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WTB slicer or ssb adapter
Looking for a central electronics or similar slicer in at least restorable
condition. Might consider an ssb adapter such as the Hammarlund HC-10 if it has the conncting cables. Condition and price is an e-mail directly to me at 73 Dave K4JRB |
WTB slicer or ssb adapter
David Thompson wrote:
Looking for a central electronics or similar slicer in at least restorable condition. Might consider an ssb adapter such as the Hammarlund HC-10 if it has the conncting cables. Would you consider a solid-state one? I am looking at doing a design for one right now, which would work with any receiver with a 455 KC IF. --scott -- "C'est un Nagra. C'est suisse, et tres, tres precis." |
WTB slicer or ssb adapter
Richard Knoppow wrote:
It seems to me that it should not be too difficult to design one that is superior to the old vacuum tube models. There are certainly plenty of receivers out there which could use an adaptor. Have you any definite ideas about price range, features, etc? What I was thinking was to take the AM synchronous detector circuit from OH2GF which was published in the July '93 QST issue. It is based on an NE602 which does not have the best dynamic range in the world but seems to be okay. I was first going to make up a PC board layout rather than constructing it dead-bug style like the original, then I was going to try one of the new Maxim detector chips in place of the NE602, but retaining the NE804 limiter and phase detector. If I were going to do it with tubes, I would look into some of the sheet beam tubes that were intended for TV chroma detector circuits... many of them have excellent performance and are very inexpensive (as are all old TV tubes). The 7360 costs a bloody fortune when you can find one, but the 6AR8, 6JM8, and 6ME8 are effectively the same basic design but with less crosstalk. --scott -- "C'est un Nagra. C'est suisse, et tres, tres precis." |
WTB slicer or ssb adapter
Sure a solid state one would be OK. There is a solid state SSB adapter on
Ebay for the little solid state receivers ($40 or so). Just need to get one to match the 455 IF as I am betting the little Chinese RX has an odd ball IF probably 30 mhz or higher! Dave K4JRB |
WTB slicer or ssb adapter
On Fri, 16 May 2008, Scott Dorsey wrote:
Richard Knoppow wrote: It seems to me that it should not be too difficult to design one that is superior to the old vacuum tube models. There are certainly plenty of receivers out there which could use an adaptor. Have you any definite ideas about price range, features, etc? What I was thinking was to take the AM synchronous detector circuit from OH2GF which was published in the July '93 QST issue. It is based on an NE602 which does not have the best dynamic range in the world but seems to be okay. A slicer by definition has selectible sideband, and maybe specifically uses phasing to get it. They existed at a time when there wasn't much but AM radios, so to get around the "turn down the RF gain, turn up the AF gain and turn on the BFO" you needed to add a product detector. Once you were doing that, you might as well add selectable sideband via phasing, since it didn't add that much to the cost, but did help improve things when the receiver's IF was wide for AM. It lives on today, since most "low end" shortwave receivers that have synchronous detector uses the phasing method to increse performance without the cost of an actual better IF filter. There were external SSB adaptors that included an IF filter for SSB, but I can't think of seeing any that called themselves "slicers". Michael VE2BVW I was first going to make up a PC board layout rather than constructing it dead-bug style like the original, then I was going to try one of the new Maxim detector chips in place of the NE602, but retaining the NE804 limiter and phase detector. If I were going to do it with tubes, I would look into some of the sheet beam tubes that were intended for TV chroma detector circuits... many of them have excellent performance and are very inexpensive (as are all old TV tubes). The 7360 costs a bloody fortune when you can find one, but the 6AR8, 6JM8, and 6ME8 are effectively the same basic design but with less crosstalk. --scott -- "C'est un Nagra. C'est suisse, et tres, tres precis." |
WTB slicer or ssb adapter
"Michael Black" wrote in message mple.org... On Fri, 16 May 2008, Scott Dorsey wrote: Richard Knoppow wrote: It seems to me that it should not be too difficult to design one that is superior to the old vacuum tube models. There are certainly plenty of receivers out there which could use an adaptor. Have you any definite ideas about price range, features, etc? What I was thinking was to take the AM synchronous detector circuit from OH2GF which was published in the July '93 QST issue. It is based on an NE602 which does not have the best dynamic range in the world but seems to be okay. A slicer by definition has selectible sideband, and maybe specifically uses phasing to get it. They existed at a time when there wasn't much but AM radios, so to get around the "turn down the RF gain, turn up the AF gain and turn on the BFO" you needed to add a product detector. Once you were doing that, you might as well add selectable sideband via phasing, since it didn't add that much to the cost, but did help improve things when the receiver's IF was wide for AM. It lives on today, since most "low end" shortwave receivers that have synchronous detector uses the phasing method to increse performance without the cost of an actual better IF filter. There were external SSB adaptors that included an IF filter for SSB, but I can't