote: Good morning Garry, Well, all the tea leaves lined up here this AM. He was first discernable at 1348. Heard a good CQ call sign at :50. I started calling at :52. I made it into his log, on the hour, at 1400. He was wall to wall speaker quality for 10 minutes. He faded out at 1425, a full 10 minutes after my sunrise. His signal was audible here in SW NM, DM52lq for a total of 37 minutes. And this morning's op was NOT interleaving VK stations with NA. So the note to the pilot may have helped on that account. Good luck with your situation. 73 de Milt, N5IA -Original Message- From: Garry Shapiro Sent: Monday, February 03, 2014 9:56 PM To: topband@contesting.com Subject: Re: Topband: FT5ZM The west coast depends upon the morning bump and the only window is between their sunset around 14Z and our sunrise around 1515 and shrinking; the actual sunrise bump is, of course, short. Some areas east of the Sierra in the Mountain time zone apparently have no mutual darkness and therefore no opening at all, similar to what happened at VK0IR in 1997. Many west coast stations made good topband Q's over the weekend. Alas, I was plagued with a powerline arc exactly in line with Amsterdam SP and a deer took out my NW/SE Beverage. Now we are about to be clobbered by a CME--the high SFI of the past week heralded its arrival and I join those who are SOL. The prop gods are chortling. Garry, NI6T On 2/3/2014 6:45 PM, Les Kalmus wrote: They were on top band tonight but really weak at best. I heard them better on the inverted L than the beverage which is really weird. They didn't start calling until around 2330Z. The ditter was a pita. 73, Les W2LK On 2/3/2014 6:33 PM, Gary Smith wrote: Well, it's academic for tonight because the only signals on frequency I've heard all night were the buzzards throwing out carriers the occasional dits so to let us know they're there, waiting. Band condx or local issues there keeping them off 160 it seems. Gary, KA1J Gary, I know I worked them on 40 SSB last night, and I do not appear in the log. So, I checked about a dozen other guys in the spots for 40 SSB last night who supposedly worked them after I did. None of them appear in the log either. Methinks there are some bands missing in today's upload! 73, Tony K4QE On Mon, Feb 3, 2014 at 5:18 PM, Gary Smith g...@ka1j.com wrote: Rats, back in the chase, must have been a slim. Just checked clublogs FT5ZM log and the 160M Q didn't show up but my 17M contact an hour a half later did. I know I heard them come back to me so it must have been a slim but geez with the signals like they were, it sure sounded like their signal. Ugh... Gary KA1J Fingers crossed it wasn't a slim I worked. The signals were in out but for 4-5 minutes I could hear them clearly. Time'll tell. If I did get him it was greatly because the kiddies weren't playing so hard today. 73, Gary KA1J --- This email is free from viruses and malware because avast! Antivirus protection is active. http://www.avast.com _ Topband Reflector Archives - http://www.contesting.com/_topband --- This email is free from viruses and malware because avast! Antivirus protection is active. http://www.avast.com _ Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband --- This email is free from viruses and malware because avast! Antivirus protection is active. http://www.avast.com _ Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband - No virus found in this message. Checked by AVG - www.avg.com Version: 2014.0.4259 / Virus Database: 3684/7058 - Release Date: 02/03/14 - No virus found in this message. Checked by AVG - www.avg.com Version: 2014.0.4259 / Virus Database: 3684/7058 - Release Date: 02/03/14 _ 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: FT5ZM from South Dakota
All I can say is to not give up. I have heard ZERO from FT5ZM on 160 meters up until tonight and have been there every morning and night since they got there. Tonight I heard them for 28 minutes and for about 14 minutes about S-5-6 with a K3. I would say a couple of S-units above the noise. That reading was with the pre-amp off on the K3. They have been good on 80 meters which made it so frustrating I can not hear anything on 160M. Tonight I could hear them best on my 190 foot high drooping dipole, next on my NE beverage and last on the vertical but of course the vertical had more QRN. I worked them using the vertical and listening on the NE beverage because at that time I had not figured out I could hear him the best on the high dipole. Obviously I was very excited and started calling as soon as I could copy calls. Anyway I won't go into the details of working him but just wanted to encourage people to hang in there. He has been coming in from the north according to others and tonight my NE beverage was the best beverage of the 4 I have so they were coming from the north. The difference for me appears to be the polar absorption on the path from here. Ed W0SD _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Submerging variable caps in oil assubstituteforvacuumvariables
There are several on the HP forum that are famililar with that product Hardy. I also have one but claim no expertise since it still works well. hp_agilent_equipm...@yahoogroups.com Carl KM1H - Original Message - From: Hardy Landskov n...@cox.net To: Tom W8JI w...@w8ji.com; Bill Wichers bi...@waveform.net Cc: n...@contesting.com; topband@contesting.com; HAROLD SMITH JR w0ri...@sbcglobal.net; Shoppa, Tim tsho...@wmata.com Sent: Sunday, February 02, 2014 8:58 AM Subject: Re: Topband: Submerging variable caps in oil assubstituteforvacuumvariables FYI All, The HP4815A Vector Impedance Meter submersed the main tuning capacitor in an oil bath of some kind to get the capacitance up. Apparently dissipation factor was not of concern when the unit was designed. If there are any retired HP folks out there they may be able to identify what they used. I have read some years ago that hydraulic jack oil was very close. I need to open mine up and replace one of the capacitors because the oscillator will not start on the higher frequency ranges. I am gun shy at this point until I know exactly what I am dealing with. 73 Hardy N7RT - Original Message - From: Tom W8JI w...@w8ji.com To: Bill Wichers bi...@waveform.net Cc: n...@contesting.com; topband@contesting.com; HAROLD SMITH JR w0ri...@sbcglobal.net; Shoppa, Tim tsho...@wmata.com Sent: Sunday, February 02, 2014 6:16 AM Subject: Re: Topband: Submerging variable caps in oil as substituteforvacuumvariables The major issue with dielectrics is dissipation factor at 2 MHz, which affects losses and Q. Dissipation factor is not published all the time. I can't find dissipation factor for mineral oil. - Original Message - From: Bill Wichers bi...@waveform.net To: Tom W8JI w...@w8ji.com Cc: HAROLD SMITH JR w0ri...@sbcglobal.net; Shoppa, Tim tsho...@wmata.com; n...@contesting.com; topband@contesting.com Sent: Saturday, February 01, 2014 4:05 PM Subject: Re: Topband: Submerging variable caps in oil as substituteforvacuum variables I was reading this thread and all the concerns about oil in the capacitor. Has anyone ever thought about trying SF6 as a dielectric? It's commonly used in high voltage (hundreds of kilovolts) switchgear by utilities. Just a thought, more curiosity than anything else. -Bill Sent from my iPhon On Jan 30, 2014, at 5:32 AM, Tom W8JI w...