Re: [Elecraft] K2 + ATU + Loop antenna in the attic
Don, The fan antenna was a lashup in the attic in hopes of having another antenna, hopefully to use with the K2 upstairs in the office. If it worked out, great; if not, no big deal. The attic isn't easy to get into (no pull-down), and not a lot of room to stumble around up there. The final solution was to switch my 130' Carolina Windom between the K2 and K3. See bottom of http://wilcoxengineering.com/projects/amateur-projects/39-fan-dipole . The coax relay didn't make good contact, so I replaced it with a big 24 vdc 4PDT junk relay in a metal box: the extra contacts give solid connections AND ground the unused feed to either the K2 or K3. BTW, only one rig is ever physically connected to the coax unless it's powered up and being used. With the storms ripping around today, both the K2 and K3 are safely disconnected! Cheers, Alan Alan D. Wilcox, W3DVX (K2-5373, K3-40) 570-321-1516 http://WilcoxEngineering.com http://eBookEditor.net https://www.smashwords.com/books/view/28062?ref=awilcox Williamsport, PA 17701 On 4/15/11 7:29 PM, Don Wilhelm wrote: Alan, Sorry to hear about your lack of success with the fan dipoles. I have three of them - one for 80 and 40, another for 30, 17 and 12m, and yet another for 20, 15, and 10. They work very well. My secrets - space the wires for each band away from one another - my 80 and 40 antennas are at right angles to each other, so there is little of any interaction. The other two have the wires spaced about 1 foot apart using CPVC pipe with holes drilled in them (wires through the holes) to maintain the spacing. PVC would work too, but is heavier). The antennas do interact, so plan ahead, you will have to do some cut and try pruning. Tune the lowest band or resonance first, and then the next band higher in frequency. Trying it the other way 'round is an exercise in futility (been there, done that, and have the scars). I usually consider 3 bands on one feedline the limit of my patience, but this last weekend I helped a friend construct an antenna with 4 wires - 80, 40, 20, and 10 meters. It was a bit of a pain to tune, but it worked out well. Cut the wires at least 10% long and prune as required. One other point - do not use separate wires for bands that are close to the 3rd harmonic of another band - in other words, for HF, do not put a 30 meter radiator on a feedline that contains an 80 meter wire, and do not put a 15 meter wire on a feedline that also has a 40 meter wire. The lower band antenna may be usable on the 3rd harmonic (likely with a tuner), but trying to combine those two wires will result in even more frustration. 73, Don W3FPR On 4/15/2011 6:15 PM, Alan D. Wilcox wrote: FWIW, see my fan antenna at http://wilcoxengineering.com/projects/amateur-projects/39-fan-dipole A bright idea that didn't work out so well! Cheers, Alan Alan D. Wilcox, W3DVX (K2-5373, K3-40) __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
Re: [Elecraft] K2 + ATU + Loop antenna in the attic
On 04/11/2011 04:11 PM, Wayne Conrad wrote: My radio (K2 with the internal ATU) hasn't shipped yet, but that shouldn't stop me from putting up an antenna, right? If only I knew what to put up, that is. That's where I'm asking for help. (snip) Thank you to everyone who replied, both publicly and privately. Your responses were great. Most of you urged me to put the antenna outside. As Fred Jensen said, Even something laid over the roof will probably work better for you. So, outside it will be. I also got several requests that I put in a proper safety ground no matter where my antenna is, so I will do that, too. Best Regards, Wayne Conrad __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
Re: [Elecraft] K2 + ATU + Loop antenna in the attic
FWIW, see my fan antenna at http://wilcoxengineering.com/projects/amateur-projects/39-fan-dipole A bright idea that didn't work out so well! Cheers, Alan Alan D. Wilcox, W3DVX (K2-5373, K3-40) 570-321-1516 http://WilcoxEngineering.com http://eBookEditor.net https://www.smashwords.com/books/view/28062?ref=awilcox Williamsport, PA 17701 On 4/15/11 1:08 PM, Wayne Conrad wrote: On 04/11/2011 04:11 PM, Wayne Conrad wrote: My radio (K2 with the internal ATU) hasn't shipped yet, but that shouldn't stop me from putting up an antenna, right? If only I knew what to put up, that is. That's where I'm asking for help. (snip) Thank you to everyone who replied, both publicly and privately. Your responses were great. Most of you urged me to put the antenna outside. As Fred Jensen said, Even something laid over the roof will probably work better for you. So, outside it will be. I also got several requests that I put in a proper safety ground no matter where my antenna is, so I will do that, too. Best Regards, Wayne Conrad __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
Re: [Elecraft] K2 + ATU + Loop antenna in the attic
On 4/15/2011 3:15 PM, Alan D. Wilcox wrote: FWIW, see my fan antenna at http://wilcoxengineering.com/projects/amateur-projects/39-fan-dipole A bright idea that didn't work out so well! If I had a dollar for every Gee, it seemed like a good idea at the time situation I've found myself in, I'd have a LOT more radio equipment. 73, Fred K6DGW - Northern California Contest Club - CU in the 2011 Cal QSO Party 1-2 Oct 2011 - www.cqp.org __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
Re: [Elecraft] K2 + ATU + Loop antenna in the attic
Alan, Sorry to hear about your lack of success with the fan dipoles. I have three of them - one for 80 and 40, another for 30, 17 and 12m, and yet another for 20, 15, and 10. They work very well. My secrets - space the wires for each band away from one another - my 80 and 40 antennas are at right angles to each other, so there is little of any interaction. The other two have the wires spaced about 1 foot apart using CPVC pipe with holes drilled in them (wires through the holes) to maintain the spacing. PVC would work too, but is heavier). The antennas do interact, so plan ahead, you will have to do some cut and try pruning. Tune the lowest band or resonance first, and then the next band higher in frequency. Trying it the other way 'round is an exercise in futility (been there, done that, and have the scars). I usually consider 3 bands on one feedline the limit of my patience, but this last weekend I helped a friend construct an antenna with 4 wires - 80, 40, 20, and 10 meters. It was a bit of a pain to tune, but it worked out well. Cut the wires at least 10% long and prune as required. One other point - do not use separate wires for bands that are close to the 3rd harmonic of another band - in other words, for HF, do not put a 30 meter radiator on a feedline that contains an 80 meter wire, and do not put a 15 meter wire on a feedline that also has a 40 meter wire. The lower band antenna may be usable on the 3rd harmonic (likely with a tuner), but trying to combine those two wires will result in even more frustration. 73, Don W3FPR On 4/15/2011 6:15 PM, Alan D. Wilcox wrote: FWIW, see my fan antenna at http://wilcoxengineering.com/projects/amateur-projects/39-fan-dipole A bright idea that didn't work out so well! Cheers, Alan Alan D. Wilcox, W3DVX (K2-5373, K3-40) __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
Re: [Elecraft] K2 + ATU + Loop antenna in the attic
I played with a fan dipole back in the 1960's, and played and played and played trying to get a decent (less than 3:1) match to 50 ohm coax. Never was happy. That experiment taught me the efficiency, ease and simplicity of a doublet* fed with open wire line. Working out the process of getting the open wire line into the shack wasn't nearly as difficult as trying to get the antenna to present a decent match to the coax, and it was a wonderfully efficient and effective all band antenna mounted at an inverted V with the apex at 50 feet. BTW, my doublet was 100 feet end-to-end and worked beautifully on 160 through 10 meters. Granted, at so close to the ground the radiation was mostly straight up on 160 but on that band I was mostly interested in working locals out to 100 miles or so. We had a lot of mobiles active on 160 back then as well as fixed stations. And none of the rude nonsense so often found on 75. Ron AC7AC *Wire fed at the center but not necessarily a dipole - i.e. 1/2 wavelength long - on any band. -Original Message- Subject: Re: [Elecraft] K2 + ATU + Loop antenna in the attic Alan, Sorry to hear about your lack of success with the fan dipoles. I have three of them - one for 80 and 40, another for 30, 17 and 12m, and yet another for 20, 15, and 10. They work very well. My secrets - space the wires for each band away from one another - my 80 and 40 antennas are at right angles to each other, so there is little of any interaction. The other two have the wires spaced about 1 foot apart using CPVC pipe with holes drilled in them (wires through the holes) to maintain the spacing. PVC would work too, but is heavier). The antennas do interact, so plan ahead, you will have to do some cut and try pruning. Tune the lowest band or resonance first, and then the next band higher in frequency. Trying it the other way 'round is an exercise in futility (been there, done that, and have the scars). I usually consider 3 bands on one feedline the limit of my patience, but this last weekend I helped a friend construct an antenna with 4 wires - 80, 40, 20, and 10 meters. It was a bit of a pain to tune, but it worked out well. Cut the wires at least 10% long and prune as required. One other point - do not use separate wires for bands that are close to the 3rd harmonic of another band - in other words, for HF, do not put a 30 meter radiator on a feedline that contains an 80 meter wire, and do not put a 15 meter wire on a feedline that also has a 40 meter wire. The lower band antenna may be usable on the 3rd harmonic (likely with a tuner), but trying to combine those two wires will result in even more frustration. 73, Don W3FPR On 4/15/2011 6:15 PM, Alan D. Wilcox wrote: FWIW, see my fan antenna at http://wilcoxengineering.com/projects/amateur-projects/39-fan-dipole A bright idea that didn't work out so well! Cheers, Alan Alan D. Wilcox, W3DVX (K2-5373, K3-40) __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
Re: [Elecraft] K2 + ATU + Loop antenna in the attic
I have an array of dipoles, some trapped, some using W9INN style chokes. I also have a tribander. But the antenna that gets used all the time is 160' doublet fed with 300 ohm line which goes into a DX Engineering 1:1 balun with short piece of RG-8 type coax coming into the house. The tuners on the K1, K2, and K3 will tune it to any band. I have experimented a great deal with fan dipoles. They certainly work. And also Off-Center fed antennas; they also work well. Loops a good too. I have a notebook with 40 years of wire antenna experiments. For me the most satisfying antenna so far is the simple doublet. It will always be the first antenna I recommend. With the great tuners in the Elecraft gear, it seems like a no-brainer. 73, Doug -- K0DXV On 4/15/2011 6:16 PM, Ron D'Eau Claire wrote: I played with a fan dipole back in the 1960's, and played and played and played trying to get a decent (less than 3:1) match to 50 ohm coax. Never was happy. That experiment taught me the efficiency, ease and simplicity of a doublet* fed with open wire line. Working out the process of getting the open wire line into the shack wasn't nearly as difficult as trying to get the antenna to present a decent match to the coax, and it was a wonderfully efficient and effective all band antenna mounted at an inverted V with the apex at 50 feet. BTW, my doublet was 100 feet end-to-end and worked beautifully on 160 through 10 meters. Granted, at so close to the ground the radiation was mostly straight up on 160 but on that band I was mostly interested in working locals out to 100 miles or so. We had a lot of mobiles active on 160 back then as well as fixed stations. And none of the rude nonsense so often found on 75. Ron AC7AC *Wire fed at the center but not necessarily a dipole - i.e. 1/2 wavelength long - on any band. -Original Message- Subject: Re: [Elecraft] K2 + ATU + Loop antenna in the attic Alan, Sorry to hear about your lack of success with the fan dipoles. I have three of them - one for 80 and 40, another for 30, 17 and 12m, and yet another for 20, 15, and 10. They work very well. My secrets - space the wires for each band away from one another - my 80 and 40 antennas are at right angles to each other, so there is little of any interaction. The other two have the wires spaced about 1 foot apart using CPVC pipe with holes drilled in them (wires through the holes) to maintain the spacing. PVC would work too, but is heavier). The antennas do interact, so plan ahead, you will have to do some cut and try pruning. Tune the lowest band or resonance first, and then the next band higher in frequency. Trying it the other way 'round is an exercise in futility (been there, done that, and have the scars). I usually consider 3 bands on one feedline the limit of my patience, but this last weekend I helped a friend construct an antenna with 4 wires - 80, 40, 20, and 10 meters. It was a bit of a pain to tune, but it worked out well. Cut the wires at least 10% long and prune as required. One other point - do not use separate wires for bands that are close to the 3rd harmonic of another band - in other words, for HF, do not put a 30 meter radiator on a feedline that contains an 80 meter wire, and do not put a 15 meter wire on a feedline that also has a 40 meter wire. The lower band antenna may be usable on the 3rd harmonic (likely with a tuner), but trying to combine those two wires will result in even more frustration. 73, Don W3FPR On 4/15/2011 6:15 PM, Alan D. Wilcox wrote: FWIW, see my fan antenna at http://wilcoxengineering.com/projects/amateur-projects/39-fan-dipole A bright idea that didn't work out so well! Cheers, Alan Alan D. Wilcox, W3DVX (K2-5373, K3-40) __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
Re: [Elecraft] K2 + ATU + Loop antenna in the attic
I have had two fan dipole in use maybe 15-20 years ago, before the time of widespread use of auto tuners. One was a commercial model, with the various lengths of wire on each side of the center insulator spaced about an inch apart (spacers were used). I did not have so much success with it. The other was homebrew, with 3 dipoles sharing the same center insulator and coax, but each going in different directions with the trees available. It was a great antenna that gave me good performance with low swr on my bands of interest without need for a tuner. Currently my most often used antenna is a dipole fed with ladder line. The ladder line connects to a balun and a short piece of coax to the radio with built in tuner. This setup tunes well but seems to pick up noise from the house. I should probably use more coax to get the ladder line a bit away from the house. I also have a vertical with decent radial system, coax fed, a fair distance from the house (100 feet) that picks up much less noise from the house. I do think the dipole works better than the vertical, at least for transmitting. 73 - Mike WA8BXN __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
Re: [Elecraft] K2 + ATU + Loop antenna in the attic
That's a sign the dipole is significantly unbalanced or you have common mode signals getting into the receiver. The balun is supposed to take care of the common mode suppression, but that often depends upon the impedance it sees, which varies widely in a tuned feeder system. A truly balanced line won't pick up RF or radiate significantly. OTOH, it could be that your dipole itself is simply closer to the house and noise than the vertical. BTW, every foot of coax in a system with high SWR costs you dearly in RF losses. Ron AC7AC -Original Message- From: elecraft-boun...@mailman.qth.net [mailto:elecraft-boun...@mailman.qth.net] On ...Currently my most often used antenna is a dipole fed with ladder line. The ladder line connects to a balun and a short piece of coax to the radio with built in tuner. This setup tunes well but seems to pick up noise from the house. I should probably use more coax to get the ladder line a bit away from the house. 73 - Mike WA8BXN __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
Re: [Elecraft] K2 + ATU + Loop antenna in the attic
On Fri, Apr 15, 2011 at 7:16 PM, Ron D'Eau Claire r...@cobi.biz wrote: the efficiency, ease and simplicity of a doublet* fed with open wire line... Ron is so right. At the risk of re-re-repeating myself, whether or not an antenna is resonant, or matches coax, has nothing to do with its effectiveness as a radiator or receiver of signals. You don't have to feed it with coax. If you can put up an antenna with multiple radiators or traps or matching sections, you can put up a single antenna with no traps and no matching sections, feed it with ladder line or window line (or even twin lead), and get equal (or usually better) results. I guess guys like coax-fed antennas because they see that SO239 on the back of the rig, but it doesn't have to go any farther than a balun at the shack exit. Enough RF is wasted every day in long lossy runs of coax to power a year's worth of DXpeditions. Tony KT0NY __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
Re: [Elecraft] K2 + ATU + Loop antenna in the attic
Wayne, If you have no choice and have to use an antenna in the attic placed close to the rafters, I would suggest that you do use iinsulators to prevent any part of the antenna touching a rafter. A fire risk could exist if the antenna's wire is simply laid on the rafters, especially if using higher power on several bands. Welcome to the hobby, and have fun!! 73, Geoff GM4ESD (Licensed 1946) On April 12, 2011 at 12:11 AM, Wayne Conrad wrote: snip I don't know whether I need to keep the antenna wire off of the rafters with insulators, or can I just let it lay there. Nor do I know if the answer to that question changes if I eventually go QRO. __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
Re: [Elecraft] K2 + ATU + Loop antenna in the attic
Wayne : You got some good advice so far. I am in agreement that an outside antenna will perform better than one in the attic but you can always start with an attic antenna and add an outdoor antenna later. An attic antenna makes a great backup antenna as it will not succumb to severe weather (i.e icing, wind etc). As some have suggested, instead of a loop you could put up a doublet (ie dipole). The advantage will be that it may be easier to match on a lower bands. If you run the wire diagonally across the attic and then bend the ends in to form a Z shape you can probably get more wire up and that will help. Best of luck Michael VE3WMB __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
[Elecraft] K2 + ATU + Loop antenna in the attic
My radio (K2 with the internal ATU) hasn't shipped yet, but that shouldn't stop me from putting up an antenna, right? If only I knew what to put up, that is. That's where I'm asking for help. I want to start out with an loop antenna in the attic. Why loop? Mostly the very American idea that more wire must be better, plus it's balanced--I hope to not need a separate RF ground, or counterpoises, or any of that jazz). Why the attic? So I don't have to worry about lightning protection, and because it ought to be incredibly cheap to put up. I've spent every dime I have on the radio, you see. The house is the usual ~60' x ~30 feet and L shaped, single story, and the major axis is North/South. The attic is full of trusses and fiberglass, but I can get to most of it, sometimes slithering on my belly like a snake. There are the usual electrical wires, network cabling (OK, maybe not everyone has CAT6 in their attic), TV coax, and AC ducts going hither and thither. My shingles are asphault. I have no idea what band or bands I'll be on. I don't even have my license yet. My thought is that I run the loop around the perimeter of the attic, as close to the eaves as possible. Over the radio bench, I'll punch a hole in the ceiling and drop feedline down the wall. I was thinking of open-wire feeder, because I read on the internet that it might be better for this application. It occurs to me that I could omit the 4' of feedline and just drop the two wires down. Using the self-adhesive conduit that the hardware store sells, I could keep those two wires at an appropriate distance from each other, and white conduit looks better against a white wall than a black cable. I don't know if that's a good idea, or what an appropriate distance would be. I don't know if I need a balun, or even what kind. I don't know whether I need to keep the antenna wire off of the rafters with insulators, or can I just let it lay there. Nor do I know if the answer to that question changes if I eventually go QRO. I don't know if the length of the loop matters. As you can tell, the ratio of things I know to things I don't know is pretty small. Can you please help me improve that ratio? Thanks, and best regards, Wayne Conrad __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
Re: [Elecraft] K2 + ATU + Loop antenna in the attic
Wayne, you can put up an outdoor antenna for precious little more money than that attic antenna. I'd recommend doing that if at all possible. After all, it's just wire. Even an end-fed random wire is likely to work better than anything indoors. As for the dreaded counterpoise, try to make your antenna at 1/4 wavelength on the lowest frequency band you'll use (longer is better) and you won't need much of a counterpoise. Perhaps a 1/4 wavelength long wire on the lowest frequency band running along the baseboards or outside along the side of the house. BACK IN THE ATTIC I've used attic antennas in many places. In my case I was an apartment dweller for a few years so I made a point of renting the top floor apartment (usually second story) and figuring out how to get into the attic space above. (There usually is an access through a closet ceiling somewhere). I always put up a doublet - a center fed wire of whatever length I could squeeze in. I ran it along the highest place - under the ridge board just under the shingles. That put it as far as possible from wiring, ducts, etc. It can zig-zag somewhat, but I strived to keep the two halves pretty symmetrical. Frequently I ran the length of the ridge board (which in an apartment was usually about 30 feet or so between the security/firewalls that to go the roof between each apartment) then run down at the ends to the eaves - one end went one way the other end went the other for maximum separation. (That's an easy outside antenna too.) I insulated the ends where there will always be a high impedance. A bit of plastic bottle with holes punched in it works FB. But doing that helps avoid more unbalance and losses. (Insulators made from scrap bottle or clothes hangar plastic will work FB outdoors too.) For feedline I used two small-gauge white wires (apartment walls are invariably white). Plastic-bottle-bit spacers handle the run in the attic to a point directly over my operating desk. A fine pointed tool (e.g. ice pick) made two small holes in the ceiling right against the wall above the operating desk. The white wires come down the wall - held with a couple of staples - right to my ATU. The feeder was virtually invisible. One visitor at the desk kept asking where the feed line was. It ran up the wall 2 feet in front of his face. A balun isn't strictly necessary. Just connect one side to the rig case and the other side to the center conductor. Yes, it will be somewhat unbalanced. The only downside of that is that the feeder will radiate, but it's not a very long feeder. If you notice some hand effects (touching the radio changes SWR, etc.) try a balun. Elecraft has some great baluns that do well in that use. The issue with baluns is that they can become lossy at extreme impedances, and you can't really predict it too well in that environment. But many hams use them with excellent results. I had a homebrew balanced tuner on my system. ROOF You mentioned asphalt shingle roof. Excellent. I had great success radiating through those. In one apartment I couldn't get out worth a darn. One day I noticed a piece of tile from the roof. The building had concrete tiles. Put it in my microwave (with the obligatory glass of water) for a couple of minutes and that tile got smokin' hot. Concrete is a better conductor than the earth - or perhaps better said that it's a better lossy dielectric than the earth. In either case it did a bonza job absorbing my RF. QRO? I ran up to about 15 watts output in my apartment environments. Worked a lot of stations and a far share of DX - enough to keep it interesting - all CW. Even 15 watts got into our telephone but I was able to squelch it. I chose not to run more power so I'd not have to worry about neighbors sound systems, etc. Ron AC7AC -Original Message- From: elecraft-boun...@mailman.qth.net [mailto:elecraft-boun...@mailman.qth.net] On Behalf Of Wayne Conrad Sent: Monday, April 11, 2011 4:12 PM To: elecraft@mailman.qth.net Subject: [Elecraft] K2 + ATU + Loop antenna in the attic My radio (K2 with the internal ATU) hasn't shipped yet, but that shouldn't stop me from putting up an antenna, right? If only I knew what to put up, that is. That's where I'm asking for help. I want to start out with an loop antenna in the attic. Why loop? Mostly the very American idea that more wire must be better, plus it's balanced--I hope to not need a separate RF ground, or counterpoises, or any of that jazz). Why the attic? So I don't have to worry about lightning protection, and because it ought to be incredibly cheap to put up. I've spent every dime I have on the radio, you see. The house is the usual ~60' x ~30 feet and L shaped, single story, and the major axis is North/South. The attic is full of trusses and fiberglass, but I can get to most of it, sometimes slithering on my belly like a snake. There are the usual electrical wires, network cabling (OK, maybe not everyone has CAT6 in their attic), TV
Re: [Elecraft] K2 + ATU + Loop antenna in the attic
Wayne, I understand your reasons for putting an antenna in the attic, but that will offer no additional lightning protection over putting it outside. An outside antenna will pick up more noise from the house wiring, so why go to the trouble. Even if you mount your loop antenna on short standoffs just above the roof (look for electric fence insulators if you want to do that, they work very well). it will work better than it will inside. Your idea of just bringing the ends of the wire loop into the shack using two pieces of conduit to maintain the spacing between the wires will work very well - you would be creating an open wire feedline, which is quite efficient. You will need a balun between the coaxial output from the tuner and any parallel transmission line. Use a current balun. Many use a 4:1 balun, but in many cases (most cases), a 1:1 balun will be better. If the impedance at the shack end of the balanced line is low, a 4:1 balun will make it even lower. You might want to consider the Elecraft BL2 which is switchable between 1:1 and 4:1 so you can choose the best ratio for each band. On 4/11/2011 7:11 PM, Wayne Conrad wrote: My radio (K2 with the internal ATU) hasn't shipped yet, but that shouldn't stop me from putting up an antenna, right? If only I knew what to put up, that is. That's where I'm asking for help. I want to start out with an loop antenna in the attic. Why loop? Mostly the very American idea that more wire must be better, plus it's balanced--I hope to not need a separate RF ground, or counterpoises, or any of that jazz). Why the attic? So I don't have to worry about lightning protection, and because it ought to be incredibly cheap to put up. I've spent every dime I have on the radio, you see. The house is the usual ~60' x ~30 feet and L shaped, single story, and the major axis is North/South. The attic is full of trusses and fiberglass, but I can get to most of it, sometimes slithering on my belly like a snake. There are the usual electrical wires, network cabling (OK, maybe not everyone has CAT6 in their attic), TV coax, and AC ducts going hither and thither. My shingles are asphault. I have no idea what band or bands I'll be on. I don't even have my license yet. My thought is that I run the loop around the perimeter of the attic, as close to the eaves as possible. Over the radio bench, I'll punch a hole in the ceiling and drop feedline down the wall. I was thinking of open-wire feeder, because I read on the internet that it might be better for this application. It occurs to me that I could omit the 4' of feedline and just drop the two wires down. Using the self-adhesive conduit that the hardware store sells, I could keep those two wires at an appropriate distance from each other, and white conduit looks better against a white wall than a black cable. I don't know if that's a good idea, or what an appropriate distance would be. I don't know if I need a balun, or even what kind. I don't know whether I need to keep the antenna wire off of the rafters with insulators, or can I just let it lay there. Nor do I know if the answer to that question changes if I eventually go QRO. I don't know if the length of the loop matters. As you can tell, the ratio of things I know to things I don't know is pretty small. Can you please help me improve that ratio? Thanks, and best regards, Wayne Conrad __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
Re: [Elecraft] K2 + ATU + Loop antenna in the attic
On 4/11/2011 4:11 PM, Wayne Conrad wrote: I want to start out with an loop antenna in the attic. Why loop? Mostly the very American idea that more wire must be better, plus it's balanced--I hope to not need a separate RF ground, or counterpoises, or any of that jazz). You need a safety ground on your radio, a loop antenna does not normally care about ground, except in what ground does to the radiation elevation angle. Why the attic? So I don't have to worry about lightning protection, and because it ought to be incredibly cheap to put up. I've spent every dime I have on the radio, you see. Is it the K2/10? Anything outside will be better. Trees? Even something laid over the roof will probably work better for you. I have no idea what band or bands I'll be on. I don't even have my license yet. That will be a necessity :-) My thought is that I run the loop around the perimeter of the attic, as close to the eaves as possible. Over the radio bench, I'll punch a hole in the ceiling and drop feedline down the wall. Elevating the wire above the ceiling joists might help some. Many of the Attic Designs that have been published seem to use the open space of the attic rather than out near the eaves. I was thinking of open-wire feeder, because I read on the internet that it might be better for this application. A balun is probably going to be important, the K2 output is inherently unbalanced. Since you will have the ATU, putting the balun at the radio will eliminate any losses on the coax. It occurs to me that I could omit the 4' of feedline and just drop the two wires down. Using the self-adhesive conduit that the hardware store sells, I could keep those two wires at an appropriate distance from each other, and white conduit looks better against a white wall than a black cable. I don't know if that's a good idea, or what an appropriate distance would be. 2 or 3 cm is