Topband: Welcome back IV3PRK
Just noticed IV3PRK a couple of times in the night report of my 160m skimmer Welcome back Luis ! Hope you and family are doing well. 73 Mark, PA5MW _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
Re: Topband: Feedline Grounding and Feedline Chokes
About a simple Bulkhead-Entry-Point. A success at lowering man-made local noise for me. This is a simple solution I use successfully at home: https://www.flickr.com/photos/pa5mw/28796976750/in/album-72157667970861390/ 73 Mark PA5MW -Original Message- From: Topband On Behalf Of Bob K6ZZ Sent: Wednesday, March 25, 2020 23:24 PM To: topband Subject: Topband: Feedline Grounding and Feedline Chokes Folks, I see a lot of references to grounding coaxial feedlines at the top of towers, bottom of towers, and at house entry points. Is this purely for static and lightening protection purposes or does it also help mitigate Common Mode problems as well? If feedlines are well grounded, are chokes still useful for controlling Common Modes problems? I suspect that both can be used, and should be used, in a well designed station. Are there specific recommendations on the use of chokes on grounded feedlines? Does placement matter? Thanks, Bob K6ZZ _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
Re: Topband: DXCC Committe
Hi Mike Please forgive my blunt words, but It's about your tone what is bothering me. I see that all too often happening on this list. You are the first one responding here on his message. Surely one could ask OK1RD some questions, pass some information/experience on topic? OK1RD in the end, might be right or wrong. I still do not get the picture. 73 Mark PA5MW -Original Message- From: Mike Smith VE9AA Sent: Monday, March 23, 2020 13:13 PM To: pa...@home.nl; topband@contesting.com Subject: RE: Topband: DXCC Committe I'm not sure what your beef is with me , Mark/PA5MW. All I did was summarize his emails and brought no extra facts, opinions or innuendo's into play. I jumped to no conclusions. I asked a question at the end (the hail-mary bit) He started this, not me. In the end, he's the guy that has to look back at himself in the mirror. If there is some mistake or misunderstanding, I sure didn't make it. I can appreciate that English is probably not his first language, but I am not understanding his side of it and seek clarification. 73 Mike VE9AA Mike, Coreen & Corey Keswick Ridge, NB -Original Message- From: pa...@home.nl [mailto:pa...@home.nl] Sent: March 23, 2020 9:06 AM To: 'Mike Smith VE9AA'; topband@contesting.com Subject: RE: Topband: DXCC Committe OK, so let me get this straight: You sent the DXCC desk a Doctored card ==> *check* (that was clearly explained up front) got busted ==> negative contribution (that is the 'fact' needing to be peer-reviewed) then claimed you didn't send it ==> your interpretation (you just wanted them to admire your skills?) ==> negative contribution got kicked out of the DXCC program and are now mad about it, ==> yes he is. (still see that negative tone here) so are throwing a Hail-Mary so someone here might help? ==> negative contribution **See a pattern here Mike?** If there is any uncertainties on OK1RD's topic or, if you just must jump to that conclusion immediately, I would rather suggest you put in some elements which can help the discussion here. Some of us might see things differently and it would be helpful if people share their knowledge ON topic. Have a nice day, Mark, PA5MW -Original Message- From: Topband On Behalf Of Mike Smith VE9AA Sent: Monday, March 23, 2020 12:38 PM To: topband@contesting.com Subject: Re: Topband: DXCC Committe OK, so let me get this straight. You sent the DXCC desk a Doctored card, got busted, then claimed you didn't send it (you just wanted them to admire your skills?), got kicked out of the DXCC program and are now mad about it, so are throwing a Hail-Mary so someone here might help? I think all you've done is make it worse. Now we all know how it happened ! Hi, Above all, to all of us previously born solid health during the period of the COVID-19 pandemic. Let me show you how one can be easily kicked out from 1 position in spite of meeting all the competition rules. Please read carefully all E-mails copies sequentially sorted. No more notes just facts from my side. Orginals of correspondence are available. 73, Jarda-OK1RD _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
Re: Topband: DXCC Committe
OK, so let me get this straight: You sent the DXCC desk a Doctored card ==> *check* (that was clearly explained up front) got busted ==> negative contribution (that is the 'fact' needing to be peer-reviewed) then claimed you didn't send it ==> your interpretation (you just wanted them to admire your skills?) ==> negative contribution got kicked out of the DXCC program and are now mad about it, ==> yes he is. (still see that negative tone here) so are throwing a Hail-Mary so someone here might help? ==> negative contribution **See a pattern here Mike?** If there is any uncertainties on OK1RD's topic or, if you just must jump to that conclusion immediately, I would rather suggest you put in some elements which can help the discussion here. Some of us might see things differently and it would be helpful if people share their knowledge ON topic. Have a nice day, Mark, PA5MW -Original Message- From: Topband On Behalf Of Mike Smith VE9AA Sent: Monday, March 23, 2020 12:38 PM To: topband@contesting.com Subject: Re: Topband: DXCC Committe OK, so let me get this straight. You sent the DXCC desk a Doctored card, got busted, then claimed you didn't send it (you just wanted them to admire your skills?), got kicked out of the DXCC program and are now mad about it, so are throwing a Hail-Mary so someone here might help? I think all you've done is make it worse. Now we all know how it happened ! Hi, Above all, to all of us previously born solid health during the period of the COVID-19 pandemic. Let me show you how one can be easily kicked out from 1 position in spite of meeting all the competition rules. Please read carefully all E-mails copies sequentially sorted. No more notes just facts from my side. Orginals of correspondence are available. 73, Jarda-OK1RD _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
