Re: Topband: E51D and OHQP
You can never have too many antennas. (Despite your wife’s opinion) Chuck W5PR On Fri, Aug 25, 2023 at 10:05 AM Mike VE9AA ve...@nbnet.nb.ca < ve...@nbnet.nb.ca> wrote: > > Contrary to popular belief, sometimes a low dipole CAN be useful on TB. > > I worked 9M6 (from here in VE9) one morning(greyline) with a low full > wave dipole up around 30-35' or so while other locals in VE1 and VE9 > were hearing virtually nothing. > > Not every day that happens of course,(the inverted L usually outshines > the DP 40:1 or so) and my local buddies thought I was joking when I > announced on the packetcluster I had done it. > > Run what ya brung seems to be the important thing. I have similar > stories where 6m DX has been worked with the most raggedy cross > polarized low-ish pos antenna while high stacks heard almost nothing, so > never say never when it comes to antennas or prop. > > 73, Mike VE9AA > > _ > Searchable Archives: http://www.contesting.com/_topband - Topband > Reflector > _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
Re: Topband: Beverage Antennas on Sloping Ground
I keep it beside my chair in the living room. Chuck W5PR On Fri, Aug 4, 2023 at 9:42 AM Mike Waters wrote: > If you don't already have it, *Low Band DXing* by John Devoldere, ON4UN > (published by the ARRL) has a very informative chapter about receiving > antennas. Most of it is about Beverage antennas. Highly recommended. > > 73 Mike > W0BTU > https://web.archive.org/web/20190827040547/http://w0btu.com/ > > > On Thu, Aug 3, 2023, 10:16 PM Chuck Dietz wrote: > >> Thank you everyone who replied. The consensus was that sloping ground will >> not matter much. >> I was discussing with Tree that I may have the opportunity to put up a >> similar, same direction, but temporary Beverage on the opposite side of >> the >> hill which slopes in the opposite direction to compare. The A-B comparison >> would be interesting. >> >> Chuck W5PR >> >> _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
Topband: Beverage Antennas on Sloping Ground
Thank you everyone who replied. The consensus was that sloping ground will not matter much. I was discussing with Tree that I may have the opportunity to put up a similar, same direction, but temporary Beverage on the opposite side of the hill which slopes in the opposite direction to compare. The A-B comparison would be interesting. Chuck W5PR _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
Topband: Beverage Antennas on Sloping Ground
Am I correct in assuming that Beverage wires sloping downward from the feed point to the termination will work better than ones that slope upward? I have two places I would like to put bidirectional Beverages, but they are both on sloping ground. I’m wondering if it would be worth the effort to make them bidirectional or should I just go with unidirectional ones toward the downslope direction? Soil is good and the slope would be about 10’ or a little less in the 500’ or so lengths. They will be about 10’ high so the tractor will go under them. Quiet country local. Thanks, Chuck W5PR _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
Re: Topband: I asked AI how to make more Stew Perry Contacts!
Dang! I need to move my antenna outdoors. Chuck W5PR On Thu, Jun 22, 2023 at 1:13 PM Michael Rutkaus wrote: > Being fairly low on the Perry Totem Pole, I only made about 31 contacts > last weekend. So I (seriously) asked Google's AI "Bard" how to make more > contacts. Here are the results after a few seconds: > > I asked Google’s Bard how to make more cw contacts during the Stew Perry > contest! After a few seconds: > > Here are some tips on how to make more CW contacts during the Stew Perry > Top Band Distance Challenge: > >- Start early. The band tends to be less crowded early in the contest, >so you’ll have a better chance of making contacts with stations from all >over the world. >- Use a good antenna. A good antenna is essential for making contacts on >160 meters. If you can, set up your antenna outdoors in a clear area. >- Operate at a high power level. This will give you a better chance of >being heard by stations in distant locations. >- Use a good CW key. A good CW key will make it easier for you to send >and receive CW at high speeds. >- Be patient. It can take some time to make contacts on 160 meters, >especially during a busy contest. Don’t get discouraged if you don’t > make a >lot of contacts right away. > > Here are some additional tips that may help you make more CW contacts: > >- Use a contest logging program. This will help you keep track of your >contacts and make it easier to submit your log after the contest. >- Listen to the band before you start calling. This will give you an >idea of what stations are active and what their call signs are. >- Call CQ slowly and clearly. This will help stations to hear you and >identify your call sign. >- Be responsive to calls. If you hear a station calling you, respond as >quickly as possible. >- Use a friendly and encouraging tone. This will make it more likely >that stations will want to work you again. > > I hope these tips help you make more CW contacts during the Stew Perry Top > Band Distance Challenge! > > > Mike > > K4QET > Reply > > > > > < > https://www.avast.com/sig-email?utm_medium=email_source=link_campaign=sig-email_content=webmail > > > Virus-free.www.avast.com > < > https://www.avast.com/sig-email?utm_medium=email_source=link_campaign=sig-email_content=webmail > > > <#DAB4FAD8-2DD7-40BB-A1B8-4E2AA1F9FDF2> > _ > Searchable Archives: http://www.contesting.com/_topband - Topband > Reflector > _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
Topband: mini oscilloscope
Hi - I have been looking for the oscilloscope equivalent of the nanoVNA or miniSA. Of particular importance is that it be a small instrument that supports most control functions via a PC. I need maybe 100 MHZ BW. The small screens if the nanoVNA / miniSA are a problem for my eyesight, hence the need to use a PC. I have done a lot of searching on Amazon and eBay but have not had luck. Most of the mini scopes have just a few MHZ of BW. Of the rest, most support only screen captures via USB and not any control functions. Product descriptions normally do not say anything bout the USB interface leading to time consuming Q and A with the dealers. Of course I could get a Rigol but they are relatively large and expensive. So does my dream exist out there, waiting to be found? Chuck _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
Topband: Ground loop isolator that passes DC
Hi - Many years ago I saw some ground loop isolators that pass DC. That is exactly what I need so that power can be sent over coax feeds to preamp at the antenna. I cant find anything on eBay that mentions passing DC in an isolator. None of the isolators I have will pass DC. Does anyone know an isolator that passes DC? I would like to avoid building one. Chuck _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
Re: Topband: Soldering aluminum coax shield to copper wire
Jim - Thanks. Of course one can use crimp connectors. There a zillions of those in common use. But that was not the question. I wish to solder copper wire to the shield. Chuck From: Topband on behalf of Jim Brown Sent: Monday, June 1, 2020 7:20 PM To: topband@contesting.com Subject: Re: Topband: Soldering aluminum coax shield to copper wire On 5/31/2020 8:56 PM, Chuck Hutton wrote: > So what is the easy reliable cheap method to get the job done? The only methods I know of are some form of crimp. Many variations of RG6 and RG11 with Al shields are widely used in the CATV industry. "SnapNSeal" is a widely used brand of Type F connectors that come in different physical sizes to fit those different cables, and there are crimpers to go with them. I've used these RG6 cables for receive antennas for more than 40 years. On one of my gigs almost 50 years ago, I installed a lot of MATV outlets in Sears Tower and in apartment buildings on Lake Shore Drive when they were under construction. The only Al shielded cable I'm using for transmitting is some vintage 1/2-in CATV hard line that I inherited from a neighbor SK. That hard line has Cu-clad Al center and Al shield. I'm using sections of it for parts of the run to two mono-banders. There are photos and text of page 6 of http://k9yc.com/Coax-Stubs.pdf showing the method I used. Where I used braid, other hams have slit copper tubing in half lengthwise, and are also listed on that page. 73, Jim K9YC _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
Topband: Soldering aluminum coax shield to copper wire
Many many years ago I had partial success soldering aluminum coax shield to copper wire using the motor oil technique. I also believe I had some flux (unknown type) that helped. But I had no luck with motor oil last week and can not find the flux I had, which might be a good thing as it is 20 years old. So what is the easy reliable cheap method to get the job done? Chuck _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
Topband: Measuring Common Mode Chokes
In the past, I have simply used my N2PK VNA to measure impedance of the choke by connecting the shield of the coax to the VNA ports. Recently I've been discussing common mode chokes with others who have a different methodology. They prefer to do a transmission test through the choke and report the "common mode rejection". This is done by placimg a crossover cable between the VNA output and the choke. The choke output is connected in a normal fashion (center to center, shield to shield) to the VNA input. This does not seem ideal to me. First, the choke is being driven in differential mode rather than common mode. Second, the measurement depends on (varying) isolation between the coax center and shield. So it's not truly common mode rejection. Am I on thr right track? A handful of Googles has not netted me any clear summary of test methodology for reportimg CMRR. I fimd a small number of tests reportimg impedance. Chuck _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
Re: Topband: BOG Beverage on Ground Help
In one of Beverage's old articles, there is a page or two devoted to adding coils to lower the velocity of the antenna. If I recall correctly, it has both theory and measurements. Chuck From: Topband on behalf of Mikek Sent: Thursday, November 21, 2019 12:13 PM To: topband@contesting.com Subject: Topband: BOG Beverage on Ground Help Hi guys, Just saw this page and it presented info that a BOG is a resonant antenna. It gives me a little boost about adding inductance to the antenna to artificially lengthen it. > http://www.iv3prk.it/bog-modeling.htm Is there any agreement about this or anyone want to shoot it down? Mikek Hi guys, I see certain measurements for the length of a BOG, such as 200ft for for 160 meters. And even a warning on one page, /* "The biggest mistake is making the BOG antenna too long. Try not to go */ /*over 200 feet for 160 meters." */So, if I tried to use this 200ft BOG on 80 Meters, I assume it has receive problems. A short explanation of those problems would be helpful, Impedance? Pattern? I've been pondering over W8JI's Loaded beverage page. > https://www.w8ji.com/slinky_and_loaded_beverages.htm I'd like to apply the loading to a BOG to slow the VF and make it seems longer. ie. make a 80 meter BOG length work on 160 Meters. But then make the reactance go away for 80 Meters My actual goal is to have a BOG that covers 500kHz to 4MHz. To that end, I have been working on a variable inductor that I can insert into the length of the BOG. In reality, it would be eight Variable inductors spaced about 35 to 40ft apart. I'm land limited to about 270ft. I want to control the inductors with a DC current through the BOG wire. I have a 100uh toroid inductor that I can partially saturate with an electromagnet. The electromagnet is energized by an adjustable current through the BOG wire. This means I need to RF bypass the Electromagnet, so it's inductance is not seen by the RF. Also I must block the RF from seeing the Power supply/current source. I have a drawing showing my proposed circuit here. > https://www.dropbox.com/s/wrfpubqvsfd11nq/bog%20with%20variable%20inductors..jpg?dl=0 I want to be told what problems you see and ways to overcome them. _If it is at all feasible_, I would wonder about the values of the blocking caps and Chokes. I appreciate any thought you can give this idea. Mikek _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
Re: Topband: An oddball question about a BOG.
And, by the way, K5GN and W5KU report that their Beverage above a barbed wire fence is the BEST Beverage at their place. Chuck W5PR On Sat, Aug 24, 2019 at 12:41 PM Chuck Dietz wrote: > I seem to remember someone saying the modelling programs are unreliable > when a wire is close to the ground. Also, there is really no way to model > the properties of "ground." It can vary in just a few feet and the moisture > content varies from day to day. I think this is a "try it" kind of antenna. > Read other's reported results. > > Chuck W5PR > > On Sat, Aug 24, 2019 at 12:29 PM Mike Waters wrote: > >> The only way to predict the RDF and pattern is by modeling it. I don't >> know >> of anyone who has done this. I have a few of my .ez Beverage models in >> w0btu.com/files/ as a starting point, but I don't think that I uploaded >> everything there. >> >> There are free antenna modeling programs out there. I have only ever used >> EZNEC. Maybe someone can suggest something. >> >> 73, Mike >> www.w0btu.com >> >> On Sat, Aug 24, 2019, 12:05 PM Mikek wrote: >> >> > > But what did you mean by "proper pattern"? >> > >> > I should have said, the best pattern that adjusting the Inductive loads >> > will provide. >> > >> > Yes, I understand the pattern changes with frequency. What I want to do >> is >> > inductively load the antenna, so it will have the same pattern as if we >> > increased the length. >> > >> > Say I have a BOG with a length that is ideal to give me the best RDF >> > number available at say 1.8Mhz. >> > Now, I move down to 1MHz, and I inductively load it, can I get that >> same >> > RDF number? >> > ie. can I reduce the VF to make it act like the correct length? >> > What are the caveats? >> > >> >Thanks, Mikek >> > >> _ >> Searchable Archives: http://www.contesting.com/_topband - Topband >> Reflector >> > _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
Re: Topband: An oddball question about a BOG.
I seem to remember someone saying the modelling programs are unreliable when a wire is close to the ground. Also, there is really no way to model the properties of "ground." It can vary in just a few feet and the moisture content varies from day to day. I think this is a "try it" kind of antenna. Read other's reported results. Chuck W5PR On Sat, Aug 24, 2019 at 12:29 PM Mike Waters wrote: > The only way to predict the RDF and pattern is by modeling it. I don't know > of anyone who has done this. I have a few of my .ez Beverage models in > w0btu.com/files/ as a starting point, but I don't think that I uploaded > everything there. > > There are free antenna modeling programs out there. I have only ever used > EZNEC. Maybe someone can suggest something. > > 73, Mike > www.w0btu.com > > On Sat, Aug 24, 2019, 12:05 PM Mikek wrote: > > > > But what did you mean by "proper pattern"? > > > > I should have said, the best pattern that adjusting the Inductive loads > > will provide. > > > > Yes, I understand the pattern changes with frequency. What I want to do > is > > inductively load the antenna, so it will have the same pattern as if we > > increased the length. > > > > Say I have a BOG with a length that is ideal to give me the best RDF > > number available at say 1.8Mhz. > > Now, I move down to 1MHz, and I inductively load it, can I get that > same > > RDF number? > > ie. can I reduce the VF to make it act like the correct length? > > What are the caveats? > > > >Thanks, Mikek > > > _ > Searchable Archives: http://www.contesting.com/_topband - Topband > Reflector > _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
Re: Topband: Which RX antenna is better?
I wasn’t intending to slight what you said either, I do think I misinterpreted it though. At this moment, the SAL-30 is certainly my best receive antenna as well. I would not enjoy working 160/80 meters without it. Chuck W5PR Sent from Mail for Windows 10 From: Rodman, David Sent: Thursday, August 1, 2019 9:15 PM To: Cecil; Lee STRAHAN Cc: Chuck Dietz; topband@contesting.com Subject: Re: Topband: Which RX antenna is better? Reading all these replies makes me think that the intent of my post might have been somewhat misinterpreted. My post was not intended to be a scientific analysis of only RDF or performance in rating or ranking various antennas. It was, however, intended to introduce possibly significant (in my opinion) other factors or roadblocks or logistical impediments to the readers minds in order to add those observations into the mix of what everyone deals with when planning or building any antenna. Those factors included, cost, maintenance, time and ease of construction, multidirection capability, size and usefulness in a contest environment. I was not considering ground (mine is good) or beverage length (mine 600-900') or F/B or whether a particular antenna had optimal low angles. Not wishing to insult anyone and trying to stay as neutral as possible, I reached the conclusion that the most appropriate (best performance) for my location, based on all these factors, was the SAL-30. 73, Dave --- David J Rodman MD Assistant Clinical Professor Department of Ophthalmology SUNY/Buffalo Office 716-857-8654 _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
Re: Topband: Beverage length
I previously had 4 Beverages with 3 of them being about 300’ They definitely worked! However, the 650’ was better… On my new property, I hope to compare Beverages, SAL-30 and an 8 circle. First, I have to get it cleared and fenced… Sigh! Chuck W5PR Sent from Mail for Windows 10 From: Chortek, Robert L. Sent: Thursday, August 1, 2019 2:40 PM To: Drew Vonada-Smith Cc: topband@contesting.com Subject: Re: Topband: Beverage length I’ve got an unterminated 300’ foot beverage about 36” high. WorkS GREAT so I respectfully disagree with the implication a beverage much shorter than 1-2 wavelengths means you should use something else. I’ve got multiple rx antennas and that short beverage is the best one,on average, in its favored direction based on years of comparison. That said, I’ve never been sorry I had multiple options. Bob AA6VB Robert L. Chortek > On Aug 1, 2019, at 12:27 PM, Drew Vonada-Smith > wrote: > > Joe, > > > For a simple Beverage, you just point the antenna (unfed end) at the target. > For length, "longer is better" is approximately true, but the ideal lengths > are about 1 to 2 wavelengths. Much longer than that, and phased shorter > Beverages work better. Much shorter than that, and you might as well use > some other type of RX antenna. One Bev can work pretty well on both 160 and > 80, and will occasionally be useful on other bands also. During > spring/summer precip static, common in KS, the Bev is often my only usable RX > antenna on ANY HF band! > > > A Beverage has negative gain. But you don't care about absolute strength, > you only care about S/N, as any modern radio has enough gain on 160M for the > smallish Beverage signal to be fine. Some, like me, use a preamp just so the > various RX antenna gains are approximately equal when switching between them. > A 15 dB preamp brings my 600 ft Bev signal strengths to the level of my TX > Inv-L on 160. But you don't need it. > > > Beverages are not in the great favor they once were, mostly due to the advent > of excellent vertical arrays. But they still have the big advantage of being > the simplest RX antenna one can imagine, that nearly always works as > described without difficulty, assuming you have the space. And cheap! > > > Reversible Beverages are only slightly more complicated and give you another > direction with no more space required. Lots of good articles out there for a > Google. > > > 73, > > Drew K3PA > > > > > -- > > Message: 18 > Date: Thu, 1 Aug 2019 13:25:25 -0500 > From: Joe > To: Wes , topband@contesting.com > Subject: Re: Topband: BOG height > Message-ID: > Content-Type: text/plain; charset=utf-8; format=flowed > > beverages have always fascinated me. But I have never had the property > to have one. > > I might now, BUT, how do you know how long and what direction to lay it > out to maximize signal to the desired direction? > > I assume the longer it is, the higher gain it has and more towards the > ends the lobe is? > > Joe WB9SBD > > _ > Searchable Archives: http://www.contesting.com/_topband - Topband Reflector _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
Re: Topband: Which RX antenna is better?
Your results of the order of performance of these antennas are somewhat different than other, published results. I wonder if the composition of your ground would have something to do with that? Good or poor soil? Also, how long was the Beverage? I have a SAL-30, which is by far my best receive antenna since I had to take down my Beverages, but my take away was the Beverages beat the SAL-30 most of the time. This is over medium to good soil. I would have expected the 8 circle to be better than all the others at least 90% of the time. (At least over good soil.) I have been pondering which receive array to put up in a new location with plenty of room, so I have been looking at this. Chuck W5PR On Thu, Aug 1, 2019 at 11:19 AM Rodman, David wrote: > > > > This is possibly a more complicated subject than just performance. I gave > a lecture on this topic, comparing a Hi-Z circle 8, SAL-20, SAL-30, > beverage (unidirectional and bidirectional and BOG) and the K9AY array. > > > In this talk, I considered performance as a factor, but also considered > maintenance, size, mechanical stability, cost and ease of construction and > installation. > > > All things considered, the top 2 at my QTH were the Hi-Z circle 8 and the > SAL-30. > > > Here is a quick summary of my findings. > > > Circle 8: highest cost, most complex to install and construct, requires > large footprint of land, best of all antennas as it requires almost NO > maintenance and performance second overall to the SAL-30. > > > SAL-30: modest cost, modest install and construct, modest footprint, > requires minimal repairs (usually to the coupler wires) but overall > performance best of all for directionality and gain. > > > SAL-20: modest cost and somewhat simpler than SAL-30 to install and small > footprint. Performance almost identical to the K9AY array. > > > K9AY: modest cost but slightly more complex to construct as compared to > SAL-20 and about the same size. Performance less than SAL-20 due to fewer > directions. > > > Beverage unidirectional: mechanical stability good when constructed with > copper coated steel wire #14 or larger. Gain fine when desiring only 1 > direction. Depending on the location may be placed in half a day from > start to finish. > > > Beverage bidirectional: mechanically unstable when constructed with > commercial products using either RG6 or twin lead. Requires frequent > repairs due to fatigue or failed connections. Performance overall is not > on par with other directional arrays. > > > BOG: simplest of all antennas to construct, install and maintain. Can be > installed in an hour or two. Should be unfolded at spring time each year > to keep wire from being incorporated into lawn. Convenient when only 200' > available. Can be band specific. > > > > Just a quick summary. My location does not lend itself to beverage > construction. about 2/3 of my 25 acres are heavily and complexly treed with > brush so overgrown that it can be a chore to do almost anything for > installation or repair. This is why I prefer the SAL-30 overall. The > circle 8 took me one summer (as my only project to install) by the time the > land was cleared, site measured, antennas constructed and all the coax > installed. The trade off is that this antenna has been the most > mechanically stable of any antenna that I have ever had. > > > --- > David J Rodman MD > Assistant Clinical Professor > Department of Ophthalmology > SUNY/Buffalo > > Office 716-857-8654 > _ > Searchable Archives: http://www.contesting.com/_topband - Topband > Reflector > _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
Re: Topband: BOG height
When I tried a BOG compared to a Beverage, I found the BOG to be almost useless compared to the Beverage. I would put up one of the arrays K9AY, SAL-30, 4sq rec, etc. I don't think you will be happy with a BOG after using a Beverage. Chuck W5PR On Thu, Aug 1, 2019 at 12:08 PM Paul Mclaren wrote: > Just a ‘simple’ question hopefully - How close to the ground should a BOG > be for best/good performance? > > I am looking for any additional info that I can get to supplement what I > have found online already so good on the balun, wire type and termination > resistor. > > My single unterminated beverage I have at the moment was transformational > compared to a Wellbrooke loop but the location it is in will soon be 80 new > homes so time to look elsewhere. Current plan is a small number (maybe > three) BOG antennas switched by a remote relay but distance is limited to > 200ft maximum in any direction. > > Plan is to use the BOGs for 160 but also 80,40 and maybe 30m. > > Regards > > Paul MM0ZBH > _ > Searchable Archives: http://www.contesting.com/_topband - Topband > Reflector > _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
Re: Topband: RFI on TB
In the Houston, Texas area the hams know the cell number of the guy who works for the electric distribution company locating the noise sources. We can call him and leave a very detailed message about the noise source location and he is quick to verify it and have it repaired. Ask around. Logan Dietz W5PR On Tue, Jul 23, 2019 at 12:03 PM Ken K6MR wrote: > I want to know how you guys get the power company to respond so quickly. > I’ve been calling Pacific Gas and Electric for 6 weeks now and nothing. I > can’t even get a phone call. > > > > Ken K6MR > > > > > From: Topband on behalf of K4SAV < > radi...@charter.net> > Sent: Tuesday, July 23, 2019 8:43:56 AM > To: topband@contesting.com > Subject: Re: Topband: RFI on TB > > > Don't know why the mail system thinks this message is spam... Trying again. > > Lightning surge suppressor on power poles can be big noise generators > when they go bad. The worst one I found was three miles from my house > and created S9 noise on my receiving array. Its characteristics fooled > me at first because it didn't sound like something a power pole could > generate. It sounded like someone holding down the dash lever on a > keyer set at about 10 wpm and running continuously 24/7. Then one day I > heard it break into a more random pattern. That's when I went looking > for it. > > Found it easily because of the huge noise signature. Called it in to > the power company, gave them the pole number and which component on the > pole was at fault. Went back home and turned on the radio and the noise > was gone. Couldn't believe that so I drove back to the pole and they > had already disconnected the surge suppressor. Best repair time ever. > > I use an MFJ-856 to get close and a homebrew ultrasonic detector to > identify the exact component on the pole. MFJ also now makes an > ultrasonic detector, the MFJ-5008. > > Jerry, K4SAV > _ > Searchable Archives: http://www.contesting.com/_topband - Topband > Reflector > _ > Searchable Archives: http://www.contesting.com/_topband - Topband > Reflector > _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
