[amsat-bb] Re: 70cm Helicoil Good/Bad expensive?
What, exactly, is a helicoil antenna? On 12-Jul-11 00:39, Kevin Deane wrote: > > Hello all, whats the take on these antennas? I am sure someone on here has > used them and they certainly look cool but how do they perform? > > Dont you have to switch polerization on a cross polerized yagi? > > I know there is not a perfect antenna, just wondering about the Helicoil... > > Kevin > KF7MYK > > ___ > Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. > Not an AMSAT-NA member? Join now to support the amateur satellite program! > Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb > -- Nigel A. Gunn, 1865 El Camino Drive, Xenia, OH 45385-1115, USA. tel +1 937 825 5032 Amateur Radio G8IFF W8IFF (was KC8NHF 9H3GN), e-mail ni...@ngunn.net www http://www.ngunn.net Member of ARRL, GQRP #11396, QRPARCI #11644, SOC #548, Flying Pigs QRP Club International #385, Dayton ARA #2128, AMSAT-NA LM-1691, AMSAT-UK 0182, MKARS, ALC, GCARES, XWARN, EAA382. ___ Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
[amsat-bb] Re: 70cm Helicoil Good/Bad expensive?
A "Helicoil" is a threaded insert used to repair stripped threads. I think you're asking about a HELICAL antenna. They work very well, and are easy to build. They're very forgiving in construction errors, but have a few pitfalls you want to watch out for. You do NOT want to wind one on PVC pipe for a support, as the dielectric constant of the PVC will throw off the antenna from the design numbers you use to wind the "coil". This type of helical is called an "Axial Mode" antenna. A "Normal Mode" helical is how a rubber duck is made, and is not what you want. The ARRL Antenna Handbook has several designs that work well, and there's a TON of information on the Web about building an "Axial Mode Helical Antenna". They're fixed polarization, determined when you wind it, and the only way to switch between left-hand and right-hand is to have another antenna, and switch to it. I've built several, and they work pretty well. They get pretty big at 2 Meters, but are manageable (at least for me!) at 70cm and up. 73, Jim KQ6EA On 07/12/2011 12:39 AM, Kevin Deane wrote: > Hello all, whats the take on these antennas? I am sure someone on here has > used them and they certainly look cool but how do they perform? > > Dont you have to switch polerization on a cross polerized yagi? > > I know there is not a perfect antenna, just wondering about the Helicoil... > > Kevin > KF7MYK > > ___ > Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. > Not an AMSAT-NA member? Join now to support the amateur satellite program! > Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb > ___ Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
[amsat-bb] Re: 70cm Helicoil Good/Bad expensive?
I second Jim's assessment here. Helical antennas are the only way I will build an antenna at 1.2 ghz or higher. It's not worth the stress trying to measure things to the precision needed for a Yagi at those frequencies. The less stress (and time) taken to build the antenna, the more enjoyment you will get from actually using it! For 2m and 70cm, Yagis are good, but also consider making a Quad or a Quagi (a 2 element Quad with more Yagi elements in front). I used a home-built 8 element Quagi from the ARRL Antenna Handbook for several years as a satellite antenna, until I found a crossed Yagi antenna at a Ham Swap for a price I couldn't pass up. Still have the Quagi, just in case. Greg KO6TH > Date: Tue, 12 Jul 2011 01:38:17 + > From: kq...@verizon.net > To: amsat-bb@amsat.org > Subject: [amsat-bb] Re: 70cm Helicoil Good/Bad expensive? > > A "Helicoil" is a threaded insert used to repair stripped threads. > > I think you're asking about a HELICAL antenna. > > They work very well, and are easy to build. They're very forgiving in > construction errors, but have a few pitfalls you want to watch out for. > > You do NOT want to wind one on PVC pipe for a support, as the dielectric > constant of the PVC will throw off the antenna from the design numbers > you use to wind the "coil". > > This type of helical is called an "Axial Mode" antenna. A "Normal Mode" > helical is how a rubber duck is made, and is not what you want. > > The ARRL Antenna Handbook has several designs that work well, and > there's a TON of information on the Web about building an "Axial Mode > Helical Antenna". > > They're fixed polarization, determined when you wind it, and the only > way to switch between left-hand and right-hand is to have another > antenna, and switch to it. > > I've built several, and they work pretty well. They get pretty big at 2 > Meters, but are manageable (at least for me!) at 70cm and up. > > 73, Jim KQ6EA > > > On 07/12/2011 12:39 AM, Kevin Deane wrote: > > Hello all, whats the take on these antennas? I am sure someone on here has > > used them and they certainly look cool but how do they perform? > > > > Dont you have to switch polerization on a cross polerized yagi? > > > > I know there is not a perfect antenna, just wondering about the Helicoil... > > > > Kevin > > KF7MYK > > > > ___ > > Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. > > Not an AMSAT-NA member? Join now to support the amateur satellite program! > > Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb > > > > ___ > Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. > Not an AMSAT-NA member? Join now to support the amateur satellite program! > Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb ___ Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
[amsat-bb] Re: 70cm Helicoil Good/Bad expensive?