Re: Topband: CQ...CQ...CQ
Correct on the CQ CQ ! As of last weekend I am running a 160m CW skimmer feed to the RBN and notice: - ratio between correct heard callsigns vs those sent to the RBN server is roughly 5 :1 (excluding calls from a pile-up) - only those callsigns with CQ CQ in their message are forwarded to RBN network (Duh) 73 Mark PA5MW -Original Message- From: Topband On Behalf Of VE6WZ_Steve Sent: Wednesday, March 18, 2020 0:15 AM To: topband Subject: Topband: CQ...CQ...CQ With many hams around the world staying home and "practicing social distancing” to “flatten the CV-19 curve”, what a great time to be on the radio! Lets get out there and call CQ to stir up the band. (or ANY band for that matter) There may be some out there that somehow think calling CQ is just for the rare DX, and not for the average ham. I know there are many that have no interest in woking just “plain old DX” that aren't new DXCC counters. I also realize there are many that live in high noise city locations that have a legitimate “alligator risk” by calling CQ. However, to state the obvious, if no one calls CQ, no one is going to work anyone! The conclusion will be “the band is dead”. Speaking of another benefit of RBN…..one comment…..”if I look at my waterfall and don't see any traces, then the band is dead”. Well….often NOT true. It is not unusual to see a blank pan-adapter, but then when checking the RBN there is NO-ONE calling CQ….anywhere in the world! Is the band really dead?? How do we know it's dead if no one is calling? (And yes, there are enough RBN skimmers worldwide that almost any CQ will be decoded within a few seconds) Many nights I have CQ'd into a “dead band” (blank pan-adapter, but also no RBN activity) and been rewarded with lots of EU DX callers. There are a number of NA stalwarts calling CQ regularly on TB and a handful from EU, VK and JA, but it would be great to see more activity. (last night I heard Jon AA1K filling his log with EU). This winter I have worked quite a few EU that have been running 100w from backyard antennas so it's not limited to the big guns. For those that lament that everyone is on FT-8, perhaps it would be a good idea to get on the band and make some CW noise instead of waiting for some else to call CQ??? Thats what the FT-8 guys are doing…they hit the send key on the FT-8 program and wait to see what happens. There is a lot of FT-8 CQing going on…every 15 seconds, for hours. Maybe thats why it seems there is more DX being worked on that mode? This season I have logged 1,587 EU QSOs on CW with 498 unique callsigns, so CQing can be rewarding. 113 DXCC since August. This has been one of the best TB seasons here at VE6WZ. The season is not over yet. While stuck at home, turn on the radio and call CQ….on ANY band. See what happens. Kinda like “old school” radio…using the “legacy" mode. CQ..CQ…CQ….. Why not? 73, de steve ve6wz _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
Re: Topband: Inverted L with elevated radials for topband
Hi Gabriel, There is too many variables in your antenna setup to determine the expected impedance. I have built and measured several inverted L's with/without elevated radials and/or sloping top wires. So I will refrain from putting out estimations, other than guesses from what I learned during the last 30yrs. What I do know: Fact: an inverted L with 1/8 vertical and 1/8 straight horizontal offers a radiation resistance Rs=18 Ohm. No more. Fact: Antenna impedance (Z)= Rs+Rg. Rground refers to energy not radiated but lost in the radials to ground. Your Antenna Analyzer/VNA will offer at resonance (find the frequency at which Xc=0) is Z. You now have two unknown variables(Rs and Rg) and one measured value Z Fact: Z, SWR_usable_Bandwidth, Rground, Rs and any device to match it all to 50 Ohm are variables which can be a challenge. But don't sweat it. Fact: making the vertical part higher v.s. sloping wire=> get the sloping wire up. That is much more effective. My experience: - A straight horizontal L-part is just to about impossible; at 1/8 length any wire will droop in the middle and lower Rs substantially. Spent two days measuring just that when I had two 23m HD tubular towers. - A sloping single top wire quickly lowers the Rs. In your setup I would expect it to be between 11 and 13 Ohm - knowing that guestimated value; when your analyzer shows Z=40 Ohm SWR=great at resonance (Xc=0) one can calculate the ground losses Rg=40-12=28Ohm. That will be with 4 radials on ground probably. A nice SWR but effectivity is 12/40= 30% the other 28/40-70% of the power goes into ground. - Good SWR does not mean the antenna is 'really good'. But don't seat it, sometimes you have limited options. And you have to start somewhere. - Elevated radials: been there. 4 resonant elevated radials is possible, but difficult to measure correctly such that all four behave similar. We had them at 4m height. Higher is better, more is better. - If you lengthen the L-part so the total becomes 50 to 54m and tune out that extra length using a series Cap at the feedpoint, you can raise the Z. We did it with our 4 elevated radials and got a Z=34 Ohms which was nice to use a W2FMI 32:50 Ohm transformer. - Radials; put down about 30-50pcs with 25 to max 30m length. Want to lower Rground more effectively? Go to 120 radials at longer lengths, OR - Additionally put lengths of chicken wire directly under the vertical. Do not try to make length in a start config like radials; instead just closely cover straight lengths, make a square. It does not have to make electrical contact (it will help a bit but not the effort worth). Been there, measured it. - At a good setup you probably will have a Z= 12+15=27 Ohms (there it is I did make an estimation!) my point here: - You will need a matching device / transformer (one toroid <500W, two or three at 1K5) to get from the guestimation value to connect it to your 50 Ohms coax feeder into the shack. - There will be many other voices from other people having less/similar/more/different experience. My tips: - Don't sweat it. At 1/8 vertical part, even with