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Sherwood SE-3 MK III D Synchronous High-Fidelity Phase-Locked AM Product Detector
For One and All,
First of these that I have seen on eBay Sherwood SE-3 MK III D Synchronous High-Fidelity Phase-Locked AM Product Detector - Any Good ? http://cgi.ebay.com/_W0QQitemZ9734932430 What would be better a Drake R8 with the Sherwood SE-3 ? - - - o r - - - a Drake R8B using it's own Sync Detector ? Any one used them both ? {or have an opinion ?} i want to know ~ RHF |
Sherwood SE-3 MK III D Synchronous High-Fidelity Phase-Locked AM Product Detector
John Plimmer wrote:
There was also a long thread on this newsgroup that claimed the AOR 7030 had the best sync detector in the business, but I still punt the R8B as the 7030 sync was NOT sideband selectable, which is required for most good listening. Dear John, Contrary to what you write, the AR7030's synchronous detection circuit IS most definitely sideband-selectable and features double-sideband detection as well (so does the Drake R8B). It does not feature a "fixed" sideband selection as does the Drake R8B (or the Drake SW8/Grundig Satellit 800), but rather a "variable" one using the passband tuning. (You can tune the circuit this way as well on the Drake.) A good argument could be made that the Drake's sync circuit thus has more options - but I have found that using the variable selectable sideband on the AR7030 Plus offers much better control. I should think the same would apply to the Drake R8B. You will find the sound to be slightly better and the lock to be somewhat more robust when you tune this way - you use the passband offset at the minimum distance necessary away from true center rather than at some "fixed" offset determined by the factory. (The Drake's circuit will make a low-pitched noise as you tune this way [the AOR's does not] but when you reach the desired passband offset, the noise goes away and the sync circuit stablizes.) Neither of the circuits, however, are "perfect." The Drake circuit often "warbles" (my very poor term but you know what I'm talking about) - especially noticeable on musical notes - as the signal varies in strength. The AOR circuit "hunts" and momentarily "mutes" as a station is changed (NOT, however, when using the free RxWINGS computer-control program). But it then stays "rock-solid" regardless what the signal subsequently does. The AR7030's sync circuit does not "struggle" to maintain lock as does Drake's circuit. AOR's "shortcoming" has been verified to me as being inherent by Richard Hillier of AOR-UK. Drake's "shortcoming" has been verified to me as being inherent by two different service technicians at Drake. PLEASE NOTE that these so-called "shortcomings" are minor in nature in the overall scheme of things and should certainly not be blown out of proportion. Either one of these sync detectors is far better than any other currently being offered today (with the possible exception of that Sherwood SE-3, with which I have no experience - though about which I have read only very good things) and I use both of them - one on my AR7030 Plus and the other on my Grundig Satellit 800 (which uses the same circuit as the Drake R8B, the sole control exception being not offering double-sideband detection). Of the two, I much prefer AOR's. And note this well - I'd rather have SOME sync circuit than NO sync circuit!. Best, Joe P.S. to RHF (after all, it's your post!): Sherwood can install a 455 kHz output on your Drake R8B should you wish to incorporate an SE-3. |
Sherwood SE-3 MK III D Synchronous High-Fidelity Phase-Locked AM Product Detector
HFguy ) writes:
Joe Analssandrini wrote: John Plimmer wrote: There was also a long thread on this newsgroup that claimed the AOR 7030 had the best sync detector in the business, but I still punt the R8B as the 7030 sync was NOT sideband selectable, which is required for most good listening. Dear John, Contrary to what you write, the AR7030's synchronous detection circuit IS most definitely sideband-selectable and features double-sideband detection as well (so does the Drake R8B). It does not feature a "fixed" sideband selection as does the Drake R8B (or the Drake SW8/Grundig Satellit 800), but rather a "variable" one using the passband tuning. (You can tune the circuit this way as well on the Drake.) If your description (above) is technically accurate, the 7030 does not have a 'real' sideband sync' detector because it requires using the passband tuning to select the desired sideband in the double-sideband mode. The sideband sync' detector on the R8B uses phase cancellation for rejecting the unwanted sideband. This is a more effective rejection method than using only passband tuning. But are you arguing semantics, or outcome? Because the phasing method of selectable sideband reception is not as good as the filter method. A filter really knocks out the unwanted sideband, while the phasing method tends to give far less rejection of the unwanted sideband. Michael |
Sherwood SE-3 MK III D Synchronous High-Fidelity Phase-Locked AM Product Detector
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Sherwood SE-3 MK III D Synchronous High-Fidelity Phase-LockedAM Product Detector
Michael Black wrote:
HFguy ) writes: Joe Analssandrini wrote: John Plimmer wrote: There was also a long thread on this newsgroup that claimed the AOR 7030 had the best sync detector in the business, but I still punt the R8B as the 7030 sync was NOT sideband selectable, which is required for most good listening. Dear John, Contrary to what you write, the AR7030's synchronous detection circuit IS most definitely sideband-selectable and features double-sideband detection as well (so does the Drake R8B). It does not feature a "fixed" sideband selection as does the Drake R8B (or the Drake SW8/Grundig Satellit 800), but rather a "variable" one using the passband tuning. (You can tune the circuit this way as well on the Drake.) If your description (above) is technically accurate, the 7030 does not have a 'real' sideband sync' detector because it requires using the passband tuning to select the desired sideband in the double-sideband mode. The sideband sync' detector on the R8B uses phase cancellation for rejecting the unwanted sideband. This is a more effective rejection method than using only passband tuning. But are you arguing semantics, or outcome? Because the phasing method of selectable sideband reception is not as good as the filter method. A filter really knocks out the unwanted sideband, while the phasing method tends to give far less rejection of the unwanted sideband. Michael A sync' detector which implements sideband rejection using the quadrature method (phase shifting) allows the user to select one of two signals (either sideband) which are 180-deg. out of phase. This is a more effective way to reject the unwanted sideband of an AM signal than using *only* passband tuning. In the case of the R8B you can reject the unwanted sideband much better with the selectable sideband sync' than by using just the passband tuning. It occurred to me that we may be talking about different subjects, since you referred to phasing and filtering, which are two methods of bandwidth selection. |
Sherwood SE-3 MK III D Synchronous High-Fidelