Re: [Elecraft] Attic Antenna
Hi antenna challenged fellow hams. You can do your own stealth gutter antenna these days. Two easy ways: 1) Get a combination of metal gutter and one short section of plastic gutter to join two metal halves of a dipole. Remember, you can use shorter than quarter wave lengths of elements, since their cross section is large compared to wavelength. 2) Even easier: Get all plastic. Lay dipole elements in bottom of plastic gutter. Even hook up wire can be used for elements. Glue them to corner of gutter bottom that will be furtherest from the house. Better still, glue them UNDER the gutter corner, so water in gutter will not stand on antenna wire. Use 1/4 inch coax feed to feedpoint, or twin lead, again glued to underside of gutter. Run it into soffit, and then to rig. An all band tuner, will facilitate operations on multiple bands, especially if the dipole is at least 60 per cent of a half wave for the lowest frequency of interest. Your nearest Lowe's or Home Depot is already a stealth antenna store, and you did not know it. Even coax can be purchased there! I regularly use insulators and standoff's from Home Depot's electric fence department for various home antenna projects. They have a compression spring for electric fence gates that is ideal for relieving stress in a dipole element tied to a tree. Unlike a door spring which is extension type, this spring will not elongate with use. At least, not as much as extension springs. Stuart K5KVH ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
Re: [Elecraft] Attic Antenna
Looking like ELECRAFT should consider getting into the STEALTH ANTENNA game. A stealth vertical perhaps, one could just lean up against the home. Or a gutter-shaped antenna, that would easily attach to one's home front facia. There's certainly interest and need for one. Fred N3CSY displaced Buffalonian Access over 1 million songs - Yahoo! Music Unlimited (http://music.yahoo.com/unlimited) ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
Re: [Elecraft] Attic Antenna
In a message dated 10/27/06 4:38:23 PM Eastern Daylight Time, [EMAIL PROTECTED] writes: The Diamond bottom tube may, (and likely) contains a broad band ferrite cable choke. Probably - to keep RF off the outside of the coax. Such a choke would cost a few dollars at most. Or there may be a combination trap/ loading coil such as used on some tri band beams for multibands. No, that wouldn't work. Traps are used in the radiator itself, not at one end. The BB7 claims SWR of less than 2:1 over the entire range. Traps and loading coils won't do that. It's resistively loaded. 73 de Jim, N2EY ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
Re: [Elecraft] Attic Antenna
[EMAIL PROTECTED] wrote: In a message dated 10/27/06 4:38:23 PM Eastern Daylight Time, [EMAIL PROTECTED] writes: The Diamond bottom tube may, (and likely) contains a broad band ferrite cable choke. Probably - to keep RF off the outside of the coax. Such a choke would cost a few dollars at most. Actually, a choke on the coax would *prevent* the antenna from working unless it was mounted on a metal mast. It needs a counterpoise and the coax shield provides it unless a mast or radials are present. This is actually similar to the 'e-h' antenna, in which the alleged 'antenna' at the end of the feedline serves to tune the shield of the feedline to resonance. The shield actually does the radiating. Adding a bead balun to an e-h antenna causes the antenna to stop working and the balun to get hot! No, I don't want to start a thread on this antenna either! In the Diamond antenna, the feedline is only half of the antenna, with the 22-foot radiator being the other half and the resistor smoothing out the SWR variations. -- 73, Vic, K2VCO Fresno CA http://www.qsl.net/k2vco ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
Re: [Elecraft] Attic Antenna
In a message dated 10/29/06 11:12:34 AM Eastern Standard Time, [EMAIL PROTECTED] writes: [EMAIL PROTECTED] wrote: In a message dated 10/27/06 4:38:23 PM Eastern Daylight Time, [EMAIL PROTECTED] writes: The Diamond bottom tube may, (and likely) contains a broad band ferrite cable choke. Probably - to keep RF off the outside of the coax. Such a choke would cost a few dollars at most. Actually, a choke on the coax would *prevent* the antenna from working unless it was mounted on a metal mast. It needs a counterpoise and the coax shield provides it unless a mast or radials are present. Agreed. Note that in the literature, the unit is shown on a metal mast. This is actually similar to the 'e-h' antenna, in which the alleged 'antenna' at the end of the feedline serves to tune the shield of the feedline to resonance. The shield actually does the radiating. Adding a bead balun to an e-h antenna causes the antenna to stop working and the balun to get hot! No, I don't want to start a thread on this antenna either! Good idea. In the Diamond antenna, the feedline is only half of the antenna, with the 22-foot radiator being the other half and the resistor smoothing out the SWR variations. Or the mast. So what's probably in the matcher is really just a resistor. $400 for 22 feet of tubing, a mast clamp, and a nice noninductive resistor. 73 de Jim, N2EY ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
