KX1 Output Power
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In researching the KX1, I thought I had read that it's possible to get 4
watts of output. However, the manual shows 2 watts as the max from internal batteries. Is 4 watts possible? Does it require external batteries? -- John Overbaugh blog: http://kf7dvj.blogspot.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 |
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Hi John,
Basically, yes; if you want to get more than 2 watts out of the KX1, you need an external power source. If you look at the specs on page 5 of the manual, it says: Transmitter Max. power output (approx.) 9 V supply 1.5 - 2 W 12 V supply 3 - 4 W The internal battery holders have space for 6 AA cells, so the best you can get from internal batteries (using ordinary batteries) is 1.5V x 6 = 9 V 73 -- Joe KB8AP On Dec 4, 2010, at 1:20 PM, John Overbaugh wrote: > In researching the KX1, I thought I had read that it's possible to get 4 > watts of output. However, the manual shows 2 watts as the max from internal > batteries. Is 4 watts possible? Does it require external batteries? > > -- > John Overbaugh > blog: http://kf7dvj.blogspot.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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In reply to this post by John Overbaugh
John,
The power output of the KX1 is dependent on the power supply voltage. A well constructed KX1 will normally deliver 4 watts on 80, 40 and 30 meters, and 3.5 watts on 20 meters with a 13.8 volt power source. Some will do a little better and some a bit worse than that target figure. The voltage produced by the 6 internal cells is less than 13.8, and the exact voltage depends on the battery type. Lithium batteries normally are the best if the power level is important to you, with alkalines running in second place. NiCad or NiMH batteries will produce lower voltages and therefore lower power. To get to that 13.8 volt level, each of the 6 AA cells would have to produce 2.3 volts. But yes, as a general rule, 2 watts is to be expected when using the internal batteries. There is just not enough room to pack additional batteries inside. A few KX1 owners have modified the KX1 to use rechargable Lithium Ion batteries which produce a higher voltage (and more power as a result). I want to offer a caution - running the the KX1 at greater than 4 watts can cause damage to the components following the PA amplifier - with a good 50 ohm pure resistive load, one can go a bit higher without harm, but as the SWR increases, the voltages in the low pass filter will also increase and could exceed their voltage ratings. In other words, don't try to push the KX1 power too high - the difference between 3.5 watts and 5 watts is almost imperceptible on the receiving end. 73, Don W3FPR On 12/4/2010 4:20 PM, John Overbaugh wrote: > In researching the KX1, I thought I had read that it's possible to get 4 > watts of output. However, the manual shows 2 watts as the max from internal > batteries. Is 4 watts possible? Does it require external batteries? > ______________________________________________________________ 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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Wow--I received a plethora of responses, all pretty much saying what Don's
said here - external 13.8 power supply will yield just about 4 watts. Internal batteries, which are only going to run around 9v (6 x 1.5 = 9) will only crank out around 2 watts. Many thanks for the help. I'm dutifully saving up for my first Elecraft, which will be the KX1. I'm hoping to have a nice project for the holidays! 73's, John O. K7JTO On Sat, Dec 4, 2010 at 4:27 PM, Don Wilhelm <[hidden email]> wrote: > John, > > The power output of the KX1 is dependent on the power supply voltage. > A well constructed KX1 will normally deliver 4 watts on 80, 40 and 30 > meters, and 3.5 watts on 20 meters with a 13.8 volt power source. Some will > do a little better and some a bit worse than that target figure. > > The voltage produced by the 6 internal cells is less than 13.8, and the > exact voltage depends on the battery type. Lithium batteries normally are > the best if the power level is important to you, with alkalines running in > second place. NiCad or NiMH batteries will produce lower voltages and > therefore lower power. To get to that 13.8 volt level, each of the 6 AA > cells would have to produce 2.3 volts. > > But yes, as a general rule, 2 watts is to be expected when using the > internal batteries. There is just not enough room to pack additional > batteries inside. > > A few KX1 owners have modified the KX1 to use rechargable Lithium Ion > batteries which produce a higher voltage (and more power as a result). > > I want to offer a caution - running the the KX1 at greater than 4 watts can > cause damage to the components following the PA amplifier - with a good 50 > ohm pure resistive load, one can go a bit higher without harm, but as the > SWR increases, the voltages in the low pass filter will also increase and > could exceed their voltage ratings. > In other words, don't try to push the KX1 power too high - the difference > between 3.5 watts and 5 watts is almost imperceptible on the receiving end. > > 73, > Don W3FPR > > > On 12/4/2010 4:20 PM, John Overbaugh wrote: > >> In researching the KX1, I thought I had read that it's possible to get 4 >> watts of output. However, the manual shows 2 watts as the max from >> internal >> batteries. Is 4 watts possible? Does it require external batteries? >> >> -- John Overbaugh blog: http://kf7dvj.blogspot.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 |