a sloping wire, one can make a good signal. Even at some crooked elevated radials. - Read Low Band Dx'ing by ON4UN; it tells you how to do it, both in KISS mode as well as freaking nerd-mode. There will not be a great difference unless you have the hardware AND lots of real estate. - Use an antenna analyzer which shows Xc, Z and SWR; the cheapest Rig Expert or any like is best in the field (no MFJ). I have had several different ones in the past 20yrs. - Use a portable VNA if you must, but only if you have the experience how to use it. Or have someone come over to do that . No Smith chart crap; that's for nerds and NOT effective in the field, unless you use smith charts on a daily basis. - Measure at the antenna, using a pigtail coax to about 0,5 to 1m length. Yes one can measure it in the shack using professional network analyzers/ VNA's etc. when the feedline is properly calibrated out. Been there. A friend has a large HP in his shack. In the end we prefer that small but very practical Rig Expert. Happy experimenting! 73 Mark, PA5MW -Original Message- From: Topband On Behalf Of Gabriel - EA6VQ via Topband Sent: Thursday, March 05, 2020 19:02 PM To: topband@contesting.com Subject: Topband: Inverted L with elevated radials for topband I have some doubts about installing and inverted L with elevated radials for 160m. I have been searching in Google and find some contradictory information, so I would appreciate very much if you can help me with your own experience. The antenna would be supported by a 16 m (52.5 ft) high fiberglass pole placed on top of a 3m (10 ft) high small tower with the horizontal part of the L slopping down to a 5 m (16 ft) high mast about 23 m (75 ft) away. Two to four tuned elevated radials can be placed, al
Re: Topband: K9ay loop not performing
Hi Pete, Over some 20 years have setup some at least 15 K9AY's at about 10 different locations. On some locations it worked better than others. There is always 15 dB F/B at minimum. Top height, length of the loops, optimal balanced corner positions; never noticed anything critical. This thing is a superb starter RX antenna. The max F/B I measured was 42dB, both measured with a Perseus SDR. Above spec are achieved in my puny backyard where the K9AY's corners are close (as in 1 to 10ft)to either a metal fence, my shack(and alu windows) and the neighbors TV. I use two 8ft copper ground rods. Have tried radials and chicken mesh on the floor additionally, but that did not help. Guess my type of soil is already good. See pictures for the simple setup and F/B performance both on 160m and 1400 kHz at: flickr.com/photos/pa5mw/albums/72157688739777191 73 Mark PA5MW -Original Message- From: Topband On Behalf Of N4ZR Sent: Saturday, December 07, 2019 22:14 PM To: topband reflector Subject: Topband: K9ay loop not performing I just put up a K9AY loop, using the Array Solutions control boxes, and am pretty disappointed. There is no audible or visible difference in the noise level, while the received signal strength is down whenever I A/B it with my inverted L. There does seem to be a little directivity, but not much, and subjectively I find that weak signals are all heard better on the transmit antenna. Judging by results in the current contest, I've got an alligator on my hands! The preamp amplifies by a couple of S units, and I can hear the relays out at the antenna switching when I change directions or termination resistances, although gain and directivity do not change noticeably. From this I assume there's nothing wrong with the electronics I tried to do my installation "by the book." Ground is provided at the base of the antenna by a 6-foot ground rod. There are two common-mode chokes on the feedline, one at each end of approximately 100 feet of RG-6. About the only deviation from the published design is that the top of the crossed loops is at 28 feet, not 25, and the loops have their bases more or less horizontal, where the published designs show them tilting upward approximately 15-20 degrees from the center in each direction. I can make that happen with some more rigging, but before I do that, I'm looking for suggestions of other places to look for the problem. -- 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: Ground under a K9AY Loop
Hi Pete, Maybe... I have 3pcs 8ft GND rods under my K9AY which I install each winter in my (puny) 23x28ft backyard. Going from one to three rods, water them regularly etc. showed me a constant F/B on AM BC stations between 25 and 42dB ( no S-meter; but s/n differences on an SDR Perseus) Interesting though is the relatively high termination values I have to set in on the K9AY control box; settings 2, 3 or 4 usually offer the best F/B. The standard advised settings per band would offer 10 to 15 dB less F/B performance. Knowing that such value alters both the depth and t.o. angle of the backside lobe it is still interesting to see that it is relatively higher in value than 4 seasons ago when I only had 1 GND rod. I also tried 4 and 8 radials once ( + a 4ft single GND rod) which did not perform that well. YMMV. I have tried this setup at several contest field-day locations on farm-soil successfully, using a single copper GND-rod 5ft/ 1 inch dia. **Answering your question; yes, GND can be too good, especially if you cannot match the optimal termination. 73 Mark PA5MW -Original Message- From: Topband On Behalf Of N4ZR Sent: Wednesday, October 23, 2019 3:36 AM To: topband reflector Subject: Topband: Ground under a K9AY Loop Thanks to everyone who responded to my earlier question about substituting radials for a ground rod. We just had 3 days of rain - our first in 6 weeks, so I don't think I have a ground rod driving problem any longer. I'll find out tomorrow. But all those suggestions raised an interesting question - is there any such thing as too good a ground under a K9AY? For example, if I drive an 8-foot ground rod and then run 4 radials from it, out under and past the elements of the K9AY, might that be TOO much? It's really not that much extra effort, and my last lawn mowing for this fall is Thursday. -- 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: Why no NA 160m Activity?
