Re: [Elecraft] SSB Power Creep
Jack, I would suggest that you do not have sufficient audio drive. That is the normal behavior of Elecraft products in digital modes when the audio drive is low. If you are following the typical 'wisdom' of using the audio level to control the output power, forget that - the Elecraft transceivers are different in the way they control power, and that method will not work. It will produce exactly the symptoms you state. For the K3 and KX3, adjust the audio so the ALC meter shows 4 bars solid and the 5th bar solid, then adjust the power knob for the desired power level. If you have a K2, set the LED display to show ALC and adjust the audio until you see 1 bar of ALC, then back down the audio until that bar just goes out. Again, adjust the power level with the power knob. 73, Don W3FPR On 7/31/2014 8:57 PM, Jack Berry via Elecraft wrote: I notice on MARS frequencies (slightly outside ham bands) that my power output starts out low and builds to full output over 10-20 seconds of transmit. The symptom is easily observed during an MT63 transmission and receiving stations comment that my signal starts out light and builds to a strong signal as the transmission progresses. I have run the calibration routine several times into a dummy load and all seems to go well but the problem persists. I see the same symptom in some ham bands but to a lesser extent, perhaps starting at half power and coming up to full power in a 10 seconds. __ 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] SSB Power Creep
Which Elecraft rig? —wunder, K6WRU On Jul 31, 2014, at 5:57 PM, Jack Berry via Elecraft wrote: > I notice on MARS frequencies (slightly outside ham bands) that my power > output starts out low and builds to full output over 10-20 seconds of > transmit. The symptom is easily observed during an MT63 transmission and > receiving stations comment that my signal starts out light and builds to a > strong signal as the transmission progresses. > I have run the calibration routine several times into a dummy load and all > seems to go well but the problem persists. > I see the same symptom in some ham bands but to a lesser extent, perhaps > starting at half power and coming up to full power in a 10 seconds. > > Has anyone else experienced this or have ideas about a fix? > > > God Bless & 73! > Jack - WE5ST > __ > 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 wun...@wunderwood.org __ 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] SSB Power
On Fri, 10 Feb 2006 18:52:03 -0600, Matt Osborn <[EMAIL PROTECTED]> wrote: >I'm not certain I know how to understand what it is I'm measuring. In >my mind, I think much the 20 watts RF out of a CW signal is actually >carrier and of not much use. When in SSB, I want to think that I can >still put out the 20 watts, only now all concentrated in one sideband. > >Why does the power meter fail to show the 20 watts? Thanks for the all the replies. One of the difficulties of any new venture is comprehending what it is that we see. What I've learned here is that the V50 RF finals have a dynamic range of 20 watts and will supply what the input signal demands up to 20 watts. The CW signal, due to its increased intensity, demands more average power when compared to an SSB signal. Using the Elecraft two tone generator, I found that the 1900hz tone demands more power than the 700hz tone and when both tones are on, the demand approaches that of the CW signal and is confirmed by the power meter. Thanks again for the education. ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
RE: [Elecraft] SSB Power
Don, W3FPR wrote: No need to guess, that certainly is true - a single audio tone transmitted without a carrier present will produce a single signal at a frequency of the carrier + or - the tone pitch (depends on the sideband). The amplitude will of course depend on how strong the audio signal is, but it could develop as much as the CW signal before driving the signal into a non-linear region (that non-linear maximum will depend on the transmitter design - I do not believe that is any need for concern on the K2) A few of the 1960's-vintage SSB rig designs used exactly this method of producing CW. It quickly fell from favor because the suppression of the opposite sideband and even the carrier suppression often was not good enough to avoid unnecessary and perhaps illegal levels of spurious signals. Some SSB rigs had no more than 30 dB of opposite sideband suppression, perhaps less. That's about five S-units, so an S-9 signal would have a image signal at about S-4 somewhere between 1 and 2 kHz away (twice the modulating frequency). Ron AC7AC ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
RE: [Elecraft] SSB Power
Nick, No need to guess, that certainly is true - a single audio tone transmitted without a carrier present will produce a single signal at a frequency of the carrier + or - the tone pitch (depends on the sideband). The amplitude will of course depend on how strong the audio signal is, but it could develop as much as the CW signal before driving the signal into a non-linear region (that non-linear maximum will depend on the transmitter design - I do not believe that is any need for concern on the K2) 73, Don W3FPR > -Original Message- > > Don Wilhelm wrote: > > This can be observed easily on an oscilloscope - first observe the > > amplitude of your power setting in CW, and then switch to SSB. If > > the voice peaks come up to the same amplitude as you observed for the > > CW signal, you are achieving that same level of PEP (peak envelope > > power). The average power will be considerably less than the PEP > > power for SSB. > > I'm guessing, if you can produce a single nice clean sine wave on an > audio frequency signal generator, sending a clean sine in SSB ought to > be approximately equivalent to sending a single carrier in CW? > > -- > "Nosey" Nick Waterman, G7RZQ, K2 #5209. > use Std::Disclaimer;[EMAIL PROTECTED] > You never find the what you want, until you replace it. > ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
Re: [Elecraft] SSB Power
Don Wilhelm wrote: > This can be observed easily on an oscilloscope - first observe the > amplitude of your power setting in CW, and then switch to SSB. If > the voice peaks come up to the same amplitude as you observed for the > CW signal, you are achieving that same level of PEP (peak envelope > power). The average power will be considerably less than the PEP > power for SSB. I'm guessing, if you can produce a single nice clean sine wave on an audio frequency signal generator, sending a clean sine in SSB ought to be approximately equivalent to sending a single carrier in CW? -- "Nosey" Nick Waterman, G7RZQ, K2 #5209. use Std::Disclaimer;[EMAIL PROTECTED] You never find the what you want, until you replace it. ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
RE: [Elecraft] SSB Power
Matt, I would surmise that you are being confused by your external wattmeter. The XV50 LEDs will flash on voice peaks, but if your wattmeter is showing you average power, its indication will be much less than the peak power. This 'confusion' leads many folks to overdrive their equipment on SSB. The K2 has a good indicator in the ALC LED display. If you see the ALC indicator lighted at all, you are driving to the proper peak power. This can be observed easily on an oscilloscope - first observe the amplitude of your power setting in CW, and then switch to SSB. If the voice peaks come up to the same amplitude as you observed for the CW signal, you are achieving that same level of PEP (peak envelope power). The average power will be considerably less than the PEP power for SSB. 73, Don W3FPR > -Original Message- > > I'm a little confused about measured transmitted power when in SSB vs > CW. > > As an example, I have an XV50 Transverter that is adjusted to produce > 20 watts RF out when using the K2 'tune' control. This output is > adjusted by reading 20 watts on an external power meter. The power > indicator LEDs are then adjusted to read 20 watts as well. > > When using SSB, however, the RF out is much, much lower, maxing out at > 7-8 watts PEP on the external power meter. The indicator LEDs, > however, indicate 10 - 20 watts of power. > > I'm not certain I know how to understand what it is I'm measuring. In > my mind, I think much the 20 watts RF out of a CW signal is actually > carrier and of not much use. When in SSB, I want to think that I can > still put out the 20 watts, only now all concentrated in one sideband. > > Why does the power meter fail to show the 20 watts? > ___ > Elecraft mailing list > Post to: Elecraft@mailman.qth.net > You must be a subscriber to post to the list. > Subscriber Info (Addr. Change, sub, unsub etc.): > http://mailman.qth.net/mailman/listinfo/elecraft > > Help: http://mailman.qth.net/subscribers.htm > Elecraft web page: http://www.elecraft.com > > > -- > No virus found in this incoming message. > Checked by AVG Free Edition. > Version: 7.1.375 / Virus Database: 267.15.5/256 - Release Date: 2/10/2006 > > ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
Re: [Elecraft] SSB Power
It depends on the wattmeter. If the wattmeter had a PEP or peak-hold mode, it would show the actual peak power. Many simple meters are affected by the duty cycle of the signal, especially analog ones where ballistics come into play. There are a number of meters on the market that show peak power. One you can build is my LP-100 project which is featured on the cover of the latest QEX. You can read more about it and the simpler LP-300 kit on my website... link below. They are both digital with peak-hold, but also have very fast pseudo-analog bargraph displays that track voice peaks. Larry N8LP www.telepostinc.com Ron D'Eau Claire wrote: -Original Message- Matt wrote: I'm a little confused about measured transmitted power when in SSB vs CW. As an example, I have an XV50 Transverter that is adjusted to produce 20 watts RF out when using the K2 'tune' control. This output is adjusted by reading 20 watts on an external power meter. The power indicator LEDs are then adjusted to read 20 watts as well. When using SSB, however, the RF out is much, much lower, maxing out at 7-8 watts PEP on the external power meter. The indicator LEDs, however, indicate 10 - 20 watts of power. I'm not certain I know how to understand what it is I'm measuring. In my mind, I think much the 20 watts RF out of a CW signal is actually carrier and of not much use. When in SSB, I want to think that I can still put out the 20 watts, only now all concentrated in one sideband. Why does the power meter fail to show the 20 watts? ___ Of course CW is ONLY carrier, on and off, so the information is in the keying. But when the key is down, you are putting out full power. Your transverter should be configured to put 20 watts out when driven at either 5 watts or 1 mW, key down in CW mode, depending upon whether you have the K60XV interface installed in your K2 and are using the RF output at the antenna connector or the K60XV connection. When your K2 is in TUNE, the power is reduced and no longer controlled by the K2's automatic power controlling system. That's so you can tune up with an ATU and the K2 won't go nuts trying to adjust its power output as the SWR changes. If you set up your transverter for 20 watts output with the K2 in TUNE, you may overdrive it in normal operation. SSB has a very low duty cycle. That is, the average power output is far, far below the peaks. You can raise the average power a bit using the K2's speech compression, but its average is still well below the peak CW level. The very brief transient peaks in your voice will hit full 20 watts out and unless your Power meter is designed to register peak RF and not average RF (like most meters) it'll show a much, much lower RF AVERAGE output even though your voice peaks are hitting 20 watts. The LED display on the transverter (and K2's RF bargraph) show the actual output, so you'll see them both flicker on voice peaks. Ron AC7AC ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
RE: [Elecraft] SSB Power
-Original Message- Matt wrote: I'm a little confused about measured transmitted power when in SSB vs CW. As an example, I have an XV50 Transverter that is adjusted to produce 20 watts RF out when using the K2 'tune' control. This output is adjusted by reading 20 watts on an external power meter. The power indicator LEDs are then adjusted to read 20 watts as well. When using SSB, however, the RF out is much, much lower, maxing out at 7-8 watts PEP on the external power meter. The indicator LEDs, however, indicate 10 - 20 watts of power. I'm not certain I know how to understand what it is I'm measuring. In my mind, I think much the 20 watts RF out of a CW signal is actually carrier and of not much use. When in SSB, I want to think that I can still put out the 20 watts, only now all concentrated in one sideband. Why does the power meter fail to show the 20 watts? ___ Of course CW is ONLY carrier, on and off, so the information is in the keying. But when the key is down, you are putting out full power. Your transverter should be configured to put 20 watts out when driven at either 5 watts or 1 mW, key down in CW mode, depending upon whether you have the K60XV interface installed in your K2 and are using the RF output at the antenna connector or the K60XV connection. When your K2 is in TUNE, the power is reduced and no longer controlled by the K2's automatic power controlling system. That's so you can tune up with an ATU and the K2 won't go nuts trying to adjust its power output as the SWR changes. If you set up your transverter for 20 watts output with the K2 in TUNE, you may overdrive it in normal operation. SSB has a very low duty cycle. That is, the average power output is far, far below the peaks. You can raise the average power a bit using the K2's speech compression, but its average is still well below the peak CW level. The very brief transient peaks in your voice will hit full 20 watts out and unless your Power meter is designed to register peak RF and not average RF (like most meters) it'll show a much, much lower RF AVERAGE output even though your voice peaks are hitting 20 watts. The LED display on the transverter (and K2's RF bargraph) show the actual output, so you'll see them both flicker on voice peaks. Ron AC7AC ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
