Re: Topband: An oddball question about a BOG.
ZL3IX I think by accident had a fence with a break in it. My not working Beverage was 4'up over a continuous welded wire fence. Then some NEC2 modeling of a 600' Beverage 6' above a continuous 3 wire (wires at 2,3, & 4') barb wire fence, showed poor F/B. Mine was worse over the welded 6"x 6" mesh fence (it's been a while but I recall none). Some NEC2 modeling (just re-confirmed with NEC4) showed that breaking the fence into three 200 ft insulated sections, for the length of the Beverage solved the problem. More fence continuing off the ends didn't matter. I didn't build it before I moved. Having seen a good selection of barb wire fences, many probably don't have electrical continuity, including many of mine. Since there seems to be wide agreement and sound engineering reasons that Beverages don't work over high conductivity ground, so I trust that modeling. Regarding NEC not working near the the ground, the EZNEC manual claims NEC2 is ok within a few wire diameters. Neither NEC2 or 4 will work really close to or with any part of the wire in the ground plane. N6LF did some very nice work confirming how NEC4 was accurate for buried wires with some very good experimental data. He includes some comments about ground variability. https://rudys.typepad.com/files/qexjul-aug-2016-bog.pdf Re MikeK's adventure with loading inductor permeability made variable with DC current bias of the B-H curve, I think it's an interesting idea. I suspected he was trying to do that and hope he finds a way to make it work. Grant KZ1W On 8/24/2019 10:52 AM, Mike Waters wrote: As long as the fence is pointed in the right direction. :-) www.w0btu.com/Beverage_antennas.html#Misc_Beverage_antenna_notes On this page, there are some links to ZL3IX (?) experiences with his Beverages mounted at different heights above metal fences. 73, Mike www.w0btu.com On Sat, Aug 24, 2019, 12:47 PM Chuck Dietz wrote: 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 _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
Re: Topband: BOG questions
This is interesting. Thanks for sharing, Mikek. I put down 200 feet of insulated wire BOG pointed at EU, just set it down on the ground...sometimes over a fallen small tree but almost always within 12 inches of ground. I fed it with 75 ohm TV cable. I did not terminate it, and I used a KD9SV transformer and added a pre-amp right next to it. It picked up EU signals sooner than my HiZ or dipole at 60 feet that was broadside to EU. It worked on 80, though not as well. On 160 it was highly susceptible to AM BCB. I started listening in October. Something changed in March. Suddenly it went deaf. Not sure if it was because of all the rain in the winter, or the sprouting of the grasses. I have not been out into the field, because it is covered with thorny bushes. I already ripped up and scarred my shin badly when I moved 2 of the HiZ vertical elements in April. It was not painful, but it looked like my shin was in a knife fight or that I was attached by a big dog. Anyway, I am wondering why the bog went so deaf suddenly. I will try it again when we get into November. Mark Lunday, WD4ELG Greensboro, NC FM06be wd4...@arrl.net http://wd4elg.blogspot.com SKCC #16439 FISTS #17972 QRP ARCI #16497 Topband Reflector _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
Re: Topband: 160m Season Has Begun Here
Sig One of the few things I miss about living in New England (don't miss it enough to own a snow shovel again), Is the 160/80 path to EU My theory is LA/SM/OH and OJ0 all have a really "long" gray line. right now. What time did you work OJ0O ?� I just finished my "prototype" N/S R-BOG today so am looking forward to losing some sleep 8^) WE too have worked a couple of EU's and the 5T5 in the last week even down here in FL,� South America (LU/CE/CX/ YV and PY) are all nightly occurrences for the last few weeks Dave NR1DX On 8/24/2019 4:13 PM, k1zm--- via Topband wrote: Hi There Two days ago I hooked up the 160m antenna and can report that the season is off to a start - at least here it is. Two pages of Eu stations on CW, 5T5 on FT8 - and OJ0O last night also on CW - RST 599 on 1824. For some reason the LA's and SM's and OH's are the best signals at this time of year - dunno why - but all are 599 while other Eu signals are down in the 579 region or so. Time to start looking at 160m at sunset again I guess. GL to all this season - it should be really good given the current state of the solar cycle. 73 JEFF �K1ZM/VY2ZM Jeff BriggsDXing on the Edge: The Thrill of 160 Meters�Available worldwide through�BookBaby,�Array Solutions,�DX Engineering,�Radio Society of Great Britain, &�Amazon _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector -- Dave manu...@artekmanuals.com www.ArtekManuals.com --- This email has been checked for viruses by Avast antivirus software. https://www.avast.com/antivirus _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
Topband: Modeling close to earth ( was Odd-ball question)