@w8ji.com wrote: Still I am intrigued by the thought of a remote tuning capacitor via hydraulic tubing :-). The capacitor plates could be as simple as two concentric cylinder conductors with appropriate spacers. I betcha crud collecting on the top of the oil would set voltage limit. I would be as concerned, or more concerned, with the dissipation factor of the oil at short wave frequencies. The thing that worries me is I cannot recall every seeing a single good high-Q oil-dielectric capacitor above power line and audio frequencies. As a matter of fact, many years ago I tried to use a surplus 20-40kV oil capacitor from Fair Radio as a plate blocking capacitor, and it overheated so badly it exploded. I looked for HF data on mineral oil as a dielectric and couldn't find anything. That would be my main concern. I guess I could stick mineral oil between the plates of a capacitor and see what happens to Q. _ Topband Reflector Archives - http://www.contesting.com/_topband - No virus found in this message. Checked by AVG - www.avg.com Version: 2014.0.4259 / Virus Database: 3684/7051 - Release Date: 02/01/14 _ Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband - No virus found in this message. Checked by AVG - www.avg.com Version: 2014.0.4259 / Virus Database: 3684/7053 - Release Date: 02/02/14 _ Topband Reflector Archives - http://www.contesting.com/_topband
Topband: circular polarization on 160m
I hope everyone has had a chance to work FT5ZM on topband. With respect to circular polarization on our HF bands (3.5 - 28 MHz) and on 6m, theory says both the ordinary and extraordinary waves propagate thru the ionosphere with pretty much equal ionospheric absorption. Thus circularly polarized antennas can provide an advantage. Some of the real-world examples I'm aware of have been documented by G2HCG on 10m (in the old Communications Quarterly), by the original K6CT on 20m (in the RSGB Bulletin) and by WA3WDR on 75m (a web paper). I'm sure there are others out there, too. On 160m, theory says the extraordinary wave incurs much more ionospheric absorption (more heavily attenuated) due to 1.8 MHz being so close to the electron-gyro frequency. Thus in theory only the ordinary wave is useful on 160m, which says circular polarization wouldn't do any good. Now things happen on 160m in the real-world that we simply don't understand. For example, an ordinary wave can excite an extraordinary wave under certain ionospheric conditions (if you'd like to read more, curl up in a warm place on a cold night with Chapter 3 in Ionospheric Radio by Kenneth Davies). Could this be happening? I don't think we can rule it out. In my opinion based on all the reports on this reflector over the years, it seems to me that having selectable elevation angles is more important than polarization. But I also admit that there hasn't been much work in the polarization field (no pun intended) on 160m (except for N4IS with his horizontal Waller flag - which makes sense with theory for roughly East-West propagation close to the geomagnetic equator). Carl K9LA _ Topband Reflector Archives - http://www.contesting.com/_topband
Topband: Shunt feeding the Skyneedle
Topbanders If you followed my post on 'In search of resonance' you'll see that I was struggling with feeding a 160m inverted L up close to my 90' Skyneedle. Tom W8JI suggested that I cut back the L to 129' but the same phenomenon was seen...that being the VERTICAL section of the inverted L was being completely suppressed by the Skyneedle. At 129' long the antenna resonated nicely on 8.2 MHz or so...indicating the vertical section was still suppressed and the top 29' was resonating. With this in mind I decided to run a shunt wire from the top to see where the antenna resonates. Here's what I found... The Skyneedle is 90' tall and has a 13' mast sticking out the top that mounts a Telrex 20M546 yagi on a 15m boom. The aluminum gamma arm was attached at the 90' level at 24 away from the tower and held in place by PVC standoffs. See attached photo if the reflector lets me post an attachment. The MFJ read 380 ohms at 1825 and the X is way off the scale. I inserted an EF Johnson 10-160pf air variable capacitor at the base...in series...and was able to tune the antenna to 60 ohms and the X=22. If I played with the cap there was a real sharp drop in reactance showing X=12. The air variable was about ¾ meshed. Here are the other resonant points... 15.8 MHz X=0 R=37 with pos and neg reactance on either side of X=0. This freq showed the sharpest dip of any of the three. Next was 10.6 MHz X=0 R=23 with pos and neg reactance on either side of X=0. The last real dip I saw was at 5.3 Mhz with X=0 R=10 No dips below these frequencies but as I stated earlier I tuned the MFJ 259 to 1825 and then played with the variable cap where I saw the big drop in impedance. (58-60 ohms at X=12 to 22. Here are my questions for the gurus... Do I attempt to match the antenna using a gamma match by tapping the Skyneedle at the 67' level to see how it reacts with regards to R and X? (Note - I cannot vary my gamma arm height as this is a tubular tower and there are few places to bolt on the gamma arm...90', 67', 46' and 25' with the latter being the crows nest platform). Or Can I leave the gamma arm at 90' and rely on an Omega match to tune the antenna? Carl _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Shunt feeding the Skyneedle
Tom and group The SWR is 2.4:1 at 1822 I have an old Heathkit tuner that has a pair of air variables that I may temporarily yank to experiment with gamma vs. omega matching. I've got a wing wang capacitance meter that would tell me the values once I get something to resonate. The 160pf Johnson variable is 3/4 meshed so I don't see additional C being needed in series. I think I will have to add a parallel C to get it down to 50 ohms and x=0. If I can get the tower to 50/x=0 then I'll substitute a vac variable in for the Johnson. The Johnson SHOULD work as a parallel cap as it's good for 7KV according to the Johnson literature. See pic. Also, I've been basing a lot of my values (tap height and gamma spacing) on ON4UNs charts. But I found some English amateur who did a study on gamma/Omega/Beta matching and found that ON4UNs calculations are up to 2X out of whack. I also found an old article on shunt feeding towers from Ham Radio magazine that gave tap height, gamma spacing and C curves. His calculations were off quite a bit as compared to ON4UNs. I attributed this to computer modeling vs. none back in the day and would tend to think the modeling results are more accurate. See attached article. I see a good 20-40 degrees difference between the old school article and ON4UNs calculations. I don't do any modeling though I'd like to try EZNEC or? one of these days to see what my various antennas really look like. So, i'm assuming you're suggesting that I drop the gamma arm down to the 67' level and see what the impedance looks like? If so, I'm guessing the series C required to tune would increase in value? Please advise Thanks Carl AG6X -Original Message- From: Tom W8JI [mailto:w...@w8ji.com] Sent: Monday, February 03, 2014 8:58 AM To: Carl Braun; '160' Subject: Re: Shunt feeding the Skyneedle the vertical section was still suppressed and the top 29' was resonating. With this in mind I decided to run a shunt wire from the top to see where the antenna resonates. Here's what I found.. I was afraid the tower was messing up the L. This is what happens when they are are nearly resonant. You can't measure tower resonance with a drop wire. The drop wire is a stub or shorted transmission line in parallel with the common mode impedance presented by the drop wire and tower combination. It is just a mess of stuff going on. The MFJ read 380 ohms at 1825 and the X is way off the scale. I inserted an EF Johnson 10-160pf air variable capacitor at the base.in series.and was able to tune the antenna to 60 ohms and the X=22. If I played with the cap there was a real sharp drop in reactance showing X=12. The air variable was about ¾ meshed. Reducing the lenth (tap point height) of the drop wire is a better way to get impedance right. Or, better still, use a multiple wire drop to make the drop diameter look larger. That will reduce Q, require more C, and should reduce impedance. You are so close at 60 ohms I would not worry. Adjust the cap for lowest SWR. What is the SWR?? _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: circular polarization on 160m
