Re: [Elecraft] K3 + LP100A + Dummy Load
Just a comment on dummy loads: I do a lot of ham radio work at VHF and higher (up to 10-GHz), so making good power measurements involves having a good 50-ohm termination (load). For most of my testing I have several coaxial loads: A 25w Termaline (Bird) is used a lot in the shack as it tests Z=51 + j0 on my MFJ-269B antenna analyzer and shows zero reflected on a Bird43 power meter. Some of the other loads show 52 or even 54 ohms on the MFJ, and not quite resistive (I marked all them so I would know). In all cases resistance measurement with an ohmmeter agrees with the R parameter in the complex impedance equation. I even have a 500w Sierra termination (door stop load) which has a integral power meter, but it is not exactly 50-ohms and the meter is not in agreement with the Bird43, so I use it as a safe load for high power but not for high accuracy measurements. I have seen coax loads shift way off 50-ohms due to overheating from too much or too long a transmission. I bought some of the Cadsoft 100w surface-mount attenuators to use in a 900-MHz amplifier to permit driving with 10w exciter. They were in the $12 range from Mouser. One can make very fine 50-ohm loads using them on a proper heat sink at a fraction of the cost of coaxial loads. 73, Ed - KL7UW, WD2XSH/45 == BP40IQ 500 KHz - 10-GHz www.kl7uw.com EME: 50-1.1kw?, 144-1.4kw, 432-QRT, 1296-?, 3400-? DUBUS Magazine USA Rep 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] K3 + LP100A + Dummy Load
I have been recommending the dummy loads and power attenuators from Ridge Equipment for years. They usually have a good selection, excellent quality and great prices. They will also provide a VNA plot for 10 bucks more as I recall. Remember that these loads usually have N connectors, so you may need an adapter. 73, Larry N8LP On 12/23/2011 6:48 AM, elecraft-requ...@mailman.qth.net wrote: > Date: Thu, 22 Dec 2011 14:29:14 -0800 (PST) > From: ab2tc > Subject: Re: [Elecraft] K3 + LP100A + Dummy Load > To:elecraft@mailman.qth.net > Message-ID:<1324592954992-7120191.p...@n2.nabble.com> > Content-Type: text/plain; charset=us-ascii > > Hi, > > I highly recommend the 75W dummy load from Ridge Equipment. I have one > permanently connected in my system. I believe it is a military surplus piece > of equipment with absolutely superior characteristics like an SWR at 500MHz > of 1.05 or less. It has no problem with 100W for a minute or less for sure. > > AB2TC - Knut > > > Phil, > > All dummy loads are not created equal. Connect yours directly (no coax) > to the LP-100 or an antenna analyzer to determine its characteristics > with frequency (I assume Larry calibrated your LP-100 to NIST > standards). A common ham dummy load is something to tune your amplifier > into and use for general purposes. If you are going to do measurements, > you will need something more like lab quality dummy loads. > > Both your dummy load and the 6 feet of RG8X will show a frequency > dependency since you do not have a precision 50 ohm dummy load. A > transmission line that is not terminated in its characteristic impedance > acts like an impedance transformer, and that transformation ratio is > frequency dependent. > > If you want a dummy load that is flat WRT frequency and suitable for > instrumentation use, take a look at the Caddock 50 ohm Thick Film > Resistors - they are available up to 100 watt rating. You must use them > on a heat sink, and keep the leads as short as possible, and you will > have a precision dummy load. Caution - even with the heat sink, do not > exceed their power ratings, they will go open circuit in an instant. > I use several of those as instrumentation precision loads. > > Other sources of precision dummy loads is Ridge Equipment - > https://www.ridgeequipment.com/store/dummyloads.html. They have one > rated at 75 watts for $12 and one rated at 15 watts for $7.50 - those > are quite good for instrumentation purposes. > > 73, > Don W3FPR > > __ 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] K3 + LP100A + Dummy Load