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John,
You're going to really enjoy building and using the KX1. I've been "hooked" on the KX1 for a few years, and it's my favorite rig. I don't go hiking, camping, or mountaintop operating -- but the KX1 is fantastic for sitting out on the deck, throwing a line into the trees (or putting up the Buddipole), and making a few QSOs. The KX1 is my "ham radio in a bag" when we go to the beach or take a trip somewhere. Also, building it is pure joy. 73, Steve, KW4H On Sat, Dec 4, 2010 at 11:08 PM, John Overbaugh <[hidden email]>wrote: > Wow--I received a plethora of responses, all pretty much saying what Don's > said here - external 13.8 power supply will yield just about 4 watts. > Internal batteries, which are only going to run around 9v (6 x 1.5 = 9) > will > only crank out around 2 watts. > > Many thanks for the help. I'm dutifully saving up for my first Elecraft, > which will be the KX1. I'm hoping to have a nice project for the holidays! > > 73's, > > John O. > K7JTO > > On Sat, Dec 4, 2010 at 4:27 PM, Don Wilhelm <[hidden email]> wrote: > > > John, > > > > The power output of the KX1 is dependent on the power supply voltage. > > A well constructed KX1 will normally deliver 4 watts on 80, 40 and 30 > > meters, and 3.5 watts on 20 meters with a 13.8 volt power source. Some > will > > do a little better and some a bit worse than that target figure. > > > > The voltage produced by the 6 internal cells is less than 13.8, and the > > exact voltage depends on the battery type. Lithium batteries normally > are > > the best if the power level is important to you, with alkalines running > in > > second place. NiCad or NiMH batteries will produce lower voltages and > > therefore lower power. To get to that 13.8 volt level, each of the 6 AA > > cells would have to produce 2.3 volts. > > > > But yes, as a general rule, 2 watts is to be expected when using the > > internal batteries. There is just not enough room to pack additional > > batteries inside. > > > > A few KX1 owners have modified the KX1 to use rechargable Lithium Ion > > batteries which produce a higher voltage (and more power as a result). > > > > I want to offer a caution - running the the KX1 at greater than 4 watts > can > > cause damage to the components following the PA amplifier - with a good > 50 > > ohm pure resistive load, one can go a bit higher without harm, but as the > > SWR increases, the voltages in the low pass filter will also increase and > > could exceed their voltage ratings. > > In other words, don't try to push the KX1 power too high - the difference > > between 3.5 watts and 5 watts is almost imperceptible on the receiving > end. > > > > 73, > > Don W3FPR > > > > > > On 12/4/2010 4:20 PM, John Overbaugh wrote: > > > >> In researching the KX1, I thought I had read that it's possible to get 4 > >> watts of output. However, the manual shows 2 watts as the max from > >> internal > >> batteries. Is 4 watts possible? Does it require external batteries? > >> > >> > > > -- > John Overbaugh > blog: http://kf7dvj.blogspot.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 |
Re: KX1 Output Power
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In reply to this post by Joe Planisky
For an easy way to get more power with internal batteries, you might look into using PowerGenix NiZn rechargeables. They give have over 1.7v/cell and are rechargeable. They're not as cheap as some of the NiMH rechargeables, but that chemistry at 1.2v/cell is a poor match for the voltages needs of the KX1; and they're cheaper than two sets of the 1.5V Energizer Lithium primary (non-rechargeable) cells.
Leigh/WA5ZNU |
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If you're willing to spend about $40, a small [like 750mAh] Li-Poly
battery will work great. Mine is a little smaller than a small box of matches, 12V for about 4W on 40/30/20, and it will last through a 4-hr Flight of the Bumblebees. You do need an Li charger. Mine would easily fit inside my KX1 but I really don't recommend that, my motto is, "Keep the chemistry lab on the outside of my radio." You'll find them at RC Model shops. 73, Fred K6DGW - Northern California Contest Club - CU in the 2011 Cal QSO Party 1-2 Oct 2011 - www.cqp.org On 12/5/2010 10:58 AM, Leigh L. Klotz Jr WA5ZNU wrote: > > For an easy way to get more power with internal batteries, you might look > into using PowerGenix NiZn rechargeables. They give have over 1.7v/cell and > are rechargeable. They're not as cheap as some of the NiMH rechargeables, > but that chemistry at 1.2v/cell is a poor match for the voltages needs of > the KX1; and they're cheaper than two sets of the 1.5V Energizer Lithium > primary (non-rechargeable) cells. > > Leigh/WA5ZNU ______________________________________________________________ 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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