Re: [Elecraft] Boost power supplies for RF amps
On 2/20/17 at 5:35 PM, jackbrin...@me.com (Jack Brindle) wrote: To be fair, we have had one instance of the problem, and that station was running the battery critically low. In fact the battery failed at that voltage (something like 10 volts) and had to be permanently removed from service. Perhaps the answer is to take the battery manufacturer’s advice and not to run the batteries below 11.5 volts. I believe the K3 has a low-voltage alarm that can be applied to the problem so that it gives a warning at the critical voltage and won’t continue until the power is corrected. Thanks for reminding me of the details. The 100W CQP incidents and the 5W FD ones get blurred in my mind. Yes, the K3 has a low voltage warning. The level is controlled by the "BAT MIN" CONFIG menu setting with a default of 11V. It sends out a beep tone and flashes BAT LOW on the display. If you use a boost regulator like the TG Electronics Boost Regulator, note that these may introduce a junction voltage drop which will cause the warning to sound at a higher voltage. 73 Bill AE6JV --- Bill Frantz| I don't have high-speed | Periwinkle (408)356-8506 | internet. I have DSL.| 16345 Englewood Ave www.pwpconsult.com | | Los Gatos, CA 95032 __ 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] Boost power supplies for RF amps
On 2/20/2017 3:11 PM, Matthew Cook wrote: > I believe we will see a return of the 50V MOSFET PA's in commercial > equipment again, especially with the explosion of LDMOS devices and the > ever decreasing availability of 16-18V bi-polar RF transistors. Modern commercial communication sites have all gone to 48V "Bell Telephone Standard - positive ground" with corresponding radio equipment. Inverters for 120V AC and 12/24V DC where needed. It's a whole new world for us "old timers". 73 de K2ASP - Phil Kane Elecraft K2/100 s/n 5402 >From a Clearing in the Silicon Forest Beaverton (Washington County) Oregon VP - General Counsel & Engineering Manager CSI Telecommunications, Inc. - Consulting Engineers San Francisco, CA - Beaverton, OR __ 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] Boost power supplies for RF amps
At my home station I run my transmitters on a "boosted" 14+ V bus using a TG Electronics Boost Regulator - and "the knobs" at about "3 o'clock". The station battery can go as low as 11.5 V but the 14V bus stays there. On 2/20/2017 3:56 PM, Ron D'Eau Claire wrote: > For the rigs running off of 12 (13.8) Vdc, how about simply not running the > rig "all knobs full right"? > > Reducing the power by 25% will improve IMD performance at lower voltages, > yet that power difference is virtually impossible to detect on the H.F. > bands. 73 de K2ASP - Phil Kane Elecraft K2/100 s/n 5402 >From a Clearing in the Silicon Forest Beaverton (Washington County) Oregon __ 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] Boost power supplies for RF amps
Bill; To be fair, we have had one instance of the problem, and that station was running the battery critically low. In fact the battery failed at that voltage (something like 10 volts) and had to be permanently removed from service. Perhaps the answer is to take the battery manufacturer’s advice and not to run the batteries below 11.5 volts. I believe the K3 has a low-voltage alarm that can be applied to the problem so that it gives a warning at the critical voltage and won’t continue until the power is corrected. In general, we have found the K3 to be an excellent performer when running off battery at 12 to 13.8 volts, whether charging or not. Anyone wishing to hear us, just listed for K6EI in Field Day. And for those who wonder, having great antennas 500 or so feet above San Francisco Bay gives us great signals, even at 5 watts. - Jack, W6FB > On Feb 20, 2017, at 4:57 PM, Bill Frantzwrote: > > I'm trying to reconcile this advice with our experience running QRP field > day. We frequently have two or 3 K3s on a single band (CW, SSB, > Digital/GOTA). We use batteries and solar cells since our site does not > permit generators. When the radios are being fed from a charged battery or a > battery being charged from the solar cells, we don't have a significant > problem with interference between stations. (Antenna placement helps a lot > too.) When the voltage drops, the complaints increase. > > Of course, our 5 watts is quite a bit below the full power of the low power > RF amp in the K3. > > 73 Bill AE6JV > > On 2/21/17 at 4:05 PM, k9...@live.com (Bill Johnson) wrote: > >> Reducing the power by 25% will improve IMD performance at lower voltages, >> yet that power difference is virtually impossible to detect on the H.F. >> bands. > --- > Bill Frantz| Truth and love must prevail | Periwinkle > (408)356-8506 | over lies and hate. | 16345 Englewood Ave > www.pwpconsult.com | - Vaclav Havel | Los Gatos, CA 95032 > > __ > 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] Boost power supplies for RF amps
I'm trying to reconcile this advice with our experience running QRP field day. We frequently have two or 3 K3s on a single band (CW, SSB, Digital/GOTA). We use batteries and solar cells since our site does not permit generators. When the radios are being fed from a charged battery or a battery being charged from the solar cells, we don't have a significant problem with interference between stations. (Antenna placement helps a lot too.) When the voltage drops, the complaints increase. Of course, our 5 watts is quite a bit below the full power of the low power RF amp in the K3. 73 Bill AE6JV On 2/21/17 at 4:05 PM, k9...@live.com (Bill Johnson) wrote: Reducing the power by 25% will improve IMD performance at lower voltages, yet that power difference is virtually impossible to detect on the H.F. bands. --- Bill Frantz| Truth and love must prevail | Periwinkle (408)356-8506 | over lies and hate. | 16345 Englewood Ave www.pwpconsult.com | - Vaclav Havel | Los Gatos, CA 95032 __ 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] Boost power supplies for RF amps
And there is little difference in signal strength, might actually be stronger as copy is better and less signal wasted by eliminating IMD, etc. 73, Bill K9YEQ -Original Message- From: Elecraft [mailto:elecraft-boun...@mailman.qth.net] On Behalf Of Ron D'Eau Claire Sent: Monday, February 20, 2017 5:56 PM To: elecraft@mailman.qth.net Subject: Re: [Elecraft] Boost power supplies for RF amps For the rigs running off of 12 (13.8) Vdc, how about simply not running the rig "all knobs full right"? Reducing the power by 25% will improve IMD performance at lower voltages, yet that power difference is virtually impossible to detect on the H.F. bands. 73, Ron AC7AC __ 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 k9...@live.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] Boost power supplies for RF amps
For the rigs running off of 12 (13.8) Vdc, how about simply not running the rig "all knobs full right"? Reducing the power by 25% will improve IMD performance at lower voltages, yet that power difference is virtually impossible to detect on the H.F. bands. 73, Ron AC7AC __ 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] Boost power supplies for RF amps
I have a Codan 6924 lunch box radio that does just this. ( http://www.hfradiosales.com.au/codan_%20barrett_hf_radio_information/RADIOS/files/6924%20MK2-2.jpg ) It takes in 10-15V and boosts it to 28V to feed a 25W PA, it does so only on TX. This radio was designed in 1969 and released to market in 1971, I got mine given to me in 1979. So this concept is not new. Way back when the 28V RF transistors of the day did not operate well with low collector voltages at 12V, IMD was way too high. For reference the 6924 IMD is better than -40dB PEP for a 38 yr old radio. I believe we will see a return of the 50V MOSFET PA's in commercial equipment again, especially with the explosion of LDMOS devices and the ever decreasing availability of 16-18V bi-polar RF transistors. 73 Matthew VK5ZM On 21 February 2017 at 09:10, Mel Farrer via Elecraft < elecraft@mailman.qth.net> wrote: > I have long wondered why some manufacture did not think of it. That is a > amp with built in 12 VDC boost PS. With all of the new switching tech, it > should be a KISS solution and make the amp SOUND GREAT all of the time > Just my opinion hi. > Mel, K6KBE > > From: Bill Frantz <fra...@pwpconsult.com> > To: elecraft@mailman.qth.net > Sent: Monday, February 20, 2017 2:08 PM > Subject: [Elecraft] Boost power supplies for RF amps > > The short answer is they can. It is only a matter of engineering > time, cost, resulting price, number of customers and competing > projects. In other words, the usual business considerations. > > Lets work the idea through for several of the Elecraft RF amplifiers: > > The 10-15W K3(s) amp: This amp can have significant IMD at low > voltages as we have discovered with our QRP, all Elecraft, field > day operation. The KX3 seems to do better, so reengineering the > amp may be a better solution. For field day, we try to have > fresh batteries available. > > The 100W K3(s) internal amp: This amp also has low voltage IMD > as we found during our 100W California QSO party expeditions. > But, consider the K3(s)'s construction. The front of the radio > is the digital portion, including the DSPs and the front panel > computer. All of this digital