Re: [Elecraft] KX1 Output Power
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: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] KX1 Output Power
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 -- View this message in context: http://elecraft.365791.n2.nabble.com/KX1-Output-Power-tp5803866p5805693.html Sent from the [KX1] 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] KX1 Output Power
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 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 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: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] KX1 Output Power
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 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: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] KX1 Output Power
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: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] KX1 Output Power
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: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] [KX1]Output Power Measurement
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Re: [Elecraft] [KX1]Output Power Measurement
Ron, I just went through this scenario. With the help of Don Wilhelm I was able accurately measure my power out on my KX1 and K3. I first used a homebrew load with "free" resistors given away at a club meeting. They only worked at low frequencies. At 20 meters the SWR to far off to be of use! I bought an Elecraft DL1 because it uses one of the correct types of resistors for this application and it has a built in VDC test point! The only thing to be wary of is that the DL1 test point is at the 25 ohm point in the series of resistors!!! Don's formula (and mine) differs from that found in the DL1 manual. Elecraft: P(in watts) = ((Volts * 1.414) +(.15))^2 / 50 Don: P(in watts) = ((Volts) + (diode drop))^2 / 25 Jack: P(in watts) = (((Volts) + (diode drop) * 2)) / (square root of 2)))^2 / 50 There are 3 points to be aware of. 1. Use the square root of 2 and not the 1.414 figure. 2. Measure your diode drop. 3. Combine the drop with the VDC before doing any other calculations. 4. If you do not use Don's formula, DIVIDE by the square root of 2. The Schottky diode in my DL1 measures .330 mv. A 1N34a (germanium diode) has a drop of about .3 volts. A Schottky's drop is a little more but offers more linearity! In any case, the VDC voltage must be divided by the square root of 2 to get the RMS. In other words the VDC(0-Peak) is 1.414(approximately) times the RMS voltage If you measure the VDC at the 50 ohm point then my formula becomes: P(in watts) = ((VDC + (diode drop)) / (square root of 2))^2 /50 After getting an accurate measurement of my KX1's power I found that the KX1 ATU was showing values that were too high. By adjusting C9 and R1 I was able to get the KX1 and the DL1 to agree! BTW, I also used the DL1 to calibrate my K3 at low power. Now the K3, my DL1 and my Versa Tuner V all agree! -Original Message- .snip. I've now completed the construction of the basic KX1 and would like to have a fairly reasonable measurement of the output power on 20M and 40M I have a very decent dummy load but do not have a very accurate RF Power meter. I do have a decent DMM and could measure the voltage drop across the 50 ohm dummy load - I'm not sure how accurate the DMM would be at 7 or 14 MHZ. Is there a recommended method to measure the power output without an RF power meter ? Thanks in advance, Ron, AC2C .snip __ 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] [KX1]Output Power Measurement
Ron, Use a diode detector. A 1N4148 diode will do fine up to about 12 watts. Connect the anode of the diode to the center conductor of your coax *at* the dummy load (use a coax TEE adapter if you have no other access). From the cathode end of your diode, connect a 0.01 uF capacitor to the shield side of the coax. Your DMM leads connect across the capacitor. Measure the forward voltage of the diode with your DMM if it has that function, otherwise, assume that the diode forward voltage is 0.6 volts. With this probe, the DVM will read the peak RF voltage. You can calculate the power from the DMM reading as follows: The peak voltage across the resistor is equal to the DVM reading plus the diode forward voltage, so add them. You may then calculate the RMS value of the result above. Then square that result and divide by the resistance. Or you may accept (or derive) the formula will be as follows with no intermittent RMS calculation. P = (Vdvm+Vdiode)^2/2R = (Vdvm+Vdiode^2/100 for a 50 ohm dummy load OR, if you assume the diode drop is 0.6 volts P=(Vdvm+0.6)^2/100 73, Don W3FPR Ron Bower wrote: > I have searched the archives and have not been able to find a definitive > answer. > > > > I've now completed the construction of the basic KX1 and would like to have > a fairly reasonable measurement of the output power on 20M and 40M > > > > I have a very decent dummy load but do not have a very accurate RF Power > meter. I do have a decent DMM and could measure the voltage drop across the > 50 ohm dummy load - I'm not sure how accurate the DMM would be at 7 or 14 > MHZ. > > > > Is there a recommended method to measure the power output without an RF > power meter ? > > > > Thanks in advance, > > Ron, AC2C > > __ 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] [KX1]Output Power Measurement
You might use a diode, such as a 1N914, 1N4148 or (preferably) a 1N5711 to rectify the voltage developed across the load and then measure the DC out of the diode. With a high Z load such as a DMM, the DC voltage will be close to the RF peak voltage. A standard DMM, even a good one, will not provide usable results above a few hundred KHz, unless it's a specialized instrument intended for RF measurements. Jack K8ZOA Ron Bower wrote: > I have searched the archives and have not been able to find a definitive > answer. > > > > I've now completed the construction of the basic KX1 and would like to have > a fairly reasonable measurement of the output power on 20M and 40M > > > > I have a very decent dummy load but do not have a very accurate RF Power > meter. I do have a decent DMM and could measure the voltage drop across the > 50 ohm dummy load - I'm not sure how accurate the DMM would be at 7 or 14 > MHZ. > > > > Is there a recommended method to measure the power output without an RF > power meter ? > > > > Thanks in advance, > > Ron, AC2C > > > > __ > 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] KX1 output power measurements
Sorry for the typo - the max power indication on the KX1 is 6.3 watts, not 6.8. 73, Don W3FPR Don Wilhelm wrote: Paul, Yes, what you observed is true. The KXAT1 wattmeter will indicate more power with increasing SWR *if^ the load impedance is higher than 50 ohms, but if it is lower than 50 ohms, the power indication will be lower. In ATU CAL mode, when the power output is 4 watts into a 50 ohm load - if the load is 25 ohms pure resistive, the power indication will typically be 2.2 to 2.5, and if the load is 100 ohms pure resistive, the power indication will be typically 6.8 watts (the max value that will be displayed). I cannot say how the indication varies with complex impedance loads, but I see the same thing here with the precision 25 ohm and 100 ohm loads that I use when adjusting for the SWR=2 point. This phenomenon seems to be due to the absence of total power calculation by the firmware. The difference of the squares between the forward power and the reverse power must be calculated to indicate the actual power to the antenna (with the phase angle properly included in the calculation) - yes, the calculation seems to be incomplete in that regard, but the relative indication is still informative. After a tune cycle which reduces the SWR to somewhere near 1.0, the power reading will be correct, but I have not measured just how close to SWR=0 that must be. That same characteristic is also true on the KAT1 wattmeter used in the K1. and at the moment, I can't recall what happens with the K2 tuners. 73, Don W3FPR Paul Huff wrote: I was using my KX1 in the backyard yesterday to make some final adjustments and tests on a portable vertical that I will be using for field day. I noticed that when the KX1's antenna tuner indicated a high SWR it also indicated a much higher "output power." I assume that the reflected power throws off the measurement. Does anyone know what the maximum SWR is that will still provide a fairly accurate power reading? Thanks and 73, Paul - N8XMS ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
Re: [Elecraft] KX1 output power measurements
Paul, Yes, what you observed is true. The KXAT1 wattmeter will indicate more power with increasing SWR *if^ the load impedance is higher than 50 ohms, but if it is lower than 50 ohms, the power indication will be lower. In ATU CAL mode, when the power output is 4 watts into a 50 ohm load - if the load is 25 ohms pure resistive, the power indication will typically be 2.2 to 2.5, and if the load is 100 ohms pure resistive, the power indication will be typically 6.8 watts (the max value that will be displayed). I cannot say how the indication varies with complex impedance loads, but I see the same thing here with the precision 25 ohm and 100 ohm loads that I use when adjusting for the SWR=2 point. This phenomenon seems to be due to the absence of total power calculation by the firmware. The difference of the squares between the forward power and the reverse power must be calculated to indicate the actual power to the antenna (with the phase angle properly included in the calculation) - yes, the calculation seems to be incomplete in that regard, but the relative indication is still informative. After a tune cycle which reduces the SWR to somewhere near 1.0, the power reading will be correct, but I have not measured just how close to SWR=0 that must be. That same characteristic is also true on the KAT1 wattmeter used in the K1. and at the moment, I can't recall what happens with the K2 tuners. 73, Don W3FPR Paul Huff wrote: I was using my KX1 in the backyard yesterday to make some final adjustments and tests on a portable vertical that I will be using for field day. I noticed that when the KX1's antenna tuner indicated a high SWR it also indicated a much higher "output power." I assume that the reflected power throws off the measurement. Does anyone know what the maximum SWR is that will still provide a fairly accurate power reading? Thanks and 73, Paul - N8XMS ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
RE: [Elecraft] kx1 output power?
Tom, KM4CU wrote: hello all. just completed myKx1. Power output is only 3w on 40, 2w on 20 @ 13.7v. Any suggestions on any additional output power? Is there an adjustment for the output indicator in the Kx1. thanks.. First make sure trimmer pot R4 is fully CLOCKwise now. Check the two inductors wound on yellow cores: L1 and L2. L1 should have 13 turns and L2 14 turns. It's easy to get them reversed! Finally, while transmitting into a dummy load adjust the position of the turns on L1 and L2 for best balance between 20 and 14 meter output. They should be within 1/2 watt of each other, and can usually be closer. That will often improve the overall output. I am not aware of any adjustment for the output monitor in the KX1. The KXAT1 ATU, which displays the power out in watts, is adjustable. Ron AC7AC ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