Re: Topband: AM interference on 1840
I would think that FT8 is a mode uniquely able to operate through such interference. Chuck W5PR On Tue, May 21, 2019 at 6:52 AM Edward Sawyer wrote: > I agree with the 2 messages. But there is a 3rd. The inability for the > FT8 crowd to QSY around some interference. Interference is a fact of > life. And we have QSY’s around it (even as it is being worked) for a > century. > > > > Ed N1UR > > > > From: GEORGE WALLNER [mailto:aa...@atlanticbb.net] > Sent: Tuesday, May 21, 2019 7:50 AM > To: Edward Sawyer; topband@contesting.com > Subject: Re: Topband: AM interference on 1840 > > > > There are two messages in this topic: One is the interference from this > particular BC station. Not a crisis, not yet. Two is a warning: Newly > installed solid-state AM broadcast amplifiers in poorly regulated regions, > over time, will have the potential to fill the entire 160 meter band with > harmonics. The second part is not trivial and should be a heads-up. The > earlier we find ways to deal with it, the better. > > > > 73, > > George, > > AA7JV > > > > On Tue, 21 May 2019 05:32:24 -0400 > > "Edward Sawyer" wrote: > > While the harmonic interference is unacceptable and needs to be dealt with, > > isn't this only "a crisis" because of the simplistic FT8 solution of > > bunching everyone up on a small channel? It reminds me of the old CB days > > when something would happen on a certain channel but no one would move > > because they have always had the radio on channel 2 and that's where all > > their buddies are. Or the 75M pig farmers that refuse to move but complain > > and harass on QRM that was there before their daily time started. > > > > For those of us using CW on topband, this isn't a real problem except for a > > contest weekend. And honestly, it will just get moved around, like the > > Middle East jammer on 3807. > > > > 73 > > > > Ed N1UR > > > > _ > > Searchable Archives: http://www.contesting.com/_topband - Topband > Reflector > > > > _ > Searchable Archives: http://www.contesting.com/_topband - Topband > Reflector > _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
Re: Topband: 10 to 1 Ferrite Balun
Wouldn’t you connect the secondarys in series and the primaries in parallel? Chuck W5PR On Tue, Mar 19, 2019 at 2:02 PM Richard (Rick) Karlquist < rich...@karlquist.com> wrote: > > On 3/19/2019 8:47 AM, Herbert Schoenbohm wrote: > > I am working on an RX antenna that requires about balanced 800 match to > 75 > > ohm RG-6. I have some type 43 and 73 ferrite binocular cores but since > > this is just an experimental RX antenna I wanted to use an easier > approach. > > I have two commercial baluns that are unmarked but bridge out to a 75-ohm > > to 200- ohm match. What would be the problem if I connected them with > the > > first balun output feeding the 75-ohm input of the second one with the > > 200-ohm output of the first one? Anyone ever tried this. Would this also > > give me excellent ground loop decoupling between the RG-6 and the > antenna? > > What you have proposed (cascading transformers) would not work well. > What I have done that does work is to connect two MiniCircuits > ADT8-1+ transformers in series to form a 100 ohm to 800 ohm transformer. > "Connect in series" means to connect the two primaries in series, and > connect the two secondaries in series. This is different from cascading > transformers. > > This is an amazing transformer, much better specs than similar models > from MCL. I dissected one of these in an attempt to reverse engineer > it but was unsuccessful. So you can't make your own with binocular > cores. At least not with the same performance. > > 73 > Rick N6RK > _ > Searchable Archives: http://www.contesting.com/_topband - Topband > Reflector > _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
Re: Topband: Satisfactory fiberglass pole for K9AY loop
Was the 1" OD cut into 2 pieces 4' long? One sticking out the top and the other inside the 1.25" OD at the top joint to stiffen it? Or 2' each to stiffen both joints? Chuck W5PR On Wed, Feb 20, 2019 at 10:45 AM Russ Tobolic via Topband < topband@contesting.com> wrote: > I use 3 pcs of DXE-FT1250-8 (8', 1.25" OD) and 1 pc DXE-FT1000-8 (8', > 1" OD). I cut the 1" OD into 2 pcs 2' long which nested inside the larger > tubing and used the rest to stick out the top. The total height is 25' for > my K9AY loops. I did try the cheaper route with similar dia PVC but it > flopped around too much and was not easy to handle. The fiberglass is > stiffer. With a set of dacron rope guys in the middle and the loop for top > guys it has been very stable up against snow, wind and ice storms here in > Michigan. > Russ, N3CO > On Wednesday, February 20, 2019, 9:27:38 AM EST, N4ZR < > n...@comcast.net> wrote: > > Maybe 15-20 years ago, I used a very inexpensive push-up fiberglass > pole to support the loops of a K9AY loop system. Alas. details and > source have fled my brain, and much of what I've studied on line is much > more expensive (and probably much sturdier) that what I had then. I'd > appreciate any current suggestions. > > -- > > 73, Pete N4ZR > Check out the Reverse Beacon Network > at <http://reversebeacon.net>, now > spotting RTTY activity worldwide. > For spots, please use your favorite > "retail" DX cluster. > > _ > Searchable Archives: http://www.contesting.com/_topband - Topband > Reflector > > _ > Searchable Archives: http://www.contesting.com/_topband - Topband > Reflector > _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
Re: Topband: Topband Digest, Vol 192, Issue 33
Unfortunately, most are just deleting the conversation without reading it like I usually do, because of the title... Chuck W5PR On Sat, Dec 29, 2018 at 5:31 PM Mike Waters wrote: > On Sat, Dec 29, 2018, 8:58 AM wrote: > > > ... to bring this discussion to the high level technical discussion this > > group is used to > > > YE! :-) > > 73, Mike > www.w0btu.com > _ > Searchable Archives: http://www.contesting.com/_topband - Topband > Reflector > _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
Re: Topband: FT8 - How it really works
Ok, ok. I said it wrong. When I think of 160, I say “night,” It was about 4:00 pm local time. Chuck W5PR On Mon, Dec 24, 2018 at 5:46 PM JC wrote: > Jerry > > The new mode FT8 is not all that new, actually, there are several aspects > to > consider, like detect the signal, decode the signal detected, make a > decision to accept the decoded signal. The improvement on signal to noise > ratio concept is very old, just the internet made it possible with time > synchronization. The decode uses new algorithms and some very intelligent > way to guest the decoded signal. > > Check this out. 1975 Sept QST; Coherent cw test! Experiments show 20 db > Signal Boost over QRM, > > http://www.arrl.org/files/file/Technology/tis/info/pdf/7509026.pdf > > The improvement on signal to noise ratio is just because a narrow > bandwidth. > The gates opens at the right millisecond window. On FSK the secret salvage > is time synchronization. You can record the audio and play it back, the > decode will happen only if you synchronize the time of the recording with > the time in ms of the PC clock. > > I did that, and it worked, I have a SDR QS1R and using HDSDR software to > record the I/Q file, RF file. I used to record rare DX expedition signal > and > the bandwidth is 50 KHz, I can see the FT8 guys on 1840, My question was , > can I decode them from the digital file recorded several month ago? > > I started plaining the file at the top of the second count, and voalah!!!, > The WSJT-X decoded several station, weak as -21 db. The weak signals are > there, buried in the noise on my old digital recorded file. > > Then I decided to test my HWF, the practical result measuring cw signal is > that the signal to noise increase around 20 db, 10 db due the directivity > RDF 11.5 and another 10 db from the polarization filter. The Horizontal WF > attenuation on vertical signals is over -90 db. The manmade noise vertical > polarized is reduced below the MDS of the receiver and cannot be amplified > by the receiver. > > The IC-7800 has two identical receivers. I connected my HWF on receiver > MAIN > and the TX antenna on the receiver SUB, I installed two instances of the > WSJTX program, one for each receiver. After 15 minutes the number of > decodes > on the HWF was 20 or times more than the vertical full size vertical, my TX > antenna 120 Ft high. > > Signals decoded around -21 db on the vertical was decoded on the HWF 0 to > +1 > db. Signals less the -5db decoded on the HWF was not decoded using the > vertical, The HWF was decoding hundreds of signals that would be -40 db on > the decode using the vertical. > > I think the s/n reported by the program as ball part is actually very good > and close to the real s/n improvement of 2 Hz BW, depending on the mode. > > The only real way to increase signal to noise ratio is increasing the > directivity of the RX antenna, more real RDF means real signal to noise > ratio improvement. I used real because it is very easy to destroy the > directivity with integration, leaking, intermodulation, low noise figure > etc. > > One bad concept, bidirectional unterminated beverage with two lobes one in > the back and one front, it just does not work because the RDF is 6 db down > a > terminated beverage. Same for BOG's the RDF is bad, a K9AY works better > because has more RDF. A simple Flag can deliver 9 db RDF is tis easy to > hide > too. Two Flags in phase 11.5 db and four Flags 14 db RDF, and a very clean > pattern besides real broadband from 1 MHz to 10 MHz > > As you can see on the ARRL 1975 article, there is nothing new about > improvement of signal to noise ratio reducing the bandwidth. On the > article, > the test was CW at 12 wpm and 9 Hz filter BW , no ring using WWV as time > source for the synchronization. > > That was state of the art back in the early 70's, almost 50 years ago. > > 73's > JC > N4IS > > > -Original Message- > From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of K4SAV > Sent: Monday, December 24, 2018 3:10 PM > To: topband@contesting.com > Subject: Re: Topband: FT8 - How it really works > > Although I have finished my FT8 testing, there is one final thought I would > like to leave with you, and also to correct one statement I made earlier. > Someone thought FT8 measured the noise in the interval when the FT8 signals > were off, and I replied that would result in a real S/N number. That is > not > true as you will see in the info below. You would get a real S/N number if > the RF was sampled, but not if the audio is sampled. > > I spent many years designing electronic circuits professionally, so I still > think that way. So for a few minutes
Re: Topband: FT8 - How it really works
I think I understand much of what you are saying, but I know that I was on 160 meter FT=8 two nights ago with the speaker up fairly loud. I only heard noise. I set the AGC off and adjusted the RF gain so that it did not overload. Still no hint of any signals, but I decoded two stations! Just sayin’. Chuck W5PR Sent from Mail for Windows 10 From: K4SAV Sent: Monday, December 24, 2018 2:10 PM To: topband@contesting.com Subject: Re: Topband: FT8 - How it really works Although I have finished my FT8 testing, there is one final thought I would like to leave with you, and also to correct one statement I made earlier. Someone thought FT8 measured the noise in the interval when the FT8 signals were off, and I replied that would result in a real S/N number. That is not true as you will see in the info below. You would get a real S/N number if the RF was sampled, but not if the audio is sampled. I spent many years designing electronic circuits professionally, so I still think that way. So for a few minutes lets think about a circuit that can decode something below the noise floor .If you think about FT8 or anything similar, from a designers point of view, you suddenly realize that making a statement of "the circuit can decode down to X dBs below the noise floor" is almost an impossible task, that is, if you are talking RF noise floor as most people will be assuming. Since you will be dealing with audio, not RF, the receiver will convert the RF into audio and compress it into something that has a lot less dynamic range. How much less? Say the volume is set to a level such that the strongest signals do not clip, then how far down is the noise? You can expect that to vary on each band too. Now comes a real complication. If you were taking samples in the RF world, you could see the noise level on your S meter and estimate it relative to the strongest signals. However your circuit will be dealing with audio. Surprisingly, when the signals disappear, the receiver AGC voltage drops and the receiver gain increases. That produces a lot more audio signal. The audio noise in the case of no signals becomes higher than the audio level for strong signals if you are using USB bandwidth and receiving something similar to FT8. That condition is not nearly as pronounced when using a narrow CW bandwidth. Even if you put the receiver into AGC slow mode it won't hold for the 3 seconds when FT8 is off, so you still get the increased audio in the off period. Then there will be a sudden increase in audio when the first signal reappears, until the ACG kicks in and lowers it. This happens even with fast AGC selected. It's fast enough that you don't notice it when listening, but if you put a scope on it you can see it. Yeah, all that surprised me too when first thinking about it. Take a close listen and see if you agree. If you can't hear it, put it on a scope or anything that displays an audio waveform and it will become very obvious. If you made a statement that this circuit can decode X dBs below the noise floor, most people will be thinking RF noise floor. So what is it in the audio world that represents the noise floor in the RF world, and what would your statement mean? Of course you could turn off the AGC and decrease the receiver RF gain and that would make the audio very low when the signals disappear. That would also severely limit the dynamic range for your circuit since you would no longer have the compression supplied by the receiver.. Your circuit would have to cover a much wider dynamic range, similar to what a receiver does. So your circuit would need what? maybe 100 dB dynamic range to cover the strongest signals to the weakest noise floor, forgetting about decoding below the noise floor. Actually that wouldn't really happen because receivers can't produce a dynamic range of 100 dB in the audio. They may do it in the RF world, but not in audio. Receivers have no need to do that. Jerry _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
Re: Topband: choke/bleeder resistor on RXvertical?
The choke bleeds off static charges that accumulate on the vertical. While I have witnessed noise from huge static charging to a 32 foot vertical mounted on the roof of the engineering building at Texas Tech in West Texas, the choke does not bleed off “noise”. Noise is radio frequency emissions from noise sources which can be local or distant. Chuck W5PR On Wed, Dec 19, 2018 at 12:19 PM Jamie WW3S wrote: > Since verticals are know to be "noisy" on receive, and a fix is a rf choke > or bleeder resistor to ground, anyone try that on short verticals used for > receive only to quiet some noise? > _ > Searchable Archives: http://www.contesting.com/_topband - Topband > Reflector > _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
Re: Topband: elevated radials
That worked for me. Chuck W5PR On Sat, Oct 20, 2018 at 8:45 PM N4ZR wrote: > I am contemplating 4 elevated radials for a 160-meter inverted L. Am I > correct to think that I need to resonate each pair of radials in their > final location as if they were a very low dipole? > > -- > > 73, Pete N4ZR > Check out the Reverse Beacon Network > at <http://reversebeacon.net>, now > spotting RTTY activity worldwide. > For spots, please use your favorite > "retail" DX cluster. > > _ > Searchable Archives: http://www.contesting.com/_topband - Topband > Reflector > _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
Re: Topband: WB6RSE Flag type loop question
But that gain is in the vicinity of small pennants, f;ags and others. I often use smaller loops and flags with a preamp. At 160 and nearby, I believe my preamps (Clifton Labs, ARR etc) have goodenough IM and NF properties to not affect results in a negative way. Having said that, the pattern is pretty lousy. I wouldn't bother with the LOG unless I was desperate man in a desperate situation. Chuck From: Topband on behalf of Mike Waters Sent: Wednesday, August 1, 2018 1:15 PM To: Nick Hall-Patch Cc: topband Subject: Re: Topband: WB6RSE Flag type loop question That's a terrible RX antenna. Did you see the losses?! Minus-forty-something dB on 160. 73, Mike www.w0btu.com<http://www.w0btu.com> WØBTU's Radio Communication Technical Articles and File ...<http://www.w0btu.com/> www.w0btu.com Amateur radio technical information by Mike Waters, W0BTU On Wed, Aug 1, 2018, 3:00 PM Nick Hall-Patch wrote: > DuckDuckGo brought up this at the top of its search: > http://kk5jy.net/LoG/ > > Presumably that is what you mean? > > best wishes, > > Nick > VE7DXR > > At 19:04 2018-08-01, CUTTER DAVID via Topband wrote: > >Drifting the thread slightly: I read an article recently regarding 2 > >loops of 15ft square separated by 15ft which the author called Loop > >On Ground, LOG. He claimed good results on receive over a period of > >a year. It was very low gain but had directional properties and was > >said to be quiet.I can't lay my hands on the site just now, but > >it might be of interest. > > > >David G3UNA > _ Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Shunt Fed Tower Question
I would not use any inductance unless the tower naturally resonates above 1800 kHz. If I were going to use a cage for the gamma connection, I would make a small cage that would only be on one side of the tower. I find that the shield of old coax spaced a couple of feet from the tower works fine. I would start with a variable capacitor in series with the coax center conductor feed to the gamma connection to the tower. Find the best dip, replace it with the closest fixed cap and use the variable cap from the gamma connection to ground to find the value that resonates it perfectly. (The dips will be sharp.) Good luck Herb! Chuck, W5PR On Thu, Aug 2, 2018 at 8:04 AM Herbert Schoenbohm < herbert.schoenb...@gmail.com> wrote: > I recently installed a 2 element 40-meter beam and a 4 element 20-meter > beam on top of a 90-foot tower which I use for TX on Topband. The tower is > cage fed with a 3-wire cage spaced24 inches around the tower, I am able to > get 1.2 to 1 on 1845 by putting about 1200 pf and a 500 pf fixed HV cap to > ground. The coax feed goes to the wires with about 40 mh in series. My > taps to the tower are at 60' which may be too high up on the tower > considering all the toploading I have now. My question is: How far down > should I move the tower taps to make the feed appear inductive rather than > the capacitive value currently what I believe I have? > > Any suggestions would be appreciated. > > Thanks, > > Herb Schoenbohm, KV4FZ > _ > Topband Reflector Archives - http://www.contesting.com/_topband > _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Beverage transformers tht work down to 630 m
Tim - What spec on 73 material are you referring to? I have never seen a published Al value for the 287300292 (BN73-202). Here's the Fair-Rite page with the 287300292: https://www.fair-rite.com/product-category/suppression-components/multi-aperture-cores/ And here's the Amidon page for the BN73-202: http://www.amidoncorp.com/bn-73-202/ The BN73-202 has been discussed before here and Al of 8500 was quoted. However, way back upon prodict release someone posted an Al od 2500. Kits and Parts quote an Al of 12000. My rqo caores have an average Al of 13,333. I;ve seen no manufacturer Al data. But bottom line I think we borh believe the true Al is higher than might be believed and therefore better low end response. Note these turns versus frequency curves: http://www.qsl.net/in3otd/ham_radio/160m_transformers/160m_trafos.html The 3rd chart down is the heart of the issue. Two turns is of the edge of the cliff. Better to use 3 turns I believe. Chuck. From: Tim Shoppa Sent: Monday, July 16, 2018 5:07 AM To: Chuck Hutton Cc: kd9sv; topband@contesting.com Subject: Re: Topband: Beverage transformers tht work down to 630 m I think the spec on 73 material permeability is also conservative. Few EMI suppressing customers suffer if the impedance is higher than guaranteed. The Fair-Rite 73 curves also show permeability peaking up even higher in the 500 kHz region. W8JI has in the past made some remarks about stray winding capacitance which would get worse with more turns. I believe his drawing shows some “dummy turns” put in on the far side of ground, to cancel the stray capacitance? An important advantage of fewer turns, is that you can use ordinary plastic insulated hookup wire or kynar wire wrap wire to put the small number of turns through the holes. If I use enamel magnet wire with these cores to get more turns I end up nicking the enamel insulation on the core corners. Tim N3QE > On Jul 15, 2018, at 8:49 PM, Chuck Hutton wrote: > > Yes, I think we all agree on the meaning of the 4X rule and the other basics. > > The mystery to me remains that a 1 turn transformer was good to 270 kHz in > the Clifton data. I calculate at 500 kHz: > > 1 turn on a BN73-202 with Al = 8500 gives 9 uH > > 9 uH is only 28 Ohms > > For reference, 2 turns = 34 uH and 107 Ohms. 3 turns is 77 uH and 242 Ohms. > > > So theory seems to tell me I need 3 turns. > > > Chuck > > > > ____ > From: kd9sv > Sent: Sunday, July 15, 2018 4:43 PM > To: 'Chuck Hutton' > Subject: RE: Topband: Beverage transformers tht work down to 630 m > > Guys, the 4x rule is to my understanding that the measured impedance at the > lowest frequency to be used at should be at least 4 times the operating > impedance. In other words a 50 ohm system would require 200 ohms open > circuit impedance measured at the primary winding of the xfmr. If 2 turns > only measures about 100 ohms then 3 turns would likely be close enough and 4 > turns would also work and would measure 400 ohms which is 8 times the > operating impedance of the antenna system. My test equipment can only > measure down to about 450khz so below that I cannot give an opinion. > > 73, de gary...ps: the BN202-73 will likely work well with two/6 turns and > 3/9 for a 9:1 system for 50 ohms > -Original Message- > From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Chuck > Hutton > Sent: Sunday, July 15, 2018 7:26 PM > To: Tim Shoppa > Cc: topband@contesting.com > Subject: Re: Topband: Beverage transformers tht work down to 630 m > > Tim: > > > Thanks for digging that out. It makes me worry much less about using > BN73-303's with 2 or 3 turns in the primary at 630m. > > > My only problem is that I don't understand why the low end is so good for > the 1 turn primary. Using the "4x" rule for the transformer, 4 turns should > be needed. > > Since I don't understand the response and I don't care about the high end > response, I'm still tempted to use 4 turns and be sure. > > > Perhaps part of the answer is that reality and theory do not coincide. > According to the published Al, 2.7 turns is need at 500 kHz. to have 64 uH > and satisfy the 4X rule. Yet my 3 turn windings measure 108 uH and 120 uH. > That explains a good bit of the low end response. > > > Chuck > > > > > From: Tim Shoppa > Sent: Sunday, July 15, 2018 3:50 PM > To: Chuck Hutton > Cc: topband@contesting.com > Subject: Re: Topband: Beverage transformers tht work down to 630 m > > I agree the usual rule of thumb (Transformer winding Z should be several > times larger than nominal line impedance) would cause you to think you > should have mor
Re: Topband: Beverage transformers tht work down to 630 m
