A long time ago I was sitting with an old ham in his shack discussing
purchasing a new SWR meter. I was going to buy some twenty buck job and he told me the following. "If you buy the 20 buck model, soon you will get the 30 buck and then the 40 buck and on and on until you finally buy the Bird. If you start with the Bird you won't need all those others. I took his advice and I bought the Bird. Buy the good stuff, as good as you can afford and stop worrying about the price or the deal. N2WL ______________________________________________________________ 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 Message delivered to [hidden email] |
Bill,
As long as one keeps in mind that Bird's reputatiom for accuracy has become a thing of the past. There are many more current products that surpass them. Always bear in mind that their odd meters (30 uA) are very non-linear and measurements made using element ranges that fall in the bottom 1/3 or so of the scale are the most accurate. Overall, they claim to be accurate to +/- 20 percent of full scale. HORRIBLE in today's world! FWIW ... 73! K0PP On Mon, Mar 19, 2018, 12:09 William Levy <[hidden email]> wrote: > A long time ago I was sitting with an old ham in his shack discussing > purchasing a new SWR meter. > I was going to buy some twenty buck job and he told me the following. > > "If you buy the 20 buck model, soon you will get the 30 buck and then the > 40 buck and on and on until you finally buy the Bird. > If you start with the Bird you won't need all those others. > > I took his advice and I bought the Bird. > > Buy the good stuff, as good as you can afford and stop worrying about the > price or the deal. > > N2WL > ______________________________________________________________ > 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 > Message delivered to [hidden email] > 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 Message delivered to [hidden email] |
Bird advertised and prints in the manual +/- 5% of full scale power. I remember some digital meters ARRL tested a few years back that did not do that well. Are your numbers something you experienced?
Chuck KE9UW [hidden email] Sent from my iPad > On Mar 19, 2018, at 1:41 PM, Ken G Kopp <[hidden email]> wrote: > > Bill, > > As long as one keeps in mind that Bird's reputatiom for accuracy has become > a thing of the past. There are many more current products that surpass > them. > > Always bear in mind that their odd meters (30 uA) are very non-linear and > measurements made using element ranges that fall in the bottom 1/3 or so of > the scale are the most accurate. Overall, they claim to be accurate to +/- > 20 percent of full scale. HORRIBLE in > today's world! > > FWIW ... > > 73! > > K0PP > >> On Mon, Mar 19, 2018, 12:09 William Levy <[hidden email]> wrote: >> >> A long time ago I was sitting with an old ham in his shack discussing >> purchasing a new SWR meter. >> I was going to buy some twenty buck job and he told me the following. >> >> "If you buy the 20 buck model, soon you will get the 30 buck and then the >> 40 buck and on and on until you finally buy the Bird. >> If you start with the Bird you won't need all those others. >> >> I took his advice and I bought the Bird. >> >> Buy the good stuff, as good as you can afford and stop worrying about the >> price or the deal. >> >> N2WL >> ______________________________________________________________ >> 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 >> Message delivered to [hidden email] >> > ______________________________________________________________ > 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 > Message delivered to [hidden email] 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 Message delivered to [hidden email]
Chuck, KE9UW
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My use is as to check forward or reverse, really that my antennas are
working. If I am running 500 watts out I put in a 500 watt element. If I have a 1500 watt amp I put in 2500w element. 100 watts here or there at 1500 watts doesn't matter. That the antenna is OK *really does matter!* I have not found anything that even comes close. My delight over 50 years of hamming is that Model 43s and their panel mounted equivalents are found on Ebay and at Hamfests and surplus venues so I pretty much have one on any serious amp I have. Bill N2Wl On Mon, Mar 19, 2018 at 3:39 PM, hawley, charles j jr <[hidden email] > wrote: > Bird advertised and prints in the manual +/- 5% of full scale power. I > remember some digital meters ARRL tested a few years back that did not do > that well. Are your numbers something you experienced? > > Chuck KE9UW > [hidden email] > > Sent from my iPad > > > On Mar 19, 2018, at 1:41 PM, Ken G Kopp <[hidden email]> wrote: > > > > Bill, > > > > As long as one keeps in mind that Bird's reputatiom for accuracy has > become > > a thing of the past. There are many more current products that surpass > > them. > > > > Always bear in mind that their odd meters (30 uA) are very non-linear and > > measurements made using element ranges that fall in the bottom 1/3 or so > of > > the scale are the most accurate. Overall, they claim to be accurate to > +/- > > 20 percent of full scale. HORRIBLE in > > today's world! > > > > FWIW ... > > > > 73! > > > > K0PP > > > >> On Mon, Mar 19, 2018, 12:09 William Levy <[hidden email]> wrote: > >> > >> A long time ago I was sitting with an old ham in his