RE: [Elecraft] Attic Antenna
I'm surprised with all this talk of dipoles and doublets that no-one has mentioned loops. I'm not an antenna expert, but it has always seemed to me that the efficiency of an antenna is somewhat related to the amount of wire in the radiating element. You can get more wire in a loop round the periphery of an attic than you will get in a dipole strung in the apex of it. It may not give a 50 ohm match, but nor will the dipole except at one frequency. If you feed it with ladder line and a balun, or a very short length of co-ax, feeder losses will be kept to a minimum. That's what I use. 73 de Julian, G4ILO. K2 #392 G4ILO's Shack: http://www.g4ilo.com ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
Re: [Elecraft] Attic Antenna
Julian I agree with your sentiment. My 'doublet' was nearly a loop, ie it followed the beams around the loft. The ends were left open, about a foot apart. David G3UNA - Original Message - From: [EMAIL PROTECTED] To: elecraft@mailman.qth.net Sent: Saturday, October 28, 2006 12:22 PM Subject: RE: [Elecraft] Attic Antenna I'm surprised with all this talk of dipoles and doublets that no-one has mentioned loops. I'm not an antenna expert, but it has always seemed to me that the efficiency of an antenna is somewhat related to the amount of wire in the radiating element. You can get more wire in a loop round the periphery of an attic than you will get in a dipole strung in the apex of it. It may not give a 50 ohm match, but nor will the dipole except at one frequency. If you feed it with ladder line and a balun, or a very short length of co-ax, feeder losses will be kept to a minimum. That's what I use. 73 de Julian, G4ILO. K2 #392 G4ILO's Shack: http://www.g4ilo.com ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
[Elecraft] Attic Antenna
Hi - I notice Diamond Antennas - now offers a BB7V and BB6W VERTICAL NO-COUNTERPOISE HF ANTENNA - for the ham bands. They look to be built very well. The BB6W version, offers a HORIZONTAL top section, up above the antenna's loading coil. Whole thing mounts on a single vertical pole, etc. The BB7V is sold by Universal Radio Inc. in Ohio. I think the BB6W is not yet available at any U.S. ham stores. But may be wrong on that. I saw an article where the Australian hams were using the BB7V with success. I'm sure a tuner is required. Fred N3CSY .stealth, association restricted too __ Do You Yahoo!? Tired of spam? Yahoo! Mail has the best spam protection around http://mail.yahoo.com ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
Re: [Elecraft] Attic Antenna
-Original Message- Diamond Antennas - now offers a BB7V and BB6W VERTICAL NO-COUNTERPOISE HF ANTENNA - for the ham bands. They look to be built very well. --- I would want a lot more info before spending any money. The BB7V is priced at US$400. It's a 22 foot vertical aluminum radiator with a nice mast clamp (mast not included) and a cylindrical feedpoint device. The big question is: What's in the feedpoint device? None of the literature gives any detail on how the feedpoint device converts the complex impedance at the bottom of the 22 foot vertical radiator into 50 ohms. SWR of 2 or less from 2 to 30 MHz is claimed. The feedpoint device does not have any external controls or indications. The radiator and mast clamp assembly can't be worth more than $100 retail. So what is in the feedpoint device that is worth $300? The name Maxx-Comm comes to mind. 73 de Jim, N2EY Check out the new AOL. Most comprehensive set of free safety and security tools, free access to millions of high-quality videos from across the web, free AOL Mail and more. ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
Re: [Elecraft] Attic Antenna
[EMAIL PROTECTED] wrote: I would want a lot more info before spending any money. The BB7V is priced at US$400. It's a 22 foot vertical aluminum radiator with a nice mast clamp (mast not included) and a cylindrical feedpoint device. The big question is: What's in the feedpoint device? Here's some more information (but no mention of what's in the magic cylinder): http://www.hamradio.co.uk/pdf/Diamond/BB7V.pdf However, it is possible to see that the radiator is a continuous conductor. Therefore, the counterpoise function must be provided by the mast, coax shield, or lossy ground (depending on mounting). This means the antenna's performance would be highly dependent on mounting, and it would be prone to RFI and RF-in-the-shack issues. The antenna supposedly works from 3-30 MHz with SWR less than 2:1. The SWR curve shown is suspiciously similar to that of a resistively loaded antenna. Such antennas can be useful in certain circumstances (BW makes several versions), but the efficiency can be quite low on frequencies where the impedance of the radiating part is high or reactive. The BW antennas are well designed and relatively large; even so, the efficiency is significantly below that of a dipole. A 22-foot vertical without top loading will be inefficient on 7 MHz (it will be a dummy load on 3.5), especially without a decent counterpoise. Even if one only has room for a 22-foot vertical there are lots of better choices. I agree with Jim. Put up a dipole and spend the leftover $395 on beer. -- 73, Vic, K2VCO Fresno CA http://www.qsl.net/k2vco ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
Re: [Elecraft] Attic Antenna
It reminds me of the verticals Gotham made in the 1950s. Bob, N7XY ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
Re: [Elecraft] Attic Antenna
-Original Message- From: [EMAIL PROTECTED] It reminds me of the verticals Gotham made in the 1950s. But it's very different. The Gotham verticals were just 22 feet of tubing, some mounting straps, and a big custom-made coil of B W miniductor. The only difference between the various models was how big a coil they sent. You supplied the feedline, mounting, some hardware, a ground or counterpoise, and a weatherproof cover for the coil. The way the Gotham verticals worked was that you connected the coil between the bottom of the 22 foot radiator and ground/counterpoise. Then you connected the coax braid to ground. You also needed to tap the coax center conductor onto the coil, and to short out turns at the top of the coil. The trick was that with the right number of turns shorted out at the top of the coil, and the center conductor tapped on at the right spot, you'd get a low SWR on the frequency of your choice. Of course if you QSYd, you had to go change the taps and shorting jumper. Since the coil was at the base of the antenna, that could be convenient - maybe. Depending on how good the ground connection was, and what band you were using, performance could range from great to awful. 22 feet is about 5/8 wave on 10 meters, too. The BB7W doesn't work like that. There's some sort of magic, nonadjustable network inside the feedpoint device. I suspect it has a near-unity power factor. 73 de Jim, N2EY Check out the new AOL. Most comprehensive set of free safety and security tools, free access to millions of high-quality videos from across the web, free AOL Mail and more. ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
Re: [Elecraft] Attic Antenna
The Diamond bottom tube may, (and likely) contains a broad band ferrite cable choke. Or there may be a combination trap/ loading coil such as used on some tri band beams for multibands. Stuart K5KVH ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
Re: [Elecraft] Attic Antenna
Stuart Rohre wrote: The Diamond bottom tube may, (and likely) contains a broad band ferrite cable choke. Or there may be a combination trap/ loading coil such as used on some tri band beams for multibands. No way that a choke would produce the SWR curve shown in their spec sheet. Whatever else is in there, there's also a resistor. -- 73, Vic, K2VCO Fresno CA http://www.qsl.net/k2vco ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
Re: [Elecraft] Attic Antenna
WARNING! This same scheme (scam?) happened quite a few years ago. Don't remember the name of the device, but is was a black box type proprietary antenna coupler. The price was rather high ($300-400) and it was guaranteed flat SWR between 3-30 Mhz. SO-239 input and two standoff insulators with wing nuts (output). Was said to match a random wire or a balanced line dipole! Someone finally x-rayed one and it turned out to be a dummy load actually. It was enclosed in a cast aluminum Bud box and potted with some sort of opaque epoxy if you took the lid off! They didn't last too long, but long enough for the manufacturer to make a bundle! It was not guaranteed to radiate with high efficiency but was guaranteed to have an input VSWR no greater than 2:1! BEWARE of ANY MAGIC DEVICE that makes these claims. More than likely it is a large pile of bovine fecal matter that they are feeding you! No, I didn't buy one, but in some unusual installations it was tried on some commercial marine limited coast station installations. The results were very mediocre no matter what 'antenna' was tried. Low SWRBUT! Not much radiation! 73, Sandy W5TVW - Original Message - From: Vic K2VCO [EMAIL PROTECTED] To: [EMAIL PROTECTED] Cc: elecraft@mailman.qth.net Sent: Friday, October 27, 2006 12:01 PM Subject: Re: [Elecraft] Attic Antenna | [EMAIL PROTECTED] wrote: | | I would want a lot more info before spending any money. | | The BB7V is priced at US$400. It's a 22 foot vertical aluminum radiator | with a nice mast clamp (mast not included) and a cylindrical feedpoint | device. | | The big question is: What's in the feedpoint device? | | Here's some more information (but no mention of what's in the magic | cylinder): http://www.hamradio.co.uk/pdf/Diamond/BB7V.pdf | | However, it is possible to see that the radiator is a continuous | conductor. Therefore, the counterpoise function must be provided by the | mast, coax shield, or lossy ground (depending on mounting). This means | the antenna's performance would be highly dependent on mounting, and it | would be prone to RFI and RF-in-the-shack issues. | | The antenna supposedly works from 3-30 MHz with SWR less than 2:1. The | SWR curve shown is suspiciously similar to that of a resistively loaded | antenna. Such antennas can be useful in certain circumstances (BW | makes several versions), but the efficiency can be quite low on | frequencies where the impedance of the radiating part is high or | reactive. The BW antennas are well designed and relatively large; even | so, the efficiency is significantly below that of a dipole. | | A 22-foot vertical without top loading will be inefficient on 7 MHz (it | will be a dummy load on 3.5), especially without a decent counterpoise. | | Even if one only has room for a 22-foot vertical there are lots of | better choices. | | I agree with Jim. Put up a dipole and spend the leftover $395 on beer. | -- | 73, | Vic, K2VCO | Fresno CA | http://www.qsl.net/k2vco | ___ | Elecraft mailing list | Post to: Elecraft@mailman.qth.net | You must be a subscriber to post to the list. | Subscriber Info (Addr. Change, sub, unsub etc.): | http://mailman.qth.net/mailman/listinfo/elecraft | | Help: http://mailman.qth.net/subscribers.htm | Elecraft web page: http://www.elecraft.com | | | | -- | No virus found in this incoming message. | Checked by AVG Free Edition. | Version: 7.1.408 / Virus Database: 268.13.17/505 - Release Date: 10/27/2006 | | ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
Re: [Elecraft] Attic Antenna
I would want a lot more info before spending any money. The BB7V is priced at US$400. It's a 22 foot vertical aluminum radiator with a nice mast clamp (mast not included) and a cylindrical feedpoint device. The big question is: What's in the feedpoint device? Sandy wrote of an earlier example: ... the device ... was a black box type proprietary antenna coupler. The price was rather high ($300-400) and it was guaranteed flat SWR between 3-30 Mhz BEWARE of ANY MAGIC DEVICE that makes these claims. More than likely it is a large pile of bovine fecal matter that they are feeding you! That was about 25 years ago, and it was a QST review that exposed this scam. The x-ray showed some junk PCB board that had been potted with the 50 ohm resistor, so that it would appear to have circuitry, should someone actually x-ray the unit. Vic wrote: I agree with Jim. Put up a dipole and spend the leftover $395 on beer. No truer words have ever been written! Even honestly described and advertised HF verticals without a very very very good radial system are terrible performers compared to a simple dipole. Commercial *portable* verticals are especially so, and are also usually absurdly expensive. An example of a money and power waster is the Outbacker-series with their ground coupling base for portable use. It is one of those $400 systems that performs very poorly, compared to a $5 dipole. I've done side-by-side testing of both on several occasions. I was tempted to repeat the old saw about there being no such thing as a free lunch, but that would be wrong. The simple dipole is very close to being free, and it will normally way outperform any HF vertical no matter how much money is dumped into some expensive exotic or bogus design. Reports of success using HF verticals with poor radial systems only show that sometimes contacts can be made with the poorest of radiators. Friends don't let friends use portable HF verticals! 73, Mike / KK5F ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
Re: [Elecraft] Attic Antenna
In a message dated 10/27/06 6:38:11 PM Eastern Daylight Time, [EMAIL PROTECTED] writes: WARNING! This same scheme (scam?) happened quite a few years ago. Don't remember the name of the device, but is was a black box type proprietary antenna coupler. You may be thinking of the Maxx-Com Matcher. The price was rather high ($300-400) and it was guaranteed flat SWR between 3-30 Mhz. Less than 2:1 over the range. And it did! SO-239 input and two standoff insulators with wing nuts (output). Was said to match a random wire or a balanced line dipole! Someone finally x-rayed one and it turned out to be a dummy load actually. It was enclosed in a cast aluminum Bud box and potted with some sort of opaque epoxy if you took the lid off! Someone was the ARRL Lab. They X-rayed the thing and then dissolved the epoxy (a long and messy process), and found what was inside. There was a toroidal transformer, some noninductive resistors, and some circuit boards with ICs on them. The circuit boards were obviously scrapped boards from some digital system or other, and performed no electrical function at all. They simply looked good on the X-ray. They didn't last too long, Not true. Maxx-Com is still around: http://www.maxx-com.com/InstallationInfo.html with a bunch of products. They claim 80% or better efficiency, which is absolute bunk on most frequencies. However, if the wire length is right, it may be possible for the system to be almost that efficient. (See below). but long enough for the manufacturer to make a bundle! It was not guaranteed to radiate with high efficiency but was guaranteed to have an input VSWR no greater than 2:1! BEWARE of ANY MAGIC DEVICE that makes these claims. More than likely it is a large pile of bovine fecal matter that they are feeding you! No, I didn't buy one, but in some unusual installations it was tried on some commercial marine limited coast station installations. The results were very mediocre no matter what 'antenna' was tried. Low SWRBUT! Not much radiation! Here's how such a system *could* work on a few frequencies: Suppose the matcher consists of a T or pi attenuator. The SWR of such a system will not be worse than 2:1 if the attenuator is designed right. IIRC, a 3 dB attenuator will do the job. Suppose an antenna with an impedance of 50 ohms is connected to the other end. The attenuator loss will be minimum, and the SWR 1:1. Such a system could be as efficient as 50% (!) Of course if the attenuator is removed, the efficiency is 100%. The big problem is that as you move away from those few perfect frequencies, the losses grow enormously and the system efficiency goes way down. Of course if you feed 100 watts into an antenna system with 5% efficiency, the result is the same as feeding 5 watts to an antenna system with 100% efficiency. 73 de Jim, N2EY 73 de Jim, N2EY ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
Re: [Elecraft] Attic Antenna
Oh yee of little faith, on non-counterpoise HF Verticals! Some of those mentioned are real junkers. Back to subject - what type of ATTIC ANTENNAS are good, for us living in restricted communities (no antennas) - with attics? BW makes a Folded Dipole, 7-30mhz, 45 feet long - with supposed flat swr? Like $245. Our attic antenna needs to be pretty much left by itself - no trips up there to change frequencies. And 40 thru 10 would be nice. I'm suprised no-one mentioned the performance of that octagonal sheet metal HF antenna that is always advertised in QST. I guess I could get my old ARRL Antenna Book out, and build a trap dipole for the attic .. Or stick a Buddipole up there. ... Stealth 100W Fred N3CSY Get your email and see which of your friends are online - Right on the New Yahoo.com (http://www.yahoo.com/preview) ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
FW: [Elecraft] Attic Antenna
I had some good laughs reading the review of the tuner. The comparisons are quite favorable. Of course, they were comparing their product to a halfway dipole. I guess that meant a dipole halfway assembled, or maybe halfway burried. They didn't sayg. But anyhow, their pos is 80%-90% as efficient. Also, I've never read a review before with no attribution. 15,000 suckers! P.T. Barnum was right (assuming they are telling the truth!). Dan / WG4S / K2 #2456 snip They didn't last too long, Not true. Maxx-Com is still around: http://www.maxx-com.com/InstallationInfo.html /snip ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
Re: [Elecraft] Attic Antenna
Fred (FL) wrote: Back to subject - what type of ATTIC ANTENNAS are good, for us living in restricted communities (no antennas) - with attics? BW makes a Folded Dipole, 7-30mhz, 45 feet long - with supposed flat swr? Like $245. Our attic antenna needs to be pretty much left by itself - no trips up there to change frequencies. And 40 thru 10 would be nice. This *is* resistively loaded. It is not a scam like some, but it is less efficient than an ordinary dipole. A dipole as long as possible in the attic, not parallel to wires/pipes if possible, and fed with ladder line and a balanced tuner would be close to optimum. I'm suprised no-one mentioned the performance of that octagonal sheet metal HF antenna that is always advertised in QST. It's poor. Like anything, it works to some extent. Again, a simple dipole would be much better. I guess I could get my old ARRL Antenna Book out, and build a trap dipole for the attic .. Or stick a Buddipole up there. A trap dipole might require a lot of adjustment due to coupling to nearby conductors. It might be a complicated process to get a reasonable SWR on many bands. It would be easier to just make a tuned doublet and let the balanced tuner take care of it. A buddipole would work, of course, but it is too short for good efficiency on the lower bands and would require you to bound up the stairs to adjust it whenever you changed bands. -- 73, Vic, K2VCO Fresno CA http://www.qsl.net/k2vco ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
Re: [Elecraft] Attic Antenna
In a message dated 10/27/06 7:33:23 PM Eastern Daylight Time, [EMAIL PROTECTED] ink.net writes: Even honestly described and advertised HF verticals without a very very very good radial system are terrible performers compared to a simple dipole. I disagree! The situation is much more complex than that. Commercial *portable* verticals are especially so, and are also usually absurdly expensive. An example of a money and power waster is the Outbacker-series with their ground coupling base for portable use. It is one of those $400 systems that performs very poorly, compared to a $5 dipole. I've done side-by-side testing of both on several occasions. Of course a lossy antenna system - vertical or not - will be bested by an efficient one. There's also the factor of pattern. Verticals are often sold as great for local or DX. And they are - local (up to a few miles) via ground wave, and DX (beyond 1-2 thousand miles) by low-angle radiation. But for everything in between, a dipole is better. I was tempted to repeat the old saw about there being no such thing as a free lunch, but that would be wrong. The simple dipole is very close to being free, and it will normally way outperform any HF vertical no matter how much money is dumped into some expensive exotic or bogus design. Again, it depends. For example, a quarter wave vertical on 20 meters is only 16 feet high. With its base a few feet off the ground, and a dozen sloping radials, it will do as well or better as a dipole 40-50 feet up - *if* it's in a wide-open location. I built such a vertical for portable use from EMT and PVC, and have had great success with it on Field Day. OTOH, a loaded 80 meter vertical with a few radials isn't going to compete with a decent dipole. 73 de Jim, N2EY ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
Re: [Elecraft] Attic Antenna
My usual antenna on a quick setup afield is a 33' vertical wire hoisted by an MFJ-1910 33' fibreglass telescopic pole. This wih a K1 and KAT1 internal tuner. It will tune with no radials but the performance is lousy. Add one 33' radial and it gets much, much better. Add TWO 33' radials and much better yet. If I add two more (a total of four 33' radials and it improves more yet but not a large change. If I add more, hardly notice any change at all for the most part. All radials out of #24 hookup wire and laid on the ground. This for 40 thru 15 meter operation. For 80 meter use a 66' antenna, 33' vertical and the rest to a nearby tree limb from top of the support mast. Sort of an inverted L. This with 2-4 radials 66' long. It works but isn't the best I could do with a better antenna. My trials of whips and short verticals has been dismal. They will work but somewhat poorly so say the least. The MFJ pole and 33' wires seem to be the best setup especially in places where you have trouble finding supports like the middle of a parking lot or field! It won't work where there is a lot of 'foot traffic' or kids as they will constantly be fouling the radials!! Tried all sorts of loading schemes with whips from 4' to 15' and results fair on higher bands (15/20) but very marginal on 40 or lower. also tried shortened loaded dipoles and again it works but poorly. Sometimes you get lucky. Just my 2 cents worth on portable radiators when you are QRP afield. 73 to all, Sandy W5TVW - Original Message - From: Fred (FL) [EMAIL PROTECTED] To: elecraft@mailman.qth.net Sent: Friday, October 27, 2006 8:27 PM Subject: Re: [Elecraft] Attic Antenna | Oh yee of little faith, on non-counterpoise HF | Verticals! Some of those mentioned are real | junkers. | | Back to subject - what type of ATTIC ANTENNAS are | good, for us living in restricted communities (no | antennas) - with attics? | | BW makes a Folded Dipole, 7-30mhz, 45 feet long - | with supposed flat swr? Like $245. Our attic antenna | needs to be pretty much left by itself - no trips up | there to change frequencies. And 40 thru 10 would | be nice. | | I'm suprised no-one mentioned the performance of | that octagonal sheet metal HF antenna that is | always advertised in QST. | | I guess I could get my old ARRL Antenna Book out, | and build a trap dipole for the attic .. | Or stick a Buddipole up there. | | ... Stealth 100W | Fred | N3CSY | | | | | Get your email and see which of your friends are online - Right on the New Yahoo.com | (http://www.yahoo.com/preview) | | ___ | Elecraft mailing list | Post to: Elecraft@mailman.qth.net | You must be a subscriber to post to the list. | Subscriber Info (Addr. Change, sub, unsub etc.): | http://mailman.qth.net/mailman/listinfo/elecraft | | Help: http://mailman.qth.net/subscribers.htm | Elecraft web page: http://www.elecraft.com | | | | -- | No virus found in this incoming message. | Checked by AVG Free Edition. | Version: 7.1.408 / Virus Database: 268.13.17/505 - Release Date: 10/27/2006 | | ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
RE: [Elecraft] Attic Antenna
Fred, N3CSY, asked: what type of ATTIC ANTENNAS are good, for us living in restricted communities (no antennas) - with attics? -- I have and excellent results with doublets. That's a center fed wire as long as I had room for in the attic. In an apartment that was at least 33 feet, perhaps a little more, by making it slightly Z shaped. It doesn't hurt to bend the ends a bit; just try to keep the angles of the bends as large as you have room for. I strung them inverted V style from the rafters with the center up at the peak as much as possible. No RF ground is needed and the antenna is quite efficient. They were fed with invisible open wire line. I made it out of whatever wire was handy for the part in the attic and the visible part was white wire-wrap wire sold by RS and others. It's quite small, about #30. That's not ideal for a feeder but then again my feed line was rather short, especially the part inside the apartment. I tried to arrange the operating desk next to a wall as nearly as possible under the center of the antenna. Directly above the operating position, I used an ice pick to put two small holes in the ceiling right where it joins the wall. The resulting holes are no larger than those produced by hanging a picture. The holes were about 2 inches apart. I used a miniature homebrew ATU that hung on the wall at a convenient height. I positioned the holes to be directly above it. Most apartment walls are white or nearly so the white wire wrap wire is invisible against the wall. I ran two lengths, one for each side of the feeder, up the wall and through the tiny holes into the attic. One or two staples held the wires tightly against the wall. Thumbtacks that match the wall work FB too. Drywall is a good insulator. Up in the attic I ran the two feed wires to the center of the antenna. Bits of plastic cut from film cans, old plastic coat hangars or whatever is handy made up the spacers. It is NOT necessary to have the wires running exactly parallel. Just make sure they don't touch and are sort of parallel to the center of the antenna. I had visitors come to the shack and look all around for the feeders from two feet away without seeing them until I pointed them out. A better choice for the feeder wire might be white hookup wire (if you have white walls), #20 or #22. If your walls are a different color, consider a little touchup paint matching the walls to dip the wire in to color it before installing the feeder. Touch the heads of a couple of thumbtacks with the same paint to hold the wires securely against the wall. Two at the top and two at the bottom are usually plenty. I never had an apartment higher than two floors, but I worked a LOT of DX running 5 to 15 watts on HF CW, mostly 40, 30, and 20 meters. Made a lot of contacts running 2 watts with an HW-8 as well. At 33 feet long, the antenna was full sized for 40 meters. On 80 it was only slightly less efficient than a full half wave. On the higher bands it was really FB. The biggest problems on 80 for me were, 1) Noise from the electrical systems in the apartments including things like touch-lamps and cheap dimmers. Most apartments have the power lines running around the ceilings (grr) and 2) Since my highest apartment was on the second level, the antenna was no more than 30 feet above the ground. That's very low for an 80 meter antenna. But on the higher bands it worked great. You can build that antenna for perhaps $10 if you buy the wire and regular antenna insulators new. If you get creative about what to use for insulators the only cost is the wire and a little time. Ron AC7AC ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
RE: [Elecraft] Attic Antenna
Whups... At 33 feet long my antenna was full sized for 20 meters, not 40 meters as I wrote. It was still quite efficient on 40 - only a tiny bit less efficient than a full size antenna - and would work short skip on 80. I could usually get between 40 and 50 feet up by making the bent ends of the Z about 5 feet or so long. Ron AC7AC ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
RE: [Elecraft] Attic Antenna
Larry originally asked about attic antennas and a concrete tile roof. I have both. I am in Lot 1 next to the gate, and blackmailed my HOA into outdoor HF antennas. I have a Cushcraft R7000 up, which is a half wave trapped antenna, but no radials. Works great. But I also have antennas in my attic. And they get used. A lot. My dipole for 20m has been used a lot and works well. My roof peak is about 22 feet and I have 14 foot ceilings. The main part of the house is about 42x46 feet, so I have a straight shot of about 45 feet in my attic where I can run the wire about 21 feet above the concrete slab. The 20m dipole has been replaced by a dipole with an SGC SG-239 coupler at the feed point. All bands and no SWR on feedline. Works quite well. No problem working Europe on 100 watts. Worked a bit od DX with the K2 barefoot too. The other HF antenna in the attic is a TFD, or terminated folded dipole. This is 45 feet long and homebrewed. I got 2 watt carbon film resistors from eBay, and a 16/1 QRP balun. I used the information from the Cebik site. Basically a squashed terminated loop. Excellent receiving antenna. I do a lot of SW broadcast listening, so this antenna is used for my Palstar R30. My attic antennas work fine. After Hurricane Frances and especially Wilma which passed right over my house, I didn't have any trouble checking into the SATERN net to pass HW. During Wilma I even I even checked in to the Hurricane Watch Net and passed on my reading of 28.00 inches of mercury from my barometer to the NHC. This was while the eye of Wilma was over the house. So attic antennas work. Just (as a lot of the fellows have pointed out) put up a doublet with as much wire as high as you can. And if you can afford to put one of those automatic couplers at the feedpoint(no SWR on the feedline). My 2 cents, but from practical experience and 30 years of ham radio. 73 all de Bob K3YT ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
[Elecraft] Attic Antenna
I live in a restricted community and am thinking about putting a 20 meter dipole in the attic. I know most of the issues with doing this but I don't know the effect the roofing material will have on my signal. The roof is 1/2 in thick cement tiles. Has anyone had experience with this setup? Thanks, Larry, KB5DXY K1 #2269 ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
RE: [Elecraft] Attic Antenna
I live in a restricted community and am thinking about putting a 20 meter dipole in the attic. I know most of the issues with doing this but I don't know the effect the roofing material will have on my signal. The roof is 1/2 in thick cement tiles. Has anyone had experience with this setup? Thanks, Larry, KB5DXY K1 #2269 --- Yep! Not all tiles are equal, so you may be better off. I moved several times about 15 years ago, always living in an apartment. I managed to get a top (second) floor apartment in each case and installed a doublet in the attic in each case. It was hung just under the rafters. In one apartment I noticed that I didn't get out very well, compared to my previous QTH, but my antenna arrangement was very similar! On air testing is just about useless to determine how well an antenna is working so I didn't panic over it. But, over several months a suspicion grew. One day I noticed walk near my building a piece of roofing tile that had apparently dropped there while some repairs were being done. Curious, I took it indoors. It was a hot summer day and the tile piece was quite dry. I put it in my microwave oven (with a glass of water to avoid running it 'empty') let it cook for a minute or two. The roof tile was very hot! That's a sure sign it's pretty opaque to RF. Of course, it's probably more opaque at microwave frequencies than at HF, but it's still going to be lossy. If you can get a piece of tile, do the test for yourself. You may be a lot better off than I was. I did a little research and found that those tile mixes often have a lot of stuff not normally found in concrete and that the formulas vary substantially from one supplier to another. That's about all I could dig up on the subject. Let me say that I made a LOT of contacts from under those tiles, using QRP on 40 and 20 meters, including substantial DX. That's the problem with on-air testing. A punk poor antenna can sound *great* when the band conditions are right. So if that's what you have to do to get on the air, go for it. Ron AC7AC ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
Re: [Elecraft] Attic Antenna
I live in a restricted community and am thinking about putting a 20 meter dipole in the attic. I know most of the issues with doing this but I don't know the effect the roofing material will have on my signal. The roof is 1/2 in thick cement tiles. Has anyone had experience with this setup? Thanks, Larry, KB5DXY K1 #2269 = The attenuation of any materal is a function of its thickness, measured in wavelengths, as well as its electrical properties. This means that for a given roof material, you will have less signal attenuation at 160 M then at 10 M. This should be true for trees, rain or snow also. This is why the US Navy uses extreme low frequencies to communicate with subs under water. Like in the audio range, except its still radio. I tried a 20 M. dipole in my wood framed attic before I hade an antenna tuner. The SWR was way high, like 4:1. I think this was due to the close proximity of electrical wires. The antenna would probably have worked fine with a tuner. Rick Dettinger K7MW ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
Re: [Elecraft] Attic Antenna
Thanks for all of the great feedback. I am going to research some of the antenna suggestions that I have received. I feel a lot more confident in trying an antenna in the attic now. I am currently building my K1. I have finished the receiver and am starting the transmitter section. I will also be adding a KAT1. I will report back with results when I get the whole thing working. Larry, KB5DXY K1 #2269 (in progress) ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
[Elecraft] Attic Antenna
Larry . I have experience with a similar situation. I'm also in a HOA restricted development. I put up an antenna in the attic here when I first started operating from this QTH. Basically a 17 meter doublet with 300 ohm ladderline feeder that I can load on all bands from 10 to 40 with the internal tuner in my K2 and an Elecraft balun. My shingles are the more normal asphalt type, but the exterior sheathing of the house has an aluminum coating on one side which no doubt attenuates the RF some. And of course the antenna picks up more powerline noise and noise from household electronics than would an outside antenna. I've made a few hundred contacts on it on 40, 30, 20 and 17 using the 10 watts CW from my K2. Haven't really tried on 15, 12 and 10 due to the current sunspot situation. So it will work. That said, this year I got a Buddipole and set it up when I operate on a temporary basis on the patio. I most normally use it in a vertical arrangement with a single counterpoise wire and an extra length shock-cord whip assembly. This will run circles around the attic dipole, especially for DX. At least 2 S units better. And it is fairly low profile, so that you might be able to get away with it as far as your neighbors are concerned. Within 10 minutes yesterday I worked the XF4DL DXpedition on 20 and 17 with the Buddipole and 10W from Colorado. The day before I worked them on 40. The attic dipole has been effective mostly for stateside contacts. Another antenna I have that could be a possibility for you is a set of base-fed verticals running up one side of the house. You can feed them all with one feedline. The proximity of the house and the other radiators will detune them, but a couple of hours with an antenna analyzer will sort everything out. I have the 40 and 80 meter elements running over the rooftop in an inverted L arrangement. By inserting some base loading, I can use the 80 meter element on 160. All this is VERY stealth - use the AWG 26 stealth black insulated copperweld wire and paint it to match your house. Lay a few radials out on the ground and around your foundation. The performance of this arrangement here is about midway between the attic dipole and the outside Buddipole Vertical. The key is to be open-minded and experiment - you will find something that works. The attic dipole is a good place to begin and will always be a good secondary antenna even if you find something you like better later on. 73 . Craig AC0DS ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
