Topband: VO1HP FCP Inv L and Kitchen Oven
The Inv L FCP continues to perform. After a nice long hot summer here which is unusal here I was on last night around 0230 and worked K6ND, WJ3A, G4EIM. LY2OU, UY0ZG. While operating I started hearing at regular intervals somewhere of in the distance beep beep pause beep beep ...upon investigation I found the kitchen oven had turned itself on and was awaiting further instructions from the keypad. I was running about 600w and the flat-top of the L runs more or less over the kitchen area. I reread the RFI article re kitchen ovens in May 2012 QST and my first reaction was to try and place by-pass caps as described in the artcile. Howevere I thought I would try the simplest thing first. This morning I was able to place two snap on chokes of #43 material over the 240V wire inside the access panel at the back of the stove. The 1/2inch hole in the cores is not big enough to snap over the cable as it enters the stove. So I removed the plug from the wall and removed the access panel of the stove. There was enough room in the area to accommodate two snap on chokes -- i ran two wires through one core and one through another. There was just enough space to accomodate the cores. Upon testing at 600-700W the oven appears to be unaffected now. hopefully it remains thus. The old inv L and on the ground non-uniform and erratic radial system did not cause this issue so do I conclude that the effective radiated field from the FCP Inv l is that much stronger? Yesterday I also did some more work on the FCP ...when I initially built it I used 1/2inch pressure treated wooden spacers and tie wraps. Yesterday I replaced the those spacers with 1/2inch PEX (HDPE material) water pipe painted black. These spacers appeared to cause a slight shift in the SWR curve for the L...raising somewhat away from 1800khz. I am wondering about this material and whether its the right stuff to use? By the way the oven model Jenn-Air JES8850ACB ( same number for Maytag) 73 Frank VO1HP ___ UR RST IS ... ... ..9 QSB QSB - hw? BK
Re: Topband: 160m from 5X
Hello Nick, nice to read you here and nice to know that you are on the way to put 5X on the TopBand. See you on the air, to complete our band slots on 80 and... 160. I do not give you any tech-advice because am novice too :), just my GL 'n see you there. 73 Alessandro, IZ5MOQ DX'ing between the mountains! - Original Message - From: Nick Henwood n...@henwood.demon.co.uk Sent: Tuesday, August 28, 2012 11:24 PM Subject: Topband: 160m from 5X I have been v QRV from 5X in past 5 years. ___ UR RST IS ... ... ..9 QSB QSB - hw? BK
Re: Topband: VO1HP FCP Inv L and Kitchen Oven
The old inv L and on the ground non-uniform and erratic radial system did not cause this issue so do I conclude that the effective radiated field from the FCP Inv l is that much stronger? Hi Frank, When we confine a counterpoise to a small area, especially if we cancel the magnetic induction field, voltage and resulting electric induction field levels go way up. There just isn't any free lunch, no matter what the sign on the door says. When convenient, we often attribute increased problems to better performance without regard to 20 other bad things that could be at work. My wife does that with her occasional crispy blackened casseroles. Yesterday I also did some more work on the FCP ...when I initially built it I used 1/2inch pressure treated wooden spacers and tie wraps. Yesterday I replaced the those spacers with 1/2inch PEX (HDPE material) water pipe painted black. These spacers appeared to cause a slight shift in the SWR curve for the L...raising somewhat away from 1800khz. I am wondering about this material and whether its the right stuff to use? Like the increased RFI, no one really knows what causes what without some reasonable testing or evaluation. What we do know, without a doubt, is the less spread out the counterpoise (or antenna) the more concentrated fields become. I would expect any change in spacing or dielectric to have an exaggerated effect on stub tuning (the folded counterpoise is a stub with common mode current) compared to cases where there isn't such an intense electric field. It all makes sense for multiple reasons. The question is, how much of what. If we took a big antenna and made it into a 20 foot long antenna, no matter how we did it, we would expect more sensitive tuning and higher voltages and/or currents. We would expect increased sensitivity to close surroundings. Why would we expect anything different in this case? The very fact it needs an isolation transformer with high voltage insulation tells us we have very large localized electric fields. Logically, we should expect all that comes with those voltages. 73 Tom ___ UR RST IS ... ... ..9 QSB QSB - hw? BK
Re: Topband: Using the K2AV folded counterpoise at VK6VZ
Short Version: VK6VZ wrote: [snip] ... a Marconi-T with a 66-foot vertical section over about 30 60-foot to 100- foot radials, had proved relatively ineffective... So far the results with the 3/8 wave inverted-L ... and the folded counterpoise, fed via [isolation transformer] ... have been startling to say the least. For the first time with a Marconi antenna from this location, I can work just about anything I can hear with similar reports. ... Having a 100 foot rather than 66 foot vertical section is clearly a big help ... the only reason I have this ... vertical section is because of being able to site the antenna [where it's] impossible to put down a radial field ... along one side of the half acre block here. [snip] G'day! Thank you Steve for posting your results. In the Long Version: 1) A NEC4 evaluation of Steve's old Marconi T, supporting Steve's magnitude of change. 2) Let's go visit some small lots. 3) 3/8 wave inverted L over an FCP, NEC4 compares it to reference gold standard vertical over average dirt, partly explaining Steve's success. --- Long version: Thank you, Steve, for sharing on the reflector your positive experience with a 3/8 wave end-fed over FCP. I think there is a lot about restricted circumstances that some either don't understand or find hard to identify with. Your experience is remarkably similar to mine, and to that of many others. You said antenna A had to be down to erect antenna B. Use of the FCP as the counterpoise in antenna B allowed you to construct in the only place where a 3/8 wave was possible. You patterned your new antenna after one you read about that worked well, and got excellent results yourself. And then you got on here and told us about it. NOTHING the matter with that. Nothing AT ALL. That's about as ham radio as it gets. Looking forward to working you on Top Band. Please do enjoy the new antenna. And you're certainly welcome. - It is really not that hard to understand Steve's success, or his prior woes. Full size dense and uniform all around radials are the gold standard, the creme-de-la-creme. Really. And it is REALLY NICE to have the land to do that stuff. Full size dense and uniform all around always works well with a quarter wave vertical radiator on top. It's STILL what you do for best results if you've got the room for it. The EVIL LITTLE SECRET some aren't onto yet is why and how quickly the radial performance degrades using SHORT, IRREGULAR and/or SPARSE, CHOP-JOBS on full size dense and uniform all around. For a lot of the layouts I have seen or heard of, short, irregular and/or sparse chop-job is the correct description, for sure. But they were done that way because there was NO ROOM on the property to do anything else, if you were doing radials. That is the oh-so-common situation. You can get away with more chop if you have really great dirt. If you have bad dirt, the chop job throws away S units. Plural intended. With additional information from Steve, my NEC4 comparison of his Marconi T over chop job radials over awful dirt versus gold standard shows the difference at 10 degrees takeoff is 6-8-10 dB depending on what assumptions are used. That result certainly gives no reason to disbelieve Steve's anecdotal reports. The FCC talks about 120 times 0.4 wavelength radial fields. 430 foot diameter circle. :) 60 times 0.25 wavelength radial fields is what we hear about for hams. 250 foot diameter circle for 1/4 wave radials. I got no dog in the fight about which radius is better, or whether 60 is really 30, let someone else argue. But either way, does anyone have a feeling for the magnitude of mental disconnect when we talk about the little guy on a small lot, mostly used up by a house, trying to do a 160 meter antenna, and in the same breath bring up radials requiring 250 foot diameter circles to do well? The jarring incompatible necessities seem to go right over quite a few heads. In a series of postings some weeks ago it was suggested by some that FCP users should all get a comparison to two opposed 1/4 wave radials by using some clip leads on their FCP and extending the wires out to 1/4 wave on either side. That would get you two opposed 1/4 wave raised radials, true. To be fair they were suggesting this in order to get a common benchmark to tie into other comparison listings. However... Since the FCP isolation transformer has deliberate residual inductive reactance to help balance out deliberate residual capacitive reactance of the FCP, one would need to change out the isolation transformer for something else to use with the resonant 1/4 wave radials, muddling the results with apples and oranges issues. For example, one could wind up only measuring energy difference lost on coax shield common mode by not using the isolation transformer, with no way to attribute the source of the loss. But that aside, there's something much more basic.
Re: Topband: 160m from 5X
Nick, A 50ft tophat vertical is a good antenna. I would suggest that you put down as many 135 ft long radials as possible, at least 25. If this is not feasible, put down as may random lengths radials as you can. The problem is that it is a vertical antenna and will be noisy, particularly if you are in a populated area and near the equator. You will hear hear the loud signals, but I'm guessing, not the sigs below S4. I would suggest some sort of long wire for an RX antenna, perhaps a 300 ft BOG, beverage on ground. You may have to roll it out in the evening, and after sunrise, roll it up. We will be looking for you from W6/W7 land. Working 5X on 160m will be difficult, but on certain days condx will peak at your sunrise, and we might be able to make it. GL, Ray, N6VR Near Prescott, AZ On Thu, Aug 30, 2012 at 6:43 AM, IZ5MOQ iz5...@rrdxa.eu wrote: Hello Nick, nice to read you here and nice to know that you are on the way to put 5X on the TopBand. See you on the air, to complete our band slots on 80 and... 160. I do not give you any tech-advice because am novice too :), just my GL 'n see you there. 73 Alessandro, IZ5MOQ DX'ing between the mountains! - Original Message - From: Nick Henwood n...@henwood.demon.co.uk Sent: Tuesday, August 28, 2012 11:24 PM Subject: Topband: 160m from 5X I have been v QRV from 5X in past 5 years. ___ UR RST IS ... ... ..9 QSB QSB - hw? BK ___ UR RST IS ... ... ..9 QSB QSB - hw? BK
Re: Topband: VO1HP FCP Inv L and Kitchen Oven
When I first installed my 3/8 over FCP here, it was PRE isolation transformer. Given the unfortunate 424' length of elevated Wireman #554 450 ohm window line back to the tractor shack for conversion to 50 ohm coax into shack, it was very heavily coupled, as explicit modeling would later reveal. That degree of common mode current was exceptionally lossy. For all practical purposes, well over half my power was going to a 160 meter endfed 3/4 wave wire 8 feet above ground more or less grounded at the far end. If you have that much loss pre-conversion, you have a certain lowered field strength from the antenna. When you fix the loss the field strength is going to jump up, just the same as if you raised power. Anything that was close to interference, but not yet, may now be interfered with. As I found out when the massive common mode loss in my system was solved. I now blew away both my and my neighbor's ATT Uverse gateway boxes with anything over 400 watts out from the amp. Various local experiments proved that it was just the new higher field strength from the antenna and nothing else. Previously 1.5 kW to the feedline did not even cause pixelation that we were aware of, and afterwards over 400 watts would cause the gateway to shut down. As ATT would verify, the remainder of the problem was entirely an issue with ATT that was well known, and they had fixes for. Frank, if I remember correctly, you previously had short and irregular 160m radials in a relatively thin poor soil layer over bedrock. That might as well have been an attenuator in your feedline, which you have now removed. And, unlike my house, your antenna is very close to the house. I hope you have as good luck on other issues that may pop up as with your stove. I am not sure I have anything useful to add about the insulators. The stuff that is used for electric fence support in the US obviously has the voltage rating. The complaints about them I have heard are entirely mechanical in nature. 73, and keep working 'em! Guy K2AV On Thu, Aug 30, 2012 at 9:00 AM, VO1HP fda...@nfld.net wrote: The Inv L FCP continues to perform. After a nice long hot summer here which is unusal here I was on last night around 0230 and worked K6ND, WJ3A, G4EIM. LY2OU, UY0ZG. While operating I started hearing at regular intervals somewhere of in the distance beep beep pause beep beep ...upon investigation I found the kitchen oven had turned itself on and was awaiting further instructions from the keypad. I was running about 600w and the flat-top of the L runs more or less over the kitchen area. I reread the RFI article re kitchen ovens in May 2012 QST and my first reaction was to try and place by-pass caps as described in the artcile. Howevere I thought I would try the simplest thing first. This morning I was able to place two snap on chokes of #43 material over the 240V wire inside the access panel at the back of the stove. The 1/2inch hole in the cores is not big enough to snap over the cable as it enters the stove. So I removed the plug from the wall and removed the access panel of the stove. There was enough room in the area to accommodate two snap on chokes -- i ran two wires through one core and one through another. There was just enough space to accomodate the cores. Upon testing at 600-700W the oven appears to be unaffected now. hopefully it remains thus. The old inv L and on the ground non-uniform and erratic radial system did not cause this issue so do I conclude that the effective radiated field from the FCP Inv l is that much stronger? Yesterday I also did some more work on the FCP ...when I initially built it I used 1/2inch pressure treated wooden spacers and tie wraps. Yesterday I replaced the those spacers with 1/2inch PEX (HDPE material) water pipe painted black. These spacers appeared to cause a slight shift in the SWR curve for the L...raising somewhat away from 1800khz. I am wondering about this material and whether its the right stuff to use? By the way the oven model Jenn-Air JES8850ACB ( same number for Maytag) 73 Frank VO1HP __**_ UR RST IS ... ... ..9 QSB QSB - hw? BK ___ UR RST IS ... ... ..9 QSB QSB - hw? BK
Re: Topband: 160m from 5X
If you cannot use radials laid on the ground, you could use at least two (ideally more) elevated radials loaded with inductors or the relatively new Folded Counterpoise (FCP);bhowever, the FCP requires a special antenna matching circuit. Huh? No matching network on my FCP antenna. ___ UR RST IS ... ... ..9 QSB QSB - hw? BK
Re: Topband: 160m from 5X
I have been v QRV from 5X in past 5 years. Returning this Oct for 8 weeks and considering how best to get 160 on the air as it is the only band I have not worked and reckon there must be un-met need! I go to work (pro bono) at a community university so not a dxpedition but solo so plenty of time to get on the air. I carry all my gear with me. I am looking for help/advice in erecting a simple antenna which you guys can hear! I have access to roach poles (30 footers) and can get max height of about 50 feet. No high trees locally and insufficent room for beverage antennas. Contemplating a 50 ft vertical with capacity top loading and some induction at the feed point. I will get grounding as good as possible within local constraints(small site, vehicles near the house etc). What do you think? Are you going to be single band or multiple band? Any interest in 80 with the antenna, or just 160? Whatever you do, if you do it correctly, there will not be that much difference except in logistics and flexibility. 73 Tom ___ UR RST IS ... ... ..9 QSB QSB - hw? BK
Re: Topband: 160m from 5X
Hi Nick Like many others, I am very glad to hear you will be QRV on Topband. A few suggestions if I may: Operating on Topband has a bit of a learning curve. Not steep, but a few things that may help: Code speeds tend to be more moderate than other bands. On 20, a DXpedition can zoom along at 30+ - On topband, it is best to slow down a bit. 25 is probably more common. Chances are you will not be loud, and I would suggest operating split as much as possible, The DX Window is 18025 to 18030 - transmit in here, and listen outside the window. You will see some enhancement around sunset/sunrise. You see this on other bands as well, but the effect is more pronounced, and as you may have noticed, there is more emphasis on these times for working different parts of the world. Putting out a decent signal is (usually) not the biggest hurdle - hearing is. Others have already suggested good transmit antennas, and it sounds like you already have some good ieas (K9AY) for RX in place. Once last thing I would add as far as receive is concerned - ignore signal levels. The biggest obstacle is hearing. Period. Who cares if the signal is S2 or S9. A BOG may produce low signal levels/not be very effecient. If it helps you hear, that is all that really matters. If it is rolled up during the day, perhaps it can be rolled out in different directions at night to favour different parts of the world. Good luck with the operation!! Tom - VE3CX On 8/28/12, Nick Henwood n...@henwood.demon.co.uk wrote: I have been v QRV from 5X in past 5 years. Returning this Oct for 8 weeks and considering how best to get 160 on the air as it is the only band I have not worked and reckon there must be un-met need! I go to work (pro bono) at a community university so not a dxpedition but solo so plenty of time to get on the air. I carry all my gear with me. I am looking for help/advice in erecting a simple antenna which you guys can hear! I have access to roach poles (30 footers) and can get max height of about 50 feet. No high trees locally and insufficent room for beverage antennas. Contemplating a 50 ft vertical with capacity top loading and some induction at the feed point. I will get grounding as good as possible within local constraints(small site, vehicles near the house etc). What do you think? Grateful for advice on antennas. I would only work CW - lots of experience on HF (110k QSOs from 5X on the other bands) but novice on 160 dx - advice (polite) also invited on operating. 73 Nick G3RWF/5X1NH PS Yes, I use LOTW ___ UR RST IS ... ... ..9 QSB QSB - hw? BK ___ UR RST IS ... ... ..9 QSB QSB - hw? BK
Re: Topband: Window ?
The last information I had was this 160 meter DX window was no longer in use as a window by a international agreement of amateurs. It previously restricted North Americans from calling CQ DX in it, while allowing other countries to do so. I was one of the Americans calling CQ DX run out of the window years ago ! Has the window changed again ? The old window is, and has been, obsolete except for some contest rules. I think, for the benefit of smaller stations far from the east coast, it should have remained. The people making the decision felt it was not necessary. There are some IARU suggestions and other things, but the old 1830-35 DX-only window is long gone. I try to stay above 1835 or below 25 as much as possible, because I think removing that clear area was a bad idea for stations distant from the coast, who have to listen through the NE wall. ___ UR RST IS ... ... ..9 QSB QSB - hw? BK
Re: Topband: Using the K2AV folded counterpoise at VK6VZ
On Thu, 2012-08-30 at 12:55 -0400, Guy Olinger K2AV wrote: Short Version: ---snip--- 2) Let's go visit some small lots. ---snip--- Long version: ---snip--- I think there is a lot about restricted circumstances that some either don't understand or find hard to identify with. Your experience is Right On! ---snip--- Talking of one typical FCP user in Texas, if he extends the FCP wires to 1/4 wave either side, on the west he'd have to negotiate with his next TWO neighbors to run wire across both back yards. And as he's on a corner boundary lot, the east wire would be across the subdivision boundary street, across the boundary park strip, over the fence and into the southbound right driving lane of a limited access parkway. At my place I could put up the north extension, but the south extension would be out in the service road right of way for US 64 Highway. Try negotiating something with NCDOT. To illustrate matters of scale, in the Texas subdivision that I mentioned above, according to Google Earth, clearing property for the FCC 430 foot diameter circle would require demolishing 23 houses, give or take a couple properties. See 29.58672 -98.52185 Count them yourself. Reducing that to 1/4 wave radials and a 250 foot circle reduces the carnage to a mere 14 properties, give or take. There are places with even higher densities, particularly in Europe and Japan. See the mental disconnect yet? ---snip--- 73, Guy. ** http://www.w0uce.net/K2AVantennas.html Lucky me there is no HOA where I live. Mention HOA and everybody says huh? No way. I am about 4000 feet from the nearest runway but that is for small aircraft and the 4000 feet is from my home to the *side* of runway. The tallest tree on my place is about 40 feet high and I don't want to go very much past that due to that runway AND to just keep a low profile. I can actually work a few stations in North America during contests like the Stew Perry with my almost dummy load antenna. I have very faintly heard some DX stations too far down in the noise for me to pull them out. I know they were DX because I could the North American stations working them. I retreat to 80 and 40 meters a lot but I am not giving up on 160. I see 160 as the band where I can make the most improvements so that is what I intend to do. From my postage stamp lot I do NOT expect to be a big gun - EVER. I am going to start with a K9AY antenna for receive first (I'm rounding up the materials). If I can actually *hear* the DX then I'll see what I can do to add the FCP to my TX antenna. If the FCP is a waste of time as some suggest I will only have lost some time and can reuse all the materials in other projects. In ant case I can already work some stations. heresy Right now I don't care about working exclusively DX. Any QSOs at all will do. /heresy Maybe later I will be more interested in a paper chase. 73, Bill KU8H ___ UR RST IS ... ... ..9 QSB QSB - hw? BK
Topband: Small antenna book
While looking for something entirely different, I came across this. I wonder if anyone has this book? Grant, KM5KG, is one of the most experienced broadcast engineers around. http://www.km5kg.com/160meter.htm Grant claims: A New Book from Grant Bingeman, KM5KG 112 pages 8.5 by 11 inches This book presents 30 practical wire antenna designs that fit inside a 40 by 40 by 30 foot tall space, including the ground system. This report is specially written for the ham radio operator who lives on a typical quarter acre lot and has to maintain a practical budget. E field radiation efficiencies of 75 percent are possible over a very limited ground system of 18 buried radial wires only 20 feet long. On the surface this seems to agree with what I find. There are dozens of ways to have about the same results. I wonder what Grant has in the book? 73 Tom ___ UR RST IS ... ... ..9 QSB QSB - hw? BK
Re: Topband: Small antenna book
On the surface this seems to agree with what I find. There are dozens of ways to have about the same results. I wonder what Grant has in the book? I recently purchased a copy from the ARRL and it's well worth the $20 price. Table of Contents: - Short Antenna Behavior - A Better Way to Define Antenna Bandwidth - Why Top-loading Can Improve Short Antenna Performance - Top Hat Arrangements - Inverted Cone Antennas - Closed Antennas - Antennas with Two Driven Elements - T-shaped Antennas - Inverted L-shaped Antennas - Antennas with Four Driven Elements - Spiral Antennas - Small Horizontal Antennas - Quadrature Feed Arrangements Paul, W9AC - Original Message - From: Tom W8JI w...@w8ji.com To: Topband@contesting.com Sent: Thursday, August 30, 2012 7:02 PM Subject: Topband: Small antenna book While looking for something entirely different, I came across this. I wonder if anyone has this book? Grant, KM5KG, is one of the most experienced broadcast engineers around. http://www.km5kg.com/160meter.htm Grant claims: A New Book from Grant Bingeman, KM5KG 112 pages 8.5 by 11 inches This book presents 30 practical wire antenna designs that fit inside a 40 by 40 by 30 foot tall space, including the ground system. This report is specially written for the ham radio operator who lives on a typical quarter acre lot and has to maintain a practical budget. E field radiation efficiencies of 75 percent are possible over a very limited ground system of 18 buried radial wires only 20 feet long. On the surface this seems to agree with what I find. There are dozens of ways to have about the same results. I wonder what Grant has in the book? 73 Tom ___ UR RST IS ... ... ..9 QSB QSB - hw? BK ___ UR RST IS ... ... ..9 QSB QSB - hw? BK
Re: Topband: DX Window
Out west in flyover country we rue the day. Tom is spot on. I too stay out of 30-35 for CQing so my western brethren can potentially hear something. Very unfortunate to have the 30-35 window, which many DX stations use, clobbered by a very few thoughtless W CQ'ers. I didn't realize recognition of the window is a has been. Out here, not the case. 73 Art K6XT~~ Allison, southwest CO Success is going from failure to failure without a loss of enthusiasm. ARRL, GMCC, CW OPS, NAQCC On 8/30/2012 5:13 PM, W8JI wrote: I try to stay above 1835 or below 25 as much as possible, because I think removing that clear area was a bad idea for stations distant from the coast, who have to listen through the NE wall. ___ UR RST IS ... ... ..9 QSB QSB - hw? BK