Due to this years extended summer season temperatures, many of the (RX)antenna fields are 'not available yet'. 73 Mark PA5MW -Original Message- From: Topband On Behalf Of Roger Kennedy Sent: Thursday, October 18, 2018 11:39 AM To: topband@contesting.com Subject: Topband: Why no NA 160m Activity? Many thanks for all the replies and comments, some on here, and some direct. I guess a lot of NA stations are still suffering with QRN then . . . plus many are Farmers, waiting to get the crops out of the fields before they put their Topband antennas back up! Jeff I appreciate why quite a lot of people use FT8, especially if it's the only way they make DX contacts. But personally, it would give me no satisfaction at all . . . and I know a lot of people feel the same. So I don't think the lack of CW activity is the risk of everyone migrating to FT8 . . . it's just that people aren't coming on the band! And I suspect that one of the reasons is they look at the DX Cluster, and they see LOADS of spots for FT8 stations . . . but very few for CW stations. So if you hear anyone on CW, do please Spot them on the Cluster, as I know that helps generate more activity. And hopefully more people will make the effort to come on the band, so we can stir up activity. It certainly worked last season, when I suggested a regular Wednesday Activity Night. I'll leave it a few more weeks, then I will suggest the same on here. 73 to all Roger G3YRO _ Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Beverage F/B using oscillator
Additional question; with respect to the BOG/Beverage backlobe upwards angle, does the test-generator antenna need to be lifted from local groundlevel by say 2- 10m? Or can this test be done just as reliable on groundlevel? 73 Mark, PA5MW -Original Message- From: Topband On Behalf Of F Z_Bruce Sent: Tuesday, October 09, 2018 3:01 PM To: ash.kf5...@gmail.com; Topband Subject: Topband: Beverage F/B using oscillator Good information. Finding the best BOG F/B. I use an model MFJ-5014 white noise generator off the 'back' of the BOG antenna. Then tune the receiver to find the 'minimum noise' signal frequency.Adjust the BOG antenna length to bring it into 160 meters.. Care must be taken not to create a neighborhood noise problem. 73 Bruce-k1fz On Tue, 9 Oct 2018 09:07:42 +0100, Ashraf Chaabane wrote: Hi All, I used a 1.843 oscillator to check NA beverage F/B. The mesurements were taken 160m away from each end of the antenna. Noise level was constant. I had 4 dB difference between front and back signals. Is that what I should expect? Is 1 wavelength distance enough to do this experience? This will be repeated with different terminations and I want to make sure I'm doing it correctly. It will also be applied on the newly installed BOG to determine optimum length. Tnx and see you on the air! -- Ash ~ 3V8SF Topband: *http://www.kf5eyy.info/topband.htm * Phone/SMS/Whatsapp: (+216) 22670026 Skype: kf5eyy _ Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Beverage Antenna Tuning
Another question might be; how close by is this BC station or any other AM BCB stations? Please consider a HP BC stopfilter 73 Mark, PA5MW -Original Message- From: Topband On Behalf Of Ashraf Chaabane Sent: Wednesday, July 04, 2018 4:40 PM To: pa...@home.nl Cc: topband@contesting.com Subject: Re: Topband: Beverage Antenna Tuning Mark, I'm planning to have the termination value adjustment excercice for F/B maximisation using a BC station signal. However, does SWR measurement have to do also with the termination value? Or that's rather the matching transformer that I should act on? I now have an antenna analyzer and multimeter. What kind of optimization I can carry out? (The beverage is permanently installed). 73 Ash On Wed, Jul 4, 2018 at 3:23 PM wrote: > Based on my field installed beverages experience, I would say this is > exactly what I always read on my ant analyzer. > Ground and local air/bush moisture level changes, like after rain or > such, will affect readings too. > > I would do optimization only if this installation was permanent and > you have the time and tools available. > > 73 Mark, PA5MW > > > > -Original Message- > From: Topband On Behalf Of Ashraf > Chaabane > Sent: Wednesday, July 04, 2018 4:13 PM > To: topband@contesting.com > Subject: Topband: Beverage Antenna Tuning > > Hi All > > I measured the SWR in my beverage antenna; the SWR fluctuates between > 1.5 and 3 in a range of 1.8 to 7 MHz. (See: > > https://drive.google.com/drive/folders/0B9AtNpPfAOUMRDNsaXROMG1VUTg?us > p=shar > ing > ) > I know SWR should not vary too much. However, some people are > suggesting adjusting the termination resistor. Others suggest checking > the transformer number of windings for a good match. What shall I do? > > 73 Ash 3V8SS/KF5EYY > _ > Topband Reflector Archives - http://www.contesting.com/_topband > > -- Ash ~ 3V8SS/KF5EYY http://www.kf5eyy.info/ Phone/SMS/Whatsapp: (+216) 22670026 Skype: kf5eyy _ Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Beverage Antenna Tuning
Hi Ash, Some info: - SWR curve median will always slowly rise. No action; this has to do with parameters which slowly affect at higher freq. That is rather irrelevant on the lowbands 160-80-40 - Termination +matching adjustment is optimal at 'minimal amplitude' of the SWR curve Meaning; the waves must be 'as small as possible'. It might never be flat, I have never ben able to get there. Maybe others can give better advice here. But does it matter when not SWR 1? No. - Matching optimal beverage impedance to coax Like when all is set optimal but the whole beverage antenna is not 450 Ohms but 530 ==> stick with the 9:1 Or, at a BOG where installation is near ground, impedance is abt 220 Ohms ==> stick with 4:1 A better matching is possible by altering the transformer windings. But again, does it matter? Can you make more QSO's? I have not seen/read any proof on this yet. Please also note: Local environment, as well as length/install- height of beverage wire will determin the 3D pattern Local ground/air humidity will change performance slightly Adjusting F/B to local BC signal can be distracting because: BC freq is out of band and a good F/B at <1600kHz does not mean it is now optimal at 1830kHz as well.. Groundwave BC signals arrive at 0 degrees; you want to adjust FB at incoming skywave (10< >50 degrees) signals instead What reference you should use depends on your QTH and the first wave of incoming (Europe?) QRM I hope others, with more experience on this subject will have a better answer here. In general, my experience is a beverage antenna will work rather quickly and perform well. There is just no bad-adjustment possible. 73 Mark, PA5MW -Original Message- From: Topband On Behalf Of Ashraf Chaabane Sent: Wednesday, July 04, 2018 4:40 PM To: pa...@home.nl Cc: topband@contesting.com Subject: Re: Topband: Beverage Antenna Tuning Mark, I'm planning to have the termination value adjustment excercice for F/B maximisation using a BC station signal. However, does SWR measurement have to do also with the termination value? Or that's rather the matching transformer that I should act on? I now have an antenna analyzer and multimeter. What kind of optimization I can carry out? (The beverage is permanently installed). 