W2 Wattmeter
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W2 WATTMETER I was doing some research and considering buying the Elecraft W2 for use with my 2 K-2s and read the very negative reviews of the W2's accuracy on E-Ham. I wonder if anyone would care to refute the E-HAM reviews or offer positive comments about the W2's accuracy. At this point I would have to choose the AUTEK or OAK HILLS meters over the W2. Considering the cost of the W2 and Elecraft's attention to quality I would expect a far more accurate meter than the reviews would indicate. Many thanks.
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I have the W2 wattmeter and original production software had some issues. Those in most part appear to be corrected. I do not have the lab equipment to measure accuracy, but suggest that when any meter is placed between tuner and antenna with jumpers there will be a difference no matter what meter one uses. I think the meter rollout was under pressure to get it to production and not quite ready for release. I wouldn't be that concerned now. I use the 1.5 kw module (something like that) and I monitor my 1.5KW amp to the antenna. With the amp in and out of circuit, the K3 and W2 seem to be close; remember that jumper length, etc., will cause some difference! Bill K9YEQ K2-#35 (2 more), KX1-#35, K3, > Date: Sat, 2 Jan 2010 05:41:01 -0800 > From: [hidden email] > To: [hidden email] > Subject: [Elecraft] W2 Wattmeter > > > W2 WATTMETER I was doing some research and considering buying the Elecraft W2 > for use with my 2 K-2s and read the very negative reviews of the W2's > accuracy on E-Ham. I wonder if anyone would care to refute the E-HAM reviews > or offer positive comments about the W2's accuracy. At this point I would > have to choose the AUTEK or OAK HILLS meters over the W2. Considering the > cost of the W2 and Elecraft's attention to quality I would expect a far more > accurate meter than the reviews would indicate. Many thanks. > -- _________________________________________________________________ Your E-mail and More On-the-Go. Get Windows Live Hotmail Free. http://clk.atdmt.com/GBL/go/171222985/direct/01/ ______________________________________________________________ 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 KM4VX
On Sat, 2 Jan 2010 05:41:01 -0800 (PST), KM4VX
<[hidden email]> wrote: > >W2 WATTMETER I was doing some research and considering buying the Elecraft W2 >for use with my 2 K-2s and read the very negative reviews of the W2's >accuracy on E-Ham. I wonder if anyone would care to refute the E-HAM reviews >or offer positive comments about the W2's accuracy. At this point I would >have to choose the AUTEK or OAK HILLS meters over the W2. Considering the >cost of the W2 and Elecraft's attention to quality I would expect a far more >accurate meter than the reviews would indicate. Many thanks. First let me say that I don't pay much attention to complaints about watt meters. Bird Model 43 watt meters are only accurate to 5% of full scale. Those who complain about the accuracy of any LED watt meter can be completely ignored. The resolution of an LED watt meter with ten LEDs on a 2000 watt scale only has 100 watt resolution at any point on the scale. Hmm, that's five percent! Those who complain about the readings they get from the software (also subject to an accuracy specification can adjust the readings to suit themselves via software commands using the supplied RS232 cable. I like both of my W2's and I don't use them to make critical adjustments. I use them to keep an eye on what's happening between the rig(s) and the antennae. Did you ever try to get a good steady SWR reading on an antenna that was moving around in a wind over 10 mph? I wouldn't hesitate to buy another W2 if I had a use for it. 73, Tom, N5GE [hidden email] K3 #806 with SUB RX, K3 #1055, PR6, XV144, XV432, KRC2, W1, 2 W2's and other small kits 1 K144XV on order http://www.n5ge.com http://www.swotrc.net ______________________________________________________________ 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
Amateur Radio Operator N5GE
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In reply to this post by KM4VX
Accuracy and resolution are two different matters.