Greg, Do not overlook the 2.4 GHz grid dishes. I have successfully added a quad loop for 23 cm (1.2GHz) and have been pleasantly surprised with the performance. I have used one for transmit on 2.4 and receive on 1.2 for ATV work. A single dish with two microwave bands. Art, KC6UQH -Original Message- From: amsat-bb-boun...@amsat.org [mailto:amsat-bb-boun...@amsat.org] On Behalf Of Greg D. Sent: Monday, July 11, 2011 9:14 PM To: amsat-bb@amsat.org Subject: [amsat-bb] Re: 70cm Helicoil Good/Bad expensive? I second Jim's assessment here. Helical antennas are the only way I will build an antenna at 1.2 ghz or higher. It's not worth the stress trying to measure things to the precision needed for a Yagi at those frequencies. The less stress (and time) taken to build the antenna, the more enjoyment you will get from actually using it! For 2m and 70cm, Yagis are good, but also consider making a Quad or a Quagi (a 2 element Quad with more Yagi elements in front). I used a home-built 8 element Quagi from the ARRL Antenna Handbook for several years as a satellite antenna, until I found a crossed Yagi antenna at a Ham Swap for a price I couldn't pass up. Still have the Quagi, just in case. Greg KO6TH > Date: Tue, 12 Jul 2011 01:38:17 + > From: kq...@verizon.net > To: amsat-bb@amsat.org > Subject: [amsat-bb] Re: 70cm Helicoil Good/Bad expensive? > > A "Helicoil" is a threaded insert used to repair stripped threads. > > I think you're asking about a HELICAL antenna. > > They work very well, and are easy to build. They're very forgiving in > construction errors, but have a few pitfalls you want to watch out for. > > You do NOT want to wind one on PVC pipe for a support, as the dielectric > constant of the PVC will throw off the antenna from the design numbers > you use to wind the "coil". > > This type of helical is called an "Axial Mode" antenna. A "Normal Mode" > helical is how a rubber duck is made, and is not what you want. > > The ARRL Antenna Handbook has several designs that work well, and > there's a TON of information on the Web about building an "Axial Mode > Helical Antenna". > > They're fixed polarization, determined when you wind it, and the only > way to switch between left-hand and right-hand is to have another > antenna, and switch to it. > > I've built several, and they work pretty well. They get pretty big at 2 > Meters, but are manageable (at least for me!) at 70cm and up. > > 73, Jim KQ6EA > > > On 07/12/2011 12:39 AM, Kevin Deane wrote: > > Hello all, whats the take on these antennas? I am sure someone on here has used them and they certainly look cool but how do they perform? > > > > Dont you have to switch polerization on a cross polerized yagi? > > > > I know there is not a perfect antenna, just wondering about the Helicoil... > > > > Kevin > > KF7MYK > > > > ___ > > Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. > > Not an AMSAT-NA member? Join now to support the amateur satellite program! > > Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb > > > > ___ > Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. > Not an AMSAT-NA member? Join now to support the amateur satellite program! > Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb ___ Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb __ Information from ESET NOD32 Antivirus, version of virus signature database 6285 (20110711) __ The message was checked by ESET NOD32 Antivirus. http://www.eset.com __ Information from ESET NOD32 Antivirus, version of virus signature database 6285 (20110711) __ The message was checked by ESET NOD32 Antivirus. http://www.eset.com ___ Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
[amsat-bb] Re: 70cm Helicoil Good/Bad expensive?
Twas just a joke ... But YOU knew that ... (grin) There is an amazing gentleman out in the Palm Desert area ... met him at the Palm Springs HamFest earlier this year. He fabricates some beautiful 2M Yagis for sat work. But they're only about $100 ... Clint ___ Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
[amsat-bb] Re: 70cm Helicoil Good/Bad expensive?
Hello Kevin-I have built a few of these antennas over the years. Mostly for 1.2ghz RHCP tx and 2.4ghz LHCP rx for a dish feed. As mentioned the polarization is fixed. The helix antenna is pretty broad banded. I never built one for 70cm or 2m however I have been tempted. Here it comesOur next HEO will most certainly have L & S band capability. I can only hope I will last that long. If you want some pics I have many. Yeah they do look cool. 73 Bob W7LRD Seattle - Original Message - From: "Kevin Deane" To: amsat-bb@amsat.org Sent: Monday, July 11, 2011 5:39:25 PM Subject: [amsat-bb] 70cm Helicoil Good/Bad expensive? Hello all, whats the take on these antennas? I am sure someone on here has used them and they certainly look cool but how do they perform? Dont you have to switch polerization on a cross polerized yagi? I know there is not a perfect antenna, just wondering about the Helicoil... Kevin KF7MYK ___ Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb ___ Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
[amsat-bb] Re: 70cm Helicoil Good/Bad expensive?
Hi Art, I've got a BBQ Grill too, but used a 3 1/4 turn helix for a feed. I was able to work AO-40 at apogee with it. Definitely a nice system. How big is your dish? I've not seen a Grill antenna much bigger than the one I currently have, and I'm told it's not big enough for 1.2 ghz (only 30"). Supposed to need at least 4'. So instead I built a helix for that band and did some L/S and L/U through AO-51. Then I found a commercial long boom 1.2 ghz yagi at another Ham Swap (gotta keep me away from those!), and replaced the Helix. But, you know, I don't think the new antenna improved things. Mechanically, yes, but not RF. The Beacon off to the West is about the same on either one. Given the lack of S-band on the current birds, I was thinking about taking down the Grill for a while, just to lighten the load on the rotor motors. Maybe put up a Wi-Fi flat panel, just to keep the band open. But if I can get both 1.2 and 2.4 out of the Grill instead, might that be better? Greg KO6TH > From: kc6...@cox.net > To: ko6th_g...@hotmail.com; amsat-bb@amsat.org > Subject: RE: [amsat-bb] Re: 70cm Helicoil Good/Bad expensive? > Date: Mon, 11 Jul 2011 21:26:17 -0700 > > Greg, > Do not overlook the 2.4 GHz grid dishes. I have successfully added a quad > loop for 23 cm (1.2GHz) and have been pleasantly surprised with the > performance. I have used one for transmit on 2.4 and receive on 1.2 for ATV > work. A single dish with two microwave bands. > > Art, > KC6UQH > ___ Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
[amsat-bb] Re: 70cm Helicoil Good/Bad expensive?