73 Ash On Wed, Jul 4, 2018 at 3:23 PM wrote: > Based on my field installed beverages experience, I would say this is > exactly what I always read on my ant analyzer. > Ground and local air/bush moisture level changes, like after rain or > such, will affect readings too. > > I would do optimization only if this installation was permanent and > you have the time and tools available. > > 73 Mark, PA5MW > > > > -Original Message- > From: Topband On Behalf Of Ashraf > Chaabane > Sent: Wednesday, July 04, 2018 4:13 PM > To: topband@contesting.com > Subject: Topband: Beverage Antenna Tuning > > Hi All > > I measured the SWR in my beverage antenna; the SWR fluctuates between > 1.5 and 3 in a range of 1.8 to 7 MHz. (See: > > https://drive.google.com/drive/folders/0B9AtNpPfAOUMRDNsaXROMG1VUTg?us > p=shar > ing > ) > I know SWR should not vary too much. However, some people are > suggesting adjusting the termination resistor. Others suggest checking > the transformer number of windings for a good match. What shall I do? > > 73 Ash 3V8SS/KF5EYY > _ > Topband Reflector Archives - http://www.contesting.com/_topband > > -- Ash ~ 3V8SS/KF5EYY http://www.kf5eyy.info/ Phone/SMS/Whatsapp: (+216) 22670026 Skype: kf5eyy _ Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Beverage Antenna Tuning
Based on my field installed beverages experience, I would say this is exactly what I always read on my ant analyzer. Ground and local air/bush moisture level changes, like after rain or such, will affect readings too. I would do optimization only if this installation was permanent and you have the time and tools available. 73 Mark, PA5MW -Original Message- From: Topband On Behalf Of Ashraf Chaabane Sent: Wednesday, July 04, 2018 4:13 PM To: topband@contesting.com Subject: Topband: Beverage Antenna Tuning Hi All I measured the SWR in my beverage antenna; the SWR fluctuates between 1.5 and 3 in a range of 1.8 to 7 MHz. (See: https://drive.google.com/drive/folders/0B9AtNpPfAOUMRDNsaXROMG1VUTg?usp=shar ing ) I know SWR should not vary too much. However, some people are suggesting adjusting the termination resistor. Others suggest checking the transformer number of windings for a good match. What shall I do? 73 Ash 3V8SS/KF5EYY _ Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Post contest season: TX antenna vs RX antenna cros-stalk. What do you do?
Thanks Jim, Our learning point so far: Our fixed setups usually had harmonic coax stub filters per individual antenna. Antenna interaction was carefully measured with help of a spectrum analyzer (worst case ever found = -17dB) The RX inputs often had individual BPF's (home made or Dunestar) The TX lines always had 6-band 200W BPF's Often the TX antenna was never used for RX and switched to GND to avoid noise coupling to RX antennas. As such the TRX internal RX/TX cros-talk was never noticed. In some other cases this event was perhaps overseen? For me this is a new challenge. Our typical field-day setups only have the TX 6-band BPF's None of the other measurements/precautions have been taken as the building of the FD-style setup already takes a lot of time and the QTH offers limited access as it is being used for commercial workshops where participants fear electronics and antennas. One ham recently switched to 4O3A hardware and noticed similar positive performance results. Sheet metal boxes perform better than aluminium? About coax and plugs/sockets; we are already for years busy replacing old stuff by Amphenol or Kabel Kusch hardware. For my Wellbrook Loop antenna I used a home made 3-pole 160m BPF with a DC bypass for the head-amp. That was effective for the Topband contest. Measurements using calibrated generator ( Marconi 2955) and now the new Elecraft XG3 (very handy in the field), together with a analyzer , or even a good SDR like the Microtelecom Perseus (lowest phase noise ) is very helpful making steps forward at home. A VNWA sure can be helpful too. At least it is more portable than our L HP analyzer. In the field the challenges are different and take a lot of debugging time. Thanks for all the tips 73 Mark, PA5MW -Original Message- From: Jim Brown Sent: Thursday, March 24, 2016 6:11 PM To: topband@contesting.com Subject: Re: Topband: Post contest season: TX antenna vs RX antenna cros-stalk. What do you do? On Wed,3/23/2016 11:38 PM, Mark van Wijk, PA5MW wrote: The problem is that while listening to your receiving antennas, there is also some signal from the transmit antenna getting through thanks to the internal cross-talk of your rig's TX/RX relay. There are many heads to this snake, but also many fixes. This post is about crosstalk, NOT interaction. First, there is coupling between the antennas themselves. Cross-band interference between transmit antennas can be greatly reduced by the use of bandpass filters, but these filters don't help with RX antennas not within the filter loop. Second, there is coupling due to leakage capacitance between relays, poor layout of relay boxes, and currents within our stations. My station uses a 6x2 relay box to distribute monoband antennas between rigs for SO2R, but some have a lot more crosstalk than others. Last spring, I replaced an Array Solutions Six-Pak with a 4O3A box. I measured both boxes for isolation using the DG8SAQ VNWA -- the 4O3A unit had more than 20 dB better isolation than the SixPak. But even with that improvement in hardware, I still found isolation insufficient, so I bought a spool of BuryFlex and a box of Amphenol 83-1SP (solder-type coax connectors) and replaced every piece of coax in my station and made sure that all were wrench-tight. (I didn't count, but I'd guess about 25 cables). That provided another 10 dB or so (not measured, but looking at P3 traces while operating). Another issue I still need to address is bandpass filters on RX antennas. I often use my Beverages up to 30M. My K3 can handle the signal strength without damage, but while contesting, I hear very strong harmonics there. In one of the early chapters of his classic book, "Managing Interstation Interference," W2VJN advises us to begin by measuring the coupling between our antennas so that we understand the levels of crosstalk that can be present. It's easy to do that with a vector network analyzer like the DG8SAQ VNWA. [Note that antenna analyzers are NOT network analyzers -- they are single-port devices. The difference is that a VNA is a 2-port device, so it can measure BOTH impedance and the gain (or loss) between input and output ports.] We can, of course, make these measurements with gear as simple as an amplitude-calibrated RF generator and a calibrated voltmeter (anything from a scope to a spectrum analyzer). The VNWA 3e is a real bargain. It's full spec to 500 MHz, reduced spec to 1.3 GHz, and self-powers from the USB connection to your computer. I paid about $750 shipped to my home in W6 about 3 years ago for a unit with calibration kit. http://sdr-kits.net/VNWA3_Description.html 73, Jim K9YC _ Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Post contest season: TX antenna vs RXantenna cros-stalk. What do you do?