73, Dick - KA5KKT >Those who complain about the accuracy of any LED watt meter can be >completely ignored. The resolution of an LED watt meter with ten LEDs >on a 2000 watt scale only has 100 watt resolution at any point on the >scale. Hmm, that's five percent! ______________________________________________________________ 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 KM4VX
I look at those comments about wattmeter accuracy with a bit of
skepticism. Many hams seem to believe whatever their last used wattmeter tells them. Look at the specifications carefully. Take an example of the "much revered" Bird wattmeters, the spec is 5% OF THE FULL SCALE READING - and that is ONLY right after calibration. That specification says that if a BIRD wattmeter has been recently calibrated and handled carefully afterwards, with a 100 watt slug, it can have an error of 5 watts - and that applies to *anywhere* on the scale. A Bird wattmeter picked up at a hamfest can be much further off than that. The error for the W2 (and several other digital wattmeters) will be a percentage of the actual reading (and not of the full scale reading). There have been several upgrades to the W2 Firmware, and there will be more to come. Check the firmware release notes and you will see that there have been improvements to the sensor calibration. Those negative reports do not mention the firmware level that they were using nor did they make any statements about entering the sensor calibration data, so it may be that their W2s were actually reading low - but that *can* be corrected. 73, Don W3FPR KM4VX wrote: > W2 WATTMETER I was doing some research and considering buying the Elecraft W2 > for use with my 2 K-2s and read the very negative reviews of the W2's > accuracy on E-Ham. I wonder if anyone would care to refute the E-HAM reviews > or offer positive comments about the W2's accuracy. At this point I would > have to choose the AUTEK or OAK HILLS meters over the W2. Considering the > cost of the W2 and Elecraft's attention to quality I would expect a far more > accurate meter than the reviews would indicate. Many thanks. > > ______________________________________________________________ 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 Dick Dickinson
On Jan 2, 2010, at 8:43 AM, Edward Dickinson, III wrote: > Accuracy and resolution are two different matters. > > Yes, they are different but unfortunately they are often inextricably intertwined. ______________________________________________________________ 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 Dick Dickinson
Dick,
That is true, but they are often confused - furthermore with any resolution on a display like a bargraph, it is helpful to know to know if the LED illuminates just after the indicated power is reached or at some midpoint value. I don't know, but I suspect that Elecraft has chosen to trigger the LED illuminating at the low edge of reaching that power. So on a 200 watt scale with 10 watt resolution, the 80 watt LED would be illuminated starting at 80 watts and the next LED would not light until the power reached 100 watts - If the comparison meter is only off by a watt or two, but is reading a bit high, then yes, the comparison meter could read 100 watts with the W2 LED showing only 80 watts - for this example, bumping the power up a couple watts would have the W2 reading 100 watts and the comparison meter reading 102 watts - so it may *look* like the accuracy is bad when in fact it can be really good agreement - it all depends on knowing how to read the meters properly. 73, Don W3FPR Edward Dickinson, III wrote: > Accuracy and resolution are two different matters. > > > 73, > Dick - KA5KKT > > ______________________________________________________________ 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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Sorry, 10 watts below should have been 20 watts for my example. I hope
everyone got the point despite my error. 73, Don W3FPR Don Wilhelm wrote: > Dick, > > That is true, but they are often confused - furthermore with any > resolution on a display like a bargraph, it is helpful to know to know > if the LED illuminates just after the indicated power is reached or at > some midpoint value. I don't know, but I suspect that Elecraft has > chosen to trigger the LED illuminating at the low edge of reaching that > power. So on a 200 watt scale with 10 watt resolution, the 80 watt LED > would be illuminated starting at 80 watts and the next LED would not > light until the power reached 100 watts - If the comparison meter is > only off by a watt or two, but is reading a bit high, then yes, the > comparison meter could read 100 watts with the W2 LED showing only 80 > watts - for this example, bumping the power up a couple watts would have > the W2 reading 100 watts and the comparison meter reading 102 watts - > so it may *look* like the accuracy is bad when in fact it can be really > good agreement - it all depends on knowing how to read the meters properly. > > 73, > Don W3FPR > > Edward Dickinson, III wrote: > >> Accuracy and resolution are two different matters. >> >> >> 73, >> Dick - KA5KKT >> >> >> > ______________________________________________________________ > 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 > ------------------------------------------------------------------------ > > > No virus found in this incoming message. > Checked by AVG - www.avg.com > Version: 9.0.725 / Virus Database: 270.14.124/2597 - Release Date: 01/02/10 03:22:00 > > 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 KM4VX
Don,
Those are good points about the trigger and perception of accuracy of the W2. I have yet to see field test data of the W2 in regards to accuracy of the Wattmeter and SWR indications. 73, Dick - KA5KKT ______________________________________________________________ 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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"Those are good points about the trigger and perception of accuracy of the
W2. I have yet to see field test data of the W2 in regards to accuracy of the Wattmeter and SWR indications." According to the manual the W2 has an accuracy of +- 0.5dB typical (nothing about worst-case). This is 10-12% accuracy. Not as good as the PowerMaster/LP-100A/Telepost class of wattmeters that use NIST-traceable cal equipment (which should get you more like 3-5% accuracy). Of course, those are $100-$150 more expensive than the W2. If you use the W2 LED display, your perceived error could be greater than the 10-12%. As an example, if you really have 100 watts and the W2 reads it 1/2-dB low, then possibility only the 80-watt LED would light. So this would give you a 20% reading error. Maybe the ARRL will do a review sometime soon. 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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In reply to this post by Bill K9YEQ
Guys - The W2 is fully user adjustable for calibration. Please see the
manual for details. Basically, if you wish to adjust its absolute level up or down to match a favorite 2nd Wattmeter, you can easily do this by sending +/- serial commands to it from W2 Utility. My W2 is adjusted to almost exactlyu match my home Bird WM (which reads differently from another of my Birds...) ;-) 73, Eric _..._ Bill Johnson wrote: > I have the W2 wattmeter and original production software had some issues. Those in most part appear to be corrected. I do not have the lab equipment to measure accuracy, but suggest that when any meter is placed between tuner and antenna with jumpers there will be a difference no matter what meter one uses. I think the meter rollout was under pressure to get it to production and not quite ready for release. I wouldn't be that concerned now. I use the 1.5 kw module (something like that) and I monitor my 1.5KW amp to the antenna. With the amp in and out of circuit, the K3 and W2 seem to be close; remember that jumper length, etc., will cause some difference! > > > Bill > K9YEQ > K2-#35 (2 more), KX1-#35, K3, > > > > >> Date: Sat, 2 Jan 2010 05:41:01 -0800 >> From: [hidden email] >> To: [hidden email] >> Subject: [Elecraft] W2 Wattmeter >> >> >> W2 WATTMETER I was doing some research and considering buying the Elecraft W2 >> for use with my 2 K-2s and read the very negative reviews of the W2's >> accuracy on E-Ham. I wonder if anyone would care to refute the E-HAM reviews >> or offer positive comments about the W2's accuracy. At this point I would >> have to choose the AUTEK or OAK HILLS meters over the W2. Considering the >> cost of the W2 and Elecraft's attention to quality I would expect a far more >> accurate meter than the reviews would indicate. Many thanks. >> -- 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 Phil Salas
I'm very happy with my W2. There was an issue with an intermittent in the sensor cable but that was quickly resolved. It seems accurate enough to me on a subjective basis - I have no Bird to compare it to. As far as resolution goes the computer display resolution does rely on LED's and is a continuous bar with a switchable peak indication. This is only the 2nd version of the diplay software and I'm sure it will continue to improve. I have a friend that has the LP-100A and it's a really nice meter but I'm not sure I want to pay $120 more for it.
73 Bill NZ0T
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In reply to this post by KM4VX
Thanks Eric.