probably just fine. I don't know if I need a balun, or even what kind. See above I don't know whether I need to keep the antenna wire off of the rafters with insulators, or can I just let it lay there. That would be a good idea. Electric fence insulators are cheap and would work. Nor do I know if the answer to that question changes if I eventually go QRO. I don't know what you mean by QRO, but if it is anything over 10 or so watts, with such an antenna, you will likely not like the results :-) You also need to do a radiation safety survey which you can find on the ARRL web site. I don't know if the length of the loop matters. Basically, you're just putting up some conductor and attempting to load power into it. It's a more is better situation. The KAT2 will stuff power into some pretty weird impedances, but not all possible weird ones. As you can tell, the ratio of things I know to things I don't know is pretty small. Can you please help me improve that ratio? Hope this helps. Anything you can do outside will probably be better than anything you can do in the attic, unless you have CCR's. __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
Re: [Elecraft] K2 + ATU + Loop antenna in the attic
A loop in the attic is asking for coupling to all those nearby conductors. They will do the following: 1) Capture and dissipate your precious RF. No-one will hear you. 2) Couple large amounts of electrical noise into your receiver. You will hear nobody. 3) Pick up even QRP levels of RF and funnel it into electronic devices in your house. The best choice is to put up a balanced 'doublet' or dipole outside. It won't be more expensive than a loop in the attic. If you MUST put it in the attic, I still recommend a doublet. It will couple to the wires, etc. but not as badly as a loop, which may exhibit magnetic coupling to nearby loops of wire. My guess is that lightning is as likely to hit a wire in the attic as one just above it but outside! But the more likely problem with lightning is damage to the radio from voltages induced from nearby strokes. You should make sure to have an arrangement to dissipate static charges on whatever antenna you choose, indoor or outdoor. On 4/11/2011 4:11 PM, Wayne Conrad wrote: My radio (K2 with the internal ATU) hasn't shipped yet, but that shouldn't stop me from putting up an antenna, right? If only I knew what to put up, that is. That's where I'm asking for help. I want to start out with an loop antenna in the attic. Why loop? Mostly the very American idea that more wire must be better, plus it's balanced--I hope to not need a separate RF ground, or counterpoises, or any of that jazz). Why the attic? So I don't have to worry about lightning protection, and because it ought to be incredibly cheap to put up. I've spent every dime I have on the radio, you see. The house is the usual ~60' x ~30 feet and L shaped, single story, and the major axis is North/South. The attic is full of trusses and fiberglass, but I can get to most of it, sometimes slithering on my belly like a snake. There are the usual electrical wires, network cabling (OK, maybe not everyone has CAT6 in their attic), TV coax, and AC ducts going hither and thither. My shingles are asphault. I have no idea what band or bands I'll be on. I don't even have my license yet. My thought is that I run the loop around the perimeter of the attic, as close to the eaves as possible. Over the radio bench, I'll punch a hole in the ceiling and drop feedline down the wall. I was thinking of open-wire feeder, because I read on the internet that it might be better for this application. It occurs to me that I could omit the 4' of feedline and just drop the two wires down. Using the self-adhesive conduit that the hardware store sells, I could keep those two wires at an appropriate distance from each other, and white conduit looks better against a white wall than a black cable. I don't know if that's a good idea, or what an appropriate distance would be. I don't know if I need a balun, or even what kind. I don't know whether I need to keep the antenna wire off of the rafters with insulators, or can I just let it lay there. Nor do I know if the answer to that question changes if I eventually go QRO. I don't know if the length of the loop matters. As you can tell, the ratio of things I know to things I don't know is pretty small. Can you please help me improve that ratio? Thanks, and best regards, Wayne Conrad __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html -- Vic, K2VCO Fresno CA http://www.qsl.net/k2vco/ __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
Re: [Elecraft] K2 + ATU + Loop antenna in the attic