Chuck et all It is well documented that the the NEC-2 based programs leave something to be desired� with wires on or very near the ground, This includes most of the EZENEC� family and MMANA-G� Purportedly NEC-4 ( there is a Ezenec version which runs with NEC 4 engine ... not a cheap date) does deal with the near earth problem . How close is "Close" is a matter of conjecture. A friend of mine and I have been working on building and modeling vertical antennas ( Verticals, Inv-L and T's) for 160/80/40 with ELEVATED NON-RESONANT radials at 3' and 6' (google "K5IU Elevated Radials") . The good news is at 3' and above both NEC 2 and NEC 4 models agree within 5% or better.� We have not done any comparisons below 3' Dave NR1DX On 8/24/2019 1:41 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 -- Dave manu...@artekmanuals.com www.ArtekManuals.com --- This email has been checked for viruses by Avast antivirus software. https://www.avast.com/antivirus _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
Topband: 160m Season Has Begun Here
Hi There Two days ago I hooked up the 160m antenna and can report that the season is off to a start - at least here it is. Two pages of Eu stations on CW, 5T5 on FT8 - and OJ0O last night also on CW - RST 599 on 1824. For some reason the LA's and SM's and OH's are the best signals at this time of year - dunno why - but all are 599 while other Eu signals are down in the 579 region or so. Time to start looking at 160m at sunset again I guess. GL to all this season - it should be really good given the current state of the solar cycle. 73 JEFF K1ZM/VY2ZM Jeff BriggsDXing on the Edge: The Thrill of 160 Meters Available worldwide through BookBaby, Array Solutions, DX Engineering, Radio Society of Great Britain, & Amazon _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
Re: Topband: An oddball question about a BOG.
My own experience is that a fence does not degrade the Bev pattern too much as long as the Bev is sufficiently high above the fence wire. I mount my wires about 3 m above the fence. I have never modelled an inductively-loaded Beverage, but my intuition is that it will not perform any better than an unloaded wire of the same physical length. The pattern of the Bev is generated by virtue of the fact that it is excited by different parts of the wave front, the relative phases of which depend on the direction from which the front arrives. If the wire itself is too short this desirable decorrelation is not achieved. At HF we can inductively load a yagi to make its elements physically shorter at resonance, but we still need the same spacing between the elements if we want to duplicate the radiation pattern of the unloaded yagi. I suspect that the Beverage would behave in a similar fashion. 73, Greg, ZL3IX On 2019-08-25 05:52 a.m., Mike Waters wrote: As long as the fence is pointed in the right direction. :-) www.w0btu.com/Beverage_antennas.html#Misc_Beverage_antenna_notes On this page, there are some links to ZL3IX (?) experiences with his Beverages mounted at different heights above metal fences. 73, Mike www.w0btu.com _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
Re: Topband: An oddball question about a BOG.
As long as the fence is pointed in the right direction. :-) www.w0btu.com/Beverage_antennas.html#Misc_Beverage_antenna_notes On this page, there are some links to ZL3IX (?) experiences with his Beverages mounted at different heights above metal fences. 73, Mike www.w0btu.com On Sat, Aug 24, 2019, 12:47 PM Chuck Dietz wrote: > 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.
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.
Good point, Chuck! You are absolutely right. I would have modeled it above the ground, at least at first. 73, Mike www.w0btu.com On Sat, Aug 24, 2019, 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. >> >> _ 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: An oddball question about a BOG.
The trick is to take the dc control winding and it's inductance out of the antenna circuit, which I think can be done with a large bypass capacitor. Here's a simple drawing. The BOG goes to antenna in, through the .47uF cap (Xc=.67ohms at 500kHz, 0.1 ohm at 4Mhz) through variable inductor, (the toroid) (0uH to 100uH) and the antenna out to the BOG, 30ft later is another one, nine required. https://www.dropbox.com/s/f6w7zk74azjtvdc/saturable%20core%20inductor%20db.jpg?dl=0 >I suspected you had this idea in mind. Unfortunately, a second wire will kill the gain and pattern. Beverages don't work over wire fences (I proved this at my ranch) or salt water or other conductive surfaces. So you need to find a design (inductor) that the antenna wire can also be the current source. I'm confused by the answer. My idea was working at eliminating a control wire to each inductor wire, That's why I run the current through the antenna wire. Ahh, but, I do have a second wire, it is at the end of the bog. Is that the pattern killer? Can I optoisolate the DC control so the wire is isolated? I had a variable resistor at the end of my previous BOG and it did not kill the pattern. That required a second wire at the end of the BOG. But it used a Vactrol that isolated the antenna from the control. Mikek _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
Re: Topband: An oddball question about a BOG.
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
Topband: An oddball question about a BOG.