Good point. On 160 there was also a relatively nearby 829KHz AM BC station. The RDX PI4YLC Field-Day-style station used an OM-Power 6 BPF in its TX path. But no additional BPF or AM BCB HP filter in the RX path. A mistake I should have recognized. Thanks for the test procedure. Will use that additionally for sure at home and at any FD QTH in the future. 73 Mark, PA5MW -Original Message- From: JC Sent: Thursday, March 24, 2016 1:14 PM To: 'Mark van Wijk, PA5MW' ; 'william radice' ; topband@contesting.com Subject: Re: Topband: Post contest season: TX antenna vs RXantenna cros-stalk. What do you do? I was wondering what people do besides the obvious 'kill the TX antenna input during RX mode' ?<< There are several reasons why it is necessary to detune the TX antenna during RX, however disconnecting the center of the TX coax during RX on 160m is a MUST. If you don't understand the problem you never implement the solution. Some broadcast signal can reach -10 dbm or even 0 dbm. Most radios have very poor isolation and pin 1 problem on both the RX input and TX input. In order to open the center pin at the antenna feed point you need a fast vacuum relay to avoid hot switch. For an inverted L it will improve all RX antennas removing re-radiation noise from the TX antenna. Open the circuit between the transverter and the amplifier is a good idea. You need a fast relay but it can be small. Filters must be strong enough to hold at least 200w with low insertion loss. The test to know if you have this problem is simple, disconnect the RX antenna and use a 50ohms, shielded load to terminate the RX input. Tune on the AM band and if you hear strong BC signals coming from you TX antenna during RX with the RX port terminated with 50 ohms you have some homework to do. No carriers at all indicate that you have shield, grounding and choking in good shape, if you hear strong AM signals means that you have isolation and common node noise problems. If the BC signal can come in all QRN and other noise sources also can come in and raise the noise floor of the receiver. My station is quiet, I cannot detect any trace or light carrier doing the test above. Regards JC N4IS _ Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Post contest season: TX antenna vs RX antennacros-stalk. What do you do?
Hi Kees, That is what I successfully do at home, because my 160m vertical re-radiates to my RX antennes. But at the recent RDXC PI4YLC FD contest station both the 40 and 80m full-size deltaloops were not detuned or switched to GND or anything. The YL ops wanted to be able to listen to them as well as the separate RX antennes anyway. 73 Mark, PA5MW -Original Message- From: Kees Nijdam Sent: Thursday, March 24, 2016 11:05 AM To: Mark van Wijk, PA5MW Subject: Re: Topband: Post contest season: TX antenna vs RX antennacros-stalk. What do you do? Hi Mark, When receiving on my RX antennas, my transmit verticals are detuned by decoupling them from the feedline. A floating 1/4 wave verical is completely dead and not reradiating signals. Kees, PE5T -- From: "Mark van Wijk, PA5MW" <pa...@home.nl> Sent: Thursday, March 24, 2016 7:38 AM To: "william radice" <k4...@outlook.com>; <topband@contesting.com> Subject: Re: Topband: Post contest season: TX antenna vs RX antennacros-stalk. What do you do? Hi Bill, I think this is not what I meant here; I also do use BPF's and the Front End Savers. The problem is that while listening to your receiving antennas, there is also some signal from the transmit antenna getting through thanks to the internal cross-talk of your rig's TX/RX relay. I was wondering what people do besides the obvious 'kill the TX antenna input during RX mode' ? 73 Mark, PA5MW -Original Message- From: william radice Sent: Tuesday, March 22, 2016 2:05 PM To: topband@contesting.com Subject: Re: Topband: Post contest season: TX antenna vs RX antenna cros-stalk. What do you do? Serious multi-op contest stations face this issue all the time. Most use individual band filters and they almost completely eliminate the issue. At our station we used the Dunestar filters for operating positions on different bands. As for 160 I personally use the KD9SV "front end saver" and it does the job completely. BILL K4OWR On 3/22/2016 5:44 AM, Mark van Wijk wrote: Now that we are 'sort of in post contest season mode' and sharing some good ideas, there is another question: During recent Field-day setups I noticed severe cross-talk issues between TX antennas and the separate RX antenna circuits. For sure any TX/R relay circuitry offers roughly 50-65 dB dampening. So, during a contest with >S9+30 signals received on the large TX antennas (Deltaloop for 40m and 80m) these would still show up S1 - S4 on the FD station's K3 RX input. At home I normally de-tune my backyard TX antenna(switch to GND during RX) to avoid noise pickup at the RX antennas, so I never noticed this. Question 1: how do you manage the TX-RX cross-talk at your setup? - switch TX antenna to GND during RX - switch-in en external attenuator, so the cross-talk is below noise level, but you are still able to use the TX antenna during RX - any other solution? Question 2: is there any other basic circuitry or setup in a basic contest station which offer possible similar negative side effects? 73, Mark PA5MW _ Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Post contest season: TX antenna vs RXantenna cros-stalk. What do you do?
Hi Terry, I have no access to the K3's as they belong to someone else. But I learned there is no such thing as total isolation. Not even with the Frond end savers, unless they incorporate several relays in series. But I did check my TT ORION using the Elecraft XG3 generator; isolation is abt 65dB You do the math when you have 9+40 signals on a large antenna like a fullsize TX deltaloop on 40 & 80m 73 Mark, PA5MW -Original Message- From: Terry Posey Sent: Thursday, March 24, 2016 12:04 PM To: 'Mark van Wijk, PA5MW' ; 'william radice' ; topband@contesting.com ; Eric Swartz -WA6HHQ, Elecraft Subject: Re: Topband: Post contest season: TX antenna vs RXantenna cros-stalk. What do you do? Hi Mark - I have not experienced K3 TX/RX antenna isolation problems with my station configuration. I expect that if there is an isolation problem with your rig's TX and external RX antenna routing/switching, that problem would be nearly impossible to quantify using your station's TX and RX antennas. The rig's TX/RX isolation would need to be measured on the bench, using good laboratory grade equipment. Perhaps, Elecraft can provide a list of expected isolation values that were measured for each of the TX and external RX antenna routing/switching configurations possible with the K3 and K3S. Those measurements would surely have been done during the rigs' design performance verification tests. GL 73, Terry K4RX ++ Hi Bill, I think this is not what I meant here; I also do use BPF's and the Front End Savers. The problem is that while listening to your receiving antennas, there is also some signal from the transmit antenna getting through thanks to the internal cross-talk of your rig's TX/RX relay. I was wondering what people do besides the obvious 'kill the TX antenna input during RX mode' ? 73 Mark, PA5MW _ Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Post contest season: TX antenna vs RX antenna cros-stalk. What do you do?
Hi Bill, I think this is not what I meant here; I also do use BPF's and the Front End Savers. The problem is that while listening to your receiving antennas, there is also some signal from the transmit antenna getting through thanks to the internal cross-talk of your rig's TX/RX relay. I was wondering what people do besides the obvious 'kill the TX antenna input during RX mode' ? 73 Mark, PA5MW -Original Message- From: william radice Sent: Tuesday, March 22, 2016 2:05 PM To: topband@contesting.com Subject: Re: Topband: Post contest season: TX antenna vs RX antenna cros-stalk. What do you do? Serious multi-op contest stations face this issue all the time. Most use individual band filters and they almost completely eliminate the issue. At our station we used the Dunestar filters for operating positions on different bands. As for 160 I personally use the KD9SV "front end saver" and it does the job completely. BILL K4OWR On 3/22/2016 5:44 AM, Mark van Wijk wrote: Now that we are 'sort of in post contest season mode' and sharing some good ideas, there is another question: During recent Field-day setups I noticed severe cross-talk issues between TX antennas and the separate RX antenna circuits. For sure any TX/R relay circuitry offers roughly 50-65 dB dampening. So, during a contest with >S9+30 signals received on the large TX antennas (Deltaloop for 40m and 80m) these would still show up S1 - S4 on the FD station's K3 RX input. At home I normally de-tune my backyard TX antenna(switch to GND during RX) to avoid noise pickup at the RX antennas, so I never noticed this. Question 1: how do you manage the TX-RX cross-talk at your setup? - switch TX antenna to GND during RX - switch-in en external attenuator, so the cross-talk is below noise level, but you are still able to use the TX antenna during RX - any other solution? Question 2: is there any other basic circuitry or setup in a basic contest station which offer possible similar negative side effects? 73, Mark PA5MW _ Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Strange propagation
Can they add /RHR or such please? So I can choose if I want to make this kind of QSO. BTW, I require a remote solution for climbing Everest or participate in Car Racing. That is currently not possible from where I am sitting and I demand the option. 73 Mark, PA5MW -Original Message- From: Louis Parascondola via Topband Sent: Thursday, January 14, 2016 11:47 PM When a ham operates a remote station using his call sign that is within the continental US, it makes no difference. If a ham is operating at an alternate QTH he does not have to sign/X any longer. Those days are gone. SO even if you look him up it does not mean he is at that location. The rub comes in when you want credit for an award like WAS, so what credit do you get? I suppose he needs to know where the station is located so he can write it on a QSL card for your credit. -Original Message- From: Barry N1EU <barry.n...@gmail.com> To: topBand List <topband@contesting.com> Sent: Thu, Jan 14, 2016 5:06 pm Subject: Re: Topband: Strange propagation This is a BIG issue to grapple with. It would make sense to me that a callsign transmitted over the air should correspond to a station location in a publically viewable registry and if the location of the transmission deviates, the callsign needs to append /XX to reflect the station location. 73, Barry N1EU _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Strange propagation
Exactly my point. I find my fun in this hobby by (mutual) achievement. However, I will not try to dictate how others should have their fun. Still I have a personal choice in what kind of radio contact I prefer. But that solution will be outside a debate. Tom is also right on the spot. Turning 50 I find myself more and more into discussions where open, objective, factual discussion turns all too quickly into a bit of frustration and hence the whining. Some 20yrs ago I told myself not to go there. Sorry for that. cu in contest; lots of work to do for the next one. 73 Mark, PA5MW -Original Message- From: Herbert Schoenbohm Sent: Friday, January 15, 2016 3:00 PM To: topband@contesting.com Subject: Re: Topband: Strange propagation Climbing Mt. Everest is something of vast personal acheivement but land on top with a helicopter and having your picture taken to prove you were there is quite another. Herb Schoenbohm, KV4FZ _ Topband Reflector Archives - http://www.contesting.com/_topband
Topband: Where did OK0EV beacon on 1854kHz go?