Wayne, like many members of this list, I've been right in your shoes. Like the previous posters, I'd recommend getting your wire outside. Here's a specific recommendation: While waiting for your radio to come, build a 4:1 unun. Here's a website with instructions: http://www.pcsystems-ss.co.uk/g7lrrweb/index.php?module=pagemasterPAGE_user_op=view_pagePAGE_id=52MMN_position=77:37 I'm guessing you're on an upstairs floor, but that's okay. Run coax from your rig to the unun. Then run a single wire out the window to the farthest, highest tree limb you can reach (see below). This goes to the hot side of the unun. For the cold side, make a counterpoise. Cut three or more wires in various lengths from 10' to about 30' and drape them out the window, in the gutters, on the garage roof, or whatever. The counterpoise will be your RF ground, but you also need a good DC ground. There's plenty of info on this reflector about that. With the right counterpoise and a properly-built unun, your ATU will match the wire perfectly on all the bands for which it's long enough, and you won't have any RF in the shack. To get a wire in the tree, you can use various gizmos. I rigged up a slingshot to shoot a weight which pulls fishing mono from a spinning reel. This will get a line up about 40 - 50 feet. See radioworks.com for some advice on shooting lines into trees. This setup sounds a bit hokey, but it works. If your wire is long enough, it will even provide gain over a dipole. I am just one of many who have used such an arrangement for lots of DX exploits. For example, my barefoot K3 worked 100 countries in 100 QSOs in 24 hours last month; I also have 40 zones, 300 countries, etc. etc. This is not to say that it is better than a 3-element wide-spaced Yagi, but it's a hell of a lot better than a wire in the attic. 73, Tony KT0NY __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
Re: [Elecraft] K2 + ATU + Loop antenna in the attic
On Mon, Apr 11, 2011 at 7:11 PM, Wayne Conrad wrote: I want to start out with an loop antenna in the attic, etc Wayne, you've already gotten some pretty good advice on this subject. May I add my two cents' worth here? First, you did not make it clear at all if your attic antenna is a 'must' due to CCRs or simply your choice. Wayne, if you have any choice in the matter, put the antenna outside. I have no choice due to CCRs so my antenna has been in my attic for the past nine years since we moved into this townhouse. Second, lightning,'close strikes', and static build-up can wipe out your investment in hardware just as easily in the attic as can happen outside. I happen to know this because a Hallicrafters SX-146 practically blew up in my face several years ago. Take the necessary precautions, please! Third, how successful your attic installation will be largely depends upon the particulars of YOUR situation. Some issues can be mitigated; some cannot. Assess your attic environment and if the list of negatives outweighs the positives then you might want to start investigating some sort of outside 'stealth' setup. In my case, I found my attic to be quite RF friendly. There is no metalized insulation up there, the vents are all PVC, all wiring is below the attic floor, there is no HVAC at all, tthe shingles are asphalt, the ice dam is non-metallic, the gutter runs are extremely short (due to the architecture) and the downspouts are 90 degrees off from my antenna plane and much lower. There were two runs of slinky-like 4 bathroom vent hose. I went up and chopped them up into small segments and then put them back together again with duct tape. These are a few things you might want to check out in your attic. Fourth, I run only QRP with my attic antenna. Technically, I can meet the MPE Uncontrolled limits at 100 watts but I prefer not to run higher power. Above a nominal 30 watts I turned on my neighbor's carbon monoxide detector, put my CW signals into her telephone, and turned my own DVD player on and off, on and off. The CO problem was unfixable and probably due to the unit's design. The phone problem was solved with the addition of a filter from KY Filters. The DVD problem was solved with a single Mix 43 toroid on the DVD player's line cord. For your information, the antenna I chose to install in my attic is a homebrewed 62' doublet bent a couple times to fix the space available. I avoided doubling it back on itself. The center insulator is the Delta-C surge supressor from Alpha-Delta. I fed it with 14 feet of 450 ohm ladder line directly to an SGC-237 autocoupler on a shelf near the ceiling in a linen closet right below the feedpoint. This keeps the rather expensive autocoupler out of the winter's cold and the summer's heat in the attic. The run from the autocoupler to my station is about 25 feet of RG8X. I have a copper cold water pipe behind my operating desk and I confirmed that it is tied into the electrical panel as per code here in NY. The ground is *not required* in the sense that the doublet is already balanced but it's good practice and I use it. I'm working the world on 5 watts, frequently much less, and having all the fun I can handle. I can load up 160 through 6 meters with the doublet. My SWRs are all below 1.4:1 except for 40 meters where I am 1.8. I may need to shorten/lengthen the ladder line somewhat. I guess the message is simply this - evaluate your environment, consider the options, and then go for it. Electromagnetic particles can't read textbooks so they don't often realize that they are not supposed to propagate themselves to the far corners of the world from a measly attic antenna hi! Good luck with your loop! It may surprise you! 73, Stan WB2LQF KX1 #2411K1#2994K2# 6980K3#5244 K9 #1 (Cocoa the Chihuahua) Everything is QRP, even the dog. You seem set on a loop. They work and they work well. __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