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
Re: Topband: 160 meter antenna possibilities
Byron, I would go with the T (and a good radial field). George, AA7JV/C6AGU On Sat, 24 Aug 2019 14:14:13 + (UTC) Byron Tatum wrote: Hello- I hope I do not intrude too much here for a little advice about 160 meter antenna choices. I am getting settled in to my new QTH and am in process of getting antenna systems put up. I have a 30' x 50' metal shop building, the 50' length running east/west, sitting on about 4 acres behind the house available for antennas. There is a 130' tower off NW corner of building about 45' out, and a 140' tower sitting 20' out away the south wall of building, centered on the buildings 50' wall. The towers are about 110' apart. I have 5 total runs of 1-5/8" heliax plus other rotor, control and smaller feedlines all coming into the building from these two towers; the cables are entering building about 13' above ground. I operate VHF/UHF a lot, but want a decent 160 meter antenna. The 2 towers will have mostly 144, 222, 432, 1296 yagis plus 40 meter rotary dipole. The tower guy wires are broken up with insulators in 27' segments. Eventually I plan to put up a 160 meter vertical out in the open area but for right now I am looking for suggestions on what I can hang off of one of the towers. I have considered an inverted-V as I can fan the legs out pretty far/high to get a decent apex angle. I have considered an inverted-L but really do not want to have the several radials in the way (if I go above ground) or to do a more extensive ground radial system around building/towers areas. I have considered a compressed delta loop, fed 1/4 wave down from apex for vertical polarization. Of course, shunt feeding a tower is out of consideration due to feedlines coming off of towers about 20' up. I was considering running a heavy dacron cord from the top of one of the towers, making a span out of about 250' out to a support around 40'-50' tall. About 140' out I would have the top loading wire for a "T" vertical antenna. The top loading wire would be slanted but I believe that is not too bad a compromise. The vertical would be in the clear and I could put in a really good radial system. I believe I could get about 80' height of vertical to "T" wire center. Possibly this could be a more permanent 160 meter transmitting vertical. Just open for suggestions.Thanks, Byron W5FH _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
Topband: 160 meter antenna possibilities
Hello- I hope I do not intrude too much here for a little advice about 160 meter antenna choices. I am getting settled in to my new QTH and am in process of getting antenna systems put up. I have a 30' x 50' metal shop building, the 50' length running east/west, sitting on about 4 acres behind the house available for antennas. There is a 130' tower off NW corner of building about 45' out, and a 140' tower sitting 20' out away the south wall of building, centered on the buildings 50' wall. The towers are about 110' apart. I have 5 total runs of 1-5/8" heliax plus other rotor, control and smaller feedlines all coming into the building from these two towers; the cables are entering building about 13' above ground. I operate VHF/UHF a lot, but want a decent 160 meter antenna. The 2 towers will have mostly 144, 222, 432, 1296 yagis plus 40 meter rotary dipole. The tower guy wires are broken up with insulators in 27' segments. Eventually I plan to put up a 160 meter vertical out in the open area but for right now I am looking for suggestions on what I can hang off of one of the towers. I have considered an inverted-V as I can fan the legs out pretty far/high to get a decent apex angle. I have considered an inverted-L but really do not want to have the several radials in the way (if I go above ground) or to do a more extensive ground radial system around building/towers areas. I have considered a compressed delta loop, fed 1/4 wave down from apex for vertical polarization. Of course, shunt feeding a tower is out of consideration due to feedlines coming off of towers about 20' up. I was considering running a heavy dacron cord from the top of one of the towers, making a span out of about 250' out to a support around 40'-50' tall. About 140' out I would have the top loading wire for a "T" vertical antenna. The top loading wire would be slanted but I believe that is not too bad a compromise. The vertical would be in the clear and I could put in a really good radial system. I believe I could get about 80' height of vertical to "T" wire center. Possibly this could be a more permanent 160 meter transmitting vertical. Just open for suggestions.Thanks, Byron W5FH _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
Re: Topband: Fan dipole ruins 160 rx ?
Ciao Rik, I don't think fan dipole would contribute to 160 receiving, on the other hand, 160m legs will decrease useable bandwidth of 80 & 40m dipoles. Have been there, done that! 73, Mirko, S57AD V V sob., 24. avg. 2019 ob 08:08 je oseba Riccardo Negro napisala: > Hi all, no experience to share on the subject ? > Thanks. > Rik, IK2CAW > > Inviato da Samsung Note. > _ > Searchable Archives: http://www.contesting.com/_topband - Topband > Reflector > -- Mirko S57AD _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
Re: Topband: Fan dipole ruins 160 rx ?
Hi all, no experience to share on the subject ? Thanks. Rik, IK2CAW Inviato da Samsung Note. _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