Circular polarization cannot have an advantage on average, or over time. The problem with circular polarization on skywave is the wave has no set rotation, level, or phase. The circular antenna would be fine combining two phase-quadrature fields with a certain lead or lag (depending on rotation or sense), but the arriving signals at HF would be random. They would be just as likely to subtract as to add. Worse, the noise from both systems sums. If you use circular polarization, you are guaranteed a reduction in signal-to-noise the vast majority of time for a small improvement a fraction of the time. This is why microwave links and HF links that have random paths or multiple paths vote with signal-to-noise detectors to pick a single polarization that is optimal at any moment of time. With line-of-sight the signal could have a set, known, repeatable, rotation. With things multi-pathing and bouncing all around, there is no phase or rotation consistency, so they have to vote to the best polarization and ignore the other at any instant. There could also be a system that detects phase and corrects phase to add, but it would have to be a smart system with signal phase correction. In the systems we have, the only practical combining is through stereo diversity. Your brain has to learn to process independent identical phase-locked channels from two different antennas. It does not even have to be polarization differences, spatial differences alone will be enough on HF and MF. For example, two identical Beverage antenna systems here separated maybe 3 wavelengths or more will have entirely different fade times. Signals can be completely out on one, and still workable on the other. Your brain can then learn to sum the independent signals in each ear (if they are phase locked) and make maybe 3-6 dB improvement when both ears have signal, and not be distracted by the left ear noise if only the right ear has signal. Phase coherence is not critical, but lock is. This goes partly away if the channels are not locked. Even 0.1 Hz unlock is deleterious. This ALL goes away if the channels are a few Hz or more out of lock. The advantage goes away if channels are combined, except for seconds or minutes of luck followed by equal times of bad luck. I can sit here and flip switches to parallel channels, either into a receiver or on the output, and these results are repeatable. I can combine dipoles (which by the way are only horizontal broadside to the dipole, tilting to vertical off the ends) and verticals, Beverages and loops, Beverages and Beverages, verticals and Beverages, and it all repeats over and over the same way. I can shift phase between channels bringing wide spaced or cross-polarized systems in matched level and phase, and a few seconds to a few minutes later it is back at 180 out or one channel is adding nothing but noise. I'm afraid just like in commercial systems with scattering or multipath propagation, a circular polarized system is a net detriment. 73 Tom - Original Message - From: Carl Luetzelschwab carlluetzelsch...@gmail.com To: topband@contesting.com Sent: Monday, February 03, 2014 12:16 PM Subject: Topband: circular polarization on 160m I hope everyone has had a chance to work FT5ZM on topband. With respect to circular polarization on our HF bands (3.5 - 28 MHz) and on 6m, theory says both the ordinary and extraordinary waves propagate thru the ionosphere with pretty much equal ionospheric absorption. Thus circularly polarized antennas can provide an advantage. Some of the real-world examples I'm aware of have been documented by G2HCG on 10m (in the old Communications Quarterly), by the original K6CT on 20m (in the RSGB Bulletin) and by WA3WDR on 75m (a web paper). I'm sure there are others out there, too. On 160m, theory says the extraordinary wave incurs much more ionospheric absorption (more heavily attenuated) due to 1.8 MHz being so close to the electron-gyro frequency. Thus in theory only the ordinary wave is useful on 160m, which says circular polarization wouldn't do any good. Now things happen on 160m in the real-world that we simply don't understand. For example, an ordinary wave can excite an extraordinary wave under certain ionospheric conditions (if you'd like to read more, curl up in a warm place on a cold night with Chapter 3 in Ionospheric Radio by Kenneth Davies). Could this be happening? I don't think we can rule it out. In my opinion based on all the reports on this reflector over the years, it seems to me that having selectable elevation angles is more important than polarization. But I also admit that there hasn't been much work in the polarization field (no pun intended) on 160m (except for N4IS with his horizontal Waller flag - which makes sense with theory for roughly East-West propagation close to the geomagnetic equator). Carl K9LA _ Topband Reflector Archives -
Re: Topband: Shunt feeding the Skyneedle
ON4UNs graph in his book states that my 27m tower with 13' mast and 5 ele 20m monobander (@ 28m high) is good for about 115 degrees. Other old school references place it at 140 degrees. Per my past posts I have a gamma arm at 90' and 25-28 inches from the tower. I have 380 to 400 ohms at the bottom of the gamma wire to gnd. If I insert my EFJ 160pf air variable I can get the antenna to tune to 60 ohms and X=20 or so. This morning I was copying Asian stations on 160 and the tuned into the BC band. Using my 40m vertical array as a reference I switched back and forth between my shunt fed tower and the array. At 600AM the signal strength on the 40m antennas were stronger. At 1200AM the array and the shunted tower were equal at 1700AM ESPN radio was a good 30 to 40db stronger on the shunted tower. Then the sensitivity decreased as I approached 1800 but the tower was still 20db stronger than the 40m antenna when listening to the FT5 pileup. More experimentation with gamma arm placement today Carl AG6X Sent from my iPhone On Feb 4, 2014, at 8:13 AM, ZR z...@jeremy.mv.com wrote: Any idea how much top loading that 5 el 46' boom monster contributes? At a prior QTH in the 80's I had a 90' 25G toploaded with a 10-15-20M stack of PV-4 monobanders and about 18' of mast. The 20M boom was 40' and the tower resonated at 1620KHz if I remember. Sure worked great once I figured out that 60 radials werent so hot over sand and added a mesh extending 50' from the base. The gamma rod was the shield of 3/4 CATV coax about 2' from the tower and the best tap point was around 60' if I remember. Carl KM1H - Original Message - From: Carl Braun carl.br...