think of seeing any that called themselves "slicers". Michael VE2BVW I was first going to make up a PC board layout rather than constructing it dead-bug style like the original, then I was going to try one of the new Maxim detector chips in place of the NE602, but retaining the NE804 limiter and phase detector. If I were going to do it with tubes, I would look into some of the sheet beam tubes that were intended for TV chroma detector circuits... many of them have excellent performance and are very inexpensive (as are all old TV tubes). The 7360 costs a bloody fortune when you can find one, but the 6AR8, 6JM8, and 6ME8 are effectively the same basic design but with less crosstalk. --scott -- "C'est un Nagra. C'est suisse, et tres, tres precis." I am not sure how a synchonous detector works with suppressed carrier SSB but my understanding of it may be incorrect. To me a synchronous detector is a device for replacing the carrier of a double sideband signal, either AM or suppressed carrier and synchronized by means of the equal and opposite phase of the two sidebands. Such a detector will supply a locally generated carrier which has exactly the right phase with relation to the sidebands even when they are distorted by selective fading. Similar detectors are also used for television where there is a residual carrier and sideband since that is enough to lock the oscillator to the correct frequency and phase. Beam switching tubes were used to some extent in commercial vacuum tube equipment but Hallicrafters transmitters are the only example with come to mind at the moment, I am sure there were others. These things came along at about the same time that transistors began to supplant tubes. As far as selectable sideband in an SSB adaptor AFAIK all worked by means of either shifting the signal to the filter frequency or having two filters. I don't see how phasing would work in a receiving adaptor. There were numerous phasing type SSB generator for transmitting, for instance the one made by Barker and Williamson who also made 90degree audio phase shifting networks for use in home made ones. I still have the B&W adaptor I used in the 1960s. It worked pretty well but had to be adjusted for any large frequency change. Stable high performance filters or reasonable cost pretty much ended the use of phasing type exciters. In any case, a good performing receiving adaptor which would work on older receivers, especially tube receivers, would be welcome. The old Hammarlund and TMC units are pretty hard to come by and, I suspect, something modern would outperform them. -- --- Richard Knoppow Los Angeles, CA, USA WB6KBL |
WTB slicer or ssb adapter
"Richard Knoppow" wrote in message m... As far as selectable sideband in an SSB adaptor AFAIK all worked by means of either shifting the signal to the filter frequency or having two filters. I don't see how phasing would work in a receiving adaptor. There were numerous phasing type SSB generator for transmitting, for instance the one made by Barker and Williamson who also made 90degree audio phase shifting networks for use in home made ones. I still have the B&W adaptor I used in the 1960s. It worked pretty well but had to be adjusted for any large frequency change. Stable high performance filters or reasonable cost pretty much ended the use of phasing type exciters. In any case, a good performing receiving adaptor which would work on older receivers, especially tube receivers, would be welcome. The old Hammarlund and TMC units are pretty hard to come by and, I suspect, something modern would outperform them. -- --- Richard Knoppow Los Angeles, CA, USA WB6KBL The Central Electronic Sideband Slicer used phasing for SSB reception. On the other hand, the B&W 370 used the filter method. Pete |
WTB slicer or ssb adapter
"Tio Pedro" wrote in message ... "Richard Knoppow" wrote in message m... As far as selectable sideband in an SSB adaptor AFAIK all worked by means of either shifting the signal to the filter frequency or having two filters. I don't see how phasing would work in a receiving adaptor. There were numerous phasing type SSB generator for transmitting, for instance the one made by Barker and Williamson who also made 90degree audio phase shifting networks for use in home made ones. I still have the B&W adaptor I used in the 1960s. It worked pretty well but had to be adjusted for any large frequency change. Stable high performance filters or reasonable cost pretty much ended the use of phasing type exciters. In any case, a good performing receiving adaptor which would work on older receivers, especially tube receivers, would be welcome. The old Hammarlund and TMC units are pretty hard to come by and, I suspect, something modern would outperform them. -- --- Richard Knoppow Los Angeles, CA, USA WB6KBL The Central Electronic Sideband Slicer used phasing for SSB reception. On the other hand, the B&W 370 used the filter method. Pete I found the handbook for the CE box on BAMA and will have a look at what they are doing. -- --- Richard Knoppow Los Angeles, CA, USA |
WTB slicer or ssb adapter
Richard Knoppow wrote:
I found the handbook for the CE box on BAMA and will have a look at what they are doing. Hi, The Central Electronics Slicer was based on the GE Signal Slicer, which appeared in GE Ham News, July-Aug 1951. BANA has the issue, under the category gehamnews, filename ge0604.pdf The GE article shows how to build it, including the the 90 degree audio phase shift network. It's pretty slick - a selectable sideband adapter based on a phase shifting circuit, for any 450kc to 500kc i.f. receiver. 73, Ed Knobloch |
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