Yes, I think we all agree on the meaning of the 4X rule and the other basics. The mystery to me remains that a 1 turn transformer was good to 270 kHz in the Clifton data. I calculate at 500 kHz: 1 turn on a BN73-202 with Al = 8500 gives 9 uH 9 uH is only 28 Ohms For reference, 2 turns = 34 uH and 107 Ohms. 3 turns is 77 uH and 242 Ohms. So theory seems to tell me I need 3 turns. Chuck From: kd9sv Sent: Sunday, July 15, 2018 4:43 PM To: 'Chuck Hutton' Subject: RE: Topband: Beverage transformers tht work down to 630 m Guys, the 4x rule is to my understanding that the measured impedance at the lowest frequency to be used at should be at least 4 times the operating impedance. In other words a 50 ohm system would require 200 ohms open circuit impedance measured at the primary winding of the xfmr. If 2 turns only measures about 100 ohms then 3 turns would likely be close enough and 4 turns would also work and would measure 400 ohms which is 8 times the operating impedance of the antenna system. My test equipment can only measure down to about 450khz so below that I cannot give an opinion. 73, de gary...ps: the BN202-73 will likely work well with two/6 turns and 3/9 for a 9:1 system for 50 ohms -Original Message- From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Chuck Hutton Sent: Sunday, July 15, 2018 7:26 PM To: Tim Shoppa Cc: topband@contesting.com Subject: Re: Topband: Beverage transformers tht work down to 630 m Tim: Thanks for digging that out. It makes me worry much less about using BN73-303's with 2 or 3 turns in the primary at 630m. My only problem is that I don't understand why the low end is so good for the 1 turn primary. Using the "4x" rule for the transformer, 4 turns should be needed. Since I don't understand the response and I don't care about the high end response, I'm still tempted to use 4 turns and be sure. Perhaps part of the answer is that reality and theory do not coincide. According to the published Al, 2.7 turns is need at 500 kHz. to have 64 uH and satisfy the 4X rule. Yet my 3 turn windings measure 108 uH and 120 uH. That explains a good bit of the low end response. Chuck From: Tim Shoppa Sent: Sunday, July 15, 2018 3:50 PM To: Chuck Hutton Cc: topband@contesting.com Subject: Re: Topband: Beverage transformers tht work down to 630 m I agree the usual rule of thumb (Transformer winding Z should be several times larger than nominal line impedance) would cause you to think you should have more turns. The old Clifton Labs website is no more. But an archived page of measurements of transformers shows that the frequency response extends well below what you might think, from the rule of thumb. Archived page: https://groups.io/g/BITX20/attachment/27529/0/clifton%20Labs%20IMD%20in%20Br oadband%20Transformers.pdf Clifton Laboratories 7236 Clifton Road Clifton VA 20124 ...<https://groups.io/g/BITX20/attachment/27529/0/clifton%20Labs%20IMD%20in% 20Broadband%20Transformers.pdf> groups.io Clifton Laboratories 7236 Clifton Road Clifton VA 20124 tel: (703) 830 0368 fax: (703) 830 0711 E-mail: jack.sm...@cliftonlaboratories.com He finds that BN73-202 transformers wound with a single turn winding, have a -3dB point at 270kHz.. A two turn winding would be good 4 times as low. So the rule of thumb seems very conservative. I have made step-up power converters using these cores and have been super impressed how well they work at frequencies well below the rule of thumb. I have run 30+ watts through these dinky cores with them just barely getting warm. Tim N3QE On Sun, Jul 15, 2018 at 6:29 PM, Chuck Hutton mailto:charle...@msn.com>> wrote: The commercially available Beverage transformers I have seen are like the W8JI model: 2 primary turns on a BN73-202 core. My calculations say 4 turns are needed at 630 m. Does anyone know of commercially available transformers with isolated windings that operates well down to 630m? Chuck _ Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband --- This email has been checked for viruses by AVG. https://www.avg.com _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Beverage transformers tht work down to 630 m
Tim: Thanks for digging that out. It makes me worry much less about using BN73-303's with 2 or 3 turns in the primary at 630m. My only problem is that I don't understand why the low end is so good for the 1 turn primary. Using the "4x" rule for the transformer, 4 turns should be needed. Since I don't understand the response and I don't care about the high end response, I'm still tempted to use 4 turns and be sure. Perhaps part of the answer is that reality and theory do not coincide. According to the published Al, 2.7 turns is need at 500 kHz. to have 64 uH and satisfy the 4X rule. Yet my 3 turn windings measure 108 uH and 120 uH. That explains a good bit of the low end response. Chuck From: Tim Shoppa Sent: Sunday, July 15, 2018 3:50 PM To: Chuck Hutton Cc: topband@contesting.com Subject: Re: Topband: Beverage transformers tht work down to 630 m I agree the usual rule of thumb (Transformer winding Z should be several times larger than nominal line impedance) would cause you to think you should have more turns. The old Clifton Labs website is no more. But an archived page of measurements of transformers shows that the frequency response extends well below what you might think, from the rule of thumb. Archived page: https://groups.io/g/BITX20/attachment/27529/0/clifton%20Labs%20IMD%20in%20Broadband%20Transformers.pdf Clifton Laboratories 7236 Clifton Road Clifton VA 20124 ...<https://groups.io/g/BITX20/attachment/27529/0/clifton%20Labs%20IMD%20in%20Broadband%20Transformers.pdf> groups.io Clifton Laboratories 7236 Clifton Road Clifton VA 20124 tel: (703) 830 0368 fax: (703) 830 0711 Email: jack.sm...@cliftonlaboratories.com He finds that BN73-202 transformers wound with a single turn winding, have a -3dB point at 270kHz.. A two turn winding would be good 4 times as low. So the rule of thumb seems very conservative. I have made step-up power converters using these cores and have been super impressed how well they work at frequencies well below the rule of thumb. I have run 30+ watts through these dinky cores with them just barely getting warm. Tim N3QE On Sun, Jul 15, 2018 at 6:29 PM, Chuck Hutton mailto:charle...@msn.com>> wrote: The commercially available Beverage transformers I have seen are like the W8JI model: 2 primary turns on a BN73-202 core. My calculations say 4 turns are needed at 630 m. Does anyone know of commercially available transformers with isolated windings that operates well down to 630m? Chuck _ Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband
Topband: Beverage transformers tht work down to 630 m
The commercially available Beverage transformers I have seen are like the W8JI model: 2 primary turns on a BN73-202 core. My calculations say 4 turns are needed at 630 m. Does anyone know of commercially available transformers with isolated windings that operates well down to 630m? Chuck _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Rain noise
When it rains it does not always cause rain noise, but when it does, the solution is to listen on the lower antennas. (You can still transmit on the top antenna.) Chuck W5PR On Mon, Jul 9, 2018 at 5:19 AM, Rodman, David wrote: > First, I want to say this topic is not necessarily topband related, so if > anyone wishes to comment about my question, please do so privately so as to > cut down on band width. Thank you. > > > Very smart people live on this list and I want to reach out to them about > my system as they may know something about this too. When it rains, the > top 20m antenna hears the precipitation and the bottom does not. Is there > a way to silence this situation? More info on request. > > > Again, thank you. > > > --- > David J Rodman MD > Assistant Clinical Professor > Department of Ophthalmology > SUNY/Buffalo > > Office 716-857-8654 > _ > Topband Reflector Archives - http://www.contesting.com/_topband > _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Beverage Ant Thread
Can you be more specific about "deterioration"? - front to back? - front to side? -gain? It's my feeling that lengthening a BOG past .5 wavelength or so may bring a bearing into a null and move other bearings out of a null, just like a normal Beverage. The result may be seen as beneficial or not, depending on where you are and where the interference is. Chuck From: Topband on behalf of donov...@starpower.net Sent: Saturday, July 7, 2018 8:13 AM To: topband@contesting.com Subject: Re: Topband: Beverage Ant Thread Hi Ed, 600 feet is much too long for a BOG on any ham band except 630 meters. Performance deteriorates as you lengthen a 160 meter BOG beyond about 225 feet. Because a BOG is so lossy, an unterminated BOG has significantly reduced response from the backward direction. 73 Frank W3LPL - Original Message - From: "Edward via Topband" To: topband@contesting.com Sent: Saturday, July 7, 2018 12:12:50 PM Subject: Topband: Beverage Ant Thread I have also been planning my own Beverage antenna. My situation will only allow for a BOG which will be bidirectional and >600' long. I plan to use the DXE kit, specifically designed for ladder line. My understanding is that 600' would be too long for a BOG on 160m. Though 160 is one application, my other passion is logging foreign BCB DX reception. What would the happy medium be? Maybe two separate antennas? Advice appreciated. 73, Ed NI6S/7Z1ES _ Topband Reflector Archives - http://www.contesting.com/_topband Topband Archives - Contesting Online Home<http://www.contesting.com/_topband> www.contesting.com Topband Mailing List Archives. Search String: [How to search] Display:. Description:. Sort: _ Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: 160m inv vee questions
There was a QEX article in 2016 that examined ground mounted verticals. http://www.arrl.org/files/file/QEX_Next_Issue/2016/March-April2016/Zavrel.pdf According to the plots in the article, over average ground the signal is still pretty strong at an arrival angle of 80 degrees above the horizon (5db down from 0 deg). I’m thinking the occasional large enhancement for the low dipoles may be at least partially due to the signals being predominantly horizontally polarized at those times. Chuck W5PR Sent from Mail for Windows 10 From: Bill Tippett Sent: Monday, April 2, 2018 6:35 AM To: topband Subject: Re: Topband: 160m inv vee questions This plot shows my low inv-V (30m apex is only 0.19 wavelengths) compared to my 3 element parasitic vertical. Study the relative gain vs TOA plots carefully: Ooops...bad link. Use this one: http://users.vnet.net/btippett/new_page_10.htm On Mon, Apr 2, 2018 at 7:10 AM, Bill Tippett <btipp...@alum.mit.edu> wrote: > FYI in response to two recent threads: > > http://lists.contesting.com/archives//html/Topband/2018-03/msg00139.html > http://lists.contesting.com/archives//html/Topband/2018-04/msg00043.html > > This plot shows my low inv-V (30m apex is only 0.19 wavelengths) compared > to my 3 element parasitic vertical. Study the relative gain vs TOA plots > carefully: > > http://lists.contesting.com/archives//html/Topband/2018-03/msg00139.html > > My observations over the past 14 years comparing both: > > 1. The vertical array is best 99% of the time. Usually by ~10 dB to the > NE (e.g. EU/W1 from here). From the plots you can see this equates to TOAs > (<20 degrees). > > 2. The inv-V (wires running NNW/SSE) is occasionally (1%of the time) much > better to EU or other directions at my local sunset or sunrise. This is > striking when it happens and is easy to detect since the inv-V is also > better for RX than either Beverages or an RX4SQ. This is clearly some sort > of high angle mode around SR/SS and it usually lasts for <30 minutes. > > 3. The inv-V BW is much broader than the vertical array which is very > narrow (~30 kHz). > > 4. TX antennas are separated by about 100m on different towers and the > 30m inv-V height is near optimum for maximum radiation straight up > (intentionally). > > 5. The inv-V also works well to the SE (Caribbean/SA) even without SR/SS > enhancement. I have no idea whether how it would behave if rotated 90 > degrees since my site doesn't allow for that. > > Just FYI, > > Bill W4ZV > > > > > _ Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Recent Article on a 160M Vertical Delta Loop?
