Re: Topband: Twist a Flag into a Bowtie?
What kind of improvement in performance is observed by providing a better ground, JC? And, where would a ground wire (counterpoise?) be connected with the DHDL antenna system? Thanks and 73, Nick VE7DXR At 15:38 11-12-16, JC wrote: Hi Mike and Don The DHDL as well as few other antennas, has a hidden component. The bottom wire parallel to the ground is a transmission line, actually, any antenna parallel to the ground is a transmission line. A beverage antenna a is good example. The ground is the second leg of the transition line, for a K9AY loop it is the same, the bottom wire and the ground form a transmission line. The transmission line allows the Resistor and the Transformer to be moved to the center of the loop. The VE3DO loop is also exactly the same. The same way, a DHDL antenna uses the ground to phase the two loops, if you elevate the DHDL high far from the ground, the patter changes. The DHDL is a ground dependent antenna, improving the ground with a ground wire bellow the antenna can fix some ground problems. My two cents. 73's JC N4IS -Original Message- From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Don Kirk Sent: Sunday, December 11, 2016 10:13 AM To: D Michael Cc: topband Subject: Re: Topband: Twist a Flag into a Bowtie? Hi Mike, Funny you should ask that. A few months ago (September) I was looking at building a smaller size DHDL using 4Nec2, and there were a few things I saw that I thought needed improvement (I saw things in the full size DHDL that I thought needed improvement, it was not limited to the small size DHDL I was trying to design). Then I started to play around with the location of its termination resistor as well as routing of wires, and wound up with what I called the Terminated Bowtie. I built one in my backyard but my yard is pretty small and the antenna was too close to existing objects (house and chain link fence) and I did not realize the S/N improvement that I expected, nevertheless based on modeling it looks like a winner (9.5 RDF and front to back ratio versus elevation angle very robust). I have attached the preliminary document I put together a few months ago for you and others to view (it might not be perfect, but should convey my design / thoughts). I would love someone to build one of these out in the open to see if the real life build provides results similar to the 4Nec2 modelling I did. Note: Bringing the feedline away from the antenna properly needs to be looked at to minimize distortion of the pattern. As I recall the feedline should not drop down to the ground until it's at least 5 feet away from the antenna, and a greater distance would be best. The feedline should also use choke with ground rod similar to what's recommend for other RX antennas we use (beverages, flags, etc.) to block common mode noise from making its way to the antenna feedpoint. Let me know what you think. It might not work, but sure looked good on paper. 73, Don (wd8dsb) On Sun, Dec 11, 2016 at 9:41 AM, D Michael wrote: > > > I have two flag rx ants and I was looking at the DHDL and DK6ED Double > Loop System V2 and wondering if twisting my Flag rx ants into Bowties > would improve the forward pattern and make them narrower with better > front to back. > I would just ""flip"" the termination resistor end to form a loose > BOWTIE shape. > I have no ant modeling software so I have no way to ponder this change. > Maybe someone could model doing this. > TNX es 73, Mike W3TS > _ > Topband Reflector Archives - http://www.contesting.com/_topband > _ Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband Nick Hall-Patch Victoria, BC Canada _ Topband Reflector Archives - http://www.contesting.com/_topband
Topband: Stew Perry TopBand Challenge 21 is about Here
Greetings Radio Ruffians with a TopBand Bent, The anticipation is palpable as time draws near for the start of the 21st Running of The Stew Perry TopBand DX Challenge sponsored by the multitude of Amateurs who make up The Boring Amateur Radio Club. The contest is Dec 17/18. That is this weekend coming up, for those of you that need reminders like to remember an anniversary, put gas in the vehicle or to breathe. The rules for this contest are different. Please navigate to http://www.kkn.net/stew/ and see how they are different. Another unique aspect of The Stew is that The Boring Amateur Radio Club does not specify categories to win handsome plaques. You, the combatants do that. Yes, anyone who thinks up a stellar category and remits $60 or $63 to us will join the radio stalwarts listed below who are stoking the fires of competition. KL7RA Top # of QSOs by a S/O N0TT Top Score, S/O, <21Y/O, > 200 QSOs K7CA Longest DX, S/O, Low Power from Zone 3 K7CA Top Score S/O CQ Zone 19,24,25,27,28 or China KH6LC VK/ZL Challenge- Top S/O VK-ZL AA6VB Top Score Big City >50K, Little Pistol <100W AA6VB Top Score Base Loaded Vertical < 60' tall N6TQ/A25TQCalifornia Dreaming- Top # of QSOs with Cal VK0EK Stations by a non-California station Rochester DX Assoc Top Score,S/O, L-P, Outside N. America UX1UATop # NA + SA QSOs by Zone 16 station K7FL Top Score 100% Search and Pounce K9JWV/WC7STop QRP Score,West of Mississippi,wire antennas Dr. Beldar-L1AR Top Score,S/O, Temporary Antenna erected > Dec.3 (All parts of temporary antenna including radials must be installed after Dec. 3, 2016. This antenna must be the only antenna for TopBand at the station and may be left erected because as we all know "temporary" means "until I die") KR2QGolden Log Award K2PO Top Score, S/O, Low Power, Zone 3 N6TR Top Score,S/O, Hi Power from CN Grid Field W2GD Team Top # QSOs, NA/SA by EU Station K6ND K6SE Memorial- Top Score, S/O, World WA6CDRN5IA Memorial- Top # of Grids Worked WA8WZG Top Score, S/O, by a 6 character call (Example- KA2BFD or WD6XYZ) W7RH Top Score, Low Power Asia K1EPTop Score (>100QSOs) by YL or XYL VE9AA Yr Trees Ants? If you have your TX wires in the trees or even attached to 1 tree and your adjudicated score is closest one to tree tree tree tree (3,333), then you win this plaque VK6VZ VK6HD Memorial- Top Score by N. hemisphere station working S. hemisphere stations. Winner gets a new, fresh Flying Doctors of VK baseball hat This list grows but will become even longer after you dream up a contesting category. Just email me with the particulars so we may flesh it out as some prior plaque proposals were too obtuse, couldn't be performed by any one of our species or just a tad obscene. There will be one or two more postings of the categories and sponsors right up until and through the start of The Stew so don't delay! Also those who haven't sent off their check or PayPals for their plaque sponsorship yet should not delay either., Also follow Stalwart's VK6VZ's example and go fire up your system tonight so you won't be modally morose when the only thing that happens when you call CQ is that you open and close the neighbor's garage door with a distinctive cadence. 73 and I remain, Lew w7ew The Boring Amateur Radio Club Committee on Participation w...@arrl.net _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Bowtie Flags
Thanks Bruce. Sounds like practical constraints led to a worthwhile outcome. 73 Nick VE7DXR At 17:21 12-12-16, K1FZ-Bruce wrote: Nick, Although I did not measure it, the front to back, and front to side is better, overall more quiet. It is receiving toward the Caribbean. Europe, and USA stations, are lower in signal strength. Can often work Caribbean and South American stations through a small pile up when they are not working split. In my case it was a worth while change. The original plan was to be able to drive my car under it. 73 Bruce-K1FZ On Mon, 12 Dec 2016 16:35:14 +, Nick Hall-Patch wrote: What specific improvements did you note when the Delta was raised Bruce? Thanks, Nick VE7DXR At 16:23 12-12-16, K1FZ-Bruce wrote: Dennis, Is there a photo or sketch available of your antenna anywhere by email ? Note: Height above ground helped a lot when my receiving Delta antenna was re-installed higher. The bottom wire went from 3 feet up to ~6 feet at my QTH. 73 Bruce-k1fz http://www.qsl.net/k1fz/flag_antennas.html _ Nick Hall-Patch Victoria, BC Canada _ Topband Reflector Archives - http://www.contesting.com/_topband Nick Hall-Patch Victoria, BC Canada _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Bowtie Flags
Nick, Although I did not measure it, the front to back, and front to side is better, overall more quiet. It is receiving toward the Caribbean. Europe, and USA stations, are lower in signal strength. Can often work Caribbean and South American stations through a small pile up when they are not working split. In my case it was a worth while change. The original plan was to be able to drive my car under it. 73 Bruce-K1FZ On Mon, 12 Dec 2016 16:35:14 +, Nick Hall-Patch wrote: What specific improvements did you note when the Delta was raised Bruce? Thanks, Nick VE7DXR At 16:23 12-12-16, K1FZ-Bruce wrote: Dennis, Is there a photo or sketch available of your antenna anywhere by email ? Note: Height above ground helped a lot when my receiving Delta antenna was re-installed higher. The bottom wire went from 3 feet up to ~6 feet at my QTH. 73 Bruce-k1fz http://www.qsl.net/k1fz/flag_antennas.html _ Nick Hall-Patch Victoria, BC Canada _ Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Bowtie Flags
What specific improvements did you note when the Delta was raised Bruce? Thanks, Nick VE7DXR At 16:23 12-12-16, K1FZ-Bruce wrote: Dennis, Is there a photo or sketch available of your antenna anywhere by email ? Note: Height above ground helped a lot when my receiving Delta antenna was re-installed higher. The bottom wire went from 3 feet up to ~6 feet at my QTH. 73 Bruce-k1fz http://www.qsl.net/k1fz/flag_antennas.html _ Nick Hall-Patch Victoria, BC Canada _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Bowtie Flags
Dennis, Is there a photo or sketch available of your antenna anywhere by email ? Note: Height above ground helped a lot when my receiving Delta antenna was re-installed higher. The bottom wire went from 3 feet up to ~6 feet at my QTH. 73 Bruce-k1fz http://www.qsl.net/k1fz/flag_antennas.html On Sun, 11 Dec 2016 22:00:12 + (UTC), Dennis W0JX via Topband wrote: Mike and Don, I have been using an expanded version of a DHDL here since November 2011. I was forced into going this way because the neighborhood around me has become very noisy and the antenna seems to be less susceptible to noise than my other antennas. I call it the Dual Flag array. I essentially expanded the DHDL deltas into the shape of a flag. My flags are large, approximately 24.5 feet tall and 32.5 feet long and separated by three feet. The wires cross in the middle rather than at the bottom so the flags are 180 degrees out of phase. They are similar to a Waller Flag antenna in some respects. My dual flag antenna is supported in the middle by a 31 foot pole made up of military fiberglas poles and the ends are supported by two trees. The bottom wire is 6 feet above ground. The feed transformer was wound on a binocular core with two turns on the primary and 7 turns secondary giving 918 ohms when fed with 75 ohm cable. I think my load resistor is 1290 ohms at the back of the second flag. You can put a variable pot there and tune for best F/B but that is not necessarily the best RDF. I have found my dual flag array to be the quietest RX antenna in my RX system. It works very well on 160 through 40 although the pattern turns broadside on 40 meters. It beats all my 450 foot beverages hands down and is a great compliment to my HiZ 4 square which is now on the main RX of the K3 with the dual flag on the sub RX. You can also build a switching system to reverse directions but the circuit is rather complicated so I have two of these dual flag antennas pointed in different directions. I manually switch directions by moving the transformers and loads around using banana jacks when really need to grab a new country. As with all antennas of this type, an effective common mode choke at the feed point is an absolute must.SInce a rotatable version would be very difficult to build and support on a tower, the next logical step would be a smaller true Waller Flag like NX4D's Big Waller. I must give credit to George AA7JV who modeled this antenna for me and provided the inspiration through his TX3A DHDL RX antenna. 73, Dennis W0JX _ Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband
