Re: [Elecraft] ANTENNA QUESTION
As Wayne N6KR mentioned yesterday, "I’ll be speaking at Pacificon's antenna symposium tomorrow (Friday, Oct. 20th). My presentation, from 3:30 to 4:30 PM, is on antennas for ultra-portable HF operation. This talk was a late addition, a previous speaker having dropped out. If you’re interested in attending the symposium, check the website ( pacificon.org). Tickets must be purchase in advance. As part of my talk I’ll be discussing a new portable antenna, the Elecraft AX1, designed specifically for the KX2 and KX3. We’ll also be showing the prototype at our booth. We’re not taking orders for the AX1 yet, so please don’t call Elecraft Hq about it :) That said, I’ll be happy to send out an early draft of the FAQ on request. Please email me directly. 73, Wayne N6KR" --- 72, Rich Hurd / WC3T / DMR: 3142737 PA Army MARS, Northampton County RACES, EPA-ARRL Public Information Officer for Scouting Latitude: 40.761621 Longitude: -75.288988 (40°45.68' N 75°17.33' W) Grid: *FN20is* On Fri, Oct 20, 2017 at 3:51 PM, Gerry Miller wrote: > WHAT IS THE AX1 THAT I HAVE READ COMMENTS ABOUT. ARE THERE FURTHER > DESCRIPTIONS OR PHOTO'S RE THIS ANTENNA?GERRY MILLER, aa...@juno.com > > 1 Simple Trick Removes Eye Bags & Lip Lines In Seconds > Fit Mom Daily > http://thirdpartyoffers.juno.com/TGL3141/59ea54012a29154013571st03vuc > __ > 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 > Message delivered to r...@wc3t.us > __ 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 Message delivered to arch...@mail-archive.com
Re: [Elecraft] Antenna Question
Danny, Glad you like them. Maybe I need to start a ‘no barrel connectors’ group ;-) 73, David G3WGN M6O From: danny.higg...@keme.co.uk [mailto:danny.higg...@keme.co.uk] Sent: 13 October 2016 09:52 To: CUTTER DAVID ; David Aslin G3WGN ; elecraft Subject: RE: [Elecraft] Antenna Question Hi David. Thanks for the information. I ordered some compression PL259s and SO239s yesterday direct from Barenco, and they arrived this morning, at a fraction of the cost I last paid from a retail Ham supplier. They look quite chunky with protective caps on the end, which I would not expect from a cheap manufacturer. I can at last get rid of the SO239 barrels that have given me intermittent problems on my long co-ax cables. Regards, Danny, G3XVR From: CUTTER DAVID<mailto:d.cut...@ntlworld.com> Sent: 12 October 2016 09:17 To: Dave G3WGN M6O<mailto:da...@aslinvc.com>; elecraft<mailto:elecraft@mailman.qth.net> Subject: Re: [Elecraft] Antenna Question I bought a batch of Barenco 259s amongst others and I am mightily impressed, very chunky, very smooth and not expensive. David, G3UNA > > On 11 October 2016 at 22:50 Dave G3WGN M6O > mailto:da...@aslinvc.com>> wrote: > > > Not oddball in EU, nor expensive. Good quality ones are available from > Kabel-Kusch in Germany and Barenco in UK: > > > http://www.barenco.co.uk/uhf-line-socket-so239-jacks-rg213-clamp-top-hat-compression-body-solder-pin-165425. > China RF do some good ones via Fleabay too. > We use these extensively in our 6Gs DXpeditions, together with compression > type PL259s. A side benefit is that it's easy to terminate the coax feed > from multiple station in female connectors (forming a 'patch panel' in > effect) so there is zero risk of cross-coupling 2 stations. > My own station has mostly been converted to compression types; but there > are > Amphenols in there too. Motivation to change? Ease of waterproofing the > compression types. > Just my 2 pence/2c, > 73, David G3WGN M6O WJ6O > > > > Josh Fiden wrote > > Cable mount female UHF is an oddball and expensive. To avoid barrels, I > > use type N female cable mount which are common. > > > > 73, > > Josh W6XU > > > > On 10/11/2016 3:52 AM, Nr4c wrote: > >> Why use barrels? Doesn't Amphenol or Pastornack make a female UHF > >> connector to put on cable end. For this specific use, a custom built > >> cable seems appropriate. > > > > __ > > Elecraft mailing list > > Home: http://mailman.qth.net/mailman/listinfo/elecraft > > Help: http://mailman.qth.net/mmfaq.htm > > Post: mailto: > > > Elecraft@.qth<mailto:Elecraft@.qth> > > > > > This list hosted by: http://www.qsl.net > > Please help support this email list: http://www.qsl.net/donate.html > > Message delivered to > > > > lists+1215531472858-365791@.nabble<mailto:lists+1215531472858-365791@.nabble> > > > > > > -- > View this message in context: > http://elecraft.365791.n2.nabble.com/Antenna-Question-tp7623210p7623260.html > Sent from the Elecraft mailing list archive at Nabble.com. > __ > 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 > Message delivered to d.cut...@ntlworld.com<mailto:d.cut...@ntlworld.com> > __ 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 Message delivered to danny.higg...@keme.co.uk<mailto:danny.higg...@keme.co.uk> __ 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 Message delivered to arch...@mail-archive.com
Re: [Elecraft] Antenna Question
Hi David. Thanks for the information. I ordered some compression PL259s and SO239s yesterday direct from Barenco, and they arrived this morning, at a fraction of the cost I last paid from a retail Ham supplier. They look quite chunky with protective caps on the end, which I would not expect from a cheap manufacturer. I can at last get rid of the SO239 barrels that have given me intermittent problems on my long co-ax cables. Regards, Danny, G3XVR From: CUTTER DAVID Sent: 12 October 2016 09:17 To: Dave G3WGN M6O; elecraft Subject: Re: [Elecraft] Antenna Question I bought a batch of Barenco 259s amongst others and I am mightily impressed, very chunky, very smooth and not expensive. David, G3UNA > > On 11 October 2016 at 22:50 Dave G3WGN M6O wrote: > > > Not oddball in EU, nor expensive. Good quality ones are available from > Kabel-Kusch in Germany and Barenco in UK: > > > http://www.barenco.co.uk/uhf-line-socket-so239-jacks-rg213-clamp-top-hat-compression-body-solder-pin-165425. > China RF do some good ones via Fleabay too. > We use these extensively in our 6Gs DXpeditions, together with compression > type PL259s. A side benefit is that it's easy to terminate the coax feed > from multiple station in female connectors (forming a 'patch panel' in > effect) so there is zero risk of cross-coupling 2 stations. > My own station has mostly been converted to compression types; but there > are > Amphenols in there too. Motivation to change? Ease of waterproofing the > compression types. > Just my 2 pence/2c, > 73, David G3WGN M6O WJ6O > > > > Josh Fiden wrote > > Cable mount female UHF is an oddball and expensive. To avoid barrels, I > > use type N female cable mount which are common. > > > > 73, > > Josh W6XU > > > > On 10/11/2016 3:52 AM, Nr4c wrote: > >> Why use barrels? Doesn't Amphenol or Pastornack make a female UHF > >> connector to put on cable end. For this specific use, a custom built > >> cable seems appropriate. > > > > __ > > Elecraft mailing list > > Home: http://mailman.qth.net/mailman/listinfo/elecraft > > Help: http://mailman.qth.net/mmfaq.htm > > Post: mailto: > > > Elecraft@.qth > > > > > This list hosted by: http://www.qsl.net > > Please help support this email list: http://www.qsl.net/donate.html > > Message delivered to > > > lists+1215531472858-365791@.nabble > > > > > > -- > View this message in context: > http://elecraft.365791.n2.nabble.com/Antenna-Question-tp7623210p7623260.html > Sent from the Elecraft mailing list archive at Nabble.com. > __ > 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 > Message delivered to d.cut...@ntlworld.com > __ 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 Message delivered to danny.higg...@keme.co.uk __ 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 Message delivered to arch...@mail-archive.com
Re: [Elecraft] Antenna Question
(I am trying to get caught up on my email. Forgive me if this has been closed.) This caught my eye, and I agree. I have found when buying PL-259's that are made in a 'metric' country, there can be slight problems converting to the dimensions used in North America. I have chased SWR troubles almost in circles only to find the tip of an imported PL-259 was making intermittent contact with the SO-239 socket. A simple fix was to apply a bit of solder to the tip and then file it down until I could feel a gentle friction as I plugged it into the socket. Another important item in a PL-259 is a good tinned surface for soldering. I like the so called 'silver plated' plugs when I can find them. I don't know if they are truly silver plated, but they do take solder beautifully. Dick, n0ce On 10/11/2016 11:36 AM, Jim Brown wrote: On Tue,10/11/2016 6:29 AM, Charlie T, K3ICH wrote: I'm curious as to exactly why a "junk" connector supposedly has so much more loss than a "good" connector? Junk connectors have several issues. One of the issues is control of dimensions -- the diameter of the tip must be "right" to make a solid and reliable connection to the mating connector. I've seen junk barrels, tees, and elbows that had a tiny spring between the ends of the connector. __ 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 Message delivered to arch...@mail-archive.com
Re: [Elecraft] Antenna Question
I bought a batch of Barenco 259s amongst others and I am mightily impressed, very chunky, very smooth and not expensive. David, G3UNA > > On 11 October 2016 at 22:50 Dave G3WGN M6O wrote: > > > Not oddball in EU, nor expensive. Good quality ones are available from > Kabel-Kusch in Germany and Barenco in UK: > > > http://www.barenco.co.uk/uhf-line-socket-so239-jacks-rg213-clamp-top-hat-compression-body-solder-pin-165425. > China RF do some good ones via Fleabay too. > We use these extensively in our 6Gs DXpeditions, together with compression > type PL259s. A side benefit is that it's easy to terminate the coax feed > from multiple station in female connectors (forming a 'patch panel' in > effect) so there is zero risk of cross-coupling 2 stations. > My own station has mostly been converted to compression types; but there > are > Amphenols in there too. Motivation to change? Ease of waterproofing the > compression types. > Just my 2 pence/2c, > 73, David G3WGN M6O WJ6O > > > > Josh Fiden wrote > > Cable mount female UHF is an oddball and expensive. To avoid barrels, I > > use type N female cable mount which are common. > > > > 73, > > Josh W6XU > > > > On 10/11/2016 3:52 AM, Nr4c wrote: > >> Why use barrels? Doesn't Amphenol or Pastornack make a female UHF > >> connector to put on cable end. For this specific use, a custom built > >> cable seems appropriate. > > > > __ > > Elecraft mailing list > > Home: http://mailman.qth.net/mailman/listinfo/elecraft > > Help: http://mailman.qth.net/mmfaq.htm > > Post: mailto: > > > Elecraft@.qth > > > > > This list hosted by: http://www.qsl.net > > Please help support this email list: http://www.qsl.net/donate.html > > Message delivered to > > > lists+1215531472858-365791@.nabble > > > > > > -- > View this message in context: > http://elecraft.365791.n2.nabble.com/Antenna-Question-tp7623210p7623260.html > Sent from the Elecraft mailing list archive at Nabble.com. > __ > 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 > Message delivered to d.cut...@ntlworld.com > __ 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 Message delivered to arch...@mail-archive.com
Re: [Elecraft] Antenna Question
Not oddball in EU, nor expensive. Good quality ones are available from Kabel-Kusch in Germany and Barenco in UK: http://www.barenco.co.uk/uhf-line-socket-so239-jacks-rg213-clamp-top-hat-compression-body-solder-pin-165425. China RF do some good ones via Fleabay too. We use these extensively in our 6Gs DXpeditions, together with compression type PL259s. A side benefit is that it's easy to terminate the coax feed from multiple station in female connectors (forming a 'patch panel' in effect) so there is zero risk of cross-coupling 2 stations. My own station has mostly been converted to compression types; but there are Amphenols in there too. Motivation to change? Ease of waterproofing the compression types. Just my 2 pence/2c, 73, David G3WGN M6O WJ6O Josh Fiden wrote > Cable mount female UHF is an oddball and expensive. To avoid barrels, I > use type N female cable mount which are common. > > 73, > Josh W6XU > > On 10/11/2016 3:52 AM, Nr4c wrote: >> Why use barrels? Doesn't Amphenol or Pastornack make a female UHF >> connector to put on cable end. For this specific use, a custom built >> cable seems appropriate. > > __ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto: > Elecraft@.qth > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > Message delivered to > lists+1215531472858-365791@.nabble -- View this message in context: http://elecraft.365791.n2.nabble.com/Antenna-Question-tp7623210p7623260.html Sent from the Elecraft mailing list archive at Nabble.com. __ 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 Message delivered to arch...@mail-archive.com
Re: [Elecraft] Antenna Question
Here's what I use for the run up the mast to my HexBeam. The center conductor is stranded copper, and the jacket is thermoplastic elastomer. MUCH more flexible than standard LMR-400...thus, the name LMR-400 UltraFlex: https://www.dxengineering.com/parts/tmv-lmr-400ultra I have a run going up the mast support forming a loop at the HexBeam. About 25 feet of a run of 250 feet of standard LMR-400. Barrel connectors cause negligible signal loss. Connection is protected by internal "Stuff" application, and externally by Coax-Seal. Mark KD8EDC On Mon, Oct 10, 2016 at 9:37 PM, John Parker wrote: > There is a stranded center conductor version of the LM400, do not remember > what the designation is. I plan to use some for the same reason, going > around a rotor to a HexBeam. > 73, John WB4UHCK3 #2165 > > On Monday, October 10, 2016 6:16 PM, "hsherr...@reagan.com" < > hsherr...@reagan.com> wrote: > > > OK all. I'm installing a 6m rotating beam and feeding it with LMR400. > Would you connect the LMR to the antenna and allow it to move with the > rotation, or run a short length of something much more flexible between the > antenna and LMR? I have my concerns that the solid heavy inner conductor of > the LMR won't take much movement. > > Harlan > K4HES > > __ > 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 > Message delivered to johnj...@verizon.net > > > > __ > 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 > Message delivered to tkddr...@gmail.com > __ 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 Message delivered to arch...@mail-archive.com
Re: [Elecraft] Antenna Question
Cable mount female UHF is an oddball and expensive. To avoid barrels, I use type N female cable mount which are common. 73, Josh W6XU On 10/11/2016 3:52 AM, Nr4c wrote: Why use barrels? Doesn't Amphenol or Pastornack make a female UHF connector to put on cable end. For this specific use, a custom built cable seems appropriate. __ 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 Message delivered to arch...@mail-archive.com
Re: [Elecraft] Antenna Question
On Tue,10/11/2016 6:29 AM, Charlie T, K3ICH wrote: I'm curious as to exactly why a "junk" connector supposedly has so much more loss than a "good" connector? Junk connectors have several issues. One of the issues is control of dimensions -- the diameter of the tip must be "right" to make a solid and reliable connection to the mating connector. I've seen junk barrels, tees, and elbows that had a tiny spring between the ends of the connector. When I got back on the air in 2003, I stocked my "junk box" with a lot of these cheap connector adapters at ham flea markets, and over the next 3-5 years, they caused outright failures and intermittent problems that were difficult to track down. At one point, I had added elbow connectors in my shack to make cable routing cleaner. An hour into a contest running legal limit, I saw SWR going sky high on an antenna, found the elbow very hot to the touch. Removing it solved the problem. The tiny spring had overheated. I've had these junk connectors fall apart mechanically. I've had the dielectric in junk PL-259s melt when I soldered the center conductor. And so on. W3LPL advises to use Amphenol connectors exclusively, and to use only 83-1SP for PL-259s. I strongly agree with him. I know nothing about what's available in EU -- my comments apply to North America. 73, Jim K9YC __ 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 Message delivered to arch...@mail-archive.com
Re: [Elecraft] Antenna Question
a much better good connector that prople think Bob K3DJC On Tue, 11 Oct 2016 09:29:19 -0400 "Charlie T, K3ICH" writes: > I'm curious as to exactly why a "junk" connector supposedly has so > much more > loss than a "good" connector? > __ 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 Message delivered to arch...@mail-archive.com
Re: [Elecraft] Antenna Question
I'm curious as to exactly why a "junk" connector supposedly has so much more loss than a "good" connector? They're probably both (nickel, silver ???) plated brass with a dielectric insulator usually Teflon, phenolic or ?? Is it the plating, the insulator, the fit of the threads, the solder-ability, or what, that makes the lossy? I can understand it if the dimensions are way off or they don't thread on properly, but that should be obvious in the installation process. Not trying to start a fight or insult anyone. 73, Charlie k3ICH __ 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 Message delivered to arch...@mail-archive.com
Re: [Elecraft] Antenna Question
SOME 'junk' PL259s are fine. If there are problems with the threads you will know right away. I have had some that are plated with something that won't take solder, or which have plastic insulation that melts when you solder the center pin. But again, you will know this right away. SO239s and barrels may have contact tension problems that take awhile to manifest themselves. And elbows and Ts can have internal issues (like the famous elbows with little springs to join the two parts). For these, only Amphenol or mil-spec will do. Having said all this, just before I moved here, I ordered a bunch of Amphenol connectors, including the PL259s. 73, Vic, 4X6GP Rehovot, Israel Formerly K2VCO http://www.qsl.net/k2vco/ On 11 Oct 2016 11:38, Jim Brown wrote: On Mon,10/10/2016 4:49 PM, Josh Fiden wrote: If you're concerned about the additional loss of a barrel connector at 50MHz, you should be using feedline with lower loss than LMR400 up the tower. The loss in GOOD quality UHF connectors and barrels at 50 MHz is negligible. There are urban legends (false, as usual) claiming that every connector loses a dB. The grain of truth is that JUNK connectors may introduce significant loss, but GOOD connectors and barrels do NOT. "Good" means Amphenol 83-1SP for the PL-259s, and Amphenol or surplus MIL-spec for the barrels. Several years ago, I made up more than a dozen 100 ft cables using a cable of somewhat better construction than LMR400 (Commscope 3227) for a DX trip. The connectors were Amphenol 83-1SP that I soldered myself. To test those cables, I spliced them together using Amphenol barrels and measured the loss of about 1300 ft of cable up to 500 MHz using HP generator and spectrum analyzer. The measured loss was LESS than the manufacturer's spec. There were 27 83-1SPs and 13 barrels in line. JUNK connectors are the shiny,unbranded stuff you see at ham flea markets, and sold online and in ham magazines. 73, Jim K9YC __ 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 Message delivered to arch...@mail-archive.com
Re: [Elecraft] Antenna Question
Why use barrels? Doesn't Amphenol or Pastornack make a female UHF connector to put on cable end. For this specific use, a custom built cable seems appropriate. Sent from my iPhone ...nr4c. bill > On Oct 11, 2016, at 4:38 AM, Jim Brown wrote: > >> On Mon,10/10/2016 4:49 PM, Josh Fiden wrote: >> If you're concerned about the additional loss of a barrel connector at >> 50MHz, you should be using feedline with lower loss than LMR400 up the tower. > > The loss in GOOD quality UHF connectors and barrels at 50 MHz is negligible. > There are urban legends (false, as usual) claiming that every connector loses > a dB. The grain of truth is that JUNK connectors may introduce significant > loss, but GOOD connectors and barrels do NOT. "Good" means Amphenol 83-1SP > for the PL-259s, and Amphenol or surplus MIL-spec for the barrels. > > Several years ago, I made up more than a dozen 100 ft cables using a cable of > somewhat better construction than LMR400 (Commscope 3227) for a DX trip. The > connectors were Amphenol 83-1SP that I soldered myself. To test those cables, > I spliced them together using Amphenol barrels and measured the loss of about > 1300 ft of cable up to 500 MHz using HP generator and spectrum analyzer. The > measured loss was LESS than the manufacturer's spec. There were 27 83-1SPs > and 13 barrels in line. > > JUNK connectors are the shiny,unbranded stuff you see at ham flea markets, > and sold online and in ham magazines. > > 73, Jim K9YC > > __ > 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 > Message delivered to n...@widomaker.com __ 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 Message delivered to arch...@mail-archive.com
Re: [Elecraft] Antenna Question
On Mon,10/10/2016 4:49 PM, Josh Fiden wrote: If you're concerned about the additional loss of a barrel connector at 50MHz, you should be using feedline with lower loss than LMR400 up the tower. The loss in GOOD quality UHF connectors and barrels at 50 MHz is negligible. There are urban legends (false, as usual) claiming that every connector loses a dB. The grain of truth is that JUNK connectors may introduce significant loss, but GOOD connectors and barrels do NOT. "Good" means Amphenol 83-1SP for the PL-259s, and Amphenol or surplus MIL-spec for the barrels. Several years ago, I made up more than a dozen 100 ft cables using a cable of somewhat better construction than LMR400 (Commscope 3227) for a DX trip. The connectors were Amphenol 83-1SP that I soldered myself. To test those cables, I spliced them together using Amphenol barrels and measured the loss of about 1300 ft of cable up to 500 MHz using HP generator and spectrum analyzer. The measured loss was LESS than the manufacturer's spec. There were 27 83-1SPs and 13 barrels in line. JUNK connectors are the shiny,unbranded stuff you see at ham flea markets, and sold online and in ham magazines. 73, Jim K9YC __ 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 Message delivered to arch...@mail-archive.com
Re: [Elecraft] Antenna Question
One way to do it with a single piece of stiff coax is to place a standoff about a foot long above and below the rotor. Then form the coax into a spiral of several turns between the standoffs. Rotation will just tighten or loosen the spiral and not stress the coax at all. The standoffs also take the weight of the coax. Vic 4X6GP > On 11 Oct 2016, at 01:14, hsherr...@reagan.com wrote: > > OK all. I'm installing a 6m rotating beam and feeding it with LMR400. Would > you connect the LMR to the antenna and allow it to move with the rotation, or > run a short length of something much more flexible between the antenna and > LMR? I have my concerns that the solid heavy inner conductor of the LMR won't > take much movement. > > Harlan > K4HES > > __ > 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 > Message delivered to k2vco@gmail.com __ 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 Message delivered to arch...@mail-archive.com
Re: [Elecraft] Antenna Question
I do the same as Josh: http://www.kl7uw.com/6m&Dish_Dec-2013_1.jpg Multiple turns of LMR-400. That connects to 7/8-Heliax coming up the tower leg. 73, Ed - KL7UW From: Josh Fiden To: elecraft@mailman.qth.net Subject: Re: [Elecraft] Antenna Question Message-ID: Content-Type: text/plain; charset=windows-1252; format=flowed LMR400 is really stiff. When I used it as a rotor loop, I made a couple of hoops around rather than directly flexing the cable around the tower. Not sure if that makes sense. In any case, doing it again I would definitely use a more flexible jumper for the rotor loop running to the antenna. In the shack I'm making jumpers from RG-214 which is very flexible and would work great as a rotor loop as well. 73, Josh W6XU 73, Ed - KL7UW http://www.kl7uw.com "Kits made by KL7UW" Dubus Mag business: dubus...@gmail.com __ 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 Message delivered to arch...@mail-archive.com
Re: [Elecraft] Antenna Question
I use LMR400-FLEX for my rotor loops and have had no problems. It has been up since 1999 or 2000. LMR400-FLEX is the designator for the stranded center conductor version. I also have used Davis FLEX LMR400 equivalent and if I remember correctly Davis-FLEX that is what is stamped on the feedline. The difference between LMR400 solid center conductor and LMR400 FLEX stranded center conductor has a loss of about .1 or .2db more at 50 MHz. Again if my memory is correct. Mark, WB9CIF -Original Message- From: Elecraft [mailto:elecraft-boun...@mailman.qth.net] On Behalf Of John Parker Sent: Tuesday, October 11, 2016 1:38 AM To: hsherr...@reagan.com; Elecraft Reflector Subject: Re: [Elecraft] Antenna Question There is a stranded center conductor version of the LM400, do not remember what the designation is. I plan to use some for the same reason, going around a rotor to a HexBeam. 73, John WB4UHCK3 #2165 On Monday, October 10, 2016 6:16 PM, "hsherr...@reagan.com" wrote: OK all. I'm installing a 6m rotating beam and feeding it with LMR400. Would you connect the LMR to the antenna and allow it to move with the rotation, or run a short length of something much more flexible between the antenna and LMR? I have my concerns that the solid heavy inner conductor of the LMR won't take much movement. Harlan K4HES __ 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 Message delivered to johnj...@verizon.net __ 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 Message delivered to markmus...@sbcglobal.net __ 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 Message delivered to arch...@mail-archive.com
Re: [Elecraft] Antenna Question
On 10/10/2016 8:37 PM, Josh Fiden wrote: > On 10/10/2016 5:39 PM, Clay Autery wrote: >> All things being equal... IF you are using LMR-400 as the main feedline, >> there is NO REASON to use a different diameter at the rotator... > The point was using a lower loss cable for the long run up the tower, > such as hardline, then flexible cable for the rotor/drip loop and > short distance to the antenna feedpoint. At VHF, this is typical. Right... I'd use the best/lowest loss feedline I could afford/source, too... and then use a smaller jumper... I was simply responding to the OP who said he was using LMR 400 and saying that LMR-400 CAN and IS frequently used as that "jumper" for the rotator loop... or something similarly sized in the .4-.5 inch range >> Fail to see why an antenna failure or swap would require soldering "up >> the tower"... > Failure is not necessarily the antenna. It could be the solid center > conductor fracture after being flexed too many times :) THAT would be the result of improper design/installation > > If you swap antennas and it's a single run of cable, you have to > manipulate the antenna on the tower to access the feedpoint. Then, for > example, if you put up a longer boom yagi, the feedpoint will most > likely be further away from the tower and your existing feedline won't > reach. Point taken I'm not a big part swapper/upgrader... I build things the best I can so I don't have to upgrade, so I didn't think of that... This situation would likely not occur for me, as I said above... I would likely NEVER use LMR-400 for a feedline run up a tower. I'd use the biggest/best feedline I could source/afford. __ Clay Autery, KY5G MONTAC Enterprises (318) 518-1389 __ 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 Message delivered to arch...@mail-archive.com
Re: [Elecraft] Antenna Question
OOPS... Original left here in HTML not plain text. Don't know why. Elecraft in address book is listed as plain text only Sorry, Bob K2TK Forwarded Message Subject: Re: [Elecraft] Antenna Question Date: Mon, 10 Oct 2016 21:21:14 -0400 From: Bob To: Josh Fiden , Elecraft Reflector For sure a consideration.There never is a perfect solution all is a compromise. For me I wanted a single run because I see any extra connectors as a potential failure points. My Tower is crank up/tilt-over so not even as much of a repair or change issue. Nobody has mentioned it here but Times makes a LMR400 Ultraflex. A possible solution. The slightly increased loss on 50MC maybe about equal to the extra connector loss.Another cable I have been happy with is this: http://www.davisrf.com/buryflex.php A ham owned company that has been very responsive to requests. Of my 7 feeds 6 use it and no issues and a few pieces are getting close to 8 years old. 73, Bob K2TK ex KN2TKR (1956) & K2TKR <http://www.davisrf.com/buryflex.php> On 10/10/2016 7:49 PM, Josh Fiden wrote: With an unbroken feedline, a failure or antenna swap can require soldering connectors up the tower. Not fun. If you're concerned about the additional loss of a barrel connector at 50MHz, you should be using feedline with lower loss than LMR400 up the tower. Wrap the barrel connection with good quality 3m vinyl tape and paint over with Scotchkote to keep water out. YMMV! 73, Josh W6XU On 10/10/2016 3:44 PM, Clay Autery wrote: I believe the use of a single unbroken feedline from the antenna to the shack (when possible) trumps the inconvenience of properly engineering an install that does NOT put unnecessary repetitive bending moments on the line. __ 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 Message delivered to arch...@mail-archive.com
Re: [Elecraft] Antenna Question
Completely agree. If access isn't a problem and the additional loss of more flexible cable is tolerable, that's a great solution. I haven't used Davis Bury-FLEX but heard very positive reports about it. 73, Josh W6XU On 10/10/2016 6:21 PM, Bob wrote: For sure a consideration.There never is a perfect solution all is a compromise. For me I wanted a single run because I see any extra connectors as a potential failure points. My Tower is crank up/tilt-over so not even as much of a repair or change issue. Nobody has mentioned it here but Times makes a LMR400 Ultraflex. A possible solution. Another cable I have been happy with is this: http://www.davisrf.com/buryflex.php __ 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 Message delivered to arch...@mail-archive.com
Re: [Elecraft] Antenna Question
On 10/10/2016 5:39 PM, Clay Autery wrote: All things being equal... IF you are using LMR-400 as the main feedline, there is NO REASON to use a different diameter at the rotator... The point was using a lower loss cable for the long run up the tower, such as hardline, then flexible cable for the rotor/drip loop and short distance to the antenna feedpoint. At VHF, this is typical. Fail to see why an antenna failure or swap would require soldering "up the tower"... Failure is not necessarily the antenna. It could be the solid center conductor fracture after being flexed too many times :) If you swap antennas and it's a single run of cable, you have to manipulate the antenna on the tower to access the feedpoint. Then, for example, if you put up a longer boom yagi, the feedpoint will most likely be further away from the tower and your existing feedline won't reach. 73, Josh W6XU __ 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 Message delivered to arch...@mail-archive.com
Re: [Elecraft] Antenna Question
There is a stranded center conductor version of the LM400, do not remember what the designation is. I plan to use some for the same reason, going around a rotor to a HexBeam. 73, John WB4UHCK3 #2165 On Monday, October 10, 2016 6:16 PM, "hsherr...@reagan.com" wrote: OK all. I'm installing a 6m rotating beam and feeding it with LMR400. Would you connect the LMR to the antenna and allow it to move with the rotation, or run a short length of something much more flexible between the antenna and LMR? I have my concerns that the solid heavy inner conductor of the LMR won't take much movement. Harlan K4HES __ 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 Message delivered to johnj...@verizon.net __ 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 Message delivered to arch...@mail-archive.com
Re: [Elecraft] Antenna Question
__ 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 Message delivered to arch...@mail-archive.com
Re: [Elecraft] Antenna Question
All things being equal... IF you are using LMR-400 as the main feedline, there is NO REASON to use a different diameter at the rotator... I was simply responding to what the OP said were the conditions... NOT the "ideal"... Bottom line... IF you engineer and install things properly, the fewer breaks in the feedline, the better... Fail to see why an antenna failure or swap would require soldering "up the tower"... unless for some reason you change feedline to antenna connector type not likely... or you compromised a connector termination or failed to weather protect properly In either case, your odds of doing one of those things increase with every additional connector you add to the line. BTW, using the -DB suffix (if available) for any Times cable will radically reduce the chances of moisture ingress on the feedline... __ Clay Autery, KY5G MONTAC Enterprises (318) 518-1389 On 10/10/2016 6:49 PM, Josh Fiden wrote: > With an unbroken feedline, a failure or antenna swap can require > soldering connectors up the tower. Not fun. If you're concerned about > the additional loss of a barrel connector at 50MHz, you should be > using feedline with lower loss than LMR400 up the tower. Wrap the > barrel connection with good quality 3m vinyl tape and paint over with > Scotchkote to keep water out. > > YMMV! > > 73, > Josh W6XU > > On 10/10/2016 3:44 PM, Clay Autery wrote: >> I believe the use of a single >> unbroken feedline from the antenna to the shack (when possible) trumps >> the inconvenience of properly engineering an install that does NOT put >> unnecessary repetitive bending moments on the line. > __ 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 Message delivered to arch...@mail-archive.com
Re: [Elecraft] Antenna Question
As is military practice as well. If you really want to get picky, the 400 should come up to the connector [sealed of course] and supported on the tower, and then the jumper forms the drip loop to prevent water running down the coax from running over ... and eventually into ... the connector. I don't think I'd run 400 all the way to a rotating antenna. 73, Fred K6DGW Sparks NV USA Washoe County DM09dn On 10/10/2016 4:34 PM, Phil Kane wrote: On 10/10/2016 3:14 PM, hsherr...@reagan.com wrote: Would you connect the LMR to the antenna and allow it to move with the rotation, or run a short length of something much more flexible between the antenna and LMR? Commercial practice is to use a flexible jumper and "drip loop" between the feedline and the antenna, even if the antenna is fixed solid to the tower/mast. This relieves the stress on the antenna connector. 73 de K2ASP - Phil Kane Elecraft K2/100 s/n 5402 __ 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 Message delivered to arch...@mail-archive.com
Re: [Elecraft] Antenna Question
With an unbroken feedline, a failure or antenna swap can require soldering connectors up the tower. Not fun. If you're concerned about the additional loss of a barrel connector at 50MHz, you should be using feedline with lower loss than LMR400 up the tower. Wrap the barrel connection with good quality 3m vinyl tape and paint over with Scotchkote to keep water out. YMMV! 73, Josh W6XU On 10/10/2016 3:44 PM, Clay Autery wrote: I believe the use of a single unbroken feedline from the antenna to the shack (when possible) trumps the inconvenience of properly engineering an install that does NOT put unnecessary repetitive bending moments on the line. __ 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 Message delivered to arch...@mail-archive.com
Re: [Elecraft] Antenna Question
On 10/10/2016 3:14 PM, hsherr...@reagan.com wrote: > Would you connect the LMR to the antenna and allow it to move with the > rotation, or run a short length of something much more flexible between the > antenna and LMR? Commercial practice is to use a flexible jumper and "drip loop" between the feedline and the antenna, even if the antenna is fixed solid to the tower/mast. This relieves the stress on the antenna connector. 73 de K2ASP - Phil Kane Elecraft K2/100 s/n 5402 >From a Clearing in the Silicon Forest Beaverton (Washington County) Oregon __ 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 Message delivered to arch...@mail-archive.com
Re: [Elecraft] Antenna Question
You'll get lots of suggestions, but I believe the use of a single unbroken feedline from the antenna to the shack (when possible) trumps the inconvenience of properly engineering an install that does NOT put unnecessary repetitive bending moments on the line. Do the research There's all kinds of info on how to create/route a feedline for rotator use... Most of the people I know with tall towers and big antennae use LMR-400 (or similar size) AS the "smaller jumper". No reason NOT to use LMR-400 from the antenna to the station... __ Clay Autery, KY5G MONTAC Enterprises (318) 518-1389 On 10/10/2016 5:14 PM, hsherr...@reagan.com wrote: > OK all. I'm installing a 6m rotating beam and feeding it with LMR400. Would > you connect the LMR to the antenna and allow it to move with the rotation, or > run a short length of something much more flexible between the antenna and > LMR? I have my concerns that the solid heavy inner conductor of the LMR won't > take much movement. > > Harlan > K4HES > > __ > 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 > Message delivered to caut...@montac.com __ 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 Message delivered to arch...@mail-archive.com
Re: [Elecraft] Antenna Question
LMR400 is really stiff. When I used it as a rotor loop, I made a couple of hoops around rather than directly flexing the cable around the tower. Not sure if that makes sense. In any case, doing it again I would definitely use a more flexible jumper for the rotor loop running to the antenna. In the shack I'm making jumpers from RG-214 which is very flexible and would work great as a rotor loop as well. 73, Josh W6XU On 10/10/2016 3:14 PM, hsherr...@reagan.com wrote: OK all. I'm installing a 6m rotating beam and feeding it with LMR400. Would you connect the LMR to the antenna and allow it to move with the rotation, or run a short length of something much more flexible between the antenna and LMR? I have my concerns that the solid heavy inner conductor of the LMR won't take much movement. Harlan K4HES __ 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 Message delivered to arch...@mail-archive.com
Re: [Elecraft] Antenna Question
I don't know the suggested turning radius of LMR400. In my system I use about 6 foot jumper of RG213 to do the section around the rotating section. I use a KLM 8 el and the total length is longer. Mel, K6KBE From: John Stengrevics To: hsherr...@reagan.com Cc: Elecraft Reflector Sent: Monday, October 10, 2016 3:17 PM Subject: Re: [Elecraft] Antenna Question I run LMR400 to my 6 & 2 meter antennas with no problems. Just leave enough slack around the rotor and you’ll be fine. John WA1EAZ > On Oct 10, 2016, at 6:14 PM, hsherr...@reagan.com wrote: > > OK all. I'm installing a 6m rotating beam and feeding it with LMR400. Would > you connect the LMR to the antenna and allow it to move with the rotation, or > run a short length of something much more flexible between the antenna and > LMR? I have my concerns that the solid heavy inner conductor of the LMR won't > take much movement. > > Harlan > K4HES > > __ > 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 > Message delivered to jstengrev...@comcast.net __ 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 Message delivered to farrerfo...@yahoo.com __ 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 Message delivered to arch...@mail-archive.com
Re: [Elecraft] Antenna Question
I run LMR400 to my 6 & 2 meter antennas with no problems. Just leave enough slack around the rotor and you’ll be fine. John WA1EAZ > On Oct 10, 2016, at 6:14 PM, hsherr...@reagan.com wrote: > > OK all. I'm installing a 6m rotating beam and feeding it with LMR400. Would > you connect the LMR to the antenna and allow it to move with the rotation, or > run a short length of something much more flexible between the antenna and > LMR? I have my concerns that the solid heavy inner conductor of the LMR won't > take much movement. > > Harlan > K4HES > > __ > 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 > Message delivered to jstengrev...@comcast.net __ 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 Message delivered to arch...@mail-archive.com
Re: [Elecraft] Antenna question
In a dry climate, ladder line is fine, but good coax has low losses, too, and is less fussy about being run next to the gutters. It is rare for a dipole to be perfectly balanced (thanks to near field objects like houses), so a high-quality current balun at the antenna can really help reject common mode noise. I recommend Balun Designs. Mine dropped the noise by 6dB. Also consider the “loop skywire”. A loop often fits into the same space as a dipole and lots of people like them. For pre-built dipoles, I’m happy with my Hy Power Antenna: http://www.hypowerantenna.com/ wunder K6WRU CM87wj http://observer.wunderwood.org/ On Oct 17, 2014, at 6:35 PM, James Bennett wrote: > Fred is right about the 450-ohm stuff getting funky in wet weather. Cause my > tuners to do the clicky-click dance whenever it rains here, although we've > been pretty dry the past few years. Because of this, I plan on replacing my > 450-ohm line with 600-ohm ladder line in a couple weeks. I had the 600-ohm > stuff on that doublet initially but a change in roofing materials made me > change. Long story. Anyway, as you probably know, antennas work much better > when built or adjusted when the weather is horrible!!! > > Jim / W6JHB > > >> On Oct 17, 2014, at 4:57 PM, Fred Jensen wrote: >> >> Don pretty much described my low band antenna. Full Disclosure: I live on 5 >> acres and have a 70' tower. That said, it is a Sloping V [I'd call it an >> inverted V except is isn't resonant on any band], about 210' on a side from >> the top of the tower. 450 ohm window line to the bottom of the tower, DXE >> 4:1 balun, and coax into the house. I have chokes on the coax at the balun >> and at the weatherhead entrance, but I've never had any problems with RFITS >> [RF In The Shack] with or without the chokes. >> >> It works well on 80-40-30, requires a tuner of course [KAT500]. Works on >> 160 but warms the clouds and worms, I use an Inv-L for top band. It also >> works on all the bands up from 30 but the pattern gets fairly complex and >> squirts my RF in a lot of non-productive directions because it's so big. >> >> My experience is that an 88 ft doublet, center-fed, works really well on 40 >> and up in frequency, often used by those activating summits in Summits On >> The Air. Shorter doublets are also effective, and not being resonant >> doesn't really matter [in some cases, it helps]. Neither does what you do >> with the ends. Most of the radiation comes from the center, high current >> sections. >> >> 450 ohm window line is sensitive to moisture ... if you set up your tuner >> for dry conditions and it's now raining, things will need retuning. >> >> Keep in mind the wisdom of Tom, N6BT, "Anything conductive will radiate if >> you get power into it." >> >> 73, >> >> Fred K6DGW >> - Northern California Contest Club >> - CU in the 2015 Cal QSO Party 3-4 Oct 2015 >> - www.cqp.org >> >>> On 10/17/2014 3:54 PM, Don Wilhelm wrote: >>> >>> Make it a balanced dipole antenna (equal lengths on either side of the >>> feedpoint) for best efforts in keeping RF off the feedline. The actual >>> length does not matter a lot, but it should be greater than 80% of the >>> half wavelength for the lowest band of interest. >>> >>> Use open wire line or 450 ohm ladder line to feed it down to the point >>> where it enters the shack - hopefully you can run the feedline >>> perpendicular from the radiator for at least 1/4 wavelength on the >>> lowest frequency of interest for lowest radiator to feedline pickup. Put >>> a good 1:1 current mod choke at that point. See page 29 of K9YC's RFI >>> tutorial http://www.audiosystemsgroup.com/RFI-Ham.pdf >>> for instructions on how to construct a very effective current mode choke >>> - note: a good balun *is* a current mode choke, but many fail to perform >>> as well as the ones tested by K9YC. >>> >>> You will need a tuner, and any Elecraft tuner should do the job nicely. >>> If it does not, then you may have to make some adjustments in the length >>> of the parallel feedline to see if you can achieve success on all bands >>> of interest. >>> >>> You may want to take a look at the Antenna and Transmission Line article >>> on my website www.w3fpr.com for a bit on non-math theory on antennas. >> >> >> __ >> 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 >> Message delivered to w6...@me.com > __ > 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 emai
Re: [Elecraft] Antenna question
Fred is right about the 450-ohm stuff getting funky in wet weather. Cause my tuners to do the clicky-click dance whenever it rains here, although we've been pretty dry the past few years. Because of this, I plan on replacing my 450-ohm line with 600-ohm ladder line in a couple weeks. I had the 600-ohm stuff on that doublet initially but a change in roofing materials made me change. Long story. Anyway, as you probably know, antennas work much better when built or adjusted when the weather is horrible!!! Jim / W6JHB > On Oct 17, 2014, at 4:57 PM, Fred Jensen wrote: > > Don pretty much described my low band antenna. Full Disclosure: I live on 5 > acres and have a 70' tower. That said, it is a Sloping V [I'd call it an > inverted V except is isn't resonant on any band], about 210' on a side from > the top of the tower. 450 ohm window line to the bottom of the tower, DXE > 4:1 balun, and coax into the house. I have chokes on the coax at the balun > and at the weatherhead entrance, but I've never had any problems with RFITS > [RF In The Shack] with or without the chokes. > > It works well on 80-40-30, requires a tuner of course [KAT500]. Works on 160 > but warms the clouds and worms, I use an Inv-L for top band. It also works > on all the bands up from 30 but the pattern gets fairly complex and squirts > my RF in a lot of non-productive directions because it's so big. > > My experience is that an 88 ft doublet, center-fed, works really well on 40 > and up in frequency, often used by those activating summits in Summits On The > Air. Shorter doublets are also effective, and not being resonant doesn't > really matter [in some cases, it helps]. Neither does what you do with the > ends. Most of the radiation comes from the center, high current sections. > > 450 ohm window line is sensitive to moisture ... if you set up your tuner for > dry conditions and it's now raining, things will need retuning. > > Keep in mind the wisdom of Tom, N6BT, "Anything conductive will radiate if > you get power into it." > > 73, > > Fred K6DGW > - Northern California Contest Club > - CU in the 2015 Cal QSO Party 3-4 Oct 2015 > - www.cqp.org > >> On 10/17/2014 3:54 PM, Don Wilhelm wrote: >> >> Make it a balanced dipole antenna (equal lengths on either side of the >> feedpoint) for best efforts in keeping RF off the feedline. The actual >> length does not matter a lot, but it should be greater than 80% of the >> half wavelength for the lowest band of interest. >> >> Use open wire line or 450 ohm ladder line to feed it down to the point >> where it enters the shack - hopefully you can run the feedline >> perpendicular from the radiator for at least 1/4 wavelength on the >> lowest frequency of interest for lowest radiator to feedline pickup. Put >> a good 1:1 current mod choke at that point. See page 29 of K9YC's RFI >> tutorial http://www.audiosystemsgroup.com/RFI-Ham.pdf >> for instructions on how to construct a very effective current mode choke >> - note: a good balun *is* a current mode choke, but many fail to perform >> as well as the ones tested by K9YC. >> >> You will need a tuner, and any Elecraft tuner should do the job nicely. >> If it does not, then you may have to make some adjustments in the length >> of the parallel feedline to see if you can achieve success on all bands >> of interest. >> >> You may want to take a look at the Antenna and Transmission Line article >> on my website www.w3fpr.com for a bit on non-math theory on antennas. > > > __ > 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 > Message delivered to w6...@me.com __ 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 Message delivered to arch...@mail-archive.com
Re: [Elecraft] Antenna question
Don pretty much described my low band antenna. Full Disclosure: I live on 5 acres and have a 70' tower. That said, it is a Sloping V [I'd call it an inverted V except is isn't resonant on any band], about 210' on a side from the top of the tower. 450 ohm window line to the bottom of the tower, DXE 4:1 balun, and coax into the house. I have chokes on the coax at the balun and at the weatherhead entrance, but I've never had any problems with RFITS [RF In The Shack] with or without the chokes. It works well on 80-40-30, requires a tuner of course [KAT500]. Works on 160 but warms the clouds and worms, I use an Inv-L for top band. It also works on all the bands up from 30 but the pattern gets fairly complex and squirts my RF in a lot of non-productive directions because it's so big. My experience is that an 88 ft doublet, center-fed, works really well on 40 and up in frequency, often used by those activating summits in Summits On The Air. Shorter doublets are also effective, and not being resonant doesn't really matter [in some cases, it helps]. Neither does what you do with the ends. Most of the radiation comes from the center, high current sections. 450 ohm window line is sensitive to moisture ... if you set up your tuner for dry conditions and it's now raining, things will need retuning. Keep in mind the wisdom of Tom, N6BT, "Anything conductive will radiate if you get power into it." 73, Fred K6DGW - Northern California Contest Club - CU in the 2015 Cal QSO Party 3-4 Oct 2015 - www.cqp.org On 10/17/2014 3:54 PM, Don Wilhelm wrote: Make it a balanced dipole antenna (equal lengths on either side of the feedpoint) for best efforts in keeping RF off the feedline. The actual length does not matter a lot, but it should be greater than 80% of the half wavelength for the lowest band of interest. Use open wire line or 450 ohm ladder line to feed it down to the point where it enters the shack - hopefully you can run the feedline perpendicular from the radiator for at least 1/4 wavelength on the lowest frequency of interest for lowest radiator to feedline pickup. Put a good 1:1 current mod choke at that point. See page 29 of K9YC's RFI tutorial http://www.audiosystemsgroup.com/RFI-Ham.pdf for instructions on how to construct a very effective current mode choke - note: a good balun *is* a current mode choke, but many fail to perform as well as the ones tested by K9YC. You will need a tuner, and any Elecraft tuner should do the job nicely. If it does not, then you may have to make some adjustments in the length of the parallel feedline to see if you can achieve success on all bands of interest. You may want to take a look at the Antenna and Transmission Line article on my website www.w3fpr.com for a bit on non-math theory on antennas. __ 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 Message delivered to arch...@mail-archive.com
Re: [Elecraft] Antenna question
Dave, Make it a balanced dipole antenna (equal lengths on either side of the feedpoint) for best efforts in keeping RF off the feedline. The actual length does not matter a lot, but it should be greater than 80% of the half wavelength for the lowest band of interest. Use open wire line or 450 ohm ladder line to feed it down to the point where it enters the shack - hopefully you can run the feedline perpendicular from the radiator for at least 1/4 wavelength on the lowest frequency of interest for lowest radiator to feedline pickup. Put a good 1:1 current mod choke at that point. See page 29 of K9YC's RFI tutorial http://www.audiosystemsgroup.com/RFI-Ham.pdf for instructions on how to construct a very effective current mode choke - note: a good balun *is* a current mode choke, but many fail to perform as well as the ones tested by K9YC. You will need a tuner, and any Elecraft tuner should do the job nicely. If it does not, then you may have to make some adjustments in the length of the parallel feedline to see if you can achieve success on all bands of interest. You may want to take a look at the Antenna and Transmission Line article on my website www.w3fpr.com for a bit on non-math theory on antennas. 73, Don W3FPR On 10/17/2014 4:45 PM, david beckwith wrote: Just moved and my K3 needs a new antenna. My only option is to run a wire antenna over my roof--I have about 110-120 feet to play with and I can get one end up off the ground 25 feet and the center and other end about 35 feet. Any ideas? Or references to an antenna group that can help? Thanks Bunches and 73 Dave K6CGE __ 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 Message delivered to arch...@mail-archive.com
Re: [Elecraft] Antenna question
Dave, I have a K3 (#7360) with ATU and 347 ft. long wire 30 ft height. It tunes up ok but performance is questionable. This same antenna performs better with my external MFJ tuner. Larry W7IN On 10/17/2014 20:45, david beckwith wrote: Just moved and my K3 needs a new antenna. My only option is to run a wire antenna over my roof--I have about 110-120 feet to play with and I can get one end up off the ground 25 feet and the center and other end about 35 feet. Any ideas? Or references to an antenna group that can help? Thanks Bunches and 73 Dave K6CGE __ 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 Message delivered to w...@montana.com __ 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 Message delivered to arch...@mail-archive.com
Re: [Elecraft] Antenna question
Alpha Delta LB-PLUS. they are tough and work great George, W6GF On Friday, October 17, 2014 1:45 PM, david beckwith wrote: Just moved and my K3 needs a new antenna. My only option is to run a wire antenna over my roof--I have about 110-120 feet to play with and I can get one end up off the ground 25 feet and the center and other end about 35 feet. Any ideas? Or references to an antenna group that can help? Thanks Bunches and 73 Dave K6CGE __ 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 Message delivered to georgefrit...@yahoo.com __ 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 Message delivered to arch...@mail-archive.com
Re: [Elecraft] Antenna question
A doublet. Center fed with either 600 ohm or 450 ohm ladder line, a 4:1 balun close to your shack and as short a length of coax from the balun to your K3 as possible. Using a tuner (either the K3 internal or an external), you will be able to work 80 through 10 meters, and possibly six meters. This sort of antenna works GREAT. > On Oct 17, 2014, at 1:45 PM, david beckwith wrote: > > Just moved and my K3 needs a new antenna. My only option is to run a wire > antenna over my roof--I have about 110-120 feet to play with and I can get > one end up off the ground 25 feet and the center and other end about 35 feet. > Any ideas? Or references to an antenna group that can help? Thanks Bunches > and 73 > Dave K6CGE > __ > 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 > Message delivered to w6...@me.com __ 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 Message delivered to arch...@mail-archive.com
Re: [Elecraft] Antenna question
It depends on which side of Chicago you are talking. NW of Chicago there is a big lode of iron which makes verticals work very well with few radials as they do here on the Gulf Coast for DX. A 43 ft vertical is 5/8 wave on 20 meters which will give it about 3 db gain over a 1/4 wave vertical with equal counterpoise. Both will do better than a horizontal dipole at average heights and are easier to erect than a dipole at 50 to 100 feet. Low dipoles will usually do better at distances less than 1000 miles and well counterpoised verticals at distances more than 2000 miles. Conductive grounds will allow you to get away with fewer radials, but if you live in the desert the counterpoise will be difficult. It depends is a phrase that rings true with antennas more than other things. Read the ARRL Antenna Handbook from cover to cover then read it again. Repeat at 1 or 2 year intervals and buy a new copy every few years. Understanding antennas is difficult for Physicists and Electrical Engineers (I am both) and even more difficult for others, so plan on putting in the study, modeling time, construction time and enjoy. It is arguably the most difficult and enjoyable part of ham radio. Willis 'Cookie' Cooke, TDXS DX Chairman K5EWJ & Trustee N5BPS, USS Cavalla, USS Stewart From: Rich To: elecraft@mailman.qth.net Sent: Thursday, February 13, 2014 9:07 AM Subject: Re: [Elecraft] Antenna question Does that "middle of the country" include Chicago? Rich NU6T On 2/13/2014 5:33 AM, James Rodenkirch wrote: > > > "And QST recently published a piece showing that a better use of a 43 ft > vertical might be as the center support for horizontal dipoles for 80 and 40, > a concept with which I strongly agree." (smiley face annotation removed) > As stated by a frtend of mine, after eading the above little ditty and > replying, initially, "Snort," my friends goes on to add"obviously, the > author of that uninformed statement hasn't had to work stations on 80 and 40 > from the middle of the country when signal arrival angles start changing > dramatically and rapidly." (smiley face annotation re-inserted) > 72/u3, Jim Rodenkirch K9JWV > > > >> Date: Tue, 11 Feb 2014 23:09:23 -0800 >> From: j...@audiosystemsgroup.com >> To: elecraft@mailman.qth.net >> Subject: Re: [Elecraft] Antenna question >> >> On 2/11/2014 3:36 PM, George Thornton wrote: >>> I have a small lot. I currently am using a 3 element Yagi that barely fits >>> on the property. I was thinking about getting a vertical as a second HF >>> antenna. >> As it happens, over the past year or so I've been engaged in a serious >> modeling study that compares the performance of vertical and horizontal >> antennas at mounting heights that are practical for hams in your >> situation. So the real question is, what will that vertical add to your >> station beside a second antenna for SO2R? >> >> If I were in your situation, I would add an antenna only to cover bands >> that the tri-bander does not. Even the best vertical is unlikely to >> outperform the tribander unless you happen to be blessed with REALLY >> good ground conductivity, and even then only by a dB or so at low >> elevation angles. Second, if I were to add a vertical, it would be one >> that is configured as a center-fed dipole, and I would add it ONLY if I >> could elevate it at least 20 ft. >> >> Yes, I know this wasn't the question you asked, but it needs to be asked >> and answered. :) Also, by all means pay attention to K6DGW's comments, >> with which I completely concur. >> >> There's a link to a presentation I did last fall of the vertical height >> issue, and also one about the recently popular 43 ft vertical. >> http://k9yc.com/publish.htm >> >> I'm still working on the comparison of verticals to horizontal antennas >> -- I've done all the modeling and know the results, but haven't >> organized it to show yet. AD5X has also done some excellent work on the >> 43 ft vertical idea. And QST recently published a piece showing that a >> better use of a 43 ft vertical might be as the center support for >> horizontal dipoles for 80 and 40, a concept with which I strongly agree. :) >> >> 73, Jim K9YC >> >> >> __ >> 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 em
Re: [Elecraft] Antenna question
Quoting myself: Besides, I think that low angle is often overrated. Here's some supporting evidence: (for ARRL members) http://www.nxtbook.com/nxtbooks/arrl/qst_201203/index.php#/42 Wes N7WS __ 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] Antenna question
I'm not by any means an antenna expert. All I can say is with ft5zm, they were much stronger on the vertical than my dipole on 20 meters. Some how some way, I was able to work them on 40 cw with the hustler vertical. The conclusion I've come to is there's times where my dipole works better for DX and there's times the vertical works better. Guess that's why I still have them both up. But that's what makes Amateur Radio so fun, seeing what works and what doesn't, and how one might be great one day, but not so good the next. I love radio... Enjoy experimenting... 73 Steve KS6PD Sent from my iPhone. Forgive the typos. On Thursday, February 13, 2014, Dale Putnam wrote: > My modeling experience pretty much says the same... for higher angle > arrivals... the dipoles under 1/2 or more, will be better... especially > when placed within one hop of the ocean. (East or West.).. HOWEVER... > taking one hop off... (that's the same almost) as gaining 2 - 3 S unites... > is better.. and taking one hop off with a dipole... at less thanoptimum > height is nigh on impossible. With an optimum vertical.. or LOW angle > antenna...it IS possible. This is all derived with modeling.. AND > Since I don't believe computers have ever actually DONE IT... I kinda like > to prove it empirically. And I have... the last time was with FT5ZM... > with a very LOW angle antenna... they were attained on4 bands the > dipole didn't work. The dipole at near optimum height was 3 S units lower > in rx... on a calibratedS meter THAT particular day and it was 1 - > 3 S units less for over a week that I listened... HOWEVER.. there werea few > times.. especially when the band was ful > l of QSB..shifting and changing... that the dipole did hear better... and > significantly... for short periods of time. I, being one, and only me... > prefer to hear for a much longer period of time... more reliably... rather > than count on a few short bursts of signal, ... every cycle of the band > (about 2 times a day ) I can't count on being at the radio at the > optimum time... but I can count on being at the radio when I want to! > Have a great day, > > > --... ...-- > Dale - WC7S in Wy > > > > > __ > 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] Antenna question
My modeling experience pretty much says the same... for higher angle arrivals... the dipoles under 1/2 or more, will be better... especially when placed within one hop of the ocean. (East or West.).. HOWEVER... taking one hop off... (that's the same almost) as gaining 2 - 3 S unites... is better.. and taking one hop off with a dipole... at less thanoptimum height is nigh on impossible. With an optimum vertical.. or LOW angle antenna...it IS possible. This is all derived with modeling.. AND Since I don't believe computers have ever actually DONE IT... I kinda like to prove it empirically. And I have... the last time was with FT5ZM... with a very LOW angle antenna... they were attained on4 bands the dipole didn't work. The dipole at near optimum height was 3 S units lower in rx... on a calibratedS meter THAT particular day and it was 1 - 3 S units less for over a week that I listened... HOWEVER.. there werea few times.. especially when the band was ful l of QSB..shifting and changing... that the dipole did hear better... and significantly... for short periods of time. I, being one, and only me... prefer to hear for a much longer period of time... more reliably... rather than count on a few short bursts of signal, ... every cycle of the band (about 2 times a day ) I can't count on being at the radio at the optimum time... but I can count on being at the radio when I want to! Have a great day, --... ...-- Dale - WC7S in Wy __ 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] Antenna question
Wes and all, From my practical experience, your modeling analysis is correct. I have a vertical for 80 and 40 with elevated radials (full size except for the loading of the 40 meter trap) - in A/B tests compared with my 80 and 40 meter dipoles with the center at 45 feet and ends at 20 feet or greater, I have found that copy on *all* stations is better using the dipoles than with the vertical. The only reason the vertical stays up is because it also functions as a 160 meter inverted L which is my only 160 meter antenna at the present time. 73, Don W3FPR On 2/13/2014 4:04 PM, Wes (N7WS) wrote: Well, I was speaking of my situation. I'm in the Sonoran Desert of southern AZ with ground that varies from granite to sand to caliche within a few feet distance. Although many (most?) hams consider vertical antennas to be "low-angle" radiators, they often fail to consider the efficiency of that "low-angle" radiator. My modeling shows that even a low lambda dipole with its "high-angle" radiation often has more signal radiated at the vertical's optimum (low) angle than the vertical does. Plotting the two antennas and overlaying the plots will easily show this. Now I'm not going to argue with the guys with heroic vertical phased array installations and the like, but for the typical guy contemplating a modest vertical installation v. a straightforward dipole or "inverted-vee" I would (and did) choose the dipole. Besides, I think that low angle is often overrated. Although I'm normally loath to state anecdotal evidence, my paralleled wires 40 and 80-meter inverted-vee with apex at 40 ft and ends at 20 feet models as a NVIS antenna, but I have 148 DXCC countries (including antipodal FT5ZM) worked on 80-meters and I don't much care for 80-meters so seldom operate there. __ 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] Antenna question
On 2/13/2014 1:04 PM, Wes (N7WS) wrote: Well, I was speaking of my situation. I'm in the Sonoran Desert of southern AZ with ground that varies from granite to sand to caliche within a few feet distance. My modeling studies, as well as my results with soil that's nearly as bad, are in complete agreement with your analysis. 73, Jim K9YC __ 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] Antenna question
Well, I was speaking of my situation. I'm in the Sonoran Desert of southern AZ with ground that varies from granite to sand to caliche within a few feet distance. Although many (most?) hams consider vertical antennas to be "low-angle" radiators, they often fail to consider the efficiency of that "low-angle" radiator. My modeling shows that even a low lambda dipole with its "high-angle" radiation often has more signal radiated at the vertical's optimum (low) angle than the vertical does. Plotting the two antennas and overlaying the plots will easily show this. Now I'm not going to argue with the guys with heroic vertical phased array installations and the like, but for the typical guy contemplating a modest vertical installation v. a straightforward dipole or "inverted-vee" I would (and did) choose the dipole. Besides, I think that low angle is often overrated. Although I'm normally loath to state anecdotal evidence, my paralleled wires 40 and 80-meter inverted-vee with apex at 40 ft and ends at 20 feet models as a NVIS antenna, but I have 148 DXCC countries (including antipodal FT5ZM) worked on 80-meters and I don't much care for 80-meters so seldom operate there. Wes N7WS On 2/12/2014 4:17 PM, Jim Brown wrote: On 2/12/2014 7:29 AM, Wes (N7WS) wrote: Also known as, "The worst horizontal antenna is better than the best vertical antenna" theory. It's always worked out for me. Now if I lived on the beach... Hi Wes, Based on my model studies, I wouldn't go that far -- it depends on how high either of the antennas are, as well as the quality of the ground. If your criteria is low angle radiation and you have better than average soil, a vertical dipole that's 20 ft or more above ground will beat a low dipole. Here in the mountains, our soil is stinko, so the only band where a vertical beats a horizontal dipole is 160M. 73, Jim K9YC __ 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] Antenna question
Does that "middle of the country" include Chicago? Rich NU6T On 2/13/2014 5:33 AM, James Rodenkirch wrote: "And QST recently published a piece showing that a better use of a 43 ft vertical might be as the center support for horizontal dipoles for 80 and 40, a concept with which I strongly agree." (smiley face annotation removed) As stated by a frtend of mine, after eading the above little ditty and replying, initially, "Snort," my friends goes on to add"obviously, the author of that uninformed statement hasn't had to work stations on 80 and 40 from the middle of the country when signal arrival angles start changing dramatically and rapidly." (smiley face annotation re-inserted) 72/u3, Jim Rodenkirch K9JWV Date: Tue, 11 Feb 2014 23:09:23 -0800 From: j...@audiosystemsgroup.com To: elecraft@mailman.qth.net Subject: Re: [Elecraft] Antenna question On 2/11/2014 3:36 PM, George Thornton wrote: I have a small lot. I currently am using a 3 element Yagi that barely fits on the property. I was thinking about getting a vertical as a second HF antenna. As it happens, over the past year or so I've been engaged in a serious modeling study that compares the performance of vertical and horizontal antennas at mounting heights that are practical for hams in your situation. So the real question is, what will that vertical add to your station beside a second antenna for SO2R? If I were in your situation, I would add an antenna only to cover bands that the tri-bander does not. Even the best vertical is unlikely to outperform the tribander unless you happen to be blessed with REALLY good ground conductivity, and even then only by a dB or so at low elevation angles. Second, if I were to add a vertical, it would be one that is configured as a center-fed dipole, and I would add it ONLY if I could elevate it at least 20 ft. Yes, I know this wasn't the question you asked, but it needs to be asked and answered. :) Also, by all means pay attention to K6DGW's comments, with which I completely concur. There's a link to a presentation I did last fall of the vertical height issue, and also one about the recently popular 43 ft vertical. http://k9yc.com/publish.htm I'm still working on the comparison of verticals to horizontal antennas -- I've done all the modeling and know the results, but haven't organized it to show yet. AD5X has also done some excellent work on the 43 ft vertical idea. And QST recently published a piece showing that a better use of a 43 ft vertical might be as the center support for horizontal dipoles for 80 and 40, a concept with which I strongly agree. :) 73, Jim K9YC __ 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] Antenna question
"And QST recently published a piece showing that a better use of a 43 ft vertical might be as the center support for horizontal dipoles for 80 and 40, a concept with which I strongly agree." (smiley face annotation removed) As stated by a frtend of mine, after eading the above little ditty and replying, initially, "Snort," my friends goes on to add"obviously, the author of that uninformed statement hasn't had to work stations on 80 and 40 from the middle of the country when signal arrival angles start changing dramatically and rapidly." (smiley face annotation re-inserted) 72/u3, Jim Rodenkirch K9JWV > Date: Tue, 11 Feb 2014 23:09:23 -0800 > From: j...@audiosystemsgroup.com > To: elecraft@mailman.qth.net > Subject: Re: [Elecraft] Antenna question > > On 2/11/2014 3:36 PM, George Thornton wrote: > > I have a small lot. I currently am using a 3 element Yagi that barely fits > > on the property. I was thinking about getting a vertical as a second HF > > antenna. > > As it happens, over the past year or so I've been engaged in a serious > modeling study that compares the performance of vertical and horizontal > antennas at mounting heights that are practical for hams in your > situation. So the real question is, what will that vertical add to your > station beside a second antenna for SO2R? > > If I were in your situation, I would add an antenna only to cover bands > that the tri-bander does not. Even the best vertical is unlikely to > outperform the tribander unless you happen to be blessed with REALLY > good ground conductivity, and even then only by a dB or so at low > elevation angles. Second, if I were to add a vertical, it would be one > that is configured as a center-fed dipole, and I would add it ONLY if I > could elevate it at least 20 ft. > > Yes, I know this wasn't the question you asked, but it needs to be asked > and answered. :) Also, by all means pay attention to K6DGW's comments, > with which I completely concur. > > There's a link to a presentation I did last fall of the vertical height > issue, and also one about the recently popular 43 ft vertical. > http://k9yc.com/publish.htm > > I'm still working on the comparison of verticals to horizontal antennas > -- I've done all the modeling and know the results, but haven't > organized it to show yet. AD5X has also done some excellent work on the > 43 ft vertical idea. And QST recently published a piece showing that a > better use of a 43 ft vertical might be as the center support for > horizontal dipoles for 80 and 40, a concept with which I strongly agree. :) > > 73, Jim K9YC > > > __ > 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] Antenna question
ORIGINAL MESSAGE: (may be snipped) On 2/12/2014 3:46 PM, Phil Wheeler wrote: Bill, You don't trust the traditional "Smoke Test"? :-) 73, Phil w7ox REPLY: Of course I trust it. I use it whenever I need smoke. :-) 73, Bill W6WRT __ 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] Antenna question
Surprised me too. It ALWAYS produces results. Eric KE6US On 2/12/2014 3:46 PM, Phil Wheeler wrote: Bill, You don't trust the traditional "Smoke Test"? :-) 73, Phil w7ox On 2/12/14, 2:45 PM, Bill Turner wrote: I see a number of people are trying to calculate whether any damage would be done by the situation originally posted. Frankly, I think this is a dangerous approach. There are too many variables in a particular situation to risk depending on calculations when expensive equipment is endangered. If you must go ahead with your situation, I strongly suggest, as others have done, that you measure the interaction rather than try to calculate it. 73, Bill W6WRT __ 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] Antenna question
I love my 40 mtr 4 SQ & it's in the woods of FAR NW WI. Poor soil, good ground system (36 each vertical) and very exact construction. Antennas are surrounded by much taller aspen. I moved from a location where I had a big 2 element at 125'. It feels very similar and at 72, I'm done climbing big towers. Sure is easier to maintain/fix/adjust. For those considering, it's verybroadbanded and even has directivity on 30! Worked FT5ZM on CW and rtty on 30 using the 40 mtr 4 SQ. It stinks for ss on 40, but great band opener for DX (further away the better). John, N0IJ Sent from my iPhone > On Feb 12, 2014, at 5:34 PM, Jack wrote: > > When we had our place in Silver Springs, NV, our 40-meter 4-square, with an > excellent radial system, was killer. I cannot imagine anything short of a > full-size 2, possibly 3, element yagi up at least 70 feet even coming close. > I would think it would take the 3-element yagi to even approach the F/B ratio > of the 4-square. > > On the beach works *real* well. Any antenna we tried at Ballenita, Ecuador, > worked great. The QTH was roughly 10-meters inland from high-tide! :>) > > Jack, W6NF/VE4SNA/HC2UA > Shelley, K7MKL/HC2UB > >> On 2/12/2014 3:17 PM, Jim Brown wrote: >>> On 2/12/2014 7:29 AM, Wes (N7WS) wrote: >>> Also known as, "The worst horizontal antenna is better than the best >>> vertical antenna" theory. It's always worked out for me. Now if I lived >>> on the beach... >> >> Hi Wes, >> >> Based on my model studies, I wouldn't go that far -- it depends on how high >> either of the antennas are, as well as the quality of the ground. If your >> criteria is low angle radiation and you have better than average soil, a >> vertical dipole that's 20 ft or more above ground will beat a low dipole. >> Here in the mountains, our soil is stinko, so the only band where a vertical >> beats a horizontal dipole is 160M. >> >> 73, Jim K9YC >> __ >> 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] Antenna question
Bill, You don't trust the traditional "Smoke Test"? :-) 73, Phil w7ox On 2/12/14, 2:45 PM, Bill Turner wrote: I see a number of people are trying to calculate whether any damage would be done by the situation originally posted. Frankly, I think this is a dangerous approach. There are too many variables in a particular situation to risk depending on calculations when expensive equipment is endangered. If you must go ahead with your situation, I strongly suggest, as others have done, that you measure the interaction rather than try to calculate it. 73, Bill W6WRT __ 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] Antenna question
When we had our place in Silver Springs, NV, our 40-meter 4-square, with an excellent radial system, was killer. I cannot imagine anything short of a full-size 2, possibly 3, element yagi up at least 70 feet even coming close. I would think it would take the 3-element yagi to even approach the F/B ratio of the 4-square. On the beach works *real* well. Any antenna we tried at Ballenita, Ecuador, worked great. The QTH was roughly 10-meters inland from high-tide! :>) Jack, W6NF/VE4SNA/HC2UA Shelley, K7MKL/HC2UB On 2/12/2014 3:17 PM, Jim Brown wrote: On 2/12/2014 7:29 AM, Wes (N7WS) wrote: Also known as, "The worst horizontal antenna is better than the best vertical antenna" theory. It's always worked out for me. Now if I lived on the beach... Hi Wes, Based on my model studies, I wouldn't go that far -- it depends on how high either of the antennas are, as well as the quality of the ground. If your criteria is low angle radiation and you have better than average soil, a vertical dipole that's 20 ft or more above ground will beat a low dipole. Here in the mountains, our soil is stinko, so the only band where a vertical beats a horizontal dipole is 160M. 73, Jim K9YC __ 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] Antenna question
On 2/12/2014 7:29 AM, Wes (N7WS) wrote: Also known as, "The worst horizontal antenna is better than the best vertical antenna" theory. It's always worked out for me. Now if I lived on the beach... Hi Wes, Based on my model studies, I wouldn't go that far -- it depends on how high either of the antennas are, as well as the quality of the ground. If your criteria is low angle radiation and you have better than average soil, a vertical dipole that's 20 ft or more above ground will beat a low dipole. Here in the mountains, our soil is stinko, so the only band where a vertical beats a horizontal dipole is 160M. 73, Jim K9YC __ 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] Antenna question
Wire a small "grain-of-wheat" incandescent light bulb to the unused antenna feed and fire up the transmitter. If the bulb lights brightly, you need some protection. Admittedly, this is a crude test, but it can point to a problem and takes into account all those variables in the calculations. Try all bands and start at low power, otherwise, you may blow the bulb before any relative results can be gleaned. 73, Charlie k3ICH - Original Message - From: "Bill Turner" To: Sent: Wednesday, February 12, 2014 5:45 PM Subject: Re: [Elecraft] Antenna question I see a number of people are trying to calculate whether any damage would be done by the situation originally posted. Frankly, I think this is a dangerous approach. There are too many variables in a particular situation to risk depending on calculations when expensive equipment is endangered. If you must go ahead with your situation, I strongly suggest, as others have done, that you measure the interaction rather than try to calculate it. 73, Bill W6WRT __ 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] Antenna question
I see a number of people are trying to calculate whether any damage would be done by the situation originally posted. Frankly, I think this is a dangerous approach. There are too many variables in a particular situation to risk depending on calculations when expensive equipment is endangered. If you must go ahead with your situation, I strongly suggest, as others have done, that you measure the interaction rather than try to calculate it. 73, Bill W6WRT __ 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] Antenna question
Hi Ed, Actually, my S9+67 dB for 0dBm turned out to be wrong - I lost one "6 dB" in my book keeping, so 0dBm is S9+73 dB - or S9 equals -73 dBm (which is the number I had in mind). No doubt about the space loss formula and the far field - "free space loss" is no dissipative loss like for example loss in the ground but just a "geometry factor". Basically the free space formula calculates the "aperture area" of your rx antenna divided by the area of a sphere centered on the tx antenna and with radius r (r being the distance). But this is the "free space loss" only if E and H fields decay as 1/r because that means that power density decays as 1/r^2 and integration over the sphere yields the total emitted power (which is the idea behind the formula) and by definition 1/r decay is the far field. If the 1/r^2 and 1/r^3 components of the fields have not already decayed, the space loss formula gives wrong results (which is why the german "FCC equivalent" wants us to either perform a near field calculation or a measurement if we run more than 10 Watts ERP to be sure that we don't exceed the near field limits). Regarding the "polarization decoupling" you mentioned: one can see by a little "gedankenexperiment" (as we say in physics even in english) that all electrical field vector components exist in the near field of the transmitting antenna: a part of the near field of a (electrically short) dipole follows the charge distribution on the dipole immediately (almost no "retardation") and looks pretty much the same as the field between a positive and a negative charge (a static dipole) - or a short magnet - there are some field lines leaving the positve charge perpendicular to the antenna axis and then bending towards the other charge. If you view this from the side, you can see that even a perfectly horizontally polarized antenna has a vertical near field component, but for a short dipole, this decays as 1/r^3 (I think so) and is not present in the far field any more but might be dominant in the near field - so, with the vertical in the near field, the polarization decoupling can be d rastically reduced. Only if the "yagi plus vertical system" is symmetric - the (balanced) yagi pointing exactly towards the vertical or exactly in the opposite direction - this near field component will vanish (for symmetry reasons) and the polarization decoupling works, but for the other directions of the yagi it won't... So, regardless if you simulate or measure, don't forget to turn the yagi antenna into several directions - may be the coupling is stronger when one end of the driven element is close to the vertical... Greetings Ralf, DL6OAP Am 12.02.2014 um 21:46 schrieb Edward R Cole : > Ralf, > > Thanks for catching my mistake in the ohm's law formula. > P = E^2/R > > Regarding using the far-field loss formula it is probably prudent to try > measuring power on the receiving antenna when transmitting on the other > antenna (the yagi). At the very least check with a SWR meter in the lowest > power range and see if you detect anything. If the meter deflects or > "twitches" power is probably way too high and you need some kind of > protection device. There are some simple milliwatt power meter designs in > some ham Handbooks (look for field strength meters); simplest is a IN34 and > 1ma meter. If you blow up the 1N34 you have your answer! Better that you > use a couple 20-dB coax attenuators before the meter at first. I no power is > seen then remove one and test again. > > You can rely on using 0 dBm as maximum survivable input to the receiver, but > the receiver still will be driven into compression and not usable while > transmitting. > > My example of 130-feet was at 144-MHz so not a fair comparison with HF freq. > which have much longer wavelength. > > The space loss formula is useful for making measurements at far-field (google > it)> > > 73, Ed - KL7UW > > __ 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] Antenna question
Also known as, "The worst horizontal antenna is better than the best vertical antenna" theory. It's always worked out for me. Now if I lived on the beach. Wes N7WS On 2/12/2014 12:09 AM, Jim Brown wrote: [snip] I'm still working on the comparison of verticals to horizontal antennas -- I've done all the modeling and know the results, but haven't organized it to show yet. AD5X has also done some excellent work on the 43 ft vertical idea. And QST recently published a piece showing that a better use of a 43 ft vertical might be as the center support for horizontal dipoles for 80 and 40, a concept with which I strongly agree. :) 73, Jim K9YC __ 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] Antenna question
Good advice: I use wire antennas for 40m & 80m with a HexBeam for the higher bands & a 5BTV vertical. My sub-receiver is connected to a 50' vertical wire. The vertical wire is about 20' (horizontally) from the wire antennas and about 30' from the 5BTV and HexBeam When I installed the KPA500 I did the same test starting at 10 watts on 80m through 10m. I found that there was enough isolation on all antennas to leave the sub-receiver connected. I use the sub-receiver for diversity and would miss that feature. George -- From: "WILLIS COOKE" Sent: Tuesday, February 11, 2014 10:21 PM To: "George Thornton" ; "'elecraft @ mailman . qth . net'" Subject: Re: [Elecraft] Antenna question Since the K3 will do the QRP thing down to 100 mw, think about installing the vertical above the beam on the mast and gradually try more and more power out of the K3 until you start getting some overloading. At least you can find your answer without frying anything and some folks find QRP lots of fun. Maybe you will too! Willis 'Cookie' Cooke, TDXS DX Chairman K5EWJ & Trustee N5BPS, USS Cavalla, USS Stewart From: George Thornton To: "'elecraft @ mailman . qth . net'" Sent: Tuesday, February 11, 2014 5:36 PM Subject: Re: [Elecraft] Antenna question This might be a stupid question, but here goes. I have a small lot. I currently am using a 3 element Yagi that barely fits on the property. I was thinking about getting a vertical as a second HF antenna. If I put it up it is going to have to be pretty close to the Yagi. I have a dual receive K3. If I have both receivers going, one on each channel, and I broadcast on one of these antennas, am I in any danger of overloading and frying the other receiver? __ 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] Antenna question
Good advice: I use wire antennas for 40m & 80m with a HexBeam for the higher bands & a 5BTV vertical. My sub-receiver is connected to a 50' vertical wire. The vertical wire is about 20' (horizontally) from the wire antennas and about 30' from the 5BTV and HexBeam When I installed the KPA500 I did the same test starting at 10 watts on 80m through 10m. I found that there was enough isolation on all antennas to leave the sub-receiver connected. I use the sub-receiver for diversity and would miss that feature. George -- From: "WILLIS COOKE" Sent: Tuesday, February 11, 2014 10:21 PM To: "George Thornton" ; "'elecraft @ mailman . qth . net'" Subject: Re: [Elecraft] Antenna question Since the K3 will do the QRP thing down to 100 mw, think about installing the vertical above the beam on the mast and gradually try more and more power out of the K3 until you start getting some overloading. At least you can find your answer without frying anything and some folks find QRP lots of fun. Maybe you will too! Willis 'Cookie' Cooke, TDXS DX Chairman K5EWJ & Trustee N5BPS, USS Cavalla, USS Stewart From: George Thornton To: "'elecraft @ mailman . qth . net'" Sent: Tuesday, February 11, 2014 5:36 PM Subject: Re: [Elecraft] Antenna question This might be a stupid question, but here goes. I have a small lot. I currently am using a 3 element Yagi that barely fits on the property. I was thinking about getting a vertical as a second HF antenna. If I put it up it is going to have to be pretty close to the Yagi. I have a dual receive K3. If I have both receivers going, one on each channel, and I broadcast on one of these antennas, am I in any danger of overloading and frying the other receiver? __ 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] Antenna question
Hi George, The 130 feet corresponds to lambda/2 on 80 and you can use the far field approximation (that Ed is using) there... At short distances (less than a quarter or a sixth of the wavelength), however, 1/r^2 and 1/r^3 ("near field") components of E and H fields are still present (or dominant) and the far field approximation should not be used. You also have to be careful with the cross-polarization argument, since the electrical near field has all three vector components almost anywhere in space and the coupling can be much higher (depending on how well symmetry is preserved in the "yagi+vertical system"). Better use a NEC based program (e.g. EZNEC or the free 4nec2), if you have on access to a milliwatt-meter/scope and have to calculate... By the way, P should read P= E*I = E^2/R => E=sqrt(P*R)=223mV for a 0dBm (S9+67dB) signal (?) Greetings Ralf, DL6OAP Am 12.02.2014 um 10:31 schrieb Edward R Cole : > George, > > You do not say what power you are transmitting and it would be helpful to > know the separation between the antennas. Will the vertical be as high as the > yagi? Need to know what frequency is used. > > OK, in lieu of this data I will make some assumptions and show you the math > to calculate the power received. > F = 3.5-MHz > Po = 100w = 50 dBm > separation = 60 feet = 18.3m > cross-pol loss = 20 dB (it will not be quite this much at this close > separation) > L = 32.4 + 20 Log F + 20 Log d, where F= MHz and d= km > L = the space loss between antenna, in dB > L = 32.4 +20 Log (3.5) + 20 Log (18.3/1000) > L = 32.4 + 10.9 - 5 > L = 38 dB > Ltot = L + Lcross-pol = 58 dB > Po - Ltot = -8 dBm > > That is a very strong signal but will not hurt the receiver. Typically > anything under 0 dBm is safe. I run 1500w and have a preamp attached to the > TR coax relay and have had no problems blowing up the very sensitive > transistor in the preamp if the relay isolation is equal to the power in dBm. > > Now cross-pol loss is probably not 20 dB but more like 15 dB and your > antennas are in near-field so these formula are not quite accurate. Ideally > you would measure the power on the receiving antenna with a milliwatt power > meter but I suppose you do not have one. Also I did not include antenna > gains in this, but in close proximity they are probably not accurate. > > I have tested my tower mounted preamp by sending a test signal to an antenna > about 130-foot away and using the space loss formula pretty accurately > predicted received signal level. This let me test the preamp sensitivity > without removing it from the tower. > > If you have a scope look at the received RF signal and measure the peak > voltage. > P = E^2*R or > E = sq-rt (P/50) > P = 0 dBm = 0.001w > sq-rt(0.001/50) = .004v > > 73, Ed - KL7UW > PS: If you run more than 100w then either short the receiver antenna line or > use a coax relay to disconnect it when transmitting. > > > Date: Tue, 11 Feb 2014 23:36:09 + > From: George Thornton > To: "'elecraft @ mailman . qth . net'" > Subject: Re: [Elecraft] Antenna question > Message-ID: ><040f2ec01a53458babf11914164d5...@server.thorntonmostullaw.com> > Content-Type: text/plain; charset="us-ascii" > > This might be a stupid question, but here goes. > > I have a small lot. I currently am using a 3 element Yagi that barely fits > on the property. I was thinking about getting a vertical as a second HF > antenna. If I put it up it is going to have to be pretty close to the Yagi. > > I have a dual receive K3. If I have both receivers going, one on each > channel, and I broadcast on one of these antennas, am I in any danger of > overloading and frying the other receiver? > > > 73, Ed - KL7UW > http://www.kl7uw.com >"Kits made by KL7UW" > Dubus Mag business: >dubus...@gmail.com > > __ > 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] Antenna question
George, You do not say what power you are transmitting and it would be helpful to know the separation between the antennas. Will the vertical be as high as the yagi? Need to know what frequency is used. OK, in lieu of this data I will make some assumptions and show you the math to calculate the power received. F = 3.5-MHz Po = 100w = 50 dBm separation = 60 feet = 18.3m cross-pol loss = 20 dB (it will not be quite this much at this close separation) L = 32.4 + 20 Log F + 20 Log d, where F= MHz and d= km L = the space loss between antenna, in dB L = 32.4 +20 Log (3.5) + 20 Log (18.3/1000) L = 32.4 + 10.9 - 5 L = 38 dB Ltot = L + Lcross-pol = 58 dB Po - Ltot = -8 dBm That is a very strong signal but will not hurt the receiver. Typically anything under 0 dBm is safe. I run 1500w and have a preamp attached to the TR coax relay and have had no problems blowing up the very sensitive transistor in the preamp if the relay isolation is equal to the power in dBm. Now cross-pol loss is probably not 20 dB but more like 15 dB and your antennas are in near-field so these formula are not quite accurate. Ideally you would measure the power on the receiving antenna with a milliwatt power meter but I suppose you do not have one. Also I did not include antenna gains in this, but in close proximity they are probably not accurate. I have tested my tower mounted preamp by sending a test signal to an antenna about 130-foot away and using the space loss formula pretty accurately predicted received signal level. This let me test the preamp sensitivity without removing it from the tower. If you have a scope look at the received RF signal and measure the peak voltage. P = E^2*R or E = sq-rt (P/50) P = 0 dBm = 0.001w sq-rt(0.001/50) = .004v 73, Ed - KL7UW PS: If you run more than 100w then either short the receiver antenna line or use a coax relay to disconnect it when transmitting. Date: Tue, 11 Feb 2014 23:36:09 + From: George Thornton To: "'elecraft @ mailman . qth . net'" Subject: Re: [Elecraft] Antenna question Message-ID: <040f2ec01a53458babf11914164d5...@server.thorntonmostullaw.com> Content-Type: text/plain; charset="us-ascii" This might be a stupid question, but here goes. I have a small lot. I currently am using a 3 element Yagi that barely fits on the property. I was thinking about getting a vertical as a second HF antenna. If I put it up it is going to have to be pretty close to the Yagi. I have a dual receive K3. If I have both receivers going, one on each channel, and I broadcast on one of these antennas, am I in any danger of overloading and frying the other receiver? 73, Ed - KL7UW http://www.kl7uw.com "Kits made by KL7UW" Dubus Mag business: dubus...@gmail.com __ 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] Antenna question
On 2/11/2014 3:36 PM, George Thornton wrote: I have a small lot. I currently am using a 3 element Yagi that barely fits on the property. I was thinking about getting a vertical as a second HF antenna. As it happens, over the past year or so I've been engaged in a serious modeling study that compares the performance of vertical and horizontal antennas at mounting heights that are practical for hams in your situation. So the real question is, what will that vertical add to your station beside a second antenna for SO2R? If I were in your situation, I would add an antenna only to cover bands that the tri-bander does not. Even the best vertical is unlikely to outperform the tribander unless you happen to be blessed with REALLY good ground conductivity, and even then only by a dB or so at low elevation angles. Second, if I were to add a vertical, it would be one that is configured as a center-fed dipole, and I would add it ONLY if I could elevate it at least 20 ft. Yes, I know this wasn't the question you asked, but it needs to be asked and answered. :) Also, by all means pay attention to K6DGW's comments, with which I completely concur. There's a link to a presentation I did last fall of the vertical height issue, and also one about the recently popular 43 ft vertical. http://k9yc.com/publish.htm I'm still working on the comparison of verticals to horizontal antennas -- I've done all the modeling and know the results, but haven't organized it to show yet. AD5X has also done some excellent work on the 43 ft vertical idea. And QST recently published a piece showing that a better use of a 43 ft vertical might be as the center support for horizontal dipoles for 80 and 40, a concept with which I strongly agree. :) 73, Jim K9YC __ 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] Antenna question
Since the K3 will do the QRP thing down to 100 mw, think about installing the vertical above the beam on the mast and gradually try more and more power out of the K3 until you start getting some overloading. At least you can find your answer without frying anything and some folks find QRP lots of fun. Maybe you will too! Willis 'Cookie' Cooke, TDXS DX Chairman K5EWJ & Trustee N5BPS, USS Cavalla, USS Stewart From: George Thornton To: "'elecraft @ mailman . qth . net'" Sent: Tuesday, February 11, 2014 5:36 PM Subject: Re: [Elecraft] Antenna question This might be a stupid question, but here goes. I have a small lot. I currently am using a 3 element Yagi that barely fits on the property. I was thinking about getting a vertical as a second HF antenna. If I put it up it is going to have to be pretty close to the Yagi. I have a dual receive K3. If I have both receivers going, one on each channel, and I broadcast on one of these antennas, am I in any danger of overloading and frying the other receiver? __ 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] Antenna question
Hi George, I'm not 100% sure but I don't think your SUB RX has to be ON to be damaged. I believe that just connecting an antenna to the AUX RF input will allow RF into the SUB RX. There is an internal protective device on the input to the SUB RX called a carrier operated relay (COR). You can see it in the manual in some of the block diagrams. When you get your vertical you can try transmitting with the yagi at low power and gradually increase your power. If you hear a clicking sound you are tripping the COR. That's your positive indication that you should either decrease power or add external protection. There are devices available to put in your SUB RX antenna line for overload protection but you can also use the KEY OUT signal to energize a relay to disconnect your SUB RX antenna. There is also a lower current KEY OUT signal on pin 10 of the accessory connector. You can use that to trip a low current device that in turn activates a relay. 73, Mike K2MK George A. Thornton-2 wrote > This might be a stupid question, but here goes. > > I have a small lot. I currently am using a 3 element Yagi that barely > fits on the property. I was thinking about getting a vertical as a second > HF antenna. If I put it up it is going to have to be pretty close to the > Yagi. > > I have a dual receive K3. If I have both receivers going, one on each > channel, and I broadcast on one of these antennas, am I in any danger of > overloading and frying the other receiver? -- View this message in context: http://elecraft.365791.n2.nabble.com/Re-Antenna-question-tp7584071p7584085.html Sent from the Elecraft mailing list archive at Nabble.com. __ 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] Antenna question
NOT Sent from my iPhone > On Feb 11, 2014, at 7:20 PM, Monovasia wrote: > > I would do it at all! Especially at power > > Sent from my iPhone > >> On Feb 11, 2014, at 7:16 PM, Bill Turner wrote: >> >> ORIGINAL MESSAGE: (may be snipped) >> >>> On 2/11/2014 3:36 PM, George Thornton wrote: >>> I have a dual receive K3. If I have both receivers going, one on each >>> channel, and I broadcast on one of these antennas, am I in any danger of >>> overloading and frying the other receiver? >> >> REPLY: >> >> The field around an antenna is very strong compared to the input of a >> receiver which is expecting a fraction of a microwatt. Not something to be >> messed with. >> >> If you must do this I would recommend installing a relay to short out the >> non-transmitting antenna, and you should sequence it so it closes a few >> milliseconds before beginning TX and opens a few milliseconds after ceasing >> TX. Even better than simple shorting, use an SPDT relay so that when the >> relay activated, the antenna is disconnected and the receiver input is >> shorted to ground, separate from the antenna. This provides even more >> isolation between the two. >> >> >> >> 73, Bill W6WRT >> >> __ >> 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] Antenna question
On 2/11/2014 3:36 PM, George Thornton wrote: This might be a stupid question, but here goes. Only unasked questions are stupid. I have a small lot. I currently am using a 3 element Yagi that barely fits on the property. I was thinking about getting a vertical as a second HF antenna. If I put it up it is going to have to be pretty close to the Yagi. You will likely find that a vertical will be 1-2 S-units noisier than your horizontal yagi [or any other horizontal antenna, in general], *unless* you have essentially *no* man-made noise. You said "small lot" which suggests an urban or suburban environment. I have a tri-bander, a large sloping Vee for 160-30, and a GAP Titan vertical on the pipe that carries my coax up to the roof and to the other antennas. I can almost always count on the GAP being a couple of S-units noiser than the other two on any of the bands they work on. I have a dual receive K3. If I have both receivers going, one on each channel, and I broadcast on one of these antennas, am I in any danger of overloading and frying the other receiver? Antennas have a near-field and a far-field and the definition of "near" and "far" depends on the operating frequency, among some other things. The lower the frequency [longer wavelength], the farther "far" is from the antenna. If a second antenna is located within the near-field of the first, they will become a coupled system ... the second antenna will behave as if it was an element or elements of the first antenna. In this case, some fairly large amounts of RF power can show up at the end of the second antennas coax. Obviously, it depends a huge amount on the power you intend to run. 5W may safe. If the second antenna is clearly in the far-field of the first, the coupled power is much much lower. The signal will be huge in the second receiver, but not likely to be damaging to components. I'm on the crew that activates Alpine County in the Calif QSO Party [no permanent hams there]. First year we tried M/2, we had CW and SSB in one cabin. Considering that the aggregate ham experience of the crew was well over 200 years, I can't explain why we did this. :-) The 80 and 75 inverted Vee's were undoubtedly in each other's near-fields, not sure about the 40's, but we had bandpass filters for each rig. I was on 80 CW in the middle of the night, the phone op decided to try 75 ... he switched the filters, I called CQ, and I fried the diodes in the front end of his K3. We now have the two stations at opposite ends of the campground [maybe 500 meters?], and we have no problems. So George, I'd be very careful. The cross-polarization would be in your favor but if you're on 20 or below and "close" means less than a wavelength at best, it could mean problems. Hope this helps 73, Fred K6DGW - Northern California Contest Club - CU in the 2014 Cal QSO Party 4-5 Oct 2014 - 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] Antenna question
Check out the front-end protector in the “Articles” section of my website at www.ad5x.com. Phil – AD5X __ 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] Antenna question
I would do it at all! Especially at power Sent from my iPhone > On Feb 11, 2014, at 7:16 PM, Bill Turner wrote: > > ORIGINAL MESSAGE: (may be snipped) > >> On 2/11/2014 3:36 PM, George Thornton wrote: >> I have a dual receive K3. If I have both receivers going, one on each >> channel, and I broadcast on one of these antennas, am I in any danger of >> overloading and frying the other receiver? > > REPLY: > > The field around an antenna is very strong compared to the input of a > receiver which is expecting a fraction of a microwatt. Not something to be > messed with. > > If you must do this I would recommend installing a relay to short out the > non-transmitting antenna, and you should sequence it so it closes a few > milliseconds before beginning TX and opens a few milliseconds after ceasing > TX. Even better than simple shorting, use an SPDT relay so that when the > relay activated, the antenna is disconnected and the receiver input is > shorted to ground, separate from the antenna. This provides even more > isolation between the two. > > > > 73, Bill W6WRT > > __ > 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] Antenna question