Thanks to K4TMC, W6SZN, KB5DJX, K2CJ (and others I may have missed) for responding with the pointers to what I was remembering. Also thanks to Martin, OK1MCW for pointing out the half delta loop antenna from VE2CV that would also seem relevant to my interests. Apparently, in the words of Kip, W6SZN (and paraphrasing K2CJ), I'm "...thinking of the article by Ted Algren, KA6W, that won first place in an ARRL antenna design competition. Ted tells me that his article is scheduled for publication in the March 2018 issue of QST." This sounds right. I must've seen this antenna design mentioned elsewhere--perhaps on a blog site or social media page--and couldn't quite remember where to find it again. Relevant Links: http://www.arrl.org/news/qst-announces-2017-antenna-design-competition-winners http://www.arrl.org/files/file/QST/This%20Month%20in%20QST/March2018/ToC.pdf http://www.arrl.org/files/file/QST/This%20Month%20in%20QST/March2018/MARCH%20Editorial.pdf Thanks, all! --- Chuck Milam, N9KY n...@arrl.net On Fri, Feb 2, 2018 at 1:47 PM, Chuck Milam, N9KY <n...@arrl.net> wrote: > Perhaps it's advancing age or lack of sleep from having a new baby in the > house (or a combination of both,) but I swear I recently saw an article > describing a vertical delta loop antenna for use on 160M, with a 90' tower > as the center support. > > I want to say it was in an article describing some sort of "of the year" > award for antenna or article design (perhaps similar to the ARRL cover > awards?) > > Anyway, did anyone else see this article and if so, could you point me > toward it? I can't seem to find it in the usual places I read (QST, CQ, > NCJ.) > > (I really hope I didn't just imagine/dream this while snoozing between > late-night baby feedings.) > > Thanks and 73, > > Chuck Milam, N9KY > n...@arrl.net > _ > Topband Reflector Archives - http://www.contesting.com/_topband > _ Topband Reflector Archives - http://www.contesting.com/_topband
Topband: Recent Article on a 160M Vertical Delta Loop?
Perhaps it's advancing age or lack of sleep from having a new baby in the house (or a combination of both,) but I swear I recently saw an article describing a vertical delta loop antenna for use on 160M, with a 90' tower as the center support. I want to say it was in an article describing some sort of "of the year" award for antenna or article design (perhaps similar to the ARRL cover awards?) Anyway, did anyone else see this article and if so, could you point me toward it? I can't seem to find it in the usual places I read (QST, CQ, NCJ.) (I really hope I didn't just imagine/dream this while snoozing between late-night baby feedings.) Thanks and 73, Chuck Milam, N9KY n...@arrl.net _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: FT8 discussion
I know this has been “Discussed Out,” but I just want to ask why the window is in the 1840 area instead of the 1990 area? They are asking for QRM at 1840. It will be a losing battle during contests. Just sayin’ Chuck W5PR Sent from Mail for Windows 10 _ Topband Reflector Archives - http://www.contesting.com/_topband
Topband: RDF for Transmit 4 Square vs 8 Circle Array
I was always told that, if one had a 4 square, there would be no need for a receive array. I am finding this to be untrue when looking at the list of RDFs. (Receive Directivity Factor) I have snooped through the archives reading about RDF. Can anyone verify this from actual experience? Can you actually hear stuff on an 8 Circle that can't be heard on the transmit 4 square? I would think the difference might be more than marginal with the difference in RDFs of 2.48 db. I'm not sure of the difference in takeoff angles. That could be important too. As a practical matter, the 8 Circle is huge and expensive for a single band antenna... Chuck W5PR _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: underground cables question
I love it! Murphy should have a price on his head! Chuck W5PR On Thu, Oct 5, 2017 at 7:13 AM Guy Olinger K2AV <k2av@gmail.com> wrote: > Coming from an ancient Telco background which included keeping microwave > waveguides dry for AT, unless you are willing to pressurize the conduit > at one end and allow air to exit at the other, AND insure that the air is > dry enough to not condensate at your coldest possible ground temperature, > or run it with an unbroken slope to a point where water drains without > pumping and or can be suctioned, then make these assumptions: > > 1) Permanent performance and very long life is desired and outweighs cost. > If you move a lot and are putting up stuff at rental housing you probably > need not worry. Just remember to start with new coax and cable at the new > rental place. Throw away the old stuff. Then mark this read and move on to > the next posting. If you think you are retiring at your place of residence, > and if lucky want it to work without a worry for the next 30 years absent > direct lightning strike, then read on. > > 2) All conduits will fill with water. That is their NATURAL state unless > you specifically and effectively mitigate it. At any time other than first > installed, filled with water is their most probable state. > > This leaves the main usefulnesses of the conduit as > > a) Critter protection, and > > b) Cable replacement, if the conduit is large enough and water-proof pull > ropes are left in conduit, a method of adding or replacing cables that > avoids redigging and leaving deprecated cable in the ground. These are > significant long-term advantages, and many find those more than enough > reason to use them. However... > > 3) Even in conduit all cables must have permanent, water-proof jacketing. > Most cable has jacketing that is not rated for permanent submersion, meant > for indoor use. > > Polyethelyne (PE) jacketed or hardline cable is really the only commonly > available choice for coax with portions permanently submerged. Flooded is > nice, but probably overkill INSIDE CONDUIT if the jacketing is PE or other > permanently waterproof material. ***RG213 does NOT conform.*** Any > miscellaneous plastics do not conform. There are cables manufactured with > ham-uncommon materials to telephone company specifications, FOR DELIVERY TO > TELCO, that have all the water stuff worked out just fine. But BEWARE > knockoffs and batches for retail that mfr knows will never be sample tested > by telco. Or for that matter cable that failed telco tests and was put on > the retail market to recover costs. > > High current rotator motor leads (as opposed to control leads) should use > the commonly available UG series direct-buriable power wiring available at > home improvement stores. Less voltage drop, permanent and rated for wet > environments. > > 4) splices or cable terminations should be made indoors and elevated where > waterproofing failure will not allow water to get inside the PE jacketing. > Some manufactured multiconductor cables will have BOTH external and > internal insulation PE or teflon. Do not locate splices in conduit. You're > just asking for it. Even if 9 out of 10 get away with it, be assured you > will be # 10. Murphy KNOWS all you've done, knows all the contest and > DXpedition dates, AND has a malevolent nature. > > 73, Guy K2AV > > > On Thu, Oct 5, 2017 at 8:49 AM, Dale Putnam <daleput...@hotmail.com> > wrote: > > > I agree with Ken, with only one option, and that would be if the conduit > > is open on both ends.. allowing free air flow thru. That situation, MAY > > help dry the water from sitting on the cable, depending on the average > > humidity at the underground temp. Warm air from inside.. to cold air > > outside may not work out well either. > > > > > > > > Have a great day, > > --... ...-- Dale - WC7S in Wy > > > > "Actions speak louder than words" > > 1856 - Abraham Lincoln > > > > > > > > From: Topband <topband-boun...@contesting.com> on behalf of Ken > Claerbout > > <k...@verizon.net> > > Sent: Thursday, October 5, 2017 6:19 AM > > To: topband@contesting.com > > Subject: Re: Topband: underground cables question > > > > As you have found out, it's impossible to keep water out of a conduit > like > > that. I use direct bury cabling and put it directly in the ground. > > Granted the cable is flooded, but putting in back in the conduit ensures > it > > will sit in some water, something I would try to avoid. > > > > 73 > > Ken K4ZW > > > > > > --
Re: Topband: Solar Flare
Bruce: The solar storm was fairly minor. Both the SF and DC outages were confirmed as caused by a equipment failure and sunsequent fire in a substation. Chuck From: Topband <topband-boun...@contesting.com> on behalf of K1FZ-Bruce <k...@myfairpoint.net> Sent: Friday, April 21, 2017 7:11 PM To: Topband Subject: Topband: Solar Flare Major solar flare. Power outages in NYC and San Fransisco. Aurora noise on what few signals there are on 160.. 73 Bruce-K1FZ _ Topband Reflector Archives - http://www.contesting.com/_topband Topband Archives - Contesting Online Home<http://www.contesting.com/_topband> www.contesting.com Topband Mailing List Archives. Search String: [How to search] Display: ... _ Topband Reflector Archives - http://www.contesting.com/_topband
Topband: Xx
Xx c,t xz, , xx xz _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: VOA Antennas
And for those that like to be closer to a lot of power while producing arcs: https://www.youtube.com/watch?v=bNawh4faZM8 Chuck From: Topband <topband-boun...@contesting.com> on behalf of Mike Waters <mikew...@gmail.com> Sent: Saturday, April 9, 2016 7:00 PM To: dick.bingham Cc: topband@contesting.com Subject: Re: Topband: VOA Antennas The Sterba curtain at the old Bethany, Ohio VOA had 20 dB of gain. I saw it up close during a ham club trip years ago. Hams that worked there would sometimes drive out next to it at night, and connect their mobile transceivers to it for a night of DX fun. The RF field in front of that antenna was so intense that one could sometimes hear the program audio emanate from tiny arcs in a low, rusty barbed wire fence along the road in front of that huge Sterba. That enormous antenna, fed with huge Collins and Crosley transmitters re-defined the word "awesome". :-) Across the road from that fence were a number of newer houses, BTW. Helps prove that shortwave never hurt anyone, doesn't it? 73, Mike www.w0btu.com On Sat, Apr 9, 2016 at 12:40 PM, dick.bingham <dick.bing...@gmail.com> wrote: > What was the gain/beamwidth of these arrays ? The ERP must have been > incredible given the high power transmitters used plus the antenna gain . > Migratory Geese could have warmed themselves as they flew thru the region. > > 73 Dick/w7wkr CN97uj > _ Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: BOG question
Frank: I believe there is a large influence of height above ground on VF. >From a theoretical basis, this has been "known" since Wise's classic paper >"Propagation Of High Frequency Currents In Ground Return Circuits" (1934). This was experimentally verified in the Litva and Rook report from the CRC (Canada), and compared with theoretical results. These guys didn't extend their calculations to right-on-the-ground antennas. The attached (if it gets through the server) is from a spreadsheet of mine based on the Wise equations. The influence of height on VF is very very pronounced. Chuck > Date: Thu, 1 Oct 2015 11:23:16 -0400 > From: donov...@starpower.net > To: topband@contesting.com > Subject: Re: Topband: BOG question > > Hi Art, > Signals arriving at the BOGs are not travelling in the ground, therefore > their velocity of propagation (Vp) is unaffected by the ground. > > 73 > Frank > W3LPL > _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: BOG question
I think this is a wording issue. We all understand the difference between VF in the transmission line and VF in free space. What caused difficulty was the term "arriving at". I took this to mean "at the antenna" not free space, as there's no need to mention the antenna if the desired meaning was "free space". Chuck > From: w...@w8ji.com > To: charle...@msn.com; donov...@starpower.net; topband@contesting.com > Subject: Re: Topband: BOG question > Date: Thu, 1 Oct 2015 18:57:09 -0400 > > > I believe there is a large influence of height above ground on VF. > > From a theoretical basis, this has been "known" since Wise's classic paper > > "Propagation Of High Frequency Currents In Ground Return Circuits" (1934). > > This was experimentally verified in the Litva and Rook report from the CRC > > (Canada), and compared with theoretical results. > > These guys didn't extend their calculations to right-on-the-ground > > antennas. The attached (if it gets through the server) is from a > > spreadsheet of mine based on the Wise equations. The influence of height > > on VF is very very pronounced. > > Chuck > > Frank is absolutely correct in what he said. > > The velocity factor decrease in the Beverage has nothing to do with the > arriving wave velocity that affects the required phasing spacing. The wire > looks longer because the earth slows the wave ***in the wire's transmission > line mode***. The required spacing and stagger is set by the wave, not the > wire. It is the same in a BOG, a normal Beverage, or in a vertical. > > The broadside spacing, to increase directivity a useful amount, has to be up > around 1/2 wave or more. The end-fire or echelon spacing has to be the same > as a normal Beverage, or vertical, to have useful directivity increase. > > The only thing the earth does is slow the velocity in the transmission line > formed by the wire and earth image. The antenna cannot be a long as a > regular Beverage because of the slowed propagation in that "transmission > line". It is little different than loading the wire with any lossy > dielectric. > > While the antenna is limited to less length because of velocity factor in > the wire's transmission line mode, the fact it is a BOG has no bearing on > the wave velocity, or the required spacing or stagger. > > 73 Tom > _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: BOG antenna notes update
Guy: This I do not understand. As a Beverage is a travelling wave antenna, it has no resonance. Chuck Date: Sat, 13 Jun 2015 21:51:16 -0400 From: k2av@gmail.com To: k...@myfairpoint.net CC: topband@contesting.com; l...@iv3prk.it Subject: Topband: BOG antenna notes update CLIP It would be exceedingly interesting to get a BOG adjusted for front to back by minimizing QRN, then temporarily converted to a DOG and measured for the primary resonant frequency. I suspect that they will exhibit a narrow bell curve about a frequency around 1100 to 1200 kHz in the broadcast band. This would confirm ground composition based highly variable velocity factor in wires in/on/just above earth. 73, Guy K2AV _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Salt-Water Qth!
W3RE : Apparently you missed the references I cited for BBC Engineering reports.Apparently everyone else did also, as they've not been mentioned since. And as for only hams being aware of seaside gain, the entire MW DX community has taken that as a matter of course for a hundred years. It seems to me there has always been little cross-pollination between the MW and 160 DXers, which is a shame. MW DXers have a lot of knowledge based on the plethora of high powered transmitters all around the world operating 24 hours a day with non-changing (almost) antenna systems. Chuck Also w...@hudsonvalleytowers.com wrote: ... Is there any scientific data in print to prove the theory that ocean front property is better than a location inland about a mile or so on a ridge overlooking salt water for HF. ... I understand the theory that verticals literally in or on the water have a huge advantage It is not a theory that there is a remarkable increase in MF transmission when closely approaching saltwater waterline. It has been observed over at least a half century by what must now be millions of observers, certainly the vast majority not hams, observed at least since inexpensive transistorized portable radios were available around 1960. These and millions of others took these radios everywhere with them, and it was soon common knowledge that you could hear the New York AM stations all day long if you took the radio out over the salt water at east coast ocean beaches as far south as Cape Hatteras. Not a bit of theory involved, just undeniable observation. The wow factor of this has severely diminished since the internet, and nobody except hams thinks that hearing NYC AM stations during the day down the east coast is the least interesting. _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Salt-Water Qth!
You might want to take a look at some technical reports from the BBC Engineering Department. Two in particular: RA-25 titled Influence of Ground and Sea on MF Propagation and 1975-32 titled LF and MF propagation : An Approximate Formula for Estimating Sea Gain. Both (and many more very interesting papers on Beverages, propagation, etc) are available online at http://www.bbc.co.uk/rd/search?Type=Publications Chuck From: w...@hudsonvalleytowers.com Date: Wed, 1 Apr 2015 07:47:23 -0400 To: topband@contesting.com Subject: Topband: Salt-Water Qth! This is my first post to the Top-Band Reflector, so please excuse my ignorance if this topic has been discussed in the past. Is there any scientific data in print to prove the theory that ocean front property is better than a location inland about a mile or so on a ridge overlooking salt water for HF. I had this heated debate over the weekend with two ham friends of mine while we traveled to Maine looking at real-estate along the coast. I understand the theory that verticals literally in or on the water have a huge advantage. The debate was about how far away from the water does it become a diminishing effect. I made the claim that the Ocean-Front property would be a better location than anything inland including a location on a ridge within a mile. This heated debate went on for about 500 miles while we were driving back to NY. It was a very interesting conversation and made the long drive back much quicker! :) Additional information about the debate: In the State of Maine there is a setback regulation on shoreline property regarding structures including radio towers. To play it safe with the shoreline protective rules, the proposed array system would be setback minimum 500’ from the water or as far back as 2000'. At these distances on 80/160 meter will a vertical antenna system see any positive effects with additional gain from the salt water? What about horizontal antennas? Do they see any effects from Salt-Water? I'm sure I can use HFTA to model the terrain, which I have done in the past with great accuracy. However, I'm not sure if it calculates Salt-Water. Maybe it does. We are anxious to start building in Maine ASAP. Any input would be appreciated. Thanks, Ray W2RE W2RE.com Sent from my iPhone _ Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: RG-6 questions
My favorite source of coax / TL performance is: http://www.ac6la.com/tldetails1.html Chuck Date: Sun, 15 Mar 2015 22:39:30 -0700 From: rich...@karlquist.com To: topband@contesting.com Subject: Topband: RG-6 questions Most RG-6 has a copper clad steel center conductor. Does anyone have data on what the loss of this type of cable is at 1.8 MHz compared to solid copper center conductor? Any suggestions for RG-6 with a solid copper center conductor? I see Belden 1694A, 7915A, 7916A and 9248 in the catalog, but don't know if any of this is available in distribution. Can anyone suggest some good distributors to buy quality RG-6? Thanks. Rick N6RK _ Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: [time-nuts] Minicircuits 10% discount in December
To focus any discussion, could you be specific? It's rather hard to react to such a broad statement. Chuck Date: Thu, 27 Nov 2014 22:49:48 -0800 From: j...@audiosystemsgroup.com To: topband@contesting.com Subject: Re: Topband: [time-nuts] Minicircuits 10% discount in December On Thu,11/27/2014 4:19 PM, Tom W8JI wrote: I'd hate to see anyone accept this information as factual or accurate: Are you suggesting that Fair-Rite's published data for this part is wrong? In extensive measurements of certain of their parts, I've not yet seen that. I stand by my comments. 73, Jim K9YC _ Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: BCB interference ?
Date: Mon, 22 Sep 2014 11:21:29 -0700 From: j...@audiosystemsgroup.com To: topband@contesting.com Subject: Re: Topband: BCB interference ? On Mon,9/22/2014 6:50 AM, Ed Stallman wrote: I found I have a 25KW AM 1520 Khz BC transmitter 12 miles from me , is that close enough to interfere with me receiving weak signal DX on the top Band ? I do hear some wide band hash 1837 to 1840 ! And Jim Brown wrote: That may be because they are transmitting digital radio. No filter will remove that -- it's part of their sidebands. 73, Jim K9YC Jim: Digital sidebands for AM stations only extend +/- 15 kHz from the carrier. If noise is being heard 317 kHz above the carrier, it's not due to IBOC usage. Chuck _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: BCB interference ?
Their description (to me at least) indicates an elliptic filter with a stopband peak of -40 dB at 1 MHZ and ranging to infinity (in theory) elsewhere in the stopband. In other words, 40 dB is the maximum for the discrimination factor. Indicates is a word I feel is necessary as their filter really is poorly described. They should have said what filter type and order are used and used standard nomenclature for filter parameters. And there's no mention of passband ripple. Chuck Date: Mon, 22 Sep 2014 11:21:29 -0700 From: j...@audiosystemsgroup.com To: topband@contesting.com Subject: Re: Topband: BCB interference ? On Mon,9/22/2014 6:50 AM, Ed Stallman wrote: Has anyone used this High Pass Filter ? http://www.dunestar.com/store/160-Meter-Highpass-Filter-pid-8.html The spec for this filter is ambiguous. Is the -40dB at all frequencies below 1.6 MHz, or at 1 MHz? BIG difference. OTOH, the Dunestar filters are decent for the price. 73, Jim K9YC _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Ferrite Cores
Neither do I. It's quite common practice for distributors to have their own part numbers. Witness DigiKey - here is their ferrite page : http://www.digikey.com/product-search/en/inductors-coils-chokes/inductor-ferrite-cores/197937 Yes, Amidon has always seemed a bit high priced. However, I'd like to see some numbers rather than an opinionated post. Chuck From: bi...@waveform.net To: j...@audiosystemsgroup.com; topband@contesting.com Date: Tue, 5 Aug 2014 18:34:39 + Subject: Re: Topband: Ferrite Cores I don't think it was entirely a scam on the part of Amidon. When you think about it, FT-240-31 is easier to know Ferrite, Toroid, 2.4 OD material #31 is a lot easier to remember than 2631803802 :-) Similar in concept to using channel numbers for TV instead of frequency assignments -- it makes it easier on the users/viewers. -Bill -Original Message- From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Jim Brown Sent: Tuesday, August 05, 2014 12:25 PM To: topband@contesting.com Subject: Re: Topband: Ferrite Cores On 8/5/2014 7:46 AM, Greg wrote: The Mouser part picture does not look like a FT-240-31. The FT-series of part numbers are PHONY part numbers, dreamed up many years ago by vendors who have sold them to hams for very high prices. The ACTUAL part number for a #31 2.4-in o.d. toroid, as defined by Fair-Rite, the company that MAKES these parts, is 2631803802. You will find that part number in Appendix One of my tutorial. Kits and Parts is one of those high price vendors. Amidon may have been the originator of this scam. Palomar and DXE are in that league as well. They created these phony baloney numbers so that you wouldn't find the part from a real industrial vendor at one third the price. 73, Jim K9YC _ Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: New 160M high performance receiving antenna at W3LPL
Much much closer to home for us Pacific NW'ers: https://maps.google.com/maps?q=40+43+24+n,+141+19+44+ehl=enll=40.72308,141.328892spn=0.003313,0.006968sll=40.723876,141.329155sspn=0.026507,0.055747t=kz=18 It looks to be operational and is still gated and guarded and has cars parked at the building. Chuck On 2/4/2013 10:53 AM, donov...@starpower.net wrote: Hi Lee, You can save yourself lots of engineering effort if you simply make yourself a copy of this one: https://maps.google.com/maps?q=40+43+24+n,+141+19+44+ehl=enll=40.72308,141.328892spn=0.003313,0.006968sll=40.723876,141.329155sspn=0.026507,0.055747t=kz=18 My former employer (then Sylvania, now General Dynamics Advanced Information Systems) installed it in 1966 at Misawa Air Base, Japan. I believe its still exists, but its probably no longer in use due to technical obsolesence, high maintenance costs and unavailability of spare parts. An identical array installed at Elmendorf Air Base, Alaska is also still in existence as far as I know. Maybe you can purchase one of them! Many copies of the original 40 element German Wullenwever array were built all over USSR shortly after World War II, some may still exist. Among other things, they tracked the 10 and 20 MHz Sputnik beacons that some of us recall. 73 Frank W3LPL Original message Date: Mon, 4 Feb 2013 10:13:55 -0800 From: Lee K7TJR k7...@msn.com Subject: New 160M high performance receiving antenna at W3LPL To: Robert McGwier rwmcgw...@gmail.com, Frank Donovan donov...@starpower.net Cc: Topband topband@contesting.com Hello Bob and all, Yes I agree on the issue of needing the stable impedance from the elements to drive the passive systems. I still have some questions in my mind about the radials and here is why. I have made many field tests where I measured the actual phase and amplitude differences between two receiving elements where one is held constant and parameters around the other were changed such as ground rods, radials, and such. Both were receiving signal from an equidistant transmitted source. What I can tell you for sure about this is that with a Hi-Z system the phase and amplitude shifts become quite unstable when radials are used. I do not know this to be a fact with loaded elements but I have seen evidence of some received signal shift due to the presence of the radials to the element. This test really opened my eyes about received signals and what objects might affect them. I have plans to buy the NEC4 engine and do some more field tests using another technology that should give me more answers. It is these minute details that prevent us from making these RX antennas even smaller. There is no doubt that the state of the art is advancing in receiving antenas with all the work that is and has gone on. I am confident that what we are presently doing is not perfect and I expect the state of the art still has a ways to go. There have been many man years of work by many people. I hesitate to name calls but a few notables are K6SE, W7IUV, W8JI, K9AY, W3LPL, W5ZN, W1FV, NX4D, N4IS, AA7J, K1LT and many many others that I apologize for not having the space here or personal memory at the moment to mention. There are more man years of work to do. I still covet the 96 element Wullenwever antenna invented around 1940! Lee K7TJR The issue is getting sufficient ground radials so that changing soil conditions: dry season, wet season, etc have minimal impact on the impedance which is the easiest measurement of the changing conditions. Joel and I did measurements several times and when he was near drought he found he had to add radials to stabilize the performance. Once done, his system has been stable since. Great news on both of you successfully deploying. Bob N4HY _ Topband Reflector _ Topband Reflector
