Re: [Elecraft] Where to put the wattmeter
There's no reason the P3 can't display it if you have a way to generate the trapezoidal pattern from the transmitter. I think feeding a triangle wave from a function generator into the mic input would do it. Alan N1AL On 4/19/23 16:38, Fred Jensen wrote: and I'd buy one if it would do a trapezoidal pattern. Judging TX signal quality looking at the time-domain envelope is pretty hard, but I can judge straight sides on the T-pattern 73, Fred ["Skip"] K6DGW Sparks NV DM09dn Washoe County __ 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 Message delivered to arch...@mail-archive.com
Re: [Elecraft] Where to put the wattmeter
On 4/19/2023 3:38 PM, Fred Jensen wrote: and I'd buy one if it would do a trapezoidal pattern. N8LP makes one, very nice. http://www.telepostinc.com/n8lp.html Introduced 4-5 years ago. 73, Jim K9YC __ 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 Message delivered to arch...@mail-archive.com
Re: [Elecraft] Where to put the wattmeter
and I'd buy one if it would do a trapezoidal pattern. Judging TX signal quality looking at the time-domain envelope is pretty hard, but I can judge straight sides on the T-pattern 73, Fred ["Skip"] K6DGW Sparks NV DM09dn Washoe County Jack Brindle via Elecraft wrote on 4/19/2023 1:06 PM: The original poster was using a sensor connected to a P3. For me, the big use for this is to view the modulation pattern of my transmission. I have other devices (like the KPA500 itself) that tells me the power. And if I really want to see the match on the antenna feed (which for my tribander should be close to 50 ohms), I will use my W2 and sensor between the KAT500 and the antenna feed line. I doubt there will be much distortion in the modulation pattern with a mismatch, though, Just don’t want to surpass the KAT500's 10:1 maximum rating. OK, so truth be told, I use it to make sure my signal is going out. And to see the nice pictures it produces… 73, Jack, W6FB On Apr 19, 2023, at 2:42 PM, Al Lorona wrote: Yes, if you're willing to do the math in your head, or can set up your fancy wattmeter to do the math for you, this'll work. But the main reason why I don't like the idea of putting the wattmeter (or sensor, actually) in a non-50-ohm location is the additional uncertainty due to the mismatch(es). In the original poster's situation, there would be a mismatch at the interface between the input of the sensor and the KAT-500's output, and another mismatch at the interface between the output of the sensor and the input of the feedline. How large would the additional uncertainty be? It depends, but assuming that the wattmeter sensor has a (very good) match of 1.2:1, and the antenna has 4:1 -- which is not out of the question for many antennas-- the additional uncertainty is about ±1.0 dB. This means that if the actual forward power were 500 W, the wattmeter may read (after doing the math mentioned above) as much as 1 dB lower, which is 397 W, or 1 dB higher, which is 630 W. That's a whole heck-of-a-lot of error there that many hams wouldn't tolerate. Nobody had raised the issue of uncertainty and that's why I wanted to point it out. Y'all can have the last word on this. R, W6LX/4 I'm fairly sure that (forward power) - (reverse power) gives the correct nett output power, before cable and antenna losses. I'd need to review the maths to be sure. Most reflected power ends up re-re-reflected, as additional forward power. A high SWR will giver reflected power almost as high as forward power. -- David Wooley __ 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 Message delivered to jackbrin...@me.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 Message delivered to k6dg...@gmail.com -- This email has been checked for viruses by AVG antivirus software. www.avg.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 Message delivered to arch...@mail-archive.com
Re: [Elecraft] Where to put the wattmeter
The original poster was using a sensor connected to a P3. For me, the big use for this is to view the modulation pattern of my transmission. I have other devices (like the KPA500 itself) that tells me the power. And if I really want to see the match on the antenna feed (which for my tribander should be close to 50 ohms), I will use my W2 and sensor between the KAT500 and the antenna feed line. I doubt there will be much distortion in the modulation pattern with a mismatch, though, Just don’t want to surpass the KAT500's 10:1 maximum rating. OK, so truth be told, I use it to make sure my signal is going out. And to see the nice pictures it produces… 73, Jack, W6FB > On Apr 19, 2023, at 2:42 PM, Al Lorona wrote: > > Yes, if you're willing to do the math in your head, or can set up your fancy > wattmeter to do the math for you, this'll work. > > But the main reason why I don't like the idea of putting the wattmeter (or > sensor, actually) in a non-50-ohm location is the additional uncertainty due > to the mismatch(es). In the original poster's situation, there would be a > mismatch at the interface between the input of the sensor and the KAT-500's > output, and another mismatch at the interface between the output of the > sensor and the input of the feedline. > > How large would the additional uncertainty be? It depends, but assuming that > the wattmeter sensor has a (very good) match of 1.2:1, and the antenna has > 4:1 -- which is not out of the question for many antennas-- the additional > uncertainty is about ±1.0 dB. > > This means that if the actual forward power were 500 W, the wattmeter may > read (after doing the math mentioned above) as much as 1 dB lower, which is > 397 W, or 1 dB higher, which is 630 W. That's a whole heck-of-a-lot of error > there that many hams wouldn't tolerate. > > Nobody had raised the issue of uncertainty and that's why I wanted to point > it out. Y'all can have the last word on this. > > R, > > W6LX/4 > > > I'm fairly sure that (forward power) - (reverse power) gives the correct > nett output power, before cable and antenna losses. I'd need to review > the maths to be sure. Most reflected power ends up re-re-reflected, as > additional forward power. A high SWR will giver reflected power almost > as high as forward power. > > -- > David Wooley > > > __ > 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 > Message delivered to jackbrin...@me.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 Message delivered to arch...@mail-archive.com
Re: [Elecraft] FS: P3 Panadapter with Transmit Monitor (TX MON) Option (no SVGA) *** SOLD ***
-Original Message- From: w3sb To: Elecraft Date: Friday, 14 April 2023 8:41 AM EDT Subject: FS: P3 Panadapter with Transmit Monitor (TX MON) Option (no SVGA) FS: P3 Panadapter with Transmit Monitor (TX MON) Option (no SVGA) Downsizing and excess to needs. Purchased new, factory built, non-smoking environment. Excellent physical and working condition. Shipped in factory box with original cables and instruction manual. CONUS only. $725 plus shipping and insurance. Please contact off list. 73, Monty W3SB W3SB at PTD.net __ 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 Message delivered to arch...@mail-archive.com
Re: [Elecraft] Where to put the wattmeter
Yes, if you're willing to do the math in your head, or can set up your fancy wattmeter to do the math for you, this'll work. But the main reason why I don't like the idea of putting the wattmeter (or sensor, actually) in a non-50-ohm location is the additional uncertainty due to the mismatch(es). In the original poster's situation, there would be a mismatch at the interface between the input of the sensor and the KAT-500's output, and another mismatch at the interface between the output of the sensor and the input of the feedline. How large would the additional uncertainty be? It depends, but assuming that the wattmeter sensor has a (very good) match of 1.2:1, and the antenna has 4:1 -- which is not out of the question for many antennas-- the additional uncertainty is about ±1.0 dB. This means that if the actual forward power were 500 W, the wattmeter may read (after doing the math mentioned above) as much as 1 dB lower, which is 397 W, or 1 dB higher, which is 630 W. That's a whole heck-of-a-lot of error there that many hams wouldn't tolerate. Nobody had raised the issue of uncertainty and that's why I wanted to point it out. Y'all can have the last word on this. R, W6LX/4 I'm fairly sure that (forward power) - (reverse power) gives the correct nett output power, before cable and antenna losses. I'd need to review the maths to be sure. Most reflected power ends up re-re-reflected, as additional forward power. A high SWR will giver reflected power almost as high as forward power. -- David Wooley __ 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 Message delivered to arch...@mail-archive.com
Re: [Elecraft] FS: KAT500 *** SOLD PENDING FUNDS ***
-Original Message- From: w3sb To: Elecraft Date: Wednesday, 19 April 2023 9:55 AM EDT Subject: FS: KAT500 Downsized and excess to needs. Purchased new, factory build, non-smoking environment. Excellent working and physical condition. Includes KXSUB cable, power cord with Powerpole connectors and original manual. Will ship via FedEx in original Elecraft box. Replacement cost $900, selling for $675 with shipping and insurance included (CONUS only). Please contact off list. 73, Monty W3SB (W3SB at PTD.net) __ 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 Message delivered to arch...@mail-archive.com
[Elecraft] FS: KAT500
Downsized and excess to needs. Purchased new, factory build, non-smoking environment. Excellent working and physical condition. Includes KXSUB cable, power cord with Powerpole connectors and original manual. Will ship via FedEx in original Elecraft box. Replacement cost $900, selling for $675 with shipping and insurance included (CONUS only). Please contact off list. 73, Monty W3SB (W3SB at PTD.net) __ 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 Message delivered to arch...@mail-archive.com
