K1 on USB CW
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Re: Sideband, Which Sideband? (WAS: K1 on USB CW)
 
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Yes Bob, I corrected my post. It was 9 MHz VFO to switch SB.
-Stuart K5KVH _______________________________________________ Elecraft mailing list Post to: [hidden email] http://mailman.qth.net/mailman/listinfo/elecraft You must subscribe to post. Subscriber Info (Addr. Change, Unsub etc): http://mailman.qth.net/subscribers.htm Elecraft page: http://www.elecraft.com |
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In reply to this post by Steve Lawrence-2
In a message dated 6/17/04 10:53:15 PM Eastern Daylight Time,
[hidden email] writes: > In the 1954 ARRL book: "Single Sideband for the Radio Amateur," W2UNJ > describes a phasing exciter. (The book was $1.50, by the way.) I have a later version of that book. No mention of the W2UNJ exciter. I do have articles where the 9 MHz generator/ 5 MHz VFO scheme is used. There is always a method of flipping the sidebands, because the heterodyne scheme doesn't do it. > > The equipment is long gone but as I recall, the plus or minus mixing > scheme reversed the sidebands. The math tells the real story. With a 9 MHz SSB generator and a 5-5.5 MHz VFO, the sidebands do not invert. But with a 5.2 MHz SSB generator and an 8.7-9.2 MHz VFO, the sidebands *do* invert. This is the case for phasing exciters. > > My recollection was a crystal filter system which was not the case. It does not matter whether the SSB is generated by the phasing or filter method. The sideband inversion or lack thereof is a result of subsequent heterodyning to the ham band desired. With a phasing system, sideband inversion is very easy. All you need to do is reverse the phase of one of the audio channels. A DPDT switch does the job. > > My point - as a throw away comment - was to recall the history of why > bands below 20m use LSB as the default SSB mode. And it was because of > the phase reversal due to the mixing scheme. Understood - except it doesn't work that way for a 9 MHz SSB generator and 5 MHz VFO. The math is not complicated - we simply add 5 MHz to the 9 to get on 20 and subtract 5 to get on 75. Either way the sideband does not invert. The bigger point, and the reason for all the bandwidth, is that we do ourselves and amateur radio a disservice if we blindly accept such stories without checking out the facts. What should a nonham think when presented with such a story, and then he/she does the math and discovers it doesn't work that way? 73 de Jim, N2EY _______________________________________________ Elecraft mailing list Post to: [hidden email] http://mailman.qth.net/mailman/listinfo/elecraft You must subscribe to post. Subscriber Info (Addr. Change, Unsub etc): http://mailman.qth.net/subscribers.htm Elecraft page: http://www.elecraft.com |
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In reply to this post by Steve Lawrence-2
> The best part was the magic eye on the 20A which was used to indicate the
>suppression of the carrier and output tuning. Folks tend to forget what great >sounding CW came out of these "QRP" rigs and the amazement of working >someone with 5-10 watts. Folks still do! I use mine regularly on 20m, along with the matching VFO (which was actually a surplus WWII ARC-5 xmtr in a CE box) and sometimes an old WRL/Globe sweep tube linear. Tube stuff is great...the rig's older than I am! John K5MO --- Checked by AVG anti-virus system (http://www.grisoft.com). Version: 6.0.622 / Virus Database: 400 - Release Date: 3/13/04 _______________________________________________ Elecraft mailing list Post to: [hidden email] http://mailman.qth.net/mailman/listinfo/elecraft You must subscribe to post. Subscriber Info (Addr. Change, Unsub etc): http://mailman.qth.net/subscribers.htm Elecraft page: http://www.elecraft.com |
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In reply to this post by N2EY
I am definitely not an expert on this, however, all of the early military
manuals on the applications of SSB explained how "the only practical way of removing the unwanted sideband is with a 100 kc [old terminology for kHz] crystal filter, as the other filtering techniques are inadequate." You can even find some of these old Collins "mechanical" filters, in this range but usually up in the range of 455 kHz. I think you will find that the early ham SSB rigs used some form of these intermediate frequency mixers/filters and thus throwing in another possibility of why the sidebands are inverted. Navships 93271 "Fundamentals of Single Sideband" page 2-1 has a block diagram of a SSB receiver with a 250 kc balanced modulator (mixer-filter-etc.), 2.7 - 3.7 vfo and a 4 mhz and 11 mhz switched xtal oscillator (for 7 and 14 mhz output respectively.) That would satisfy the "math" and the present convention. Rich KE0X _______________________________________________ Elecraft mailing list Post to: [hidden email] http://mailman.qth.net/mailman/listinfo/elecraft You must subscribe to post. Subscriber Info (Addr. Change, Unsub etc): http://mailman.qth.net/subscribers.htm Elecraft page: http://www.elecraft.com |
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In reply to this post by Steve Lawrence-2
In a message dated 6/18/2004 12:20:57 PM Eastern Daylight Time, [hidden email] writes:
> I am definitely not an expert on this, however, all of the early military > manuals on the applications of SSB explained how "the only practical way of > removing the unwanted sideband is with a 100 kc [old terminology for kHz] > crystal filter, as the other filtering techniques are inadequate." > > You can even find some of these old Collins "mechanical" filters, in this > range but usually up in the range of 455 kHz. That was one philosophy, anyway. Collins held many mechanical filter patents, and RCA held some others. The earliest SSB systems (such as Ray Moore's (W6DEI) 1934 rig) was to generate the SSB at frequencies just above the voice range - typically 11 to 20 kHz. Then it took at least two heterodynes to get to 75 meters, and maybe three to get to 20! The very first SSB radio system was AT&T's transatlantic telephone system that went into service in 1927 and remained in service for at least 20 years. Besides the advantages of putting all the transmitter power into one sideband, the system reduced the need for a "wideband" antenna system because the frequency was in the LF region (55 kHz, IIRC). The phasing system was known in principle back then but was not really practical until R.B. Dome described a practical RC audio phase shift network in the late 1940s. Both systems were popular in the 1950s but the filter system won out for several reasons: 1) Filters could be made that had unwanted-sideband rejection far better than the 40 dB typically obtained in phasing systems. 2) In the mid-1950s, techniques for building high frequency lattice filters were perfected, reducing the number of heterodynes needed for the HF ham bands. (The ladder filters used in the K2 and K1 were a later development). 3) The filter system lent itself easily to transceiver implementations. This greatly reduced size, power consumption, cost and complexity, because the same oscillators could be used for both transmit and receive. Also, the task of zeroing the transmitter was mostly eliminated. (Trivia: what was the *first* manufactured HF SSB amateur transceiver?) 73 de Jim, N2EY _______________________________________________ Elecraft mailing list Post to: [hidden email] http://mailman.qth.net/mailman/listinfo/elecraft You must subscribe to post. Subscriber Info (Addr. Change, Unsub etc): http://mailman.qth.net/subscribers.htm Elecraft page: http://www.elecraft.com |
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> 3) The filter system lent itself easily to transceiver
> implementations. This greatly reduced size, power consumption, cost > and complexity, because the same oscillators could be used for both > transmit and receive. Also, the task of zeroing the transmitter was > mostly eliminated. (Trivia: what was the *first* manufactured HF SSB > amateur transceiver?) The earliest I can recall was the Collins KWM-1, introduced in 1957, but I suspect that may not be the correct answer. Transceivers of any sort were not common in the mid-1950s. My high school principal (K6AHL) had the first SSB setup I ever saw, a Collins KWS-1 transmitter with the matching 75A4 receiver, circa 1955. -- Bob Nielsen, N7XY n7xy (at) n7xy.net Bainbridge Island, WA http://www.n7xy.net _______________________________________________ Elecraft mailing list Post to: [hidden email] http://mailman.qth.net/mailman/listinfo/elecraft You must subscribe to post. Subscriber Info (Addr. Change, Unsub etc): http://mailman.qth.net/subscribers.htm Elecraft page: http://www.elecraft.com |
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In reply to this post by Steve Lawrence-2
N2EY said:
>The bigger point, and the reason for all the bandwidth, is that we do >ourselves and amateur radio a disservice if we blindly accept such stories >without >checking out the facts. The difference between high side & low side injection is something I'm always having to explain over & over again to satellite equipment vendors who should really be the ones that have to explain it to their customers - so not surprising to see spectrum perversion throwing a googlie at amateurs. 73, VR2BrettGraham _______________________________________________ Elecraft mailing list Post to: [hidden email] http://mailman.qth.net/mailman/listinfo/elecraft You must subscribe to post. Subscriber Info (Addr. Change, Unsub etc): http://mailman.qth.net/subscribers.htm Elecraft page: http://www.elecraft.com |
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In reply to this post by Steve Lawrence-2
In a message dated 6/18/04 9:44:50 PM Eastern Daylight Time, [hidden email]
writes: > (Trivia: what was the *first* manufactured HF SSB > > amateur transceiver?) > > The earliest I can recall was the Collins KWM-1, introduced in 1957, > but I suspect that may not be the correct answer. Based on when ads appeared in ham mags, that's the one! But the KWM-1 only covered 20, 15 and 10. 73 de Jim, N2EY _______________________________________________ Elecraft mailing list Post to: [hidden email] http://mailman.qth.net/mailman/listinfo/elecraft You must subscribe to post. Subscriber Info (Addr. Change, Unsub etc): http://mailman.qth.net/subscribers.htm Elecraft page: http://www.elecraft.com |
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In reply to this post by john-477
John:
In 1959-1961 I was in the US Navy and stationed at NAS Norfolk, Va. I lived in the ham shack of W4NPT and ran many phone patches on 20 meter SSB for HZ1AB a US Air Force base in Saudi Arabia. Our SSB rig was a Central Electronics 20A with the Command Set VFO, an HQ-170 Receiver, a Johnson Viking Courier Linear Amplifier and a Mosley TA-33 triband antenna.. One evening I received a phone call from the state department requesting that I run a phone patch for a high ranking offical of the Saudi government who was in the US with his daughter who was having surgery. The night of the scheduled patch I established contact with HZ1AB about 15 minutes before the schedule and checked out all the equipment. They were very strong into Norfolk at 2AM. When the call came from the state department we were all ready and started the phone patch. About 5 minutes into the phone patch I looked up to see that my Johnson Courier linear was on fire. Flames were coming out of the top of the cabinet. I stopped the phone patch and ran for a CO2 fire extinguisher to put out the fire. After I got the flames out I removed the linear from the operating position and sat it on the floor behind me. I was really worried about botching the phone patch that the state department deemed so important. So I connected the antenna directly to the output connector of the 20A and tuned it up. I called HZ1AB and asked how he copied and he repiled you seem to have the problem resolved because your 20db over S-9. We finished the phone patch in about 15 mor3e minutes with no problems and after I had hung up with the state department I told HZ1AB I was using the 20A barefoot and he could not believe it. I was running QRP and enjoying it before it became fashionalble.....Hi Hi. 73 Jim Younce K4ZM K2 SN: 18 _______________________________________________ Elecraft mailing list Post to: [hidden email] http://mailman.qth.net/mailman/listinfo/elecraft You must subscribe to post. Subscriber Info (Addr. Change, Unsub etc): http://mailman.qth.net/subscribers.htm Elecraft page: http://www.elecraft.com |
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In reply to this post by Steve Lawrence-2
In a message dated 6/19/04 7:55:57 AM Eastern Daylight Time, [hidden email]
writes: > What's really amazing is that there are so many folks who NEVER were around > then, who NEVER operated SSB at the beginning and NEVER had the very common > Central Electronics 10 or 20 rigs that can tell all of us who were there > that > it's impossible to operate the way that we did. I don't see anybody claiming that. > > I guess I am getting senile....it must have been impossible that many times > I forgot to "flip the sideband switch" when moving off of 75 meters and > being on > the wrong sideband. It's possible that you forgot to swap sidebands. > > I do recall, however, having lots of fun working to have the most carrier > suppression I could get, and the most stabile VFO....and then setting up > round > tables on 75 where some of us were on LSB and the others were on USB on the > same frequency.... > > No doubt! What is being claimed is simply this: If you generate SSB (either sideband) at 9 MHz and mix it with a 5-5.5 MHz VFO you will get the same sideband on either the sum (20 meters) or difference (75 meters) mixing product. It's not a function of the rig used, or the time period, or whether it's phasing or filter. The math proves it. 73 de Jim, N2EY _______________________________________________ Elecraft mailing list Post to: [hidden email] http://mailman.qth.net/mailman/listinfo/elecraft You must subscribe to post. Subscriber Info (Addr. Change, Unsub etc): http://mailman.qth.net/subscribers.htm Elecraft page: http://www.elecraft.com |
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Hi Jim,
Unless I missed something, neither my email nor Thom Lacosta's made any claim about how the sideband selection was made and whether the sum or difference of which way it was hetrodyned would cause a sideband flip. The 10B and 20A had toggle switches for sideband selection. For operation on 75 and 20 meters you added or substracted 5-5.5 MHz and THEN flipped the sideband switch to the correct setting. When moving from 75 to 20 meters you had to flip the sideband switch and if you forgot you would be on the wrong sideband. This thread has already been beat to death. My comments were more in the line of "QRP operation" is not new and that the Central Electronics rigs also worked very well on CW and had a pretty note. If you recall chirps and key clicks were often present in those days (50's & 60"s). 73 Allen ----- Original Message ----- From: [hidden email] To: [hidden email] ; [hidden email] Cc: [hidden email] Sent: Saturday, June 19, 2004 9:06 AM Subject: Re: [Elecraft] K1 on USB CW In a message dated 6/19/04 7:55:57 AM Eastern Daylight Time, [hidden email] writes: What's really amazing is that there are so many folks who NEVER were around then, who NEVER operated SSB at the beginning and NEVER had the very common Central Electronics 10 or 20 rigs that can tell all of us who were there that it's impossible to operate the way that we did. I don't see anybody claiming that. I guess I am getting senile....it must have been impossible that many times I forgot to "flip the sideband switch" when moving off of 75 meters and being on the wrong sideband. It's possible that you forgot to swap sidebands. I do recall, however, having lots of fun working to have the most carrier suppression I could get, and the most stabile VFO....and then setting up round tables on 75 where some of us were on LSB and the others were on USB on the same frequency.... No doubt! What is being claimed is simply this: If you generate SSB (either sideband) at 9 MHz and mix it with a 5-5.5 MHz VFO you will get the same sideband on either the sum (20 meters) or difference (75 meters) mixing product. It's not a function of the rig used, or the time period, or whether it's phasing or filter. The math proves it. 73 de Jim, N2EY _______________________________________________ Elecraft mailing list Post to: [hidden email] http://mailman.qth.net/mailman/listinfo/elecraft You must subscribe to post. Subscriber Info (Addr. Change, Unsub etc): http://mailman.qth.net/subscribers.htm Elecraft page: http://www.elecraft.com |
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