Re: Topband: Ferrite core
On 7/1/2012 8:58 AM, Mike Waters wrote: Where's a better place to get those cores, Carl? Last time I bought 100 of them from Amidon, the cost was about $0.60 each when we factored in shipping. Mouser does not stock them. 73, Mike www.w0btu.com On Sun, Jul 1, 2012 at 10:28 AM, ZR z...@jeremy.mv.com wrote: The real Fair-Rite part # is 2873000202. The BN73-202 is a made up number by Amidon which usually has the highest prices when you include shipping. ___ UR RST IS ... ... ..9 QSB QSB - hw? BK Google is your friend: http://www.newark.com/fair-rite/2873000202/aperture-oblong-dual-core-ferrite/dp/02E8908 Chuck ___ UR RST IS ... ... ..9 QSB QSB - hw? BK
Re: Topband: Laird ferrites
On 6/29/2012 8:07 AM, Jim Brown wrote: Other than those samples, I've never gotten a thing from Fair-Rite, but they have been an excellent corporate citizen, and they have been quite willing to sell directly to hams for group purchases at the same prices they sell to distributors for the same quantities.. Why would we want to bite the hand that feeds us to buy virtually unknown parts from a company we've never heard of? 73, Jim Brown K9YC ___ UR RST IS ... ... ..9 QSB QSB - hw? BK I'm quite happy with the test results for Laird #35 toroids. The price is much less that Fair Rite for a comparable part. From my point of view, there's no need to stick with IBM, GM, etc. Chuck ___ UR RST IS ... ... ..9 QSB QSB - hw? BK
Re: Topband: TB season
It is always with great reluctance that I coil up my radials and put them in the garage when the season is over. Even though I have no choice, I hate being a fair weather friend to Top Band. It is also with humility that I work stations in the Southern Hemisphere during the long nights of Winter here. During the 2009 SP TBDC, I managed to work ZL3IX. Even though it was his Summer Solstice, I think he was copying me a bit better than I was copying him! 73, Chuck NI0C Jim Brown, K9YC, wrote: How would North America and EU work VK/ZL or South America if the guys in the lower hemisphere had our parochial attitude about the season? ___ UR RST IS ... ... ..9 QSB QSB - hw? BK
Re: Topband: BUG (Beverage under ground)?
On 3/12/2012 8:41 PM, Joe Subich, W4TV wrote: Anyone know the skin depth of earth at 1.8 and 3.5MHz and how that might impact a BOG buried three to six inches? Local soil is very poor mostly sand. 73, ... Joe, W4TV ___ UR RST IS ... ... ..9 QSB QSB - hw? BK Very little. The exact answer depends on whether your sandy soil is dry or wet. The exact values are: dry sandy soil : 1.8 MHZ 165 feet (!) and 3.6 MHZ 118 feet wet sandy soil : 1.8 MHZ 12 feet and 3.6 MHZ 8 feet Medium wave DXers have occasionally used Beverages just underground with some success so it looks like skin depth is not an issue in that case. For normal soil, (.001, 12) the skin depth is around 37 feet at 1.8 MHZ in case your soil is more like soil than sand, but the effect of 3 inches is still ignorable. Chuck ___ UR RST IS ... ... ..9 QSB QSB - hw? BK
Re: Topband: Amazing Video of an extremely large circular array
Here's a Wullenweber that is intact and I believe functional although not used like it was. It's coordinates are 54.028911,-132.065256 and it is quite visible in Google Maps. Of course it belongs to the Canadian military and is on Masset Island in Haida Gwaii . I've not yet found them in a tour-giving mood. Chuck On 2/12/2012 10:13 PM, Gary K9GS wrote: There was also one of these at the University of Illinois that was decommissioned in the early 80s. I've seen this thing up close and there were even rumors of some of the W9YH club members hooking a radio to this thing. I've always wondered if it's still there. Worth a look the next time I'm down that way. http://www.ece.illinois.edu/about/history/wullenweber.html On 2/10/2012 9:55 AM, James Rodenkirch wrote: Yep - one of 'dem can be seen down in San Diego, at the southern tip of Cornado and at the northern tip of Imperial Beach - the site is, if I understand it correctly, now owned and operated by the Sealsdon't get too close! Here's a pic from some years back: http://www.californiacoastline.org/cgi-bin/image.cgi?image=200604964mode=biglastmode=sequentialflags=0year=2006 72, Jim Rodenkirch, K9JWV From: w0...@nc.rr.com To: topband@contesting.com Date: Fri, 10 Feb 2012 10:30:10 -0500 CC: donov...@starpower.net Subject: Re: Topband: Amazing Video of an extremely large circular array Frank: I think the antenna in the video is a former Soviet Union Cold War version of a German Wullenweber also known as a Circularly Disposed Antenna Array (CDAA) http://en.wikipedia.org/wiki/Wullenweber 73, Jack Anyone want to try to build one? 73 Frank W3LPL ___ UR RST IS ... ... ..9 QSB QSB - hw? BK ___ UR RST IS ... ... ..9 QSB QSB - hw? BK ___ UR RST IS ... ... ..9 QSB QSB - hw? BK ___ UR RST IS ... ... ..9 QSB QSB - hw? BK
Re: Topband: Where to place a preamp? Switching Beverages?
I feed my normal Beverages with 320' of RG-58. and sometimes (at other locations) feed a Beverage with a shorter cable. Never ever have I been able to pull the antenna from the transformer between antenna and coax and have quietness in the receiver. Always there is too much pickup from AM BC stations (which I DX) and also noise. So I'll agree with Guy that few people's coax feeds are as clean as they think. For that reason, I'd put the preamp at the transformer so that the receiver thinks there's more S in the numerator with the same N in the denominator. Of course in a low noise environment, there will be little or no difference. The loss is immaterial to me. At .4 dB/100 ft at 1 MHz, 300 feet of RG-58 has 1.4 dB loss on paper and measured results show somewhat less loss. Chuck On 1/20/2012 10:44 AM, Guy Olinger K2AV wrote: I am getting comments from people who have installed FCP plus isolation transformer 160 TX antennas, how their new TX antenna is quieter than their K9AY or pennant, maybe a third or half of respondents (!!!) with some hint or outright statement of this. But I think, rather than the TX antenna being all that good, it's really the RX antenna's common mode isolation really being that grotesquely BAD. I can make this happen in a model by putting the coax on the ground and making the now low velocity factor ELECTRICAL length of the coax on the ground somewhat near a multiple of a halfwave. Typically something in the range of 125 or 150 feet, give or take, can have this VOLTAGE node, high Z point at one or both of the typical common mode blocking points. If one models this literally, and puts an EZNEC source on the shield, then you need common mode blocks in the 100k+ order of magnitude to keep noise down low enough to protect a non-amplified pennant antenna. The reason the TX FCP + isolation transformer is so quiet is that the UNCONNECTED windings of the transformer have only the capacitance between windings as a through path, and at the low 160m frequency the isolation is in the half megohm range against a 75 ohm-ish shunt to ground at amp or RX. So from where I'm setting, transformer ISOLATED preamps at EACH RX antenna need to be PROVED OUT for naturally lossy RX antennas, rather than the other way around, and you may need to run a separate DC lead to the preamp. I'm not saying they CAN'T be proved out, it's just that the beginning assumption needs to be that they are needed UNTIL it's proven they aren't need. I think that what is amiss is our perceptions about how quiet we think coax shields are. Apparently coax shields are just plain gawd-awful noisy, and must be assumed to be just plain gawd-awful noisy in the planning and construction stages. And I still get correspondence where the writer thinks they can evaluate RX antenna performance by A/B tests and how loud the desired signal is. Signal to noise cannot be done with the human ear and an A/B switch. Nobody's ear is that good. Borrow the equipment, do the work, get it right. Good 160 RX is a nasty, technical, unforgiving business with a mean mind toward deception. 73, Guy. On Fri, Jan 20, 2012 at 12:08 PM, Don Kirkwd8...@aol.com wrote: N4ZR said : I have a 20 dB ARR preamp, My choice is whether to put it at the antenna end, incurring the added complexity of sending 12V DC to it via the coax, or to put it in the shack. Per the ON4UN book, In most cases you can put the preamplifier in the shack. The signal loss in the feed line is a loss that affects both the signal and external noise. That means that the loss in the feedline does not affect the S/N ratio. I personally have 3 point fed pennants that are very small (51.6% the size of full size pennants), and therefore their gain is around -46dbi, and my preamp is located in the shack (W1FB slightly modified preamp). I've done some simple tests with my preamp out at the feedpoint versus in the shack and I personally was unable to detect any difference in S/N performance but my measurement system was not highly sophisticated. My feedline is 160 feet of RG58/U, and I intentionally have no breaks (no connectors) in this feedline (one solid run of feedline from the connector on the back of my preamp to the primary of my transformer which is located at the antennas (my feedline is soldered directly to the transformer primary), and I did this to eliminate any and all weather related connector problems. I only use one transformer to feed my 3 pennants, and I do switch the high impedance side of the transformer (the transformer secondary), and I switch both ends of the secondary (mandatory for multiple point fed pennant systems). I have 14 turns of my coax run through 3 stacked 2.4 O.D. 31 mix cores to help prevent common mode current, and this choke is located approximately 25 feet away from the base of multiple pennant feedpoint. Also
Re: Topband: Topband QSL Library
Most digital picture frames depend on something like a USB Flash Card for their input. A 4Gb Flash Card costing about $8 will hold THOUSANDS of high-res scanned QSL cards. A great idea I never thought of before. Thanks! Chuck KØTVD www.dxham.net Just curious: How many medium quality QSL card scans will a typical digital picture frame support? I am in the process of making a display of QSLs from some 330 DXCC entities (not mine, unfortunately) and the digital picture frame would be a neat adjunct to the display! Thanks, ___ UR RST IS ... ... ..9 QSB QSB - hw? BK