shack discussing > >> purchasing a new SWR meter. > >> I was going to buy some twenty buck job and he told me the following. > >> > >> "If you buy the 20 buck model, soon you will get the 30 buck and then > the > >> 40 buck and on and on until you finally buy the Bird. > >> If you start with the Bird you won't need all those others. > >> > >> I took his advice and I bought the Bird. > >> > >> Buy the good stuff, as good as you can afford and stop worrying about > the > >> price or the deal. > >> > >> N2WL > >> ______________________________________________________________ > >> 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 > >> Message delivered to [hidden email] > >> > > ______________________________________________________________ > > 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 > > Message delivered to [hidden email] > 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 Message delivered to [hidden email] |
In reply to this post by ke9uw
Chuck,
That is 5% of full scale with a recently calibrated slug. Another way to look at that percentage of full scale is to consider a 200 watt slug. The error can be as large as 10 watts *anywhere* on the scale. That is why I don't buy Bird wattmeters at hamfests unless it is cheap enough to send to a calibration lab. At least a digital wattmeter retains its accuracy as a percentage of the reading - a very different specification. Yes, +/- 20% is up to 40 watts error at 200 watts, at 10 watts, the error is only 2 watts. Many of the digital wattmeters like the Telepost LP100 can boast of 5% accuracy because they are calibrated with NIST tracable instruments. Elecraft does use the LP100 at many of the technician workbenches. 73, Don W3FPR On 3/19/2018 3:39 PM, hawley, charles j jr wrote: > Bird advertised and prints in the manual +/- 5% of full scale power. I remember some digital meters ARRL tested a few years back that did not do that well. Are your numbers something you experienced? > ______________________________________________________________ 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 Message delivered to [hidden email] |
In reply to this post by Bill Levy
I wish I could find a used / working 5H, or if they ever made one... a 2.5H for my QRP stuff.
(I think I am up to 5 model 43s plus a few panel mounts..... I suppose I got some sort of addiction) Bert - K4AR -----Original Message----- From: [hidden email] <[hidden email]> On Behalf Of William Levy Sent: Monday, March 19, 2018 3:47 PM To: hawley, charles j jr <[hidden email]> Cc: Elecraft <[hidden email]> Subject: Re: [Elecraft] DMM recommendations My use is as to check forward or reverse, really that my antennas are working. If I am running 500 watts out I put in a 500 watt element. If I have a 1500 watt amp I put in 2500w element. 100 watts here or there at 1500 watts doesn't matter. That the antenna is OK *really does matter!* I have not found anything that even comes close. My delight over 50 years of hamming is that Model 43s and their panel mounted equivalents are found on Ebay and at Hamfests and surplus venues so I pretty much have one on any serious amp I have. Bill N2Wl On Mon, Mar 19, 2018 at 3:39 PM, hawley, charles j jr <[hidden email] > wrote: > Bird advertised and prints in the manual +/- 5% of full scale power. I > remember some digital meters ARRL tested a few years back that did not > do that well. Are your numbers something you experienced? > > Chuck KE9UW > [hidden email] > > Sent from my iPad > > > On Mar 19, 2018, at 1:41 PM, Ken G Kopp <[hidden email]> wrote: > > > > Bill, > > > > As long as one keeps in mind that Bird's reputatiom for accuracy has > become > > a thing of the past. There are many more current products that > > surpass them. > > > > Always bear in mind that their odd meters (30 uA) are very > > non-linear and measurements made using element ranges that fall in > > the bottom 1/3 or so > of > > the scale are the most accurate. Overall, they claim to be accurate > > to > +/- > > 20 percent of full scale. HORRIBLE in today's world! > > > > FWIW ... > > > > 73! > > > > K0PP > > > >> On Mon, Mar 19, 2018, 12:09 William Levy <[hidden email]> wrote: > >> > >> A long time ago I was sitting with an old ham in his shack > >> discussing purchasing a new SWR meter. > >> I was going to buy some twenty buck job and he told me the following. > >> > >> "If you buy the 20 buck model, soon you will get the 30 buck and > >> then > the > >> 40 buck and on and on until you finally buy the Bird. > >> If you start with the Bird you won't need all those others. > >> > >> I took his advice and I bought the Bird. > >> > >> Buy the good stuff, as good as you can afford and stop worrying > >> about > the > >> price or the deal. > >> > >> N2WL > >> ______________________________________________________________ > >> 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 Message delivered to > >> [hidden email] > >> > > ______________________________________________________________ > > 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 Message delivered to > > [hidden email] > 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 Message delivered to [hidden email] ______________________________________________________________ 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 Message delivered to [hidden email] |
In reply to this post by Don Wilhelm
I re-named the thread as a courtesy to the members who don't want to read this.
We're getting caught in a mathematical war between the linear and logarithmic worlds. ± 20% in Watts, is about ± 1 dB in log. 1 dB accuracy is plenty good enough for us, folks. Especially given that any impedance mismatch is a source of error that we typically can't eliminate. In addition, I have found that Bird is very conservative and typically beats this spec by a lot. And by the way, I thought the Bird spec was 5% of full scale. Where did 20% come from? Don't all rush out to sell your Birds. They're perfectly fine. Al W6LX ______________________________________________________________ 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 Message delivered to [hidden email] |
> And by the way, I thought the Bird spec was 5% of full scale. Where > did 20% come from? The Model 43 is 5% of full scale: <https://birdrf.com/Products/Test%20and%20Measurement/Power-Meters/Wattmeters-Line-Sections/RF-Wattmeters/43_General-Purpose-Wattmeter.aspx> I still have the Model 43 my wife gave me for Christmas 40 years ago, along with the ten elements (2 MHz - 2.5 GHz) and eight QC connectors of various types (UHF, N, BNC, LC) I've accumulated over the years even though I the microHAM SMΩRF vector wattmeter has replaced my original Telepost LP-100(A) in day to day use. Although the "modern" digital meters are used in the shack, the Model 43 provided years of faithful service both in the shack and in the field and is still my "go to" unit outside the shack. Again, do it once and buy quality he first time. > ± 20% in Watts, is about ± 1 dB in log. 1 dB accuracy is plenty good > enough for us, ± 5% of full scale is ± 0.22 dB - far more accurate than needed for amateur and most commercial use (although SMΩRF is NIST traceable and accurate to ± 0.04 dB or ~1.5%). 73, ... Joe, W4TV On 3/19/2018 4:22 PM, Al Lorona wrote: > I re-named the thread as a courtesy to the members who don't want to read this. > > We're getting caught in a mathematical war between the linear and logarithmic worlds. > > > ± 20% in Watts, is about ± 1 dB in log. 1 dB accuracy is plenty good enough for us, folks. Especially given that any impedance mismatch is a source of error that we typically can't eliminate. > > In addition, I have found that Bird is very conservative and typically beats this spec by a lot. And by the way, I thought the Bird spec was 5% of full scale. Where did 20% come from? > > Don't all rush out to sell your Birds. They're perfectly fine. > > > Al W6LX > ______________________________________________________________ > 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 > Message delivered to [hidden email] > 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 Message delivered to [hidden email] |
In reply to this post by Bill Levy
I spoke to someone at Bird (when they were really Bird) years ago and I
was told that the Bird wattmeter is accurate to ±5% of top scale. This means that a 100 watt slug can be off ±5 watts _anywhere_ on the meter. So, a transmitter emitting 50 watts out, using the Bird and a 100 watt slug, can read between 45 and 55 watts. That's why he said it was important to keep the reading in the top 1/3 (highest) end of the meter. This is where the error is less. When taking reflected power readings the slug should be 1/10 of the forward slug value when testing a reasonably good antenna. So, a 100 watt forward slug would require a 10 watt reverse slug for reasonable accuracy. I retired my Bird 43 and the vast assortment of slugs for a Telewave Model 44A wattmeter and never looked back. The drawback to the 44A is it is limited to 20-1000MHz. The Bird would be good for HF use. 73, Joe, K1ike Date: Mon, 19 Mar 2018 18:40:41 +0000 > Always bear in mind that their odd meters (30 uA) are very non-linear and > measurements made using element ranges that fall in the bottom 1/3 or so of > the scale are the most accurate. Overall, they claim to be accurate to +/- > 20 percent of full scale. HORRIBLE in > today's world! > > FWIW ... > > 73! > > K0PP ______________________________________________________________ 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 Message delivered to [hidden email] |
> When taking reflected power readings the slug should be 1/10 of the > forward slug value when testing a reasonably good antenna. So, a 100 > watt forward slug would require a 10 watt reverse slug for reasonable > accuracy. Unfortunately, the smallest HF slug Bird make is 25 Watts. That means any SWR less than 1.4:1 (2.8% reflected power) is suspect with a 100 W transmitter. It is a shame that Bird do not offer a 10 (or 5 W HF element) and the one reason I moved to the LP-100(A) several years ago. However, I would never think to take the LP-100(A) or microHAM SMΩRF out into the field. 73, ... Joe, W4TV On 3/19/2018 8:10 PM, JOE wrote: > I spoke to someone at Bird (when they were really Bird) years ago and I > was told that the Bird wattmeter is accurate to ±5% of top scale. This > means that a 100 watt slug can be off ±5 watts _anywhere_ on the meter. > So, a transmitter emitting 50 watts out, using the Bird and a 100 watt > slug, can read between 45 and 55 watts. That's why he said it was > important to keep the reading in the top 1/3 (highest) end of the > meter. This is where the error is less. When taking reflected power > readings the slug should be 1/10 of the forward slug value when testing > a reasonably good antenna. So, a 100 watt forward slug would require a > 10 watt reverse slug for reasonable accuracy. > > I retired my Bird 43 and the vast assortment of slugs for a Telewave > Model 44A wattmeter and never looked back. The drawback to the 44A is > it is limited to 20-1000MHz. The Bird would be good for HF use. > > 73, Joe, K1ike > > Date: Mon, 19 Mar 2018 18:40:41 +0000 >> Always bear in mind that their odd meters (30 uA) are very non-linear and >> measurements made using element ranges that fall in the bottom 1/3 or >> so of >> the scale are the most accurate. Overall, they claim to be accurate >> to +/- >> 20 percent of full scale. HORRIBLE in >> today's world! >> >> FWIW ... >> >> 73! >> >> K0PP > > ______________________________________________________________ > 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 > Message delivered to [hidden email] 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 Message delivered to [hidden email] |
You can always use an A range Bird slug (25 to 60 MHz) on the upper end of the HF spectrum.