@lairdtech.com To: '160' topband@contesting.com Cc: 'Tom W8JI' w...@w8ji.com Sent: Monday, February 03, 2014 11:17 AM Subject: Topband: Shunt feeding the Skyneedle Topbanders If you followed my post on 'In search of resonance' you'll see that I was struggling with feeding a 160m inverted L up close to my 90' Skyneedle. Tom W8JI suggested that I cut back the L to 129' but the same phenomenon was seen...that being the VERTICAL section of the inverted L was being completely suppressed by the Skyneedle. At 129' long the antenna resonated nicely on 8.2 MHz or so...indicating the vertical section was still suppressed and the top 29' was resonating. With this in mind I decided to run a shunt wire from the top to see where the antenna resonates. Here's what I found... The Skyneedle is 90' tall and has a 13' mast sticking out the top that mounts a Telrex 20M546 yagi on a 15m boom. The aluminum gamma arm was attached at the 90' level at 24 away from the tower and held in place by PVC standoffs. See attached photo if the reflector lets me post an attachment. The MFJ read 380 ohms at 1825 and the X is way off the scale. I inserted an EF Johnson 10-160pf air variable capacitor at the base...in series...and was able to tune the antenna to 60 ohms and the X=22. If I played with the cap there was a real sharp drop in reactance showing X=12. The air variable was about ¾ meshed. Here are the other resonant points... 15.8 MHz X=0 R=37 with pos and neg reactance on either side of X=0. This freq showed the sharpest dip of any of the three. Next was 10.6 MHz X=0 R=23 with pos and neg reactance on either side of X=0. The last real dip I saw was at 5.3 Mhz with X=0 R=10 No dips below these frequencies but as I stated earlier I tuned the MFJ 259 to 1825 and then played with the variable cap where I saw the big drop in impedance. (58-60 ohms at X=12 to 22. Here are my questions for the gurus... Do I attempt to match the antenna using a gamma match by tapping the Skyneedle at the 67' level to see how it reacts with regards to R and X? (Note - I cannot vary my gamma arm height as this is a tubular tower and there are few places to bolt on the gamma arm...90', 67', 46' and 25' with the latter being the crows nest platform). Or Can I leave the gamma arm at 90' and rely on an Omega match to tune the antenna? Carl _ Topband Reflector Archives - http://www.contesting.com/_topband - No virus found in this message. Checked by AVG - www.avg.com Version: 2014.0.4259 / Virus Database: 3684/7058 - Release Date: 02/03/14 _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: circular polarization on 160m
Hi Carl and top-band lovers I would like to mention Chapter 7.6 as well, polarization matching, and also 7.7 Fading. I started developing my HWF early 2009 and I think there is no more to squeeze from it. Here some update in respect of polarization on 160m. It is a game!, vertical and horizontal field changes all the time, an elliptic can describe better the waves on 160m. My last HWF tuning gave me another 6-8 db improvement on the signal noise ratio. The HWF is really an all directions noise cancelling antenna ( Va-Vb=0), the goal is maximum attenuation on the vertical field an good directivity on the horizontal field. The takeoff angle is always the same and does not change with the height above ground ,it always very close to 40 degree. It is alike high horizontal dipole that takeoff change with the height from ground. The HWF has a deep null from high angle signals at any height above ground. The game is maximum attention on the vertical signal because most of the manmade noise, power line noise, city noise propagate with vertical polarization due the proximity with the ground for 160m waves. For 160m the HWF needs to be over 100 ft. to perform well on the horizontal signals, 50 ft. is ok for 80m and up. The HWF works 160m to 30m with excellent performance depending on the area of the loops. The HWF gain is around -43 db, and the vertical attenuation can be adjusted to deep another -50db, the total attenuation front and back is -90 db , It has a front null and a back null for vertical signals. This is a weak, weak, weak signal system implementation, very complex by nature by receiving near the receiver noise floor most of the time. Depending on the direction of the wave the H/V ratio can be -20 db or more both ways, most of the time the vertical component is 10 to 20 db stronger than the horizontal component. When you combine the 4 variables, vertical gain, horizontal gain, vertical noise QRM and the signal H/V ratio you have your final signal to noise ratio, however on top of that you need to add the propagation noise as well. Another dependence is the solar cycle. We are at the peak of the solar cycle and the propagation this year has been very different . Long pass is peaking at the SS or SR and the signals from North are showing a strong horizontal component. or it could be just coincidence, just time will tell. Nowadays I can copy better weak signals with my HWV than my VWF in all directions. I just observed that recently with 8Q7BM, NH0Z,V63DX,4J6RO, 4K6FO and 4L5O, signals from NNW and NNE better on HWF. It is the first time I can hear better signals coming North with the HWF. It is all about signal noise ratio. For long path the new adjust also helped a lot. I detuned the TX tower to minimum noise on the HWF, making the diagram symmetrical on the polar plot. It looks like a butterfly for local vertical signals. Peter HS0ZKX is coming strong from SSW every 28 days. Just after the solstice last month the long path propagation was just fantastic. WV8. H40,RA0. JA. BA. BG and DU7 copy with Q5 from SSW from Dec 25th to Jan 1st , but few QSO's. only JA and DU7 on the log. FT5ZM only on the HWF as well. I agree with Carl. There hasn't been much work in polarization field on 160m, however It is a fascinate subject. Come on in folks! Regards JCarlos N4IS -Original Message- From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Carl Luetzelschwab Sent: Monday, February 03, 2014 12:17 PM To: topband@contesting.com Subject: Topband: circular polarization on 160m I hope everyone has had a chance to work FT5ZM on topband. With respect to circular polarization on our HF bands (3.5 - 28 MHz) and on 6m, theory says both the ordinary and extraordinary waves propagate thru the ionosphere with pretty much equal ionospheric absorption. Thus circularly polarized antennas can provide an advantage. Some of the real-world examples I'm aware of have been documented by G2HCG on 10m (in the old Communications Quarterly), by the original K6CT on 20m (in the RSGB Bulletin) and by WA3WDR on 75m (a web paper). I'm sure there are others out there, too. On 160m, theory says the extraordinary wave incurs much more ionospheric absorption (more heavily attenuated) due to 1.8 MHz being so close to the electron-gyro frequency. Thus in theory only the ordinary wave is useful on 160m, which says circular polarization wouldn't do any good. Now things happen on 160m in the real-world that we simply don't understand. For example, an ordinary wave can excite an extraordinary wave under certain ionospheric conditions (if you'd like to read more, curl up in a warm place on a cold night with Chapter 3 in Ionospheric Radio by Kenneth Davies). Could this be happening? I don't think we can rule it out. In my opinion based on all the reports on this reflector over the years, it seems to me that having selectable elevation angles is more important than polarization. But I also admit that there hasn't
Topband: FT5ZM on 80
Although not a Top Band QSO, the FT5ZM operation was coming in loud and clear here in northern California on 80 meters this morning. Worked him on first call amidst a rather large pileup at 15.06Z on 3.523. I'm a happy camper, as my antenna for 80 is only an Inverted L (up 40 feet), and using nothing but the K2AV-designed FCP (folded CounterPoise) under it. Jim / W6JHB _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Submerging variable caps in oil assubstituteforvacuumvariables
I contacted George A. Sanford about the oil used in the variable cap in the HP4815a and he replied that the oil was used for a shock absorber effect for frequency stability in the instrument and not for any other reason. I had a need for a vac variable and have a large air variable that I had planed to submerge in oil, but have not yet found a suitable oil. 73 es DX Pat H. Armstrong KF5YZ Carl k...@jeremy.mv.com wrote: There are several on the HP forum that are famililar with that product Hardy. I also have one but claim no expertise since it still works well. hp_agilent_equipm...@yahoogroups.com Carl KM1H - Original Message - From: Hardy Landskov n...@cox.net To: Tom W8JI w...@w8ji.com; Bill Wichers bi...@waveform.net Cc: n...@contesting.com; topband@contesting.com; HAROLD SMITH JR w0ri...@sbcglobal.net; Shoppa, Tim tsho...@wmata.com Sent: Sunday, February 02, 2014 8:58 AM Subject: Re: Topband: Submerging variable caps in oil assubstituteforvacuumvariables FYI All, The HP4815A Vector Impedance Meter submersed the main tuning capacitor in an oil bath of some kind to get the capacitance up. Apparently dissipation factor was not of concern when the unit was designed. If there are any retired HP folks out there they may be able to identify what they used. I have read some years ago that hydraulic jack oil was very close. I need to open mine up and replace one of the capacitors because the oscillator will not start on the higher frequency ranges. I am gun shy at this point until I know exactly what I am dealing with. 73 Hardy N7RT - Original Message - From: Tom W8JI w...@w8ji.com To: Bill Wichers bi...@waveform.net Cc: n...@contesting.com; topband@contesting.com; HAROLD SMITH JR w0ri...@sbcglobal.net; Shoppa, Tim tsho...@wmata.com Sent: Sunday, February 02, 2014 6:16 AM Subject: Re: Topband: Submerging variable caps in oil as substituteforvacuumvariables The major issue with dielectrics is dissipation factor at 2 MHz, which affects losses and Q. Dissipation factor is not published all the time. I can't find dissipation factor for mineral oil. - Original Message - From: Bill Wichers bi...@waveform.net To: Tom W8JI w...@w8ji.com Cc: HAROLD SMITH JR w0ri...@sbcglobal.net; Shoppa, Tim tsho...@wmata.com; n...@contesting.com; topband@contesting.com Sent: Saturday, February 01, 2014 4:05 PM Subject: Re: Topband: Submerging variable caps in oil as substituteforvacuum variables I was reading this thread and all the concerns about oil in the capacitor. Has anyone ever thought about trying SF6 as a dielectric? It's commonly used in high voltage (hundreds of kilovolts) switchgear by utilities. Just a thought, more curiosity than anything else. -Bill Sent from my iPhon On Jan 30, 2014, at 5:32 AM, Tom W8JI w...@w8ji.com wrote: Still I am intrigued by the thought of a remote tuning capacitor via hydraulic tubing :-). The capacitor plates could be as simple as two concentric cylinder conductors with appropriate spacers. I betcha crud collecting on the top of the oil would set voltage limit. I would be as concerned, or more concerned, with the dissipation factor of the oil at short wave frequencies. The thing that worries me is I cannot recall every seeing a single good high-Q oil-dielectric capacitor above power line and audio frequencies. As a matter of fact, many years ago I tried to use a surplus 20-40kV oil capacitor from Fair Radio as a plate blocking capacitor, and it overheated so badly it exploded. I looked for HF data on mineral oil as a dielectric and couldn't find anything. That would be my main concern. I guess I could stick mineral oil between the plates of a capacitor and see what happens to Q. _ Topband Reflector Archives - http://www.contesting.com/_topband - No virus found in this message. Checked by AVG - www.avg.com Version: 2014.0.4259 / Virus Database: 3684/7051 - Release Date: 02/01/14 _ Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband - No virus found in this message. Checked by AVG - www.avg.com Version: 2014.0.4259 / Virus Database: 3684/7053 - Release Date: 02/02/14 _ Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Shunt feeding the Skyneedle
Topbanders Well, after experimenting with shortening the gamma wire from the bottom I saw NO changes on the MFJnone. So, option two was to lower the whole tower down and remove the gamma arm from the 90' level and remount it at the 67' level. That done I cranked the tower back up and looked at the R at the bottom of the gamma wire. I saw 380 to 400 Ohms...the same reading that I saw when the gamma arm was at 90'!!! Frustrating. Here's what changed though...when I had the gamma arm at 90' with the 14 gauge gamma wire 24 away from the tower I was able to insert my Johnson 60-160pf variable cap in series with the gamma wire to get approx 58-60 ohms at X=20. The cap was 2/3 meshed at this point. NOW that I've lowered the gamma arm to the 67' level...I insert my variable cap and the antenna resonates at 1.970 MHz with R=36 ohms and X=0. For some odd reason the MFJ SWR reading shows 1.0:1 with this 36 ohm reading and, inside the shack, the Ft1000D shows 1.0:1 swr from 1.988 to 1.950 and a 1.5:1 range of 2.007 to 1.930. It now appears that the antenna is a bit short but why am I seeing these crazy high resistance readings with no variable cap in line? How can I lower the resonant freq without moving the gamma arm up? Increase the spacing of the gamma wire from the tower? Add more radials? I was going to build a three conductor wire cage with the wires spaced 10 apart or so once I had an idea where the antenna resonates. Would a fatter gamma trio drop the resonant freq or just change the capacitance value of the antenna? Lots of questions but I feel I'm making progress as the FLAT SWR high in the band indicates the antenna wants to work well but I need to lower the resonant frequency. Comments please Thanks Carl AG6X -Original Message- From: ZR [mailto:z...@jeremy.mv.com] Sent: Tuesday, February 04, 2014 8:13 AM To: Carl Braun; '160' Cc: 'Tom W8JI' Subject: Re: Topband: Shunt feeding the Skyneedle Any idea how much top loading that 5 el 46' boom monster contributes? At a prior QTH in the 80's I had a 90' 25G toploaded with a 10-15-20M stack of PV-4 monobanders and about 18' of mast. The 20M boom was 40' and the tower resonated at 1620KHz if I remember. Sure worked great once I figured out that 60 radials werent so hot over sand and added a mesh extending 50' from the base. The gamma rod was the shield of 3/4 CATV coax about 2' from the tower and the best tap point was around 60' if I remember. Carl KM1H - Original Message - From: Carl Braun carl.br...@lairdtech.com To: '160' topband@contesting.com Cc: 'Tom W8JI' w...@w8ji.com Sent: Monday, February 03, 2014 11:17 AM Subject: Topband: Shunt feeding the Skyneedle Topbanders If you followed my post on 'In search of resonance' you'll see that I was struggling with feeding a 160m inverted L up close to my 90' Skyneedle. Tom W8JI suggested that I cut back the L to 129' but the same phenomenon was seen...that being the VERTICAL section of the inverted L was being completely suppressed by the Skyneedle. At 129' long the antenna resonated nicely on 8.2 MHz or so...indicating the vertical section was still suppressed and the top 29' was resonating. With this in mind I decided to run a shunt wire from the top to see where the antenna resonates. Here's what I found... The Skyneedle is 90' tall and has a 13' mast sticking out the top that mounts a Telrex 20M546 yagi on a 15m boom. The aluminum gamma arm was attached at the 90' level at 24 away from the tower and held in place by PVC standoffs. See attached photo if the reflector lets me post an attachment. The MFJ read 380 ohms at 1825 and the X is way off the scale. I inserted an EF Johnson 10-160pf air variable capacitor at the base...in series...and was able to tune the antenna to 60 ohms and the X=22. If I played with the cap there was a real sharp drop in reactance showing X=12. The air variable was about ¾ meshed. Here are the other resonant points... 15.8 MHz X=0 R=37 with pos and neg reactance on either side of X=0. This freq showed the sharpest dip of any of the three. Next was 10.6 MHz X=0 R=23 with pos and neg reactance on either side of X=0. The last real dip I saw was at 5.3 Mhz with X=0 R=10 No dips below these frequencies but as I stated earlier I tuned the MFJ 259 to 1825 and then played with the variable cap where I saw the big drop in impedance. (58-60 ohms at X=12 to 22. Here are my questions for the gurus... Do I attempt to match the antenna using a gamma match by tapping the Skyneedle at the 67' level to see how it reacts with regards to R and X? (Note - I cannot vary my gamma arm height as this is a tubular tower and there are few places to bolt on the gamma arm...90', 67', 46' and 25' with the latter being the crows nest platform). Or Can I leave the gamma arm at 90' and rely on an Omega match to tune the antenna? Carl _ Topband Reflector Archives -
Re: Topband: FT5ZM from South Dakota
Congratulations, sounds like another case of high angle N-S propagation Carl KM1H - Original Message - From: Ed Gray W0SD w...@triotel.net To: topband@contesting.com Sent: Saturday, February 01, 2014 8:00 PM Subject: Topband: FT5ZM from South Dakota All I can say is to not give up. I have heard ZERO from FT5ZM on 160 meters up until tonight and have been there every morning and night since they got there. Tonight I heard them for 28 minutes and for about 14 minutes about S-5-6 with a K3. I would say a couple of S-units above the noise. That reading was with the pre-amp off on the K3. They have been good on 80 meters which made it so frustrating I can not hear anything on 160M. Tonight I could hear them best on my 190 foot high drooping dipole, next on my NE beverage and last on the vertical but of course the vertical had more QRN. I worked them using the vertical and listening on the NE beverage because at that time I had not figured out I could hear him the best on the high dipole. Obviously I was very excited and started calling as soon as I could copy calls. Anyway I won't go into the details of working him but just wanted to encourage people to hang in there. He has been coming in from the north according to others and tonight my NE beverage was the best beverage of the 4 I have so they were coming from the north. The difference for me appears to be the polar absorption on the path from here. Ed W0SD _ Topband Reflector Archives - http://www.contesting.com/_topband - No virus found in this message. Checked by AVG - www.avg.com Version: 2014.0.4259 / Virus Database: 3684/7058 - Release Date: 02/03/14 _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Shunt feeding the Skyneedle
Any idea how much top loading that 5 el 46' boom monster contributes? At a prior QTH in the 80's I had a 90' 25G toploaded with a 10-15-20M stack of PV-4 monobanders and about 18' of mast. The 20M boom was 40' and the tower resonated at 1620KHz if I remember. Sure worked great once I figured out that 60 radials werent so hot over sand and added a mesh extending 50' from the base. The gamma rod was the shield of 3/4 CATV coax about 2' from the tower and the best tap point was around 60' if I remember. Carl KM1H - Original Message - From: Carl Braun carl.br...@lairdtech.com To: '160' topband@contesting.com Cc: 'Tom W8JI' w...@w8ji.com Sent: Monday, February 03, 2014 11:17 AM Subject: Topband: Shunt feeding the Skyneedle Topbanders If you followed my post on 'In search of resonance' you'll see that I was struggling with feeding a 160m inverted L up close to my 90' Skyneedle. Tom W8JI suggested that I cut back the L to 129' but the same phenomenon was seen...that being the VERTICAL section of the inverted L was being completely suppressed by the Skyneedle. At 129' long the antenna resonated nicely on 8.2 MHz or so...indicating the vertical section was still suppressed and the top 29' was resonating. With this in mind I decided to run a shunt wire from the top to see where the antenna resonates. Here's what I found... The Skyneedle is 90' tall and has a 13' mast sticking out the top that mounts a Telrex 20M546 yagi on a 15m boom. The aluminum gamma arm was attached at the 90' level at 24 away from the tower and held in place by PVC standoffs. See attached photo if the reflector lets me post an attachment. The MFJ read 380 ohms at 1825 and the X is way off the scale. I inserted an EF Johnson 10-160pf air variable capacitor at the base...in series...and was able to tune the antenna to 60 ohms and the X=22. If I played with the cap there was a real sharp drop in reactance showing X=12. The air variable was about ¾ meshed. Here are the other resonant points... 15.8 MHz X=0 R=37 with pos and neg reactance on either side of X=0. This freq showed the sharpest dip of any of the three. Next was 10.6 MHz X=0 R=23 with pos and neg reactance on either side of X=0. The last real dip I saw was at 5.3 Mhz with X=0 R=10 No dips below these frequencies but as I stated earlier I tuned the MFJ 259 to 1825 and then played with the variable cap where I saw the big drop in impedance. (58-60 ohms at X=12 to 22. Here are my questions for the gurus... Do I attempt to match the antenna using a gamma match by tapping the Skyneedle at the 67' level to see how it reacts with regards to R and X? (Note - I cannot vary my gamma arm height as this is a tubular tower and there are few places to bolt on the gamma arm...90', 67', 46' and 25' with the latter being the crows nest platform). Or Can I leave the gamma arm at 90' and rely on an Omega match to tune the antenna? Carl _ Topband Reflector Archives - http://www.contesting.com/_topband - No virus found in this message. Checked by AVG - www.avg.com Version: 2014.0.4259 / Virus Database: 3684/7058 - Release Date: 02/03/14 _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: circular polarization on 160m