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In reply to this post by NZ0T
--- On Sat, 1/2/10, NZ0T <[hidden email]> wrote:
> As far as resolution goes the computer display > resolution does rely on LED's The resolution of the interface software's bar indicators is actually 10 times the resolution of the LED display. The FWD and REFL bar indicators have 200 units of resolution compared to only 20 LED's on the W2. The SWR bar does follow the LED's. The textual power readouts resolve to .1 watt at the 2KW range, .01 watt at the 200W range and .001 watt at the 20W and 2W ranges. The plus (+) and minus (-) buttons (lower right corner of window) can be used to calibrate the active sensor to an external source. The value is saved in EEPROM for that type of sensor (HF 200W, HF 2KW, VHF), regardless of which sensor is used. New version soon with 'Always on top' and multiple instances support. David, W4SMT ______________________________________________________________ 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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> The FWD and REFL bar indicators have 200 units of resolution
> compared to only 20 LED's on the W2. Make that 17 LED's on the W2.. ______________________________________________________________ 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 NZ0T
While Bird watt meters are rugged, revered and are the de-facto standard
watt meters in both commercial and amateur circles, their accuracy leaves a lot to be desired. Unless recently calibrated, and used under specific circumstances (ambient temperature) their use should be more properly defined as relative output indicators. Look closely and you'll see that their accuracy is listed as +/- some percentage of a full scale reading for the slug you are using. With a 2500w slug, you could be hundreds of watts off and not know it. Granted, in amateur use, absolute accuracy really does not matter, but just keep this in mind when measuring what you see with your W2 or any other modern digital wattmeter when compared to a Bird. Just because they read differently, there's nearly no justification to think the Bird is correct and your new wattmeter is not. 73, Bob W5OV -----Original Message----- From: [hidden email] [mailto:[hidden email]] On Behalf Of NZ0T Sent: Saturday, January 02, 2010 7:51 PM To: [hidden email] Subject: Re: [Elecraft] W2 Wattmeter I'm very happy with my W2. There was an issue with an intermittent in the sensor cable but that was quickly resolved. It seems accurate enough to me on a subjective basis - I have no Bird to compare it to. As far as resolution goes the computer display resolution does rely on LED's and is a continuous bar with a switchable peak indication. This is only the 2nd version of the diplay software and I'm sure it will continue to improve. I have a friend that has the LP-100A and it's a really nice meter but I'm not sure I want to pay $120 more for it. 73 Bill NZ0T Phil & Debbie Salas wrote: > > "Those are good points about the trigger and perception of accuracy of the > W2. I have yet to see field test data of the W2 in regards to accuracy of > the > Wattmeter and SWR indications." > > According to the manual the W2 has an accuracy of +- 0.5dB typical > (nothing > about worst-case). This is 10-12% accuracy. Not as good as the > PowerMaster/LP-100A/Telepost class of wattmeters that use NIST-traceable > cal > equipment (which should get you more like 3-5% accuracy). Of course, > those > are $100-$150 more expensive than the W2. If you use the W2 LED display, > your perceived error could be greater than the 10-12%. As an example, if > you really have 100 watts and the W2 reads it 1/2-dB low, then possibility > only the 80-watt LED would light. So this would give you a 20% reading > error. > > Maybe the ARRL will do a review sometime soon. > > 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 > > -- View this message in context: http://n2.nabble.com/W2-Wattmeter-tp4242517p4244535.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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In reply to this post by KM4VX
Thank you for the advice and wisdom always found on this Reflector. We can each draw our own conclusions. The K-2 built in meter is probably as accurate as the W2 at 5 watts, and the more expensive stand alone units have little to offer me operating QRP. Those flashing lights are cool on many of the latest meters, but the absence of increased accuracy over what comes with the radio anyway is more important. The expertise available on this Reflector is unmatched in the hobby.
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In reply to this post by KM4VX
The W2 does exactly what it is supposed to do. And it does it pretty well. Assembly went smoothly. The problem IMHO is that it was developed by people who know a thing or two about power measurement, accuracy, resolution, precision and the like. For people who may not always be familiar with such matters... or are just accustomed to needle meters.
With the W2 Utility and/or the W2 PC program, it is quite easy (and for some people maybe comforting) to adjust the W2 to match the 5+% error of your BIRD which is by no means supposed to be a standard (even if recently calibrated), hi... 73 Richard - HB9ANM
Richard - HB9ANM
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