It'll be accurate on 10 & 12 M and probably not too far off a little lower, but certainly not on 80 or 40 M. Low power 5W & 10W A slugs are available. 73 Charlie k3ICH ______________________________________________________________ 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 Message delivered to [hidden email] |
On 3/19/2018 8:47 PM, Charlie T wrote:
> Low power 5W & 10W A slugs are available. Yes. I have some for VHF and UHF. I also bought the very nice LP100A from the estate of an SK. It came with only one sensor, so I sent it back to Larry for him to add a second one. It's permanently wired into my SO2R station. One of its many useful features is the ability to measure the complex Z at its output terminal. 73, Jim K9YC ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] |
I was speaking specifically of the "A" range slugs for 25 to 60 MHz which
are available down to 5 W and usable in the higher HF freqs. I have a couple low power 1 & 2.5W slugs that cover very narrow VHF & UHF ranges that are handy for walkies. I always said I would never get into the "sub" hobby of Bird collecting, but I guess somewhere along I succumbed. 73,Charlie k3ICH -----Original Message----- From: [hidden email] <[hidden email]> On Behalf Of Jim Brown Sent: Monday, March 19, 2018 11:54 PM To: [hidden email] Subject: Re: [Elecraft] DMM recommendations On 3/19/2018 8:47 PM, Charlie T wrote: > Low power 5W & 10W A slugs are available. Yes. I have some for VHF and UHF. I also bought the very nice LP100A from the estate of an SK. It came with only one sensor, so I sent it back to Larry for him to add a second one. It's permanently wired into my SO2R station. One of its many useful features is the ability to measure the complex Z at its output terminal. 73, Jim K9YC ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] ______________________________________________________________ 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 Message delivered to [hidden email] |
In reply to this post by Bill Levy
Wow! I never knew the bird was a DMM! <chuckle>
You can put down the Bird43 all you want, but check nearly every professional radio shop and every prof tech's tool bag and likely you will find a Bird. They work well and are quite durable riding in pickups, helicopters, boats, snowcats, etc. I bought my first one in 1976 (and still using it). Now own three. Definitely more accurate RF power meters but the Bird survives. Professionals have 1/2 wavelength test cables to ensure accurate Reflected measurements in the field. 73, Ed - KL7UW http://www.kl7uw.com Dubus-NA Business mail: [hidden email] ______________________________________________________________ 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 Message delivered to [hidden email] |
In reply to this post by Joe Subich, W4TV-4
Bird did make a 10 Watt slug a few years ago, but there must not have been many of them and the on line Bird seller had one at a very high price. Like two times the regular price. It sold immediately as I remember.
I used a couple Birds attached with an N union and had a 25 in the rev and a 1K in the fwd with peak detector. It was a good setup. I generally don't even need a wattmeter, but set one up mostly as a project more than any other reason.. Chuck Hawley [hidden email] Amateur Radio, KE9UW aka Jack, BMW Motorcycles ________________________________________ From: [hidden email] [[hidden email]] on behalf of Joe Subich, W4TV [[hidden email]] Sent: Monday, March 19, 2018 8:29 PM To: [hidden email] Subject: Re: [Elecraft] DMM recommendations > When taking reflected power readings the slug should be 1/10 of the > forward slug value when testing a reasonably good antenna. So, a 100 > watt forward slug would require a 10 watt reverse slug for reasonable > accuracy. Unfortunately, the smallest HF slug Bird make is 25 Watts. That means any SWR less than 1.4:1 (2.8% reflected power) is suspect with a 100 W transmitter. It is a shame that Bird do not offer a 10 (or 5 W HF element) and the one reason I moved to the LP-100(A) several years ago. However, I would never think to take the LP-100(A) or microHAM SMΩRF out into the field. 73, ... Joe, W4TV On 3/19/2018 8:10 PM, JOE wrote: > I spoke to someone at Bird (when they were really Bird) years ago and I > was told that the Bird wattmeter is accurate to ±5% of top scale. This > means that a 100 watt slug can be off ±5 watts _anywhere_ on the meter. > So, a transmitter emitting 50 watts out, using the Bird and a 100 watt > slug, can read between 45 and 55 watts. That's why he said it was > important to keep the reading in the top 1/3 (highest) end of the > meter. This is where the error is less. When taking reflected power > readings the slug should be 1/10 of the forward slug value when testing > a reasonably good antenna. So, a 100 watt forward slug would require a > 10 watt reverse slug for reasonable accuracy. > > I retired my Bird 43 and the vast assortment of slugs for a Telewave > Model 44A wattmeter and never looked back. The drawback to the 44A is > it is limited to 20-1000MHz. The Bird would be good for HF use. > > 73, Joe, K1ike > > Date: Mon, 19 Mar 2018 18:40:41 +0000 >> Always bear in mind that their odd meters (30 uA) are very non-linear and >> measurements made using element ranges that fall in the bottom 1/3 or >> so of >> the scale are the most accurate. Overall, they claim to be accurate >> to +/- >> 20 percent of full scale. HORRIBLE in >> today's world! >> >> FWIW ... >> >> 73! >> >> K0PP > > ______________________________________________________________ > 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 > Message delivered to [hidden email] 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 Message delivered to [hidden email] ______________________________________________________________ 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 Message delivered to [hidden email]
Chuck, KE9UW
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