Is there not a built in loss of 3db on both TX and RX with a CP antenna compared to an Axial mode antenna? Not that it makes that much difference on RX but 3db is 3db. Another issue with CP I understand is the difference between LHCP and RHCP for space communications is supposed to be infinity for space communications. I do not know if the same rules apply for HF with skip involved. Although I have seen this on terrestrial UHF paths when the screw sense is reversed and a complete loss of signal results. I would also presume that the construction of a good CP antenna for 160 would be very difficult to perfect. I have seen some antennas for AMSAT work attempting to produce a CP type antenna by have two interlaced yagis, one vertical and the other horizontal, one space 1/4 wave in front of the other, and with a quarter wave delay line at the feed point separating each. If this could be replicated between a TB horizontal vertical and a horizontal dipole some distance away...I just don't know if this would even end up providing a CP wave front. If they were far enough apart maybe there would be some diversity gain./ Herb Schoenbohm, KV4FZ On 2/4/2014 1:03 PM, Tom W8JI wrote: Circular polarization cannot have an advantage on average, or over time. The problem with circular polarization on skywave is the wave has no set rotation, level, or phase. The circular antenna would be fine combining two phase-quadrature fields with a certain lead or lag (depending on rotation or sense), but the arriving signals at HF would be random. They would be just as likely to subtract as to add. Worse, the noise from both systems sums. If you use circular polarization, you are guaranteed a reduction in signal-to-noise the vast majority of time for a small improvement a fraction of the time. This is why microwave links and HF links that have random paths or multiple paths vote with signal-to-noise detectors to pick a single polarization that is optimal at any moment of time. With line-of-sight the signal could have a set, known, repeatable, rotation. With things multi-pathing and bouncing all around, there is no phase or rotation consistency, so they have to vote to the best polarization and ignore the other at any instant. There could also be a system that detects phase and corrects phase to add, but it would have to be a smart system with signal phase correction. In the systems we have, the only practical combining is through stereo diversity. Your brain has to learn to process independent identical phase-locked channels from two different antennas. It does not even have to be polarization differences, spatial differences alone will be enough on HF and MF. For example, two identical Beverage antenna systems here separated maybe 3 wavelengths or more will have entirely different fade times. Signals can be completely out on one, and still workable on the other. Your brain can then learn to sum the independent signals in each ear (if they are phase locked) and make maybe 3-6 dB improvement when both ears have signal, and not be distracted by the left ear noise if only the right ear has signal. Phase coherence is not critical, but lock is. This goes partly away if the channels are not locked. Even 0.1 Hz unlock is deleterious. This ALL goes away if the channels are a few Hz or more out of lock. The advantage goes away if channels are combined, except for seconds or minutes of luck followed by equal times of bad luck. I can sit here and flip switches to parallel channels, either into a receiver or on the output, and these results are repeatable. I can combine dipoles (which by the way are only horizontal broadside to the dipole, tilting to vertical off the ends) and verticals, Beverages and loops, Beverages and Beverages, verticals and Beverages, and it all repeats over and over the same way. I can shift phase between channels bringing wide spaced or cross-polarized systems in matched level and phase, and a few seconds to a few minutes later it is back at 180 out or one channel is adding nothing but noise. I'm afraid just like in commercial systems with scattering or multipath propagation, a circular polarized system is a net detriment. 73 Tom - Original Message - From: Carl Luetzelschwab carlluetzelsch...@gmail.com To: topband@contesting.com Sent: Monday, February 03, 2014 12:16 PM Subject: Topband: circular polarization on 160m I hope everyone has had a chance to work FT5ZM on topband. With respect to circular polarization on our HF bands (3.5 - 28 MHz) and on 6m, theory says both the ordinary and extraordinary waves propagate thru the ionosphere with pretty much equal ionospheric absorption. Thus circularly polarized antennas can provide an advantage. Some of the real-world examples I'm aware of have been documented by G2HCG on 10m (in the old Communications Quarterly), by the original K6CT on 20m (in the RSGB Bulletin) and by WA3WDR on 75m (a web paper). I'm sure there are others out
Re: Topband: circular polarization on 160m
Is there not a built in loss of 3db on both TX and RX with a CP antenna compared to an Axial mode antenna? Not that it makes that much difference on RX but 3db is 3db. Another issue with CP I understand is the difference between LHCP and RHCP for space communications is supposed to be infinity for space communications. I do not know if the same rules apply for HF with skip involved. Although I have seen this on terrestrial UHF paths when the screw sense is reversed and a complete loss of signal results. I would also presume that the construction of a good CP antenna for 160 would be very difficult to perfect. I have seen some antennas for AMSAT work attempting to produce a CP type antenna by have two interlaced yagis, one vertical and the other horizontal, one space 1/4 wave in front of the other, and with a quarter wave delay line at the feed point separating each. If this could be replicated between a TB horizontal vertical and a horizontal dipole some distance away...I just don't know if this would even end up providing a CP wave front. If they were far enough apart maybe there would be some diversity gain./ Herb Schoenbohm, KV4FZ On 2/4/2014 1:03 PM, Tom W8JI wrote: Circular polarization cannot have an advantage on average, or over time. The problem with circular polarization on skywave is the wave has no set rotation, level, or phase. The circular antenna would be fine combining two phase-quadrature fields with a certain lead or lag (depending on rotation or sense), but the arriving signals at HF would be random. They would be just as likely to subtract as to add. Worse, the noise from both systems sums. If you use circular polarization, you are guaranteed a reduction in signal-to-noise the vast majority of time for a small improvement a fraction of the time. This is why microwave links and HF links that have random paths or multiple paths vote with signal-to-noise detectors to pick a single polarization that is optimal at any moment of time. With line-of-sight the signal could have a set, known, repeatable, rotation. With things multi-pathing and bouncing all around, there is no phase or rotation consistency, so they have to vote to the best polarization and ignore the other at any instant. There could also be a system that detects phase and corrects phase to add, but it would have to be a smart system with signal phase correction. In the systems we have, the only practical combining is through stereo diversity. Your brain has to learn to process independent identical phase-locked channels from two different antennas. It does not even have to be polarization differences, spatial differences alone will be enough on HF and MF. For example, two identical Beverage antenna systems here separated maybe 3 wavelengths or more will have entirely different fade times. Signals can be completely out on one, and still workable on the other. Your brain can then learn to sum the independent signals in each ear (if they are phase locked) and make maybe 3-6 dB improvement when both ears have signal, and not be distracted by the left ear noise if only the right ear has signal. Phase coherence is not critical, but lock is. This goes partly away if the channels are not locked. Even 0.1 Hz unlock is deleterious. This ALL goes away if the channels are a few Hz or more out of lock. The advantage goes away if channels are combined, except for seconds or minutes of luck followed by equal times of bad luck. I can sit here and flip switches to parallel channels, either into a receiver or on the output, and these results are repeatable. I can combine dipoles (which by the way are only horizontal broadside to the dipole, tilting to vertical off the ends) and verticals, Beverages and loops, Beverages and Beverages, verticals and Beverages, and it all repeats over and over the same way. I can shift phase between channels bringing wide spaced or cross-polarized systems in matched level and phase, and a few seconds to a few minutes later it is back at 180 out or one channel is adding nothing but noise. I'm afraid just like in commercial systems with scattering or multipath propagation, a circular polarized system is a net detriment. 73 Tom - Original Message - From: Carl Luetzelschwab carlluetzelsch...@gmail.com To: topband@contesting.com Sent: Monday, February 03, 2014 12:16 PM Subject: Topband: circular polarization on 160m I hope everyone has had a chance to work FT5ZM on topband. With respect to circular polarization on our HF bands (3.5 - 28 MHz) and on 6m, theory says both the ordinary and extraordinary waves propagate thru the ionosphere with pretty much equal ionospheric absorption. Thus circularly polarized antennas can provide an advantage. Some of the real-world examples I'm aware of have been documented by G2HCG on 10m (in the old Communications Quarterly), by the original K6CT on 20m (in the RSGB Bulletin) and by WA3WDR on 75m (a web paper). I'm sure there are others out
Re: Topband: FT5ZM from South Dakota
I had a similar experience to Ed, W0SD. Having had absolutely zero copy on FT5ZM on 160 prior to today on my half-sloper, I had given up hope of hearing them on 160, let alone actually work them. Then, to my surprise, this morning they were perfect copy here in Western Washington for almost 2 hours. They were in the log at 1454z, and actually peaked at an honest s-9 about 15 minutes later. You just never know what the propagation gods will bring you on Top Band. 73, Jim W1YY -Original Message- From: Carl Sent: Tuesday, February 4, 2014 8:13 AM To: Ed Gray W0SD ; topband@contesting.com Subject: Re: Topband: FT5ZM from South Dakota Congratulations, sounds like another case of high angle N-S propagation Carl KM1H - Original Message - From: Ed Gray W0SD w...@triotel.net To: topband@contesting.com Sent: Saturday, February 01, 2014 8:00 PM Subject: Topband: FT5ZM from South Dakota All I can say is to not give up. I have heard ZERO from FT5ZM on 160 meters up until tonight and have been there every morning and night since they got there. Tonight I heard them for 28 minutes and for about 14 minutes about S-5-6 with a K3. I would say a couple of S-units above the noise. That reading was with the pre-amp off on the K3. They have been good on 80 meters which made it so frustrating I can not hear anything on 160M. Tonight I could hear them best on my 190 foot high drooping dipole, next on my NE beverage and last on the vertical but of course the vertical had more QRN. I worked them using the vertical and listening on the NE beverage because at that time I had not figured out I could hear him the best on the high dipole. Obviously I was very excited and started calling as soon as I could copy calls. Anyway I won't go into the details of working him but just wanted to encourage people to hang in there. He has been coming in from the north according to others and tonight my NE beverage was the best beverage of the 4 I have so they were coming from the north. The difference for me appears to be the polar absorption on the path from here. Ed W0SD _ Topband Reflector Archives - http://www.contesting.com/_topband - No virus found in this message. Checked by AVG - www.avg.com Version: 2014.0.4259 / Virus Database: 3684/7058 - Release Date: 02/03/14 _ Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Shunt feeding the Skyneedle
Thanks for the input Tom The only variable cap I have is the EF Johnson which is 60-160pf. I have some ham radio stuff at my parents house not the least is a Jennings 1000pf vac variable rated at 5KV or 7.5kv. I was hoping to use that with a 12v motor for QSYing up the band for contesting. I'll have to ask mom to send it to CA in a pkg with some cookies. When the gamma arm was at 90' I was able to add 160pf to get a resonance point around 1825 but the resistance was still high at 58-60 and X was 20++. Maybe the big vacuum cap would bring that R and X down to where it needs to be. ON4UNs figure 9-85 on page 9-71 of his third edition shows that a tower that is electrical 110 to 130 degrees should have a tap height around 20 meters and a matching cap of 400pf. That being said it may be a good idea to get the vac variable into service. I would assume I would want to raise the gamma arm back up to 90' as it resonated closer to 1825 than the latest iteration which shows a Fr near 1.977 Sent from my iPhone On Feb 4, 2014, at 6:40 PM, Tom W8JI w...@w8ji.com wrote: Here's what changed though...when I had the gamma arm at 90' with the 14 gauge gamma wire 24 away from the tower I was able to insert my Johnson 60-160pf variable cap in series with the gamma wire to get approx 58-60 ohms at X=20. The cap was 2/3 meshed at this point. That's the right way. You have to cancel the reatcance of the drop arm to get a good reading. Maybe you need a larger capacitor to hit the bottom of the band? Resistance normally goes up in a case like yours as frequency is drecreased. NOW that I've lowered the gamma arm to the 67' level...I insert my variable cap and the antenna resonates at 1.970 MHz with R=36 ohms and X=0. For some odd reason the MFJ SWR reading shows 1.0:1 with this 36 ohm reading and, inside the shack, the Ft1000D shows 1.0:1 swr from 1.988 to 1.950 and a 1.5:1 range of 2.007 to 1.930 What does more capacitance do? It now appears that the antenna is a bit short but why am I seeing these crazy high resistance readings with no variable cap in line? You should see them. The MFJ detector is a 50 ohm bridge. It will overflow and give all kinds of goofy readings when impedance is far away from 50 ohms. How can I lower the resonant freq without moving the gamma arm up? Increase the spacing of the gamma wire from the tower? Add more radials? I would have left it at the top and shorted the wire to the tower at different places until I found the sweet spot. But you have to dip the reactance out to really know what you have. I was going to build a three conductor wire cage with the wires spaced 10 apart or so once I had an idea where the antenna resonates. Would a fatter gamma trio drop the resonant freq or just change the capacitance value of the antenna? A fatter shunt wire will lower reactance and resistance. You will need more C, and the tuned resistance will be a bit lower. _ Topband Reflector Archives - http://www.contesting.com/_topband