Re-installing the RX antennas for this season, I noticed that OK0EV on 1854 kHz has disappeared. Anyone know what has happened? 73 Mark, PA5MW _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: CQWW160 New Rule!! ....good news
Robin, If you want to level matters and want no discussion (yes there has been a lot), then please refrain from doing it :) You say: This subject has been thoroughly beaten to death and hammered flat. Extensively. (much agree here ) There are folks out there who have decided that anything they don't happen to like or are not able to do themselves is bad for everyone and is a disaster for the hobby and for topband. To me that is : a) a bad wording/ personal opinion and b) an insult to those who apparently are in this bad category You say: There are folks out there who embrace new capabilities and work hard to make the best use of them To me that is: a) telling that the sun shines quite often b) implying this group is the 'good people' * I am sure that you will agree that only new arguments, facts etc can support a renewed debate. My personal message: Contesting is about fun and ensuring as much equal fun to all participants as is reasonable possible. Thanks to different categories and updated rules, also based on listening to the crowd, the CQ organisation shows it cares. Please support the team. 73 es hpe to work you in the contests! Mark, PA5MW _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Use of Remote Receivers During 160 Meter Contests
Hi Tree, all, I believe there 's a third basic issue here: 3. The change of the leveling playing field Adaptions of shortcuts introduces new opportunities within the rules. ***VERY TRUE With the new Remote RX possibility, to be competitive I am forced to do the allowed upgrade and add two RX sites: ***Some will challenge you on the forced to, but you are very right here. Just wait and see it happening. - One to the max west border right near the sea. This allows for easier working of more QRP stations from the British Islands and secondly it delivers a propagation advantage towards W/VE. - The second one will be at the south border, up in the hills at a top location which is even more quiet than my current QTH and offers the right downslope to create superb take-off from an 8-circle or so. ***Clear - Remote RX sites can be a strategic advantage - One will need to add one or more remote RX sites after this to keep up - Both the geographical and 'nearby sea' advantages apply more to European countries than USA - Boundary limitations can and probably will be stretched snip... Other countries might have less available strategic geographical opportunities. *** We call that an 'unbalance in the leveled playing field' Now let's see how many stations will (have to) upgrade in the next two years... *** I think this has happened often in the past after adoption of new techniques. I do recognize the standpoints on cheaters will always cheat no matter what And it is difficult here to avoid the tendency to suspect the devil after every corner or talk conspiracy etc. But the implications allowing Remote RX during 160m Contesting is more than the somehow mutual agreed +3dB effect we see at other disciplines... Please recognize the challenge of contesting on Topband. It is difficult in noisy areas; you will have to find a way to work around it and still enjoy the contest from home (MY situation). Going for gold involves you have to walk that extra mile... 73 Mark, PA5MW _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Use of Remote Receivers During 160 Meter Contests
QSL ! Congratulations on the achieved remote RX/TX station setup. I tend to regard my 23x28ft backyard quite a challenge too for Topband, nevertheless found my way too.. 73 Mark, PA5MW -Original Message- From: Cecil Sent: Wednesday, March 18, 2015 1:31 PM To: W7RH Cc: topband@contesting.com Subject: Re: Topband: Use of Remote Receivers During 160 Meter Contests Excellent application of a remote stationI see no problem with that. Cecil K5DL Sent using recycled electrons. On Mar 17, 2015, at 10:34 PM, W7RH midnigh...@cox.net wrote: I almost gave up Amateur Radio living and working here in Las Vegas, where the average subdivision lot is 4000sqft or less. Not to mention CCRs. A city acre these days is just shy of $1-million. My station is network controlled to my Arizona ranch property 200 miles away. I make it very clear that all contacts are from Arizona and not from Nevada on QRZ. It's been that way for ten years. Any real contest efforts are made on site. There have been times when weather prohibited me from getting into the remote site safely. In that case I bag the test and make a few random remote QSOs. All operation is from the remote and meets the radius rules for receivers and transmitter. Quote Mike W0MU, You need to hear my transmitter from your location and I need to hear yours from mine. I am a proponent of remote radio where ALL of the receiving and transmitting is done from the same SINGLE remote site with the same distance radius for that equipment to be in. Seems to me this is a fair and equitable solution. Enforceable, probably not. -- W7RH DM35OS Only two things are infinite, the universe and human stupidity, and I'm not sure about the former. Albert Einstein _ Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: DSP and Latency
Audio latency 'differences' can be shown in the shack already; my TT ORION vs a K2 vs a Perseus SDR show small but significant time differences. Especially the SDR is 'behind'. 73 Mark, PA5MW _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Use of Remote Receivers During 160 Meter Contests
Well said. Thank you! 73 Mark, PA5MW _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Use of Remote Receivers During 160 Meter Contests
It is OK having built successfully mastered a remote Rx site. But please, during a contest (only), walk the extra mile and take your butt to the remote location as well. If you can manage building such a remote station, a TX antenna will be possible too. 73 Mark, PA5MW From: John Crovelli Sent: Sunday, March 15, 2015 8:03 PM To: Mark van Wijk, PA5MW ; topband@contesting.com Subject: RE: Topband: Use of Remote Receivers During 160 Meter Contests Mark, Unless others speak up, N2NT is inclined to change the rules and allow remote RX systems. So the time is NOW to make your thoughts known on the reflector. 73, John _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: New beverage
I find the center/off-center feedpoint very attractive for those of us cramped in between on a city lot. You can hide a BOG-like coax along the neighbors property lines for 200 to 500 ft in two directions, whatever suits you. The termination adjustment is done at your shack. Much preferred over doing it on any open/public property, in the dark etc.. What I'm missing is detailed info on the installed height of this reversible beverage and the involved effects at typical BOG heights from 0 to 1/3 foot or so. 73 Mark, PA5MW On 17-5-2013 20:44, Herb Schoenbohm wrote: Good quality flooded RG-6 laying on the ground (BOG) might be an easy install like before contests at some locations. However I have no idea on how this would perform compared to an elevated version. If the directivety is maintained and the S/N ratio is still usable then such a concept would be worth considering. Such an installation might also be considered for DX-peditions where supports for a normal Beverage are just not available. Even for a short term use a normal consumer grade 1000 foot roll of RG-6 is competitive with the same amount of #12 or 14 THNN and certainly more competitive than 1000' of higher grade ladder line. It is nice however having a vendor who offers a unique of the shelf solution and it would nice to get some feedback on A/B checks with the conventional Beverage. Herb, KV4FZ On 5/16/2013 1:57 PM, Tom W8JI wrote: After looking at their literature it appears to me that this is nothing more then two beverages, one in each direction, with the feed unit being, perhaps, a couple relays. I don't see the merit in using RG6 as the beverage wire: its heavy, will need more supports, and compared to other solutions, perhaps more expensive. And the fact that the feed unit can be placed anywhere along the antenna? I must be missing something clever because all that would seem to do is make one direction's wire longer and the other shorter? Since the antenna is a transmission line, with suitable end and center transformers, the feedpoint can be placed anywhere and the full length used. With different transformers, any reasonable type of transmission line can be used. All good topband ops know how to put up a beverage at night. _ Topband Reflector All good topband ops know how to put up a beverage at night. _ Topband Reflector All good topband ops know how to put up a beverage at night. _ Topband Reflector
