Re: [Elecraft] KX3 and its "TUNE" selection. (With mag loop)
On 2022-08-24 16:19, Fred Jensen wrote: Tuning on most mag loops is very touchy, and more so on lower frequencies, because of the extremely high Q. My Alexloop has a reduction gearbox on the capacitor, *** What kind of motor does it have? I've been planning to use a stepper, controlled by a microcontroller. Use frequency data from the radio ( or at least band data ) to get it into the ballpark, and then zero in onto resonance. It's not going to be a portable system. The size of the capacitor alone guarantees that. I'm going to either mount it on a mast, or on top of a shed. - Jerry, KF6VB and I wish it had 3 times the reduction it has. I doubt you could get close enough with a motor-driven cap to a preset position. And, exact resonance matters. However, it's pretty easy these days to use a V-I sensor and a phase detector to determine where resonance exactly is, and have a little microcontroller drive the cap to zero phase difference. We used to do it with HF mobiles. Still may be done. Most of the cost in transmitting loops >QRP is in the vacuum variable capacitor, the construction to minimize I-squared R losses, and to withstand the extremely high voltages which, at 100+ watts can range well above 100 amps circulating current and multi-KV potentials. 73, Fred ["Skip"] K6DGW Sparks NV DM09dn Washoe County Geoffrey Feldman wrote on 8/24/2022 12:11 PM: Magloops with effective remote tuning are very pricey but those are not (as far as I know) automatic tuning, just remote) With a tiny bit of practice, it’s not hard to do manually. I give it almost no thought. To simply have a mag loop go to the perfect spot of resonance in response to instructions from the radio would be difficult if not impractical. The key thing here is that it’s not a problem (for low power) to have the mag loop close to you nor is it hard to adjust it (as I described) to be perfectly resonant to the radio. However, Julia is right. You can have the KX3 report its frequency (and everything else) through the ACC1 port. Similarly the KX3 can be controlled by this magic box (to transmit a bit) Getting a mag loop with its very high Q to perfectly tune to that frequency would be interesting. When you see how tiny the changes to the Variable Cap are – you might perceive the problem. Are there effective auto-tuning magloops that work as perfectly as hand tuning for low power levels? I’d like to know. I also think that complexity can get in the way of portability. The beauty of the mag loop I have (alex loop) is that it’s light weight, quick to set up and take down. Adding complexity would change all that. At that point, I would use the kxpa100 with its tuner. (possibly even cheaper) W1GCF Geoff From: Julia Tuttle [mailto:ju...@juliatuttle.net] Sent: Wednesday, August 24, 2022 12:53 PM To: jerry Cc: Geoffrey Feldman; Elecraft; JEROME SODUS Subject: Re: [Elecraft] KX3 and its "TUNE" selection. (With mag loop) Hi Jerry, That's absolutely possible over the serial port (ACC1)! The Programmer's Reference has the details: https://ftp.elecraft.com/K3S/Manuals%20Downloads/K3S <https://ftp.elecraft.com/K3S/Manuals%20Downloads/K3S%20Pgmrs%20Ref,%20G5.pdf> %20Pgmrs%20Ref,%20G5.pdf 73, Julie On Wed, Aug 24, 2022, 12:49 jerry wrote: I'm starting work on a magloop project. I wonder how hard it would be to have a transceiver tell the magloop what frequency it's tuned to? That could operationally be simpler than having to hit it with low-power RF so it can tune itself... - Jerry, KF6VB On 2022-08-23 14:28, Geoffrey Feldman wrote: If your antenna is a magloop - DO NOT USE the tune button. In fact, clear the tuner memory for your band per instructions. The tuner feature (assuming you have the option) is great with other antennas, especially random wire but it doesn't go well with mag loops. The xmit button is simply "PTT". For any mag loop, choose a frequency you wish to start work, somewhere in the middle of the band. Mag Loops are high Q antennas, that is they are effective in a very narrow range of frequencies to which they are adjusted with the tuning box. This fact should inform your thoughts on effective use. Turn the tuning dial (ON THE MAG LOOP) until you hear the maximum amount of noise (or blessed with a real signal). The antenna and the radio are now tuned. Turn the KX3 tuning knob SLOWLY until you hear some kind of interesting signal. (PX3 is great for this too). Tweak the tuning knob on the mag loop to get the strongest signal for your exact frequency. (just a tweak). This is important even if you hear the signal, to get the most efficient use of transmitter. If while seeking a station you hear a lot less static, adjust the mag loop as above. IF seeking up and down the band, just rinse and repeat as above until you get a station
Re: [Elecraft] KX3 and its "TUNE" selection. (With mag loop)
Tuning on most mag loops is very touchy, and more so on lower frequencies, because of the extremely high Q. My Alexloop has a reduction gearbox on the capacitor, and I wish it had 3 times the reduction it has. I doubt you could get close enough with a motor-driven cap to a preset position. And, exact resonance matters. However, it's pretty easy these days to use a V-I sensor and a phase detector to determine where resonance exactly is, and have a little microcontroller drive the cap to zero phase difference. We used to do it with HF mobiles. Still may be done. Most of the cost in transmitting loops >QRP is in the vacuum variable capacitor, the construction to minimize I-squared R losses, and to withstand the extremely high voltages which, at 100+ watts can range well above 100 amps circulating current and multi-KV potentials. 73, Fred ["Skip"] K6DGW Sparks NV DM09dn Washoe County Geoffrey Feldman wrote on 8/24/2022 12:11 PM: Magloops with effective remote tuning are very pricey but those are not (as far as I know) automatic tuning, just remote) With a tiny bit of practice, it’s not hard to do manually. I give it almost no thought. To simply have a mag loop go to the perfect spot of resonance in response to instructions from the radio would be difficult if not impractical. The key thing here is that it’s not a problem (for low power) to have the mag loop close to you nor is it hard to adjust it (as I described) to be perfectly resonant to the radio. However, Julia is right. You can have the KX3 report its frequency (and everything else) through the ACC1 port. Similarly the KX3 can be controlled by this magic box (to transmit a bit) Getting a mag loop with its very high Q to perfectly tune to that frequency would be interesting. When you see how tiny the changes to the Variable Cap are – you might perceive the problem. Are there effective auto-tuning magloops that work as perfectly as hand tuning for low power levels? I’d like to know. I also think that complexity can get in the way of portability. The beauty of the mag loop I have (alex loop) is that it’s light weight, quick to set up and take down. Adding complexity would change all that. At that point, I would use the kxpa100 with its tuner. (possibly even cheaper) W1GCF Geoff From: Julia Tuttle [mailto:ju...@juliatuttle.net] Sent: Wednesday, August 24, 2022 12:53 PM To: jerry Cc: Geoffrey Feldman; Elecraft; JEROME SODUS Subject: Re: [Elecraft] KX3 and its "TUNE" selection. (With mag loop) Hi Jerry, That's absolutely possible over the serial port (ACC1)! The Programmer's Reference has the details: https://ftp.elecraft.com/K3S/Manuals%20Downloads/K3S <https://ftp.elecraft.com/K3S/Manuals%20Downloads/K3S%20Pgmrs%20Ref,%20G5.pdf> %20Pgmrs%20Ref,%20G5.pdf 73, Julie On Wed, Aug 24, 2022, 12:49 jerry wrote: I'm starting work on a magloop project. I wonder how hard it would be to have a transceiver tell the magloop what frequency it's tuned to? That could operationally be simpler than having to hit it with low-power RF so it can tune itself... - Jerry, KF6VB On 2022-08-23 14:28, Geoffrey Feldman wrote: If your antenna is a magloop - DO NOT USE the tune button. In fact, clear the tuner memory for your band per instructions. The tuner feature (assuming you have the option) is great with other antennas, especially random wire but it doesn't go well with mag loops. The xmit button is simply "PTT". For any mag loop, choose a frequency you wish to start work, somewhere in the middle of the band. Mag Loops are high Q antennas, that is they are effective in a very narrow range of frequencies to which they are adjusted with the tuning box. This fact should inform your thoughts on effective use. Turn the tuning dial (ON THE MAG LOOP) until you hear the maximum amount of noise (or blessed with a real signal). The antenna and the radio are now tuned. Turn the KX3 tuning knob SLOWLY until you hear some kind of interesting signal. (PX3 is great for this too). Tweak the tuning knob on the mag loop to get the strongest signal for your exact frequency. (just a tweak). This is important even if you hear the signal, to get the most efficient use of transmitter. If while seeking a station you hear a lot less static, adjust the mag loop as above. IF seeking up and down the band, just rinse and repeat as above until you get a station to work. Once the mag loop is tuned to the band, you won't have to adjust it much to tune it for the particular part of the band you are on. Gentle tweaks is the way. Notice too, mag loops are very directional. Consult the manufacturing manual for where it's sensitive and turn it along a great circle to where you want to go. (In Boston, where I live, Europe is north east by great circle. I note there is something about tuning the radio
Re: [Elecraft] KX3 and its "TUNE" selection. (With mag loop)
Magloops with effective remote tuning are very pricey but those are not (as far as I know) automatic tuning, just remote) With a tiny bit of practice, it’s not hard to do manually. I give it almost no thought. To simply have a mag loop go to the perfect spot of resonance in response to instructions from the radio would be difficult if not impractical. The key thing here is that it’s not a problem (for low power) to have the mag loop close to you nor is it hard to adjust it (as I described) to be perfectly resonant to the radio. However, Julia is right. You can have the KX3 report its frequency (and everything else) through the ACC1 port. Similarly the KX3 can be controlled by this magic box (to transmit a bit) Getting a mag loop with its very high Q to perfectly tune to that frequency would be interesting. When you see how tiny the changes to the Variable Cap are – you might perceive the problem. Are there effective auto-tuning magloops that work as perfectly as hand tuning for low power levels? I’d like to know. I also think that complexity can get in the way of portability. The beauty of the mag loop I have (alex loop) is that it’s light weight, quick to set up and take down. Adding complexity would change all that. At that point, I would use the kxpa100 with its tuner. (possibly even cheaper) W1GCF Geoff From: Julia Tuttle [mailto:ju...@juliatuttle.net] Sent: Wednesday, August 24, 2022 12:53 PM To: jerry Cc: Geoffrey Feldman; Elecraft; JEROME SODUS Subject: Re: [Elecraft] KX3 and its "TUNE" selection. (With mag loop) Hi Jerry, That's absolutely possible over the serial port (ACC1)! The Programmer's Reference has the details: https://ftp.elecraft.com/K3S/Manuals%20Downloads/K3S <https://ftp.elecraft.com/K3S/Manuals%20Downloads/K3S%20Pgmrs%20Ref,%20G5.pdf> %20Pgmrs%20Ref,%20G5.pdf 73, Julie On Wed, Aug 24, 2022, 12:49 jerry wrote: I'm starting work on a magloop project. I wonder how hard it would be to have a transceiver tell the magloop what frequency it's tuned to? That could operationally be simpler than having to hit it with low-power RF so it can tune itself... - Jerry, KF6VB On 2022-08-23 14:28, Geoffrey Feldman wrote: > If your antenna is a magloop - DO NOT USE the tune button. In fact, > clear > the tuner memory for your band per instructions. The tuner feature > (assuming you have the option) is great with other antennas, especially > random wire but it doesn't go well with mag loops. The xmit button is > simply "PTT". > > > > For any mag loop, choose a frequency you wish to start work, somewhere > in > the middle of the band. Mag Loops are high Q antennas, that is they > are > effective in a very narrow range of frequencies to which they are > adjusted > with the tuning box. This fact should inform your thoughts on > effective > use. > > Turn the tuning dial (ON THE MAG LOOP) until you hear the maximum > amount of > noise (or blessed with a real signal). The antenna and the radio are > now > tuned. > > Turn the KX3 tuning knob SLOWLY until you hear some kind of interesting > signal. (PX3 is great for this too). > > Tweak the tuning knob on the mag loop to get the strongest signal for > your > exact frequency. (just a tweak). This is important even if you hear > the > signal, to get the most efficient use of transmitter. > > If while seeking a station you hear a lot less static, adjust the mag > loop > as above. > > > > IF seeking up and down the band, just rinse and repeat as above until > you > get a station to work. > > > > Once the mag loop is tuned to the band, you won't have to adjust it > much to > tune it for the particular part of the band you are on. Gentle tweaks > is the > way. Notice too, mag loops are very directional. Consult the > manufacturing > manual for where it's sensitive and turn it along a great circle to > where > you want to go. (In Boston, where I live, Europe is north east by > great > circle. > > > > I note there is something about tuning the radio in some mag loop > instructions. I find this not necessary with the KX3. What I describe > here > is what I do and it works well. > > > > I have contacted Europe USB with a KX3 at 15 watts and a mag loop. The > antenna was on the top floor of my wood frame town house for this, not > even > outdoors. If you think about what I wrote, you want the antenna in > arm's > length while working the radio. Don't worry about your body affecting > the > near field. Mag Loops are not like that. > > > > -73- > > W1GCF > > Geoff > > __
Re: [Elecraft] KX3 and its "TUNE" selection. (With mag loop)
Hi Jerry, That's absolutely possible over the serial port (ACC1)! The Programmer's Reference has the details: https://ftp.elecraft.com/K3S/Manuals%20Downloads/K3S%20Pgmrs%20Ref,%20G5.pdf 73, Julie On Wed, Aug 24, 2022, 12:49 jerry wrote: > I'm starting work on a magloop project. I wonder how hard it would be > to > have a transceiver tell the magloop what frequency it's tuned to? That > could > operationally be simpler than having to hit it with low-power RF so it > can tune > itself... > > - Jerry, KF6VB > > > > On 2022-08-23 14:28, Geoffrey Feldman wrote: > > If your antenna is a magloop - DO NOT USE the tune button. In fact, > > clear > > the tuner memory for your band per instructions. The tuner feature > > (assuming you have the option) is great with other antennas, especially > > random wire but it doesn't go well with mag loops. The xmit button is > > simply "PTT". > > > > > > > > For any mag loop, choose a frequency you wish to start work, somewhere > > in > > the middle of the band. Mag Loops are high Q antennas, that is they > > are > > effective in a very narrow range of frequencies to which they are > > adjusted > > with the tuning box. This fact should inform your thoughts on > > effective > > use. > > > > Turn the tuning dial (ON THE MAG LOOP) until you hear the maximum > > amount of > > noise (or blessed with a real signal). The antenna and the radio are > > now > > tuned. > > > > Turn the KX3 tuning knob SLOWLY until you hear some kind of interesting > > signal. (PX3 is great for this too). > > > > Tweak the tuning knob on the mag loop to get the strongest signal for > > your > > exact frequency. (just a tweak). This is important even if you hear > > the > > signal, to get the most efficient use of transmitter. > > > > If while seeking a station you hear a lot less static, adjust the mag > > loop > > as above. > > > > > > > > IF seeking up and down the band, just rinse and repeat as above until > > you > > get a station to work. > > > > > > > > Once the mag loop is tuned to the band, you won't have to adjust it > > much to > > tune it for the particular part of the band you are on. Gentle tweaks > > is the > > way. Notice too, mag loops are very directional. Consult the > > manufacturing > > manual for where it's sensitive and turn it along a great circle to > > where > > you want to go. (In Boston, where I live, Europe is north east by > > great > > circle. > > > > > > > > I note there is something about tuning the radio in some mag loop > > instructions. I find this not necessary with the KX3. What I describe > > here > > is what I do and it works well. > > > > > > > > I have contacted Europe USB with a KX3 at 15 watts and a mag loop. The > > antenna was on the top floor of my wood frame town house for this, not > > even > > outdoors. If you think about what I wrote, you want the antenna in > > arm's > > length while working the radio. Don't worry about your body affecting > > the > > near field. Mag Loops are not like that. > > > > > > > > -73- > > > > W1GCF > > > > Geoff > > > > __ > > 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 je...@tr2.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 ju...@juliatuttle.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] KX3 and its "TUNE" selection. (With mag loop)
I'm starting work on a magloop project. I wonder how hard it would be to have a transceiver tell the magloop what frequency it's tuned to? That could operationally be simpler than having to hit it with low-power RF so it can tune itself... - Jerry, KF6VB On 2022-08-23 14:28, Geoffrey Feldman wrote: If your antenna is a magloop - DO NOT USE the tune button. In fact, clear the tuner memory for your band per instructions. The tuner feature (assuming you have the option) is great with other antennas, especially random wire but it doesn't go well with mag loops. The xmit button is simply "PTT". For any mag loop, choose a frequency you wish to start work, somewhere in the middle of the band. Mag Loops are high Q antennas, that is they are effective in a very narrow range of frequencies to which they are adjusted with the tuning box. This fact should inform your thoughts on effective use. Turn the tuning dial (ON THE MAG LOOP) until you hear the maximum amount of noise (or blessed with a real signal). The antenna and the radio are now tuned. Turn the KX3 tuning knob SLOWLY until you hear some kind of interesting signal. (PX3 is great for this too). Tweak the tuning knob on the mag loop to get the strongest signal for your exact frequency. (just a tweak). This is important even if you hear the signal, to get the most efficient use of transmitter. If while seeking a station you hear a lot less static, adjust the mag loop as above. IF seeking up and down the band, just rinse and repeat as above until you get a station to work. Once the mag loop is tuned to the band, you won't have to adjust it much to tune it for the particular part of the band you are on. Gentle tweaks is the way. Notice too, mag loops are very directional. Consult the manufacturing manual for where it's sensitive and turn it along a great circle to where you want to go. (In Boston, where I live, Europe is north east by great circle. I note there is something about tuning the radio in some mag loop instructions. I find this not necessary with the KX3. What I describe here is what I do and it works well. I have contacted Europe USB with a KX3 at 15 watts and a mag loop. The antenna was on the top floor of my wood frame town house for this, not even outdoors. If you think about what I wrote, you want the antenna in arm's length while working the radio. Don't worry about your body affecting the near field. Mag Loops are not like that. -73- W1GCF Geoff __ 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 je...@tr2.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
[Elecraft] KX3 and its "TUNE" selection. (With mag loop)
If your antenna is a magloop - DO NOT USE the tune button. In fact, clear the tuner memory for your band per instructions. The tuner feature (assuming you have the option) is great with other antennas, especially random wire but it doesn't go well with mag loops. The xmit button is simply "PTT". For any mag loop, choose a frequency you wish to start work, somewhere in the middle of the band. Mag Loops are high Q antennas, that is they are effective in a very narrow range of frequencies to which they are adjusted with the tuning box. This fact should inform your thoughts on effective use. Turn the tuning dial (ON THE MAG LOOP) until you hear the maximum amount of noise (or blessed with a real signal). The antenna and the radio are now tuned. Turn the KX3 tuning knob SLOWLY until you hear some kind of interesting signal. (PX3 is great for this too). Tweak the tuning knob on the mag loop to get the strongest signal for your exact frequency. (just a tweak). This is important even if you hear the signal, to get the most efficient use of transmitter. If while seeking a station you hear a lot less static, adjust the mag loop as above. IF seeking up and down the band, just rinse and repeat as above until you get a station to work. Once the mag loop is tuned to the band, you won't have to adjust it much to tune it for the particular part of the band you are on. Gentle tweaks is the way. Notice too, mag loops are very directional. Consult the manufacturing manual for where it's sensitive and turn it along a great circle to where you want to go. (In Boston, where I live, Europe is north east by great circle. I note there is something about tuning the radio in some mag loop instructions. I find this not necessary with the KX3. What I describe here is what I do and it works well. I have contacted Europe USB with a KX3 at 15 watts and a mag loop. The antenna was on the top floor of my wood frame town house for this, not even outdoors. If you think about what I wrote, you want the antenna in arm's length while working the radio. Don't worry about your body affecting the near field. Mag Loops are not like that. -73- W1GCF Geoff __ 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
