high-power tuner
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All,
I find myself finally admitting that I need an antenna tuner that supports high power. I run a K3/P3 combo with an Ameritron AL-811H amp. Since we are still waiting on word about pricing and release date for the KAT500, I find myself looking at other alternatives for a 1 - 1.5 KW auto tuner. What are others using? Several people I know have had issues with the LDG AT-1000PRO, so I probably want to stay away from that one. Thanks in advance for the advice. 73, -- Ian Ian Kahn, KM4IK Roswell, GA EM74ua [hidden email] K3 #281, P3 #688 ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
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Hi Ian, Many of us are in that boat. I don't believe the KTA500 is vaperware. I'm just cooling my heals for the reason you cited, unreliable products from the competition. I want good products and great support from people that care about their customers. That is worth the wait, even if it is until the end of the year. Heck the K3 tuner will load a hairpin, I would expect the KTA500 will as well. If I just couldn't wait any longer ,I think I would find a manual tuner to hold me over (one that had a good resale value). :) 73, Bill AK5X On Feb 24, 2012, at 8:05 AM, Ian Kahn wrote: > All, > > I find myself finally admitting that I need an antenna tuner that supports > high power. I run a K3/P3 combo with an Ameritron AL-811H amp. Since we > are still waiting on word about pricing and release date for the KAT500, I > find myself looking at other alternatives for a 1 - 1.5 KW auto tuner. > What are others using? Several people I know have had issues with the LDG > AT-1000PRO, so I probably want to stay away from that one. > > Thanks in advance for the advice. > > 73, > > -- Ian > Ian Kahn, KM4IK > Roswell, GA EM74ua > [hidden email] > K3 #281, P3 #688 > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:[hidden email] > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html Bill Hammond [hidden email] Bill Hammond-AK5X [hidden email] [hidden email] K3 #69 P3 #817 KPA500 # 149 K2/100 #4637 K1 #2033 KX1 #1023 T1 ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
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In reply to this post by Ian Kahn, KM4IK
On 2/24/2012 6:05 AM, Ian Kahn wrote:
> What are others using? Several people I know have had issues with the LDG > AT-1000PRO, so I probably want to stay away from that one. I found the AT-1000 lacking and sold it when LDG could not improve it (and kept it for three months). I strongly recommend the Ten Tec 229 and 238 tuners, which can be bought used for around $275 and $300 respectively. Essentially the same, different appearance. Manual tuner, rated for legal limit. L-section design, so they tend to produce a match with greater bandwidth than T-section tuners. The only PITA about these tuners is the dial cord. 73, Jim K9YC. ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
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In reply to this post by Bill Hammond
We're just making sure performance is as good as possible. (The stakes
are even higher in a QRO tuner.) The most recent prototype worked great, in general, but on 6 meters we felt the loss was a fraction of a dB too high. The PCB layout has been changed to cut the RF path length and strays by a factor of two, which should do the trick. We'll receive these boards in a week or so and should have test results a week after that. This suggests that we could have some field test units out in mid/late-March. 73, Wayne N6KR On Feb 24, 2012, at 8:23 AM, Bill Hammond wrote: > > Hi Ian, > Many of us are in that boat. I don't believe the KTA500 is > vaperware. I'm just cooling my heals for the reason you cited, > unreliable products from the competition. I want good products and > great support from people that care about their customers. That is > worth the wait, even if it is until the end of the year. Heck the > K3 tuner will load a hairpin, I would expect the KTA500 will as > well. If I just couldn't wait any longer ,I think I would find a > manual tuner to hold me over (one that had a good resale value). :) > 73, > Bill > AK5X > > > > > On Feb 24, 2012, at 8:05 AM, Ian Kahn wrote: > >> All, >> >> I find myself finally admitting that I need an antenna tuner that >> supports >> high power. I run a K3/P3 combo with an Ameritron AL-811H amp. >> Since we >> are still waiting on word about pricing and release date for the >> KAT500, I >> find myself looking at other alternatives for a 1 - 1.5 KW auto >> tuner. >> What are others using? Several people I know have had issues with >> the LDG >> AT-1000PRO, so I probably want to stay away from that one. >> >> Thanks in advance for the advice. >> >> 73, >> >> -- Ian >> Ian Kahn, KM4IK >> Roswell, GA EM74ua >> [hidden email] >> K3 #281, P3 #688 >> ______________________________________________________________ >> Elecraft mailing list >> Home: http://mailman.qth.net/mailman/listinfo/elecraft >> Help: http://mailman.qth.net/mmfaq.htm >> Post: mailto:[hidden email] >> >> This list hosted by: http://www.qsl.net >> Please help support this email list: http://www.qsl.net/donate.html > > Bill Hammond > [hidden email] > Bill Hammond-AK5X > [hidden email] > [hidden email] > K3 #69 > P3 #817 > KPA500 # 149 > K2/100 #4637 > K1 #2033 > KX1 #1023 > T1 > > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:[hidden email] > > 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:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