ORIGINAL MESSAGE: (may be snipped) On 2/11/2014 3:36 PM, George Thornton wrote: I have a dual receive K3. If I have both receivers going, one on each channel, and I broadcast on one of these antennas, am I in any danger of overloading and frying the other receiver? REPLY: The field around an antenna is very strong compared to the input of a receiver which is expecting a fraction of a microwatt. Not something to be messed with. If you must do this I would recommend installing a relay to short out the non-transmitting antenna, and you should sequence it so it closes a few milliseconds before beginning TX and opens a few milliseconds after ceasing TX. Even better than simple shorting, use an SPDT relay so that when the relay activated, the antenna is disconnected and the receiver input is shorted to ground, separate from the antenna. This provides even more isolation between the two. 73, Bill W6WRT __ 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] Antenna question
I have a Pennant receiving antenna about 100' from my 160 Meter Antenna. I put a scope on the Pennant coax and keyed the rig. At about 1 KW out, I saw about 6 volts pk-pk. I bought a Receiver protection device. 73, Dick, W1KSZ On 2/11/2014 4:36 PM, George Thornton wrote: This might be a stupid question, but here goes. I have a small lot. I currently am using a 3 element Yagi that barely fits on the property. I was thinking about getting a vertical as a second HF antenna. If I put it up it is going to have to be pretty close to the Yagi. I have a dual receive K3. If I have both receivers going, one on each channel, and I broadcast on one of these antennas, am I in any danger of overloading and frying the other receiver? __ 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] Antenna question
George, That is a very good question. However, it is hard to quess. But, one thing going in your favor is that one antenna is horizontal and the other is vertical. This will minimize the amount of coupling between the two. If you can get some horizontal separation between the two, it just might be physically safe. If you get really good decoupling, it could be on the order of 30 db. that means that a 100 Watts will look like 100 mw to your receiver. I actually do a variant of what you are asking here. I have a Carolina Windom and an 18' base tuned vertical. I know there must be some interaction, but so far nothing has smoked. I know better than to try this without really looking at it, but I didn't think and did it anyway. My antennas are about 15-20 apart horizontally and 15 feet vertically. Maybe I had better have a look at it myself. But, my guess is you'll be OK as long as you don't need to receive at the same time you are transmitting. You will overdrive your receiver and not hear anything during transmissions, but the 100 mw or less into the receiver should be physically safe. That part of the answer should be answered by Elecraft as to the maximum energy the receiver can tolerate. 73, Barry K3NDM On 2/11/2014 6:36 PM, George Thornton wrote: This might be a stupid question, but here goes. I have a small lot. I currently am using a 3 element Yagi that barely fits on the property. I was thinking about getting a vertical as a second HF antenna. If I put it up it is going to have to be pretty close to the Yagi. I have a dual receive K3. If I have both receivers going, one on each channel, and I broadcast on one of these antennas, am I in any danger of overloading and frying the other receiver? __ 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] Antenna question
This might be a stupid question, but here goes. I have a small lot. I currently am using a 3 element Yagi that barely fits on the property. I was thinking about getting a vertical as a second HF antenna. If I put it up it is going to have to be pretty close to the Yagi. I have a dual receive K3. If I have both receivers going, one on each channel, and I broadcast on one of these antennas, am I in any danger of overloading and frying the other receiver? __ 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] Antenna Question
Neil, Were you able to see if the shortened fan dipole used by the county ERC has the feeder connected to all three elements, as would be the case with a typical fan dipole? If the feeder is connected *only* to the mid-point of the longest element, and the two shorter elements are unbroken lengths of wire running parallel to the longest wire, then this antenna would belong to the family of multiband antennas known as "Coupled Resonators". It would be tricky though to use linear loading with these antennas. 73, Geoff LX2AO On Monday, June 18, 2012 at 5:26 AM, Niel Skousen wrote: > I'm pretty sure I've seen this antenna on the net, but don't recall the > name nor have I been able to find a link to a description / design data. > The county ERC has a 'shortened fan dipole' with three parallel elements, > spaced about 18-24" apart on each side. the longest element folds back > around the mid-> > length element toward the shortest element. The > antenna end insulator / guy rope is attached to the long element, where it > folds back. There appears (from the > ground) to be a 6~8" insulator / gap between the end of the shortest > element, and the longest element where its been folded back. no traps, > loading coils, or loading > resistors that I can see. > I'm assuming three or four band coverage (80, 40, 20, and 15 ??) with a > 75m dipole, a 40m dipole (with 15m as a freebie), and a 20 m dipole. but > would be > interested in more technical details if anyone can decipher my text > description above… __ 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] Antenna Question
Indeed! The purpose of the inverted V was for local NVIS coverage and was mentioned anecdotally to illustrate that folded back elements can be very effective if needed. They reduce the mechanical problems of erecting and turning a rotating dipole with minimal degradation. I can see a significant advantage where a shorter antenna is needed. We are fortunate to have a wide range of designs for our wide range of antenna problems. Sent from my iPhone On Jun 18, 2012, at 10:27, Vic K2VCO wrote: > I agree that folding the low-current parts of an antenna is a good way to > make it smaller. > > But there are several things at work in the comparison between the Steppir > element and the > V. Of course the height is one of them. But if you model an inverted V (90 > degree angle > between wires) and a dipole at the same height you will see that the dipole > has > significantly more gain. Many inverted V's are constructed with even smaller > angles, which > are worse. The V pattern also has smaller nulls on the ends. > > Finally, the Steppir undoubtedly has some kind of balun, and its feedline > runs > perpendicular to the antenna for 1/2 wavelength. All of these things improve > the nulls. > They also reduce noise pickup on the feedline. > > On 6/18/2012 5:26 AM, WILLIS COOKE wrote: >> A note on folded back antennae. I have a 3 element SteppIR with the 30/40 >> kit. The >> antenna is mounted at about 67 feet above the ground. I have compared the >> folded >> antenna at 67 feet to a full sized inverted V at 40 feet and find it >> noticeably >> stronger. Even though it is only a dipole which is a little more than half >> length it >> is noticeably bi-directive with deep nulls off the element ends. It is >> quite effective >> as a DX antenna and I believe the SteppIR claim that it is only one or two >> dB down from >> a full sized rotatable dipole. Of course, its improved performance over the >> inverted V >> is mostly because of the elevation difference, but I would not hesitate to >> fold the >> ends of a dipole if restricted by lot size or other physical restraints. >> >> Willis 'Cookie' Cooke K5EWJ& Trustee N5BPS, USS Cavalla, USS Stewart >> >> >> - Original Message - From: Don Wilhelm To: Niel >> Skousen Cc: Elecraft >> Reflector; >> qr...@mailman.qth.net Sent: Monday, June 18, 2012 6:18 AM Subject: Re: >> [Elecraft] >> Antenna Question >> >> Neil, >> >> When you see an antenna element folded back on itself like that, think >> "linear loading" >> (look it up in the ARRL Handbook or similar). There is no "magic", but it >> is one way >> of shortening an antenna. It is not as efficient as a full length antenna, >> but is more >> efficient than using loading coils. Everything is relative. If you have the >> space to >> put up full size half wave dipole antennas, that is the way to go. If you >> need >> shortened antennas for the lower bands, linear loading is one way to achieve >> resonance >> with shortened length. >> >> 73, Don W3FPR >> >> On 6/17/2012 11:26 PM, Niel Skousen wrote: >>> I'm pretty sure I've seen this antenna on the net, but don't recall the >>> name nor have >>> I been able to find a link to a description / design data. >>> >>> The county ERC has a 'shortened fan dipole' with three parallel elements, >>> spaced >>> about 18-24" apart on each side. the longest element folds back around the >>> mid-length element toward the shortest element. The antenna end insulator >>> / guy >>> rope is attached to the long element, where it folds back. There appears >>> (from the >>> ground) to be a 6~8" insulator / gap between the end of the shortest >>> element, and the >>> longest element where its been folded back. no traps, loading coils, or >>> loading >>> resistors that I can see. >>> >>> I'm assuming three or four band coverage (80, 40, 20, and 15 ??) with a 75m >>> dipole, a >>> 40m dipole (with 15m as a freebie), and a 20 m dipole. but would be >>> interested in >>> more technical details if anyone can decipher my text description above… >>> >>> Thanks Niel > > -- > 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 __ 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] Antenna Question
I agree that folding the low-current parts of an antenna is a good way to make it smaller. But there are several things at work in the comparison between the Steppir element and the V. Of course the height is one of them. But if you model an inverted V (90 degree angle between wires) and a dipole at the same height you will see that the dipole has significantly more gain. Many inverted V's are constructed with even smaller angles, which are worse. The V pattern also has smaller nulls on the ends. Finally, the Steppir undoubtedly has some kind of balun, and its feedline runs perpendicular to the antenna for 1/2 wavelength. All of these things improve the nulls. They also reduce noise pickup on the feedline. On 6/18/2012 5:26 AM, WILLIS COOKE wrote: > A note on folded back antennae. I have a 3 element SteppIR with the 30/40 > kit. The > antenna is mounted at about 67 feet above the ground. I have compared the > folded > antenna at 67 feet to a full sized inverted V at 40 feet and find it > noticeably > stronger. Even though it is only a dipole which is a little more than half > length it > is noticeably bi-directive with deep nulls off the element ends. It is quite > effective > as a DX antenna and I believe the SteppIR claim that it is only one or two dB > down from > a full sized rotatable dipole. Of course, its improved performance over the > inverted V > is mostly because of the elevation difference, but I would not hesitate to > fold the > ends of a dipole if restricted by lot size or other physical restraints. > > Willis 'Cookie' Cooke K5EWJ& Trustee N5BPS, USS Cavalla, USS Stewart > > > - Original Message - From: Don Wilhelm To: Niel > Skousen Cc: Elecraft > Reflector; > qr...@mailman.qth.net Sent: Monday, June 18, 2012 6:18 AM Subject: Re: > [Elecraft] > Antenna Question > > Neil, > > When you see an antenna element folded back on itself like that, think > "linear loading" > (look it up in the ARRL Handbook or similar). There is no "magic", but it is > one way > of shortening an antenna. It is not as efficient as a full length antenna, > but is more > efficient than using loading coils. Everything is relative. If you have the > space to > put up full size half wave dipole antennas, that is the way to go. If you > need > shortened antennas for the lower bands, linear loading is one way to achieve > resonance > with shortened length. > > 73, Don W3FPR > > On 6/17/2012 11:26 PM, Niel Skousen wrote: >> I'm pretty sure I've seen this antenna on the net, but don't recall the name >> nor have >> I been able to find a link to a description / design data. >> >> The county ERC has a 'shortened fan dipole' with three parallel elements, >> spaced >> about 18-24" apart on each side. the longest element folds back around the >> mid-length element toward the shortest element. The antenna end insulator >> / guy >> rope is attached to the long element, where it folds back. There appears >> (from the >> ground) to be a 6~8" insulator / gap between the end of the shortest >> element, and the >> longest element where its been folded back. no traps, loading coils, or >> loading >> resistors that I can see. >> >> I'm assuming three or four band coverage (80, 40, 20, and 15 ??) with a 75m >> dipole, a >> 40m dipole (with 15m as a freebie), and a 20 m dipole. but would be >> interested in >> more technical details if anyone can decipher my text description above… >> >> Thanks Niel -- 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] Antenna Question
A note on folded back antennae. I have a 3 element SteppIR with the 30/40 kit. The antenna is mounted at about 67 feet above the ground. I have compared the folded antenna at 67 feet to a full sized inverted V at 40 feet and find it noticeably stronger. Even though it is only a dipole which is a little more than half length it is noticeably bi-directive with deep nulls off the element ends. It is quite effective as a DX antenna and I believe the SteppIR claim that it is only one or two dB down from a full sized rotatable dipole. Of course, its improved performance over the inverted V is mostly because of the elevation difference, but I would not hesitate to fold the ends of a dipole if restricted by lot size or other physical restraints. Willis 'Cookie' Cooke K5EWJ & Trustee N5BPS, USS Cavalla, USS Stewart - Original Message - From: Don Wilhelm To: Niel Skousen Cc: Elecraft Reflector ; qr...@mailman.qth.net Sent: Monday, June 18, 2012 6:18 AM Subject: Re: [Elecraft] Antenna Question Neil, When you see an antenna element folded back on itself like that, think "linear loading" (look it up in the ARRL Handbook or similar). There is no "magic", but it is one way of shortening an antenna. It is not as efficient as a full length antenna, but is more efficient than using loading coils. Everything is relative. If you have the space to put up full size half wave dipole antennas, that is the way to go. If you need shortened antennas for the lower bands, linear loading is one way to achieve resonance with shortened length. 73, Don W3FPR On 6/17/2012 11:26 PM, Niel Skousen wrote: > I'm pretty sure I've seen this antenna on the net, but don't recall the name > nor have I been able to find a link to a description / design data. > > The county ERC has a 'shortened fan dipole' with three parallel elements, > spaced about 18-24" apart on each side. the longest element folds back > around the mid-length element toward the shortest element. The antenna end > insulator / guy rope is attached to the long element, where it folds back. > There appears (from the ground) to be a 6~8" insulator / gap between the end > of the shortest element, and the longest element where its been folded back. > no traps, loading coils, or loading resistors that I can see. > > I'm assuming three or four band coverage (80, 40, 20, and 15 ??) with a 75m > dipole, a 40m dipole (with 15m as a freebie), and a 20 m dipole. but would > be interested in more technical details if anyone can decipher my text > description above… > > Thanks > Niel > __ 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] Antenna Question
Neil, When you see an antenna element folded back on itself like that, think "linear loading" (look it up in the ARRL Handbook or similar). There is no "magic", but it is one way of shortening an antenna. It is not as efficient as a full length antenna, but is more efficient than using loading coils. Everything is relative. If you have the space to put up full size half wave dipole antennas, that is the way to go. If you need shortened antennas for the lower bands, linear loading is one way to achieve resonance with shortened length. 73, Don W3FPR On 6/17/2012 11:26 PM, Niel Skousen wrote: > I'm pretty sure I've seen this antenna on the net, but don't recall the name > nor have I been able to find a link to a description / design data. > > The county ERC has a 'shortened fan dipole' with three parallel elements, > spaced about 18-24" apart on each side. the longest element folds back > around the mid-length element toward the shortest element. The antenna end > insulator / guy rope is attached to the long element, where it folds back. > There appears (from the ground) to be a 6~8" insulator / gap between the end > of the shortest element, and the longest element where its been folded back. > no traps, loading coils, or loading resistors that I can see. > > I'm assuming three or four band coverage (80, 40, 20, and 15 ??) with a 75m > dipole, a 40m dipole (with 15m as a freebie), and a 20 m dipole. but would > be interested in more technical details if anyone can decipher my text > description above… > > Thanks > Niel > __ 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] Antenna Question