Simple, accurate (1%) and inexpensive dummy loads you can homebrew is here: http://www.n0ss.net/dl_30w_hf-uhf.pdf They are based on the Caddock resistors Don mentioned; either 30 or 100 watts. The resistors are available for a few dollars. All that's needed with the resistor is a suitable heat sink and connector. Ron AC7AC -Original Message- Tom, I agree. Actually, right now I do not trust my dummy load for being close to pure resistive 50 ohms. Indeed, I did not test it at the beginning and this is what motivated me to post the question. I think I have enough to test the DL but won't have time to do it for a week or so. peh On Dec 22, 2011, at 12:59 PM, Tommy Alderman wrote: > BUT just because you bought it direct from Palstar does not mean it is a > good dummy load! The ONLY way you KNOW it is a good dummy load is for YOU to > measure it with known good test equipment and an ohm-meter is not how it is > done! > > 73 and Merry Christmas, > > Tom - W4BQF > __ 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] K3 + LP100A + Dummy Load
Hi, I highly recommend the 75W dummy load from Ridge Equipment. I have one permanently connected in my system. I believe it is a military surplus piece of equipment with absolutely superior characteristics like an SWR at 500MHz of 1.05 or less. It has no problem with 100W for a minute or less for sure. AB2TC - Knut Phil, All dummy loads are not created equal. Connect yours directly (no coax) to the LP-100 or an antenna analyzer to determine its characteristics with frequency (I assume Larry calibrated your LP-100 to NIST standards). A common ham dummy load is something to tune your amplifier into and use for general purposes. If you are going to do measurements, you will need something more like lab quality dummy loads. Both your dummy load and the 6 feet of RG8X will show a frequency dependency since you do not have a precision 50 ohm dummy load. A transmission line that is not terminated in its characteristic impedance acts like an impedance transformer, and that transformation ratio is frequency dependent. If you want a dummy load that is flat WRT frequency and suitable for instrumentation use, take a look at the Caddock 50 ohm Thick Film Resistors - they are available up to 100 watt rating. You must use them on a heat sink, and keep the leads as short as possible, and you will have a precision dummy load. Caution - even with the heat sink, do not exceed their power ratings, they will go open circuit in an instant. I use several of those as instrumentation precision loads. Other sources of precision dummy loads is Ridge Equipment - https://www.ridgeequipment.com/store/dummyloads.html. They have one rated at 75 watts for $12 and one rated at 15 watts for $7.50 - those are quite good for instrumentation purposes. 73, Don W3FPR -- View this message in context: http://elecraft.365791.n2.nabble.com/K3-LP100A-Dummy-Load-tp7119170p7120191.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] K3 + LP100A + Dummy Load
Phil, All dummy loads are not created equal. Connect yours directly (no coax) to the LP-100 or an antenna analyzer to determine its characteristics with frequency (I assume Larry calibrated your LP-100 to NIST standards). A common ham dummy load is something to tune your amplifier into and use for general purposes. If you are going to do measurements, you will need something more like lab quality dummy loads. Both your dummy load and the 6 feet of RG8X will show a frequency dependency since you do not have a precision 50 ohm dummy load. A transmission line that is not terminated in its characteristic impedance acts like an impedance transformer, and that transformation ratio is frequency dependent. If you want a dummy load that is flat WRT frequency and suitable for instrumentation use, take a look at the Caddock 50 ohm Thick Film Resistors - they are available up to 100 watt rating. You must use them on a heat sink, and keep the leads as short as possible, and you will have a precision dummy load. Caution - even with the heat sink, do not exceed their power ratings, they will go open circuit in an instant. I use several of those as instrumentation precision loads. Other sources of precision dummy loads is Ridge Equipment - https://www.ridgeequipment.com/store/dummyloads.html. They have one rated at 75 watts for $12 and one rated at 15 watts for $7.50 - those are quite good for instrumentation purposes. 73, Don W3FPR On 12/22/2011 11:37 AM, Phil Hystad wrote: > Is this normal or can someone explain? I was looking at the R+iX values > reported by the LP100A with my K3 feeding a dummy load. The SWR reported was > always small but never super close to 1:1. Most of the SWR in this setup was > 1.1:1 up to 1.5:1. The R values ranged from 34 ohms to up to 59 ohms and X > was ranging over a number of smallish values< 20 for all the bands. > > Is this what most of you would call normal? > > Does the K3 output R+iX vary from band to band (I assume so) and is that what > I am seeing? > > I had thought my dummy load was mostly frequency independent so I am not sure > if I am seeing mostly the K3 here or maybe the K3 plus the 6 feet of coax > (RG8X) + dummy load. > > 73, phil, K7PEH > __ 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] K3 + LP100A + Dummy Load
Naturally you can't test the flatness over a range without test equipment, but you CAN tell it's a 50 ohm load instead of a 75 ohm load. If the precision is not what you expected you can sell it for what you put into it. I test the quality over range with an AIM 4170 antenna analyzer. HNY 73, Tom Amateur Radio Operator N5GE ARRL Lifetime Member QCWA Lifetime Member "If somebody has a bad heart, they can plug this jack in at night as they go to bed and it will monitor their heart throughout the night. And the next morning, when they wake up dead, there'll be a record." --Mark S. Fowler, FCC Chairman, 1981 - 1987 On Thu, 22 Dec 2011 15:59:26 -0500, "Tommy Alderman" wrote: >BUT just because you bought it direct from Palstar does not mean it is a >good dummy load! The ONLY way you KNOW it is a good dummy load is for YOU to >measure it with known good test equipment and an ohm-meter is not how it is >done! > >73 and Merry Christmas, > >Tom - W4BQF > > >-Original Message- >From: elecraft-boun...@mailman.qth.net >[mailto:elecraft-boun...@mailman.qth.net] On Behalf Of Phil Hystad >Sent: Thursday, December 22, 2011 3:40 PM >To: n...@n5ge.com >Cc: Elecraft List >Subject: Re: [Elecraft] K3 + LP100A + Dummy Load > >The dummy load is the Palstar DL2K, full legal limit handling and I bought >it new from Palstar several years ago. None of my operating equipment was >purchased at hamfests -- I prefer to be the original owner and pass over any >potential difficulties. > >peh > > >On Dec 22, 2011, at 12:20 PM, n...@n5ge.com wrote: > >> >> Phil, >> >> You don't say what type of dummy load you are using, but all of the >cantenna >> type have about the same SWR curve you witnessed. You will need a >precision DL >> to get a flat response across a large range. I have two DECIBEL DB4304B >100 >> watt loads here that are flat up through 2m. I don't think they are made >any >> more and if they were they would be very expensive. The two I have were >bought >> at a ham hamfest for $50 each. They are bout 6" x 4" x 4" Most of which >is >> cooling fins. >> >> Be careful when you buy dummy loads like this at a Hamfest. Take a good >> ohm-meter with you. I bought a couple of really well made heavy duty DL's >that >> were rated at 300w for $100 once and when I measured them at home they >were 75 >> ohm loads, so watch out! >> >> Happy holidays, >> >> 73, >> Tom >> Amateur Radio Operator N5GE >> ARRL Lifetime Member >> QCWA Lifetime Member >> >> "If somebody has a bad heart, they can plug this jack in at >> night as they go to bed and it will monitor their heart >> throughout the night. And the next morning, when they wake up >> dead, there'll be a record." >> >> --Mark S. Fowler, FCC Chairman, >> 1981 - 1987 >> >> >> On Thu, 22 Dec 2011 08:37:37 -0800, Phil Hystad wrote: >> >>> Is this normal or can someone explain? I was looking at the R+iX values >reported by the LP100A with my K3 feeding a dummy load. The SWR reported >was always small but never super close to 1:1. Most of the SWR in this >setup was 1.1:1 up to 1.5:1. The R values ranged from 34 ohms to up to 59 >ohms and X was ranging over a number of smallish values < 20 for all the >bands. >>> >>> Is this what most of you would call normal? >>> >>> Does the K3 output R+iX vary from band to band (I assume so) and is that >what I am seeing? >>> >>> I had thought my dummy load was mostly frequency independent so I am not >sure if I am seeing mostly the K3 here or maybe the K3 plus the 6 feet of >coax (RG8X) + dummy load. >>> >>> 73, phil, K7PEH >>> >> >> >> __ >> 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 __ 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] K3 + LP100A + Dummy Load
Tom, I agree. Actually, right now I do not trust my dummy load for being close to pure resistive 50 ohms. Indeed, I did not test it at the beginning and this is what motivated me to post the question. I think I have enough to test the DL but won't have time to do it for a week or so. peh On Dec 22, 2011, at 12:59 PM, Tommy Alderman wrote: > BUT just because you bought it direct from Palstar does not mean it is a > good dummy load! The ONLY way you KNOW it is a good dummy load is for YOU to > measure it with known good test equipment and an ohm-meter is not how it is > done! > > 73 and Merry Christmas, > > Tom - W4BQF > > > -Original Message- > From: elecraft-boun...@mailman.qth.net > [mailto:elecraft-boun...@mailman.qth.net] On Behalf Of Phil Hystad > Sent: Thursday, December 22, 2011 3:40 PM > To: n...@n5ge.com > Cc: Elecraft List > Subject: Re: [Elecraft] K3 + LP100A + Dummy Load > > The dummy load is the Palstar DL2K, full legal limit handling and I bought > it new from Palstar several years ago. None of my operating equipment was > purchased at hamfests -- I prefer to be the original owner and pass over any > potential difficulties. > > peh > > > On Dec 22, 2011, at 12:20 PM, n...@n5ge.com wrote: > >> >> Phil, >> >> You don't say what type of dummy load you are using, but all of the > cantenna >> type have about the same SWR curve you witnessed. You will need a > precision DL >> to get a flat response across a large range. I have two DECIBEL DB4304B > 100 >> watt loads here that are flat up through 2m. I don't think they are made > any >> more and if they were they would be very expensive. The two I have were > bought >> at a ham hamfest for $50 each. They are bout 6" x 4" x 4" Most of which > is >> cooling fins. >> >> Be careful when you buy dummy loads like this at a Hamfest. Take a good >> ohm-meter with you. I bought a couple of really well made heavy duty DL's > that >> were rated at 300w for $100 once and when I measured them at home they > were 75 >> ohm loads, so watch out! >> >> Happy holidays, >> >> 73, >> Tom >> Amateur Radio Operator N5GE >> ARRL Lifetime Member >> QCWA Lifetime Member >> >> "If somebody has a bad heart, they can plug this jack in at >> night as they go to bed and it will monitor their heart >> throughout the night. And the next morning, when they wake up >> dead, there'll be a record." >> >> --Mark S. Fowler, FCC Chairman, >> 1981 - 1987 >> >> >> On Thu, 22 Dec 2011 08:37:37 -0800, Phil Hystad wrote: >> >>> Is this normal or can someone explain? I was looking at the R+iX values > reported by the LP100A with my K3 feeding a dummy load. The SWR reported > was always small but never super close to 1:1. Most of the SWR in this > setup was 1.1:1 up to 1.5:1. The R values ranged from 34 ohms to up to 59 > ohms and X was ranging over a number of smallish values < 20 for all the > bands. >>> >>> Is this what most of you would call normal? >>> >>> Does the K3 output R+iX vary from band to band (I assume so) and is that > what I am seeing? >>> >>> I had thought my dummy load was mostly frequency independent so I am not > sure if I am seeing mostly the K3 here or maybe the K3 plus the 6 feet of > coax (RG8X) + dummy load. >>> >>> 73, phil, K7PEH >>> >> >> >> __ >> 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 __ 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] K3 + LP100A + Dummy Load
FWIW, the manual for the DL2K specs 56ohms +/- 10%. It's not intended to be a "calibrated" 50ohm load. ~iain / N6ML On Thu, Dec 22, 2011 at 12:59 PM, Tommy Alderman wrote: > BUT just because you bought it direct from Palstar does not mean it is a > good dummy load! The ONLY way you KNOW it is a good dummy load is for YOU to > measure it with known good test equipment and an ohm-meter is not how it is > done! > > 73 and Merry Christmas, > > Tom - W4BQF > > > -Original Message- > From: elecraft-boun...@mailman.qth.net > [mailto:elecraft-boun...@mailman.qth.net] On Behalf Of Phil Hystad > Sent: Thursday, December 22, 2011 3:40 PM > To: n...@n5ge.com > Cc: Elecraft List > Subject: Re: [Elecraft] K3 + LP100A + Dummy Load > > The dummy load is the Palstar DL2K, full legal limit handling and I bought > it new from Palstar several years ago. None of my operating equipment was > purchased at hamfests -- I prefer to be the original owner and pass over any > potential difficulties. > > peh > > > On Dec 22, 2011, at 12:20 PM, n...@n5ge.com wrote: > >> >> Phil, >> >> You don't say what type of dummy load you are using, but all of the > cantenna >> type have about the same SWR curve you witnessed. You will need a > precision DL >> to get a flat response across a large range. I have two DECIBEL DB4304B > 100 >> watt loads here that are flat up through 2m. I don't think they are made > any >> more and if they were they would be very expensive. The two I have were > bought >> at a ham hamfest for $50 each. They are bout 6" x 4" x 4" Most of which > is >> cooling fins. >> >> Be careful when you buy dummy loads like this at a Hamfest. Take a good >> ohm-meter with you. I bought a couple of really well made heavy duty DL's > that >> were rated at 300w for $100 once and when I measured them at home they > were 75 >> ohm loads, so watch out! >> >> Happy holidays, >> >> 73, >> Tom >> Amateur Radio Operator N5GE >> ARRL Lifetime Member >> QCWA Lifetime Member >> >> "If somebody has a bad heart, they can plug this jack in at >> night as they go to bed and it will monitor their heart >> throughout the night. And the next morning, when they wake up >> dead, there'll be a record." >> >> --Mark S. Fowler, FCC Chairman, >> 1981 - 1987 >> >> >> On Thu, 22 Dec 2011 08:37:37 -0800, Phil Hystad wrote: >> >>> Is this normal or can someone explain? I was looking at the R+iX values > reported by the LP100A with my K3 feeding a dummy load. The SWR reported > was always small but never super close to 1:1. Most of the SWR in this > setup was 1.1:1 up to 1.5:1. The R values ranged from 34 ohms to up to 59 > ohms and X was ranging over a number of smallish values < 20 for all the > bands. >>> >>> Is this what most of you would call normal? >>> >>> Does the K3 output R+iX vary from band to band (I assume so) and is that > what I am seeing? >>> >>> I had thought my dummy load was mostly frequency independent so I am not > sure if I am seeing mostly the K3 here or maybe the K3 plus the 6 feet of > coax (RG8X) + dummy load. >>> >>> 73, phil, K7PEH >>> >> >> >> __ >> 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 __ 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] K3 + LP100A + Dummy Load
BUT just because you bought it direct from Palstar does not mean it is a good dummy load! The ONLY way you KNOW it is a good dummy load is for YOU to measure it with known good test equipment and an ohm-meter is not how it is done! 73 and Merry Christmas, Tom - W4BQF -Original Message- From: elecraft-boun...@mailman.qth.net [mailto:elecraft-boun...@mailman.qth.net] On Behalf Of Phil Hystad Sent: Thursday, December 22, 2011 3:40 PM To: n...@n5ge.com Cc: Elecraft List Subject: Re: [Elecraft] K3 + LP100A + Dummy Load The dummy load is the Palstar DL2K, full legal limit handling and I bought it new from Palstar several years ago. None of my operating equipment was purchased at hamfests -- I prefer to be the original owner and pass over any potential difficulties. peh On Dec 22, 2011, at 12:20 PM, n...@n5ge.com wrote: > > Phil, > > You don't say what type of dummy load you are using, but all of the cantenna > type have about the same SWR curve you witnessed. You will need a precision DL > to get a flat response across a large range. I have two DECIBEL DB4304B 100 > watt loads here that are flat up through 2m. I don't think they are made any > more and if they were they would be very expensive. The two I have were bought > at a ham hamfest for $50 each. They are bout 6" x 4" x 4" Most of which is > cooling fins. > > Be careful when you buy dummy loads like this at a Hamfest. Take a good > ohm-meter with you. I bought a couple of really well made heavy duty DL's that > were rated at 300w for $100 once and when I measured them at home they were 75 > ohm loads, so watch out! > > Happy holidays, > > 73, > Tom > Amateur Radio Operator N5GE > ARRL Lifetime Member > QCWA Lifetime Member > > "If somebody has a bad heart, they can plug this jack in at > night as they go to bed and it will monitor their heart > throughout the night. And the next morning, when they wake up > dead, there'll be a record." > > --Mark S. Fowler, FCC Chairman, > 1981 - 1987 > > > On Thu, 22 Dec 2011 08:37:37 -0800, Phil Hystad wrote: > >> Is this normal or can someone explain? I was looking at the R+iX values reported by the LP100A with my K3 feeding a dummy load. The SWR reported was always small but never super close to 1:1. Most of the SWR in this setup was 1.1:1 up to 1.5:1. The R values ranged from 34 ohms to up to 59 ohms and X was ranging over a number of smallish values < 20 for all the bands. >> >> Is this what most of you would call normal? >> >> Does the K3 output R+iX vary from band to band (I assume so) and is that what I am seeing? >> >> I had thought my dummy load was mostly frequency independent so I am not sure if I am seeing mostly the K3 here or maybe the K3 plus the 6 feet of coax (RG8X) + dummy load. >> >> 73, phil, K7PEH >> > > > __ > 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] K3 + LP100A + Dummy Load
The dummy load is the Palstar DL2K, full legal limit handling and I bought it new from Palstar several years ago. None of my operating equipment was purchased at hamfests -- I prefer to be the original owner and pass over any potential difficulties. peh On Dec 22, 2011, at 12:20 PM, n...@n5ge.com wrote: > > Phil, > > You don't say what type of dummy load you are using, but all of the cantenna > type have about the same SWR curve you witnessed. You will need a precision > DL > to get a flat response across a large range. I have two DECIBEL DB4304B 100 > watt loads here that are flat up through 2m. I don't think they are made any > more and if they were they would be very expensive. The two I have were > bought > at a ham hamfest for $50 each. They are bout 6" x 4" x 4" Most of which is > cooling fins. > > Be careful when you buy dummy loads like this at a Hamfest. Take a good > ohm-meter with you. I bought a couple of really well made heavy duty DL's > that > were rated at 300w for $100 once and when I measured them at home they were 75 > ohm loads, so watch out! > > Happy holidays, > > 73, > Tom > Amateur Radio Operator N5GE > ARRL Lifetime Member > QCWA Lifetime Member > > "If somebody has a bad heart, they can plug this jack in at > night as they go to bed and it will monitor their heart > throughout the night. And the next morning, when they wake up > dead, there'll be a record." > > --Mark S. Fowler, FCC Chairman, > 1981 - 1987 > > > On Thu, 22 Dec 2011 08:37:37 -0800, Phil Hystad wrote: > >> Is this normal or can someone explain? I was looking at the R+iX values >> reported by the LP100A with my K3 feeding a dummy load. The SWR reported >> was always small but never super close to 1:1. Most of the SWR in this >> setup was 1.1:1 up to 1.5:1. The R values ranged from 34 ohms to up to 59 >> ohms and X was ranging over a number of smallish values < 20 for all the >> bands. >> >> Is this what most of you would call normal? >> >> Does the K3 output R+iX vary from band to band (I assume so) and is that >> what I am seeing? >> >> I had thought my dummy load was mostly frequency independent so I am not >> sure if I am seeing mostly the K3 here or maybe the K3 plus the 6 feet of >> coax (RG8X) + dummy load. >> >> 73, phil, K7PEH >> > > > __ > 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] K3 + LP100A + Dummy Load
Phil, You don't say what type of dummy load you are using, but all of the cantenna type have about the same SWR curve you witnessed. You will need a precision DL to get a flat response across a large range. I have two DECIBEL DB4304B 100 watt loads here that are flat up through 2m. I don't think they are made any more and if they were they would be very expensive. The two I have were bought at a ham hamfest for $50 each. They are bout 6" x 4" x 4" Most of which is cooling fins. Be careful when you buy dummy loads like this at a Hamfest. Take a good ohm-meter with you. I bought a couple of really well made heavy duty DL's that were rated at 300w for $100 once and when I measured them at home they were 75 ohm loads, so watch out! Happy holidays, 73, Tom Amateur Radio Operator N5GE ARRL Lifetime Member QCWA Lifetime Member "If somebody has a bad heart, they can plug this jack in at night as they go to bed and it will monitor their heart throughout the night. And the next morning, when they wake up dead, there'll be a record." --Mark S. Fowler, FCC Chairman, 1981 - 1987 On Thu, 22 Dec 2011 08:37:37 -0800, Phil Hystad wrote: >Is this normal or can someone explain? I was looking at the R+iX values >reported by the LP100A with my K3 feeding a dummy load. The SWR reported was >always small but never super close to 1:1. Most of the SWR in this setup was >1.1:1 up to 1.5:1. The R values ranged from 34 ohms to up to 59 ohms and X >was ranging over a number of smallish values < 20 for all the bands. > >Is this what most of you would call normal? > >Does the K3 output R+iX vary from band to band (I assume so) and is that what >I am seeing? > >I had thought my dummy load was mostly frequency independent so I am not sure >if I am seeing mostly the K3 here or maybe the K3 plus the 6 feet of coax >(RG8X) + dummy load. > >73, phil, K7PEH > __ 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] K3 + LP100A + Dummy Load
Is this normal or can someone explain? I was looking at the R+iX values reported by the LP100A with my K3 feeding a dummy load. The SWR reported was always small but never super close to 1:1. Most of the SWR in this setup was 1.1:1 up to 1.5:1. The R values ranged from 34 ohms to up to 59 ohms and X was ranging over a number of smallish values < 20 for all the bands. Is this what most of you would call normal? Does the K3 output R+iX vary from band to band (I assume so) and is that what I am seeing? I had thought my dummy load was mostly frequency independent so I am not sure if I am seeing mostly the K3 here or maybe the K3 plus the 6 feet of coax (RG8X) + dummy load. 73, phil, K7PEH __ 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