Maybe he was thinking of one of these.. http://va6bc.no-ip.com/jerry_pix/Quadrifilar-helix/quadrifilar_helix_antenna.htm http://www.dxzone.com/dx23282/quadrifilar-helix-antenna.html 73, Harvey K5HV - Original Message - From: "Greg D." To: ; Sent: Tuesday, July 12, 2011 0:51 AM Subject: [amsat-bb] Re: 70cm Helicoil Good/Bad expensive? > > Hi Art, > > I've got a BBQ Grill too, but used a 3 1/4 turn helix for a feed. I was > able to work AO-40 at apogee with it. Definitely a nice system. > > How big is your dish? I've not seen a Grill antenna much bigger than the > one I currently have, and I'm told it's not big enough for 1.2 ghz (only > 30"). Supposed to need at least 4'. So instead I built a helix for that > band and did some L/S and L/U through AO-51. Then I found a commercial > long boom 1.2 ghz yagi at another Ham Swap (gotta keep me away from > those!), and replaced the Helix. But, you know, I don't think the new > antenna improved things. Mechanically, yes, but not RF. The Beacon off > to the West is about the same on either one. > > Given the lack of S-band on the current birds, I was thinking about taking > down the Grill for a while, just to lighten the load on the rotor motors. > Maybe put up a Wi-Fi flat panel, just to keep the band open. But if I can > get both 1.2 and 2.4 out of the Grill instead, might that be better? > > Greg KO6TH > > >> From: kc6...@cox.net >> To: ko6th_g...@hotmail.com; amsat-bb@amsat.org >> Subject: RE: [amsat-bb] Re: 70cm Helicoil Good/Bad expensive? >> Date: Mon, 11 Jul 2011 21:26:17 -0700 >> >> Greg, >> Do not overlook the 2.4 GHz grid dishes. I have successfully added a quad >> loop for 23 cm (1.2GHz) and have been pleasantly surprised with the >> performance. I have used one for transmit on 2.4 and receive on 1.2 for >> ATV >> work. A single dish with two microwave bands. >> >> Art, >> KC6UQH >> > > > ___ > Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. > Not an AMSAT-NA member? Join now to support the amateur satellite program! > Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb ___ Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
[amsat-bb] Re: 70cm Helicoil Good/Bad expensive?
Helical antennas are wonderful things. However with one caveat, they respond in "normal mode" over a wider bandwidth than the desired axial mode. What this means is that your receiver is more susceptible to overload from _out of band_ signals than it might be using a Yagi having a resonant match. Be sure your preamp is a high end model with coincidentally, " a helical" front end filter. -- Joe Leikhim Leikhim and Associates Communications Consultants Oviedo, Florida www.Leikhim.com jleik...@leikhim.com 407-982-0446 ___ Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
[amsat-bb] Re: 70cm Helicoil Good/Bad expensive?
Hi Mariano; I stand corrected! I concur that some Americans here in the states were caught accessing the satellites. What is their motivation? What dialect are they speaking? On 7/12/2011 11:14 AM, AMSAT-CT Engineering wrote: > > Esteemed colleague Joe Leikhim, > > The people as you referred as operators (...) A few years back I found > some "pirate" (Portuguese) (...), are not Portuguese, speaking in > Portuguese, but are Americans from Brazil, and are illegally, very > active in the satellite. > > Greetings > > > > Mariano, CT1XI > > www.amrad.pt > > > > > > > > > > - Original Message - From: "Joe Leikhim" > To: > Sent: Tuesday, July 12, 2011 3:18 PM > Subject: [amsat-bb] Re: 70cm Helicoil Good/Bad expensive? > > >> I have an Andrew bifilar helical antenna for the240-320 MHzMILSAT >> band, same antenna pictured in back of their old catalogs. I paid a >> lot of money (mostly in shipping) to acquire it. But far less than >> what this seller wants. It won't do you any good in the ham bands, >> but you might find interesting listening in the MILSAT/Fleetsatcom >> bands. A few years back I found some "pirate" (Portuguese) operators >> quite active on the satellites. I think they have all been caught by >> an interesting mix of technology and trigonometry and have been >> silenced. >> >> On 07/12/2011 04:23 AM, Clint Bradford wrote: >> >>> > I am looking for an adapter to make this satellite helical work >>> on my > handheld radio ... >>> > >>> > http://tinyurl.com/SAT-HELICAL >>> > >>> > >>> > Clint Bradford, K6LCS >>> > >>> > >>> > >>> >> -- >> Joe Leikhim >> >> Leikhim and Associates >> Communications Consultants >> Oviedo, Florida >> >> www.Leikhim.com >> >> jleik...@leikhim.com >> >> 407-982-0446 >> >> ___ >> Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. >> Not an AMSAT-NA member? Join now to support the amateur satellite >> program! >> Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb > > > -- Joe Leikhim Leikhim and Associates Communications Consultants Oviedo, Florida www.Leikhim.com jleik...@leikhim.com 407-982-0446 ___ Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