I don't recognize that one, Niel, but keep in mind that many antennas used by the Military and Emergency Comm centers are *very* inefficient. The requirement is usually for broader bandwidths and simple designs over "gain" or efficiency. For example, the famous B&W broadband broadband folded dipole (http://www.bwantennas.com/ama/fdipole.ama.htm ) has been criticized by countless hams for throwing away at least half (3 dB) of the applied RF, but high efficiency was never its goal. That antenna provides a decent match across a wide frequency range, usually covering several Ham bands, in exchange for putting twice as much RF into it as you'd need for the same signal on a narrow-bandwidth conventional antenna. Neither emergency services or the military have any need or interest in working DX or busting a pileup. They are interested in simple, easy-to-use antennas for ranges from a few dozen to a couple hundred miles, maximum. 73, Ron AC7AC -Original Message- From: elecraft-boun...@mailman.qth.net [mailto:elecraft-boun...@mailman.qth.net] On Behalf Of Niel Skousen Sent: Sunday, June 17, 2012 8:26 PM To: Elecraft Reflector; qr...@mailman.qth.net Subject: [Elecraft] Antenna Question I'm pretty sure I've seen this antenna on the net, but don't recall the name nor have I been able to find a link to a description / design data. The county ERC has a 'shortened fan dipole' with three parallel elements, spaced about 18-24" apart on each side. the longest element folds back around the mid-length element toward the shortest element. The antenna end insulator / guy rope is attached to the long element, where it folds back. There appears (from the ground) to be a 6~8" insulator / gap between the end of the shortest element, and the longest element where its been folded back. no traps, loading coils, or loading resistors that I can see. I'm assuming three or four band coverage (80, 40, 20, and 15 ??) with a 75m dipole, a 40m dipole (with 15m as a freebie), and a 20 m dipole. but would be interested in more technical details if anyone can decipher my text description above. Thanks Niel __ 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] Antenna Question for KX1
In message <[EMAIL PROTECTED]>, Paul Webb <[EMAIL PROTECTED]> writes Hi All I have been playing with my KX1 in the back yard the last week or so and found that about 26ft of wire in the hot side of the bnc connector and about the same to the cold side gets me a good match with the built in ATU on 40,30,20m Now if I use the same wires but add 20ft of coax between the radio and these wires I find it very hard to get a match on any band, do I need to use a balun at the end of the coax? Any thoughts Paul Hi Paul, I believe you are on a hiding to nothing attempting to reproduce the results via a length of coax cable. Remember those initial results were obtained with the ATU connected directly to the antenna. Everything after the ATU is effectively the antenna and is likely to radiate, including the coax. Adding a balun will do absolutely nothing except to change the electrical antenna length (where the antenna in this case is the coax and the original wires), your coax will still radiate and you are likely to get poor results. With this sort of antenna the ATU must *always* be at the antenna end of the feeder, whether that be directly after the ATU in the KX1 as in your initial trials, or at the antenna end of the 20 foot of coax as you attempted later. The only exception to this is when the antenna presents an electrical quarter wave or odd multiple thereof. In those cases, no ATU is necessary. Trev G3ZYY -- Trevor Day UKSMG #217 www.uksmg.org ___ 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] Antenna Question for KX1
Is the coax ok? Add or remove length from antenna. Guessing interaction between coax & antenna. This should demonstrate that pretty quick. What is the impedance range of auto tuner? "Don Wilhelm" <[EMAIL PROTECTED]> wrote: __ >Paul, > >A balun may or may not help. and in any case, a balun or no balun is not the >answer to your situation - the 20 ft of coax is acting like an impedance >transformer, and without a thorough analysis of your antenna and feedline >system, it is difficult to say what would help. Perhaps some >experimentation is in order - add a 4:1 balun and see what happens, simlarly >try a 1:1 balun, try changing the length of the parallel feedline, and try >changing the length of the coax. All these things will influence the >results, as will changing the length of the antenna wires. If you do not >have adequate instrumentation to analyze the system, then a bit of old >fashioned 'cut and try' may be the way to properly answer your questions - >in any case, keep notes of what happens so you will know which way to go >when making future changes. When you find something that works, rejoice and >let us know, perhaps some of us can give you some info relating to why it >works. > >73, >Don W3FPR > >> -Original Message- >> >> I have been playing with my KX1 in the back yard the last week or so and >> found that about 26ft of wire in the hot side of the bnc >> connector and about >> the same to the cold side gets me a good match with the built in ATU on >> 40,30,20m >> >> Now if I use the same wires but add 20ft of coax between the >> radio and these >> wires I find it very hard to get a match on any band, do I need to use a >> balun at the end of the coax? >> >> Any thoughts >> >> Paul >> >> M0BMN >> >> > >___ >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
Re: [Elecraft] Antenna Question for KX1
Paul You might like to check out this antenna idea on the Adventure Radio Society web site: http://www.arsqrp.com/ars/pages/back_issues/2006_text/0506_text/N7XJa.html Looks good to me, and it's been used on 40/30/20 with a KX1. 73 Dave, G4AON ___ 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] Antenna Question for KX1
Try taking a big fat toroid from somewhere and looping your coax through that about 15 times at the antenna end and see how that works for you. Alternately, put a bunch of clip-on beads on the coax at the antenna end and try that. Alternately, try lengthening the antenna on the 'hot' side as the coax braid may be acting as the ground side. Not saying I know, just saying, Try. 73 de Alex NS6Y. On Apr 30, 2006, at 5:49 PM, Don Wilhelm wrote: Paul, A balun may or may not help. and in any case, a balun or no balun is not the answer to your situation - the 20 ft of coax is acting like an impedance transformer, and without a thorough analysis of your antenna and feedline system, it is difficult to say what would help. Perhaps some experimentation is in order - add a 4:1 balun and see what happens, simlarly try a 1:1 balun, try changing the length of the parallel feedline, and try changing the length of the coax. All these things will influence the results, as will changing the length of the antenna wires. If you do not have adequate instrumentation to analyze the system, then a bit of old fashioned 'cut and try' may be the way to properly answer your questions - in any case, keep notes of what happens so you will know which way to go when making future changes. When you find something that works, rejoice and let us know, perhaps some of us can give you some info relating to why it works. 73, Don W3FPR -Original Message- I have been playing with my KX1 in the back yard the last week or so and found that about 26ft of wire in the hot side of the bnc connector and about the same to the cold side gets me a good match with the built in ATU on 40,30,20m Now if I use the same wires but add 20ft of coax between the radio and these wires I find it very hard to get a match on any band, do I need to use a balun at the end of the coax? Any thoughts Paul M0BMN ___ 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
RE: [Elecraft] Antenna Question for KX1
Paul, A balun may or may not help. and in any case, a balun or no balun is not the answer to your situation - the 20 ft of coax is acting like an impedance transformer, and without a thorough analysis of your antenna and feedline system, it is difficult to say what would help. Perhaps some experimentation is in order - add a 4:1 balun and see what happens, simlarly try a 1:1 balun, try changing the length of the parallel feedline, and try changing the length of the coax. All these things will influence the results, as will changing the length of the antenna wires. If you do not have adequate instrumentation to analyze the system, then a bit of old fashioned 'cut and try' may be the way to properly answer your questions - in any case, keep notes of what happens so you will know which way to go when making future changes. When you find something that works, rejoice and let us know, perhaps some of us can give you some info relating to why it works. 73, Don W3FPR > -Original Message- > > I have been playing with my KX1 in the back yard the last week or so and > found that about 26ft of wire in the hot side of the bnc > connector and about > the same to the cold side gets me a good match with the built in ATU on > 40,30,20m > > Now if I use the same wires but add 20ft of coax between the > radio and these > wires I find it very hard to get a match on any band, do I need to use a > balun at the end of the coax? > > Any thoughts > > Paul > > M0BMN > > ___ 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] Antenna Question for KX1
Paul The loss in poorly matched coax can be very high, you might consider using a length of 300 Ohm ribbon cable instead. You will need a balun at the KX1 end of the ribbon. With my K1 across 40/30/20/15 I find a 66 foot top (33' each side) with 32 foot of ribbon tunes with the KAT1 in my K1. I understand the tuning range of the KX1 ATU is even less than that fitted to a K1, so you might have to play around with the length of ribbon to get a satisfactory match. The advantage is you can get the dipole part of the antenna a reasonable height with a fishing pole or similar support. 73 Dave, G4AON K1 # 1154 K2 # 1892 ___ 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] Antenna Question for KX1
Hi Paul, Without modeling your antenna, I don't know what the feedpoint impedances are, but it's a good thing that you can match them with the KX-1. The 20 foot length of coax is transforming the impedance to something outside the range of your KX-1, and a balun wouldn't help unless (perhaps) it was also an impedance transformer. Hope this answers your question. 73, ed - k9ew ___ 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] Antenna question - Balun
Yes, it can be done, Mike. Remember that the 4:1 balun will be happiest seeing an impedance around 200-300 ohms, though. The 4:1 ratio really only holds when the impedances are correct. Once you throw in a mixed load that is well away from this value, plus an unknown amount of reactance, the ratio changes and losses can mount. Not a serious concern at QRP power levels, but at 100w it could cook a balun that is seriusly mismatched. The best way to use baluns is to adjust your balanced feedline length on a given band to give very little reactance, regardless of the resistive part of the load impedance. The ATU will have an easier time matching a resistive load than one with combined reactance and resistance. The baluns will work best when the loads are resistive, even if the wrong value. When you mix in reactance, the balun will have unpredictable ratios and losses. Good luck and 73 Bob N6WG The Little Station with Attitude -Original Message- From: Mike W [mailto:[EMAIL PROTECTED] Sent: Sunday, August 21, 2005 4:03 PM To: Robert Tellefsen; elecraft@mailman.qth.net Subject: RE: [Elecraft] Antenna question - Balun On 21 Aug 2005 at 8:40, Robert Tellefsen wrote: > Two things will make matching easier. Get two > baluns, 1:1 and 4:1. Put them on the two > antenna ports of the ATU Looking at the two versions of the BL1 for 1:1 and 4:1 Can you not use a 2pco ( dpdt ) switch or relay to change between the two ?. Commons to the two inner windings ( see BL1.pdf ). Short them for interconnect on the NO connections for 4:1 Parallel them on the NC connections for 1:1. ___ 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] Antenna question - Balun
You can. Somewhere on the web I saw one set up with a little DPDT slide switch, but I can't find it now that I want it. Hi. Anyway, it's not that difficult as you have already discovered. Eric KE6US www.ke6us.com -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Mike W Sent: Sunday, August 21, 2005 4:03 PM To: Robert Tellefsen; elecraft@mailman.qth.net Subject: RE: [Elecraft] Antenna question - Balun On 21 Aug 2005 at 8:40, Robert Tellefsen wrote: > Two things will make matching easier. Get two baluns, 1:1 and 4:1. > Put them on the two antenna ports of the ATU Looking at the two versions of the BL1 for 1:1 and 4:1 Can you not use a 2pco ( dpdt ) switch or relay to change between the two ?. Commons to the two inner windings ( see BL1.pdf ). Short them for interconnect on the NO connections for 4:1 Parallel them on the NC connections for 1:1. ___ 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
RE: [Elecraft] Antenna question - Balun
On 21 Aug 2005 at 8:40, Robert Tellefsen wrote: > Two things will make matching easier. Get two > baluns, 1:1 and 4:1. Put them on the two > antenna ports of the ATU Looking at the two versions of the BL1 for 1:1 and 4:1 Can you not use a 2pco ( dpdt ) switch or relay to change between the two ?. Commons to the two inner windings ( see BL1.pdf ). Short them for interconnect on the NO connections for 4:1 Parallel them on the NC connections for 1:1. ___ 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] Antenna question
Hello Tom I'm using a similar setup here for my K2. The dipole is just 60 ft long, a bit under a true half wavelength. However, with the 450 ohm tuned feeders, I use the antenna on 80, 40, 30 and 20 meters. Works very well at a height of 42 ft in center and 35 feet at ends. Two things will make matching easier. Get two baluns, 1:1 and 4:1. Put them on the two antenna ports of the ATU. Now, when you change bands, put the feeder on the balun that gives you the lowest swr while the ATU is in CAL S. This is effectively bypassing the ATU. Then switch in the ATU and match. From then on, the ATU memory will remember the settings, so you will just have to remember which balun goes with which band or bands. Works very well. Good luck and 73 Bob N6WG -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] Behalf Of Tom McCulloch Sent: Saturday, August 20, 2005 6:58 PM To: elecraft@mailman.qth.net Subject: [Elecraft] Antenna question Hi all, I'm considering putting up a 40 meter dipole fed with a 450 ladder line. I have a K2 which I run at about 5 to watts (I do not have the 100 watt amp). The K2 also has the internal ATU. I have always used 50 ohm coax up until now. Is there anything I should know about using the K2 with 450 ohm feedline? (Will I need a balun, or can I just feed the ladderline directly to the K2's ATU and that will take care of the match. Thanks for your help. Tom, WB2QDG K2 1103 ___ 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
Re: [Elecraft] Antenna question
Tom, While you can run the ladder line right to the shack and connect directly to the K2, a balun mounted outside and a coax run to the rig works well and you avoid having to run the ladder line inside which sometimes can be problematic. There are several low cost 4:1 baluns on the market including the Elecraft one, or you can use a BA-58 or BA-8 kit of ferrite beads over the coax from Palomar. As my late friend George used to say, a 1:1 balun works as well in this application as a 4:1. You need to avoid a length of feed line such that the sum of the length of the feed line times its velocity factor plus 1/2 the length of the dipole is 1/2 wave length. Then keep the length of coax times its velocity factor unequal to a 1/2 wave length too. Best to keep the coax run short. That is to avoid a current node either at the position of the balun or at the K2. 73, Chas, W1CG At 09:57 PM 8/20/2005, Tom McCulloch wrote: Hi all, I'm considering putting up a 40 meter dipole fed with a 450 ladder line. I have a K2 which I run at about 5 to watts (I do not have the 100 watt amp). The K2 also has the internal ATU. I have always used 50 ohm coax up until now. Is there anything I should know about using the K2 with 450 ohm feedline? (Will I need a balun, or can I just feed the ladderline directly to the K2's ATU and that will take care of the match. Thanks for your help. Tom, WB2QDG K2 1103 ___ 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
Re: [Elecraft] Antenna question
Hi Tom - I don't think you mentioned what bands you intend to use the antenna for. If just 40M, then you may do as well with coax and not need the tuner. If you use it for an all band doublet, the tuner may have difficulty on some bands depending on the impedence and the lenght of the feedline. Without the balun, you may have radiation from the feedline, which may not be a problem or it may cause problems in the shack with RF getting into equipment or noise on receive if the source is near the rig. I use a doublet but I increased the lenght to 88 ft and the k2 handles it well on most bands. I plan to increase the lenght to 100 ft to get better efficiency on 80 meters. I use a 1 to 1 balun. A 4 to 1 balun may work better on some frequencies but would likely give less efficiency on 80 meters due to low radiation resistance. Finally, changing the lenght of the feed line can improve the match on some bands with a possible worse match on others. Multiband antennas are always a compromise and experimenting may be required.Rick - K7MW Original Message - From: "Tom McCulloch" <[EMAIL PROTECTED]> To: Sent: Saturday, August 20, 2005 6:57 PM Subject: [Elecraft] Antenna question > Hi all, > I'm considering putting up a 40 meter dipole fed with a 450 ladder line. > I have a K2 which I run at about 5 to watts (I do not have the 100 watt > amp). The K2 also has the internal ATU. > > I have always used 50 ohm coax up until now. Is there anything I should > know about using the K2 with 450 ohm feedline? (Will I need a balun, or can > I just feed the ladderline directly to the K2's ATU and that will take care > of the match. > > Thanks for your help. > > Tom, WB2QDG > > K2 1103 > > ___ > 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