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In reply to this post by Ian Kahn, KM4IK
Thanks for the update on the KAT500 development, Wayne. In the meantime, I'm using an MFJ-988 satisfactorily. 73, Bruce, N1RX > We're just making sure performance is as good as possible. (The stakes > are even higher in a QRO tuner.) > The most recent prototype worked great, in general, but on 6 meters we > felt the loss was a fraction of a dB too high. The PCB layout has > been changed to cut the RF path length and strays by a factor of two, > which should do the trick. We'll receive these boards in a week or so > and should have test results a week after that. This suggests that we > could have some field test units out in mid/late-March. > 73, > Wayne > N6KR ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
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In reply to this post by Ian Kahn, KM4IK
Ian,
Unfortunately, I'm in the same boat: Looking for an antenna tuner that *truly* supports high power. I was hoping the Palstar balanced tuner BT1500A was it, but I found it less than robust when processing 1500 W. The tuner (fine print) is not spec'd for 1500 continuous, so forget RTTY/etc and beware full power tune-ups. The input balun toasts quite nicely. Also, the relay that switches the large section of the capacitor in/out failed on me, with the inner insulation of that relay bubbling up out of the core. The tuner ought to run relays energized forever. Mine did not. I had left it configured that way (ten meters) overnight. My bad, apparently. YMMV of course. If you ever find one that will tolerate 1.5 kW into various loads, please post it. FYI, I'm using that tuner to match to a 260' dipole, center fed with nominal 600-ohm OWL (constructed using Ladder Snaps). 73 and GL! Gary W2CS >All, > >I find myself finally admitting that I need an antenna tuner that >supports high power. I run a K3/P3 combo with an Ameritron AL-811H amp. >Since we are still waiting on word about pricing and release date for >the KAT500, I find myself looking at other alternatives for a 1 - 1.5 KW >auto tuner. >What are others using? Several people I know have had issues with the >LDG AT-1000PRO, so I probably want to stay away from that one. > >Thanks in advance for the advice. > >73, > >-- Ian >Ian Kahn, KM4IK ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
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On 2/24/2012 8:57 AM, Gary Ferdinand wrote:
> is not spec'd for 1500 continuous, so forget RTTY/etc and > beware full power tune-ups. Few power amps are rated for1.5kW continuous. Yes, there are a few, like some Alpha models. Most are rated for 1.5kW intermittent duty, and should be de-rated by a few dB for keydown modes. The Ten Tec tuners I mentioned fall into that category too -- indeed, there are a few fixed caps that will release smoke when run at 1.5kW into some loads for long periods during a contest, but those caps are easily replaced with parts rated for more current, and the replacements are not expensive. Folks should be more patient with Elecraft -- they are well known for taking enough time with engineering both at the design and manufacturing stage to produce a product we'll be happy to own, as Wayne's recent post in this thread clearly illustrates. 73, Jim K9YC ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
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In reply to this post by Ian Kahn, KM4IK
Ian -
I have been watching product developments I this power/automatic operation category: Palstar HF-AUTO http://www.palstar.com/hf-auto.php RF Concepts/Alpha 4040 Automatic Tuner http://www.rfconcepts.com/PRODUCTS/New-Products/Alpha4040 E-Z Tuner - Jim Garland, W8ZR (2002 QST article and ARRL Handbooks) http://www.w8zr.net/eztuner/index.htm I made a suggestion to Steve at RF Concepts, a couple of years ago, when RF Concepts was planning a high-power HF automatic tuner. They needed to incorporate more uProcessor/controller power (since W8ZR Basic Stamp) in their planned offering, since the state-of-art has progressed since 2002. They did, using Linux kernel with the Beagleboard XM The Palstar and RF Concepts/Alpha offerings are INDOOR tuners. I have a preference to have the tuner outdoors at the antennas or feedpoints (like commercial broadcasters). == IF Wayne, N6NR is coming to Dayton - it would be nice to SEE one of the KAT500 prototypes == Greg, w9gb === previous message === Date: Fri, 24 Feb 2012 08:32:58 -0800 From: Wayne Burdick <[hidden email]> Subject: Re: [Elecraft] high-power tuner To: Bill Hammond <[hidden email]> > We're just making sure performance is as good as possible. (The stakes > are even higher in a QRO tuner.) > > The most recent prototype worked great, in general, but on 6 meters we > felt the loss was a fraction of a dB too high. The PCB layout has > been changed to cut the RF path length and strays by a factor of two, > which should do the trick. We'll receive these boards in a week or so > and should have test results a week after that. This suggests that we > could have some field test units out in mid/late-March. > > 73,Wayne - N6KR ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
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In reply to this post by Ian Kahn, KM4IK
Wayne, thank you for the update on the KAT500 progress. While I won't be
at Dayton, I, too, would love to see at least photos of the prototype posted to the web site. All others - Thank you for the suggestions. Fortuitously, I actually was offered, at no charge, a legal limit manual inductor roller tuner. Since this one is free, I'll take it and bide my time until Wayne, Eric, and Company release the KAT500. 73, --Ian Ian Kahn, KM4IK Roswell, GA EM74ua [hidden email] K3 #281, P3 #688 On Fri, Feb 24, 2012 at 1:09 PM, Greg Beat <[hidden email]> wrote: > Ian - > > I have been watching product developments > > I this power/automatic operation category: > > > > Palstar HF-AUTO > > http://www.palstar.com/hf-auto.php > > > > RF Concepts/Alpha 4040 Automatic Tuner > > http://www.rfconcepts.com/PRODUCTS/New-Products/Alpha4040 > > > > E-Z Tuner - Jim Garland, W8ZR > > (2002 QST article and ARRL Handbooks) > > http://www.w8zr.net/eztuner/index.htm > > > > I made a suggestion to Steve at RF Concepts, a couple of years ago, > > when RF Concepts was planning a high-power HF automatic tuner. > > They needed to incorporate more uProcessor/controller power (since W8ZR > Basic Stamp) > > in their planned offering, since the state-of-art has progressed since > 2002. > > They did, using Linux kernel with the Beagleboard XM > > > > The Palstar and RF Concepts/Alpha offerings are INDOOR tuners. > > I have a preference to have the tuner outdoors at the antennas > > or feedpoints (like commercial broadcasters). > > == > > IF Wayne, N6NR is coming to Dayton - > > it would be nice to SEE one of the KAT500 prototypes > > > > == > > Greg, w9gb > > > > === previous message === > > Date: Fri, 24 Feb 2012 08:32:58 -0800 > > From: Wayne Burdick <[hidden email]> > > Subject: Re: [Elecraft] high-power tuner > > To: Bill Hammond <[hidden email]> > > > > > We're just making sure performance is as good as possible. (The stakes > > > are even higher in a QRO tuner.) > > > > > > The most recent prototype worked great, in general, but on 6 meters we > > > felt the loss was a fraction of a dB too high. The PCB layout has > > > been changed to cut the RF path length and strays by a factor of two, > > > which should do the trick. We'll receive these boards in a week or so > > > and should have test results a week after that. This suggests that we > > > could have some field test units out in mid/late-March. > > > > > > 73,Wayne - N6KR > > > > > > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:[hidden email] > > 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:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
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In reply to this post by Jim Brown-10
>-----Original Message----- >From: [hidden email] [mailto:elecraft- >[hidden email]] On Behalf Of Jim Brown >Sent: Friday, February 24, 2012 12:59 PM >To: [hidden email] >Subject: Re: [Elecraft] high-power tuner > >On 2/24/2012 8:57 AM, Gary Ferdinand wrote: >> [The Palstar BT1500A] is not spec'd for 1500 continuous, so forget RTTY/etc and beware full >> power tune-ups. > >Few power amps are rated for1.5kW continuous. Yes, there are a few, >like some Alpha models. Most are rated for 1.5kW intermittent duty, and >should be de-rated by a few dB for keydown modes. My mistake, I guess. I run an Alpha 9500. A true 1.5 kW tuner is important to me at least. > >The Ten Tec tuners I mentioned fall into that category too -- indeed, >there are a few fixed caps that will release smoke when run at 1.5kW >into some loads for long periods during a contest, but those caps are >easily replaced with parts rated for more current, and the replacements >are not expensive. Good to hear. But if a tuner is advertised to handle 1500 W, it should do so without user mods. > >Folks should be more patient with Elecraft -- they are well known for >taking enough time with engineering both at the design and manufacturing >stage to produce a product we'll be happy to own, as Wayne's recent post >in this thread clearly illustrates. The original poster talked about 1500 W. Is Elecraft considering such a tuner? That would be new (and great!) news to me. For some reason I was under the assumption it would handle around 500 W. ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
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10:1 SWR at 500w equals the same internal antenna current and voltage in
the tuner for about a 3:1 SWR at 1500W :-) 73, Eric --- www.elecraft.com On 2/24/2012 11:59 AM, Gary Ferdinand wrote: > >> -----Original Message----- >> From: [hidden email] [mailto:elecraft- >> [hidden email]] On Behalf Of Jim Brown >> Sent: Friday, February 24, 2012 12:59 PM >> To: [hidden email] >> Subject: Re: [Elecraft] high-power tuner >> >> On 2/24/2012 8:57 AM, Gary Ferdinand wrote: >>> [The Palstar BT1500A] is not spec'd for 1500 continuous, so forget > RTTY/etc and beware full >>> power tune-ups. >> Few power amps are rated for1.5kW continuous. Yes, there are a few, >> like some Alpha models. Most are rated for 1.5kW intermittent duty, and >> should be de-rated by a few dB for keydown modes. > My mistake, I guess. I run an Alpha 9500. A true 1.5 kW tuner is important > to me at least. > >> The Ten Tec tuners I mentioned fall into that category too -- indeed, >> there are a few fixed caps that will release smoke when run at 1.5kW >> into some loads for long periods during a contest, but those caps are >> easily replaced with parts rated for more current, and the replacements >> are not expensive. > Good to hear. But if a tuner is advertised to handle 1500 W, it should do so > without user mods. > >> Folks should be more patient with Elecraft -- they are well known for >> taking enough time with engineering both at the design and manufacturing >> stage to produce a product we'll be happy to own, as Wayne's recent post >> in this thread clearly illustrates. > The original poster talked about 1500 W. Is Elecraft considering such a > tuner? That would be new (and great!) news to me. For some reason I was > under the assumption it would handle around 500 W. > > > > > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:[hidden email] > > 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:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
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In reply to this post by Ian Kahn, KM4IK
I've had a MFJ-998 autotuner for about 3.5 years now. It works great, and
it is easy to upgrade its software (a new upgrade just became available). The most power I've put through it is 1200 watts feeding my 43-foot vertical, though now I'm only using it with my KPA500. I have a review on my website at www.ad5x.com, as well as a mod whereby it feeds the amp-disable input on my KPA500 when it tunes. Phil - AD5X ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
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Ditto on the MFJ-998 autotuner. I have had mine a few years and now use it with the KPA500. It has matched anything I have thrown at it. A little on the noisy side when it gets a hold of a load it has to work on a little, but it has always done what I want it to do.
Roger W5RDW
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Just curious ... have you ever measured the loss in the tuner? Most of the MFJ tuners tend to rank pretty low in that respect. Presenting a usable load to the amplifier does not in itself make it a good tuner. 73, Dave AB7E On 3/1/2012 11:16 AM, W5RDW wrote: > Ditto on the MFJ-998 autotuner. I have had mine a few years and now use it > with the KPA500. It has matched anything I have thrown at it. A little on > the noisy side when it gets a hold of a load it has to work on a little, but > it has always done what I want it to do. > > ----- > Roger W5RDW ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
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On Thu, Mar 1, 2012 at 1:25 PM, David Gilbert <[hidden email]> wrote:
>...Most of the MFJ tuners tend to rank pretty low ... =========== QST hasn't reviewed the 998, but they did have a review of the MFJ 994 back in 2006. Tested across all bands and a range of impedances, it generally showed lower losses than the other similar autotuners tested, made by Palstar and LDG. There is a mini-review of the 998 by list member AD5X at: http://www.ad5x.com/images/Presentations/MFJ998%20Review%20RevA.pdf but it doesn't include loss measurements. Other than the loss measurements for the 994 mentioned above, which looked pretty good, I can't find any other measured results for MFJ auto-tuners. Tony KT0NY -- http://www.isb.edu/faculty/facultydir.aspx?ddlFaculty=352 ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
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In reply to this post by David Gilbert
Never had any reason to wonder if my MFJ-998 has more than normal loss. It hasn't let any smoke out of the cabinet yet! I use to run a Drake L-7 thru it, but now use the KPA500 all the time and have retired the Drake.
> Most of the MFJ tuners tend to rank pretty low in that respect. Dave, I'd be interested in reading about the info you have on the MFJ tuner loss.
Roger W5RDW
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I wonder how those that claim a certain efficiency for a MFJ-998 or any other antenna matching device are measuring the output power. No watt meter that I know including the famous and antique Bird can measure power with any degree of accuracy unless the load is very near the nominal value (usually 50 ohms). If you need a tuner, your antenna does not meet this criteria so, what are you using to form your opinion? I suppose that you could compare two tuners for a relative efficiency by using the same transmitter and antenna and a field strength meter. Of course, if you are running near the rated power, you can watch for smoke and get a one time opinion that the device was not efficient enough to survive.
Willis 'Cookie' Cooke K5EWJ & Trustee N5BPS, USS Cavalla, USS Stewart ________________________________ From: W5RDW <[hidden email]> To: [hidden email] Sent: Friday, March 9, 2012 4:10 PM Subject: Re: [Elecraft] high-power tuner Never had any reason to wonder if my MFJ-998 has more than normal loss. It hasn't let any smoke out of the cabinet yet! I use to run a Drake L-7 thru it, but now use the KPA500 all the time and have retired the Drake. > /Most of the MFJ tuners tend to rank pretty low in that respect./ Dave, I'd be interested in reading about the info you have on the MFJ tuner loss. ----- Roger W5RDW -- View this message in context: http://elecraft.365791.n2.nabble.com/high-power-tuner-tp7314904p7359740.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:[hidden email] 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:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
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On Fri, Mar 9, 2012 at 4:24 PM, WILLIS COOKE <[hidden email]> wrote:
> I wonder how those that claim a certain efficiency for a MFJ-998 or any other antenna matching device are measuring the output power.... ============ Cookie, the ARRL labs have some way of doing this, but in their reviews of tuners they don't explain how they do it. I suppose they have some scheme for measuring what goes in and what comes out, but they don't say. However, as I mentioned in a previous post, the MFJ 994 tuner they tested (August 2006) had somewhat lower losses than the other similar tuners in the review. I could not find any published data to support the assertion that MFJ tuners have high losses. Tony KT0NY -- http://www.isb.edu/faculty/facultydir.aspx?ddlFaculty=352 ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
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In reply to this post by Cookie
I can think of a few ways to investigate a tuner's efficiency. Google
searching can probably give more. You can read the inductor and capacitor values selected by the 998 and then do a circuit simulation of the L network and determine current through the inductors to find their ohmic losses. Second, you can connect known non-inductive resistors (of different values, throw in some inductance or capacitance too) as the output load and then with an RF voltmeter determine the voltage across the load and then calculate the power out. You will have to calculate the phase angle of your load as well if its not purely resistive. This method could be done using low power so its easier to build the output loads. You could probably also measure the temperature rise of the tuner in operation (put it in an insulated box). Granted, there may not be a simple off the self instrument to do it, but it can be done! 73 - Mike WA8BXN -------Original Message------- From: WILLIS COOKE Date: 3/9/2012 5:31:30 PM To: W5RDW; [hidden email] Subject: Re: [Elecraft] high-power tuner I wonder how those that claim a certain efficiency for a MFJ-998 or any other antenna matching device are measuring the output power. No watt meter that I know including the famous and antique Bird can measure power with any degree of accuracy unless the load is very near the nominal value (usually 50 ohms). If you need a tuner, your antenna does not meet this criteria so, what are you using to form your opinion? I suppose that you could compare two tuners for a relative efficiency by using the same transmitter and antenna and a field strength meter. Of course, if you are running near the rated power, you can watch for smoke and get a one time opinion that the device was not efficient enough to survive. Willis 'Cookie' Cooke K5EWJ & Trustee N5BPS, USS Cavalla, USS Stewart ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
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In reply to this post by Cookie
On 3/9/2012 2:24 PM, WILLIS COOKE wrote:
> If you need a tuner, your > antenna does not meet this criteria so, what are you using to form > your opinion? Weigh the tuner, then transmit continuously, measure the temperature rise, and when it's stable, calculate the heat loss [something to do with Boltzman's Constant -- the tuner *is* painted black]. What doesn't leave as heat must leave as RF. Did it years ago on a 10 KW FM broadcast transmitter [4 ea 4-1000's], and it came within one percent of the efficiency measured with the water-cooled dummy load. YMMV however. 73, Fred K6DGW - Northern California Contest Club - CU in the 2012 Cal QSO Party 6-7 Oct 2012 - www.cqp.org ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
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