noise is isolated from the analog > circuits in the back of the radio. If Elecraft were to include a > boost power supply with the internal amp, that high-current > switcher would be in the analog section, and probably impossible > to quiet. Solution: Get an external boost power supply. > > The KXPA100 external amp: This form factor would be an ideal > place to include a boost power supply. The use profile includes > portable battery operation and designing isolation for the power > supply into the package seems straight forward. > > The KPA500 external amp: The amp setup procedure sets the > voltage to to 65v to 85v and the specifications call for about > 1000 VA of power or about 13A at 75v. That would be nearly 75A > at 13.5 volts assuming 100% efficiency, so it would be a good > idea to put the boost power supply next to the battery and run > 75v to the amp. It would make a nice high power mobil rig. > > 73 Bill AE6JV > > In thread "Re: [Elecraft] Chinese ebay amps for KX3", on 2/20/17 > at 5:47 AM, pin...@erols.com (Charlie T, K3ICH) wrote: > > >So now, tell me why a mid-sized radio can't have a built in 12 V to say, > 50 > >V converter to drive some HV FETs for cleaner output specs like the Yuge > >radios. > --- > Bill Frantz|The nice thing about standards| Periwinkle > (408)356-8506 |is there are so many to choose| 16345 > Englewood Ave > www.pwpconsult.com |from. - Andrew Tanenbaum| Los Gatos, > CA 95032 > > __ > 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 farrerfo...@yahoo.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 vk...@bistre.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] Boost power supplies for RF amps
I believe the new Anan-8000DLE does exactly this, and steps up the voltage to 50V. No idea if there's any noise related to these boost converters. Seems like a neat idea, just not sure how it will work in practice. On Mon, Feb 20, 2017 at 4:08 PM, Bill Frantzwrote: > The short answer is they can. It is only a matter of engineering time, > cost, resulting price, number of customers and competing projects. In other > words, the usual business considerations. > > Lets work the idea through for several of the Elecraft RF amplifiers: > > The 10-15W K3(s) amp: This amp can have significant IMD at low voltages as > we have discovered with our QRP, all Elecraft, field day operation. The KX3 > seems to do better, so reengineering the amp may be a better solution. For > field day, we try to have fresh batteries available. > > The 100W K3(s) internal amp: This amp also has low voltage IMD as we found > during our 100W California QSO party expeditions. But, consider the K3(s)'s > construction. The front of the radio is the digital portion, including the > DSPs and the front panel computer. All of this digital noise is isolated > from the analog circuits in the back of the radio. If Elecraft were to > include a boost power supply with the internal amp, that high-current > switcher would be in the analog section, and probably impossible to quiet. > Solution: Get an external boost power supply. > > The KXPA100 external amp: This form factor would be an ideal place to > include a boost power supply. The use profile includes portable battery > operation and designing isolation for the power supply into the package > seems straight forward. > > The KPA500 external amp: The amp setup procedure sets the voltage to to > 65v to 85v and the specifications call for about 1000 VA of power or about > 13A at 75v. That would be nearly 75A at 13.5 volts assuming 100% > efficiency, so it would be a good idea to put the boost power supply next > to the battery and run 75v to the amp. It would make a nice high power > mobil rig. > > 73 Bill AE6JV > > In thread "Re: [Elecraft] Chinese ebay amps for KX3", on 2/20/17 at 5:47 > AM, pin...@erols.com (Charlie T, K3ICH) wrote: > > So now, tell me why a mid-sized radio can't have a built in 12 V to say, 50 >> V converter to drive some HV FETs for cleaner output specs like the Yuge >> radios. >> > --- > Bill Frantz|The nice thing about standards| Periwinkle > (408)356-8506 |is there are so many to choose| 16345 Englewood Ave > www.pwpconsult.com |from. - Andrew Tanenbaum| Los Gatos, CA 95032 > > __ > 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 orma...@corenode.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] Boost power supplies for RF amps
I have long wondered why some manufacture did not think of it. That is a amp with built in 12 VDC boost PS. With all of the new switching tech, it should be a KISS solution and make the amp SOUND GREAT all of the time Just my opinion hi. Mel, K6KBE From: Bill Frantz <fra...@pwpconsult.com> To: elecraft@mailman.qth.net Sent: Monday, February 20, 2017 2:08 PM Subject: [Elecraft] Boost power supplies for RF amps The short answer is they can. It is only a matter of engineering time, cost, resulting price, number of customers and competing projects. In other words, the usual business considerations. Lets work the idea through for several of the Elecraft RF amplifiers: The 10-15W K3(s) amp: This amp can have significant IMD at low voltages as we have discovered with our QRP, all Elecraft, field day operation. The KX3 seems to do better, so reengineering the amp may be a better solution. For field day, we try to have fresh batteries available. The 100W K3(s) internal amp: This amp also has low voltage IMD as we found during our 100W California QSO party expeditions. But, consider the K3(s)'s construction. The front of the radio is the digital portion, including the DSPs and the front panel computer. All of this digital noise is isolated from the analog circuits in the back of the radio. If Elecraft were to include a boost power supply with the internal amp, that high-current switcher would be in the analog section, and probably impossible to quiet. Solution: Get an external boost power supply. The KXPA100 external amp: This form factor would be an ideal place to include a boost power supply. The use profile includes portable battery operation and designing isolation for the power supply into the package seems straight forward. The KPA500 external amp: The amp setup procedure sets the voltage to to 65v to 85v and the specifications call for about 1000 VA of power or about 13A at 75v. That would be nearly 75A at 13.5 volts assuming 100% efficiency, so it would be a good idea to put the boost power supply next to the battery and run 75v to the amp. It would make a nice high power mobil rig. 73 Bill AE6JV In thread "Re: [Elecraft] Chinese ebay amps for KX3", on 2/20/17 at 5:47 AM, pin...@erols.com (Charlie T, K3ICH) wrote: >So now, tell me why a mid-sized radio can't have a built in 12 V to say, 50 >V converter to drive some HV FETs for cleaner output specs like the Yuge >radios. --- Bill Frantz |The nice thing about standards| Periwinkle (408)356-8506 |is there are so many to choose| 16345 Englewood Ave www.pwpconsult.com |from. - Andrew Tanenbaum | Los Gatos, CA 95032 __ 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 farrerfo...@yahoo.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] Boost power supplies for RF amps
The short answer is they can. It is only a matter of engineering time, cost, resulting price, number of customers and competing projects. In other words, the usual business considerations. Lets work the idea through for several of the Elecraft RF amplifiers: The 10-15W K3(s) amp: This amp can have significant IMD at low voltages as we have discovered with our QRP, all Elecraft, field day operation. The KX3 seems to do better, so reengineering the amp may be a better solution. For field day, we try to have fresh batteries available. The 100W K3(s) internal amp: This amp also has low voltage IMD as we found during our 100W California QSO party expeditions. But, consider the K3(s)'s construction. The front of the radio is the digital portion, including the DSPs and the front panel computer. All of this digital noise is isolated from the analog circuits in the back of the radio. If Elecraft were to include a boost power supply with the internal amp, that high-current switcher would be in the analog section, and probably impossible to quiet. Solution: Get an external boost power supply. The KXPA100 external amp: This form factor would be an ideal place to include a boost power supply. The use profile includes portable battery operation and designing isolation for the power supply into the package seems straight forward. The KPA500 external amp: The amp setup procedure sets the voltage to to 65v to 85v and the specifications call for about 1000 VA of power or about 13A at 75v. That would be nearly 75A at 13.5 volts assuming 100% efficiency, so it would be a good idea to put the boost power supply next to the battery and run 75v to the amp. It would make a nice high power mobil rig. 73 Bill AE6JV In thread "Re: [Elecraft] Chinese ebay amps for KX3", on 2/20/17 at 5:47 AM, pin...@erols.com (Charlie T, K3ICH) wrote: So now, tell me why a mid-sized radio can't have a built in 12 V to say, 50 V converter to drive some HV FETs for cleaner output specs like the Yuge radios. --- Bill Frantz|The nice thing about standards| Periwinkle (408)356-8506 |is there are so many to choose| 16345 Englewood Ave www.pwpconsult.com |from. - Andrew Tanenbaum| Los Gatos, CA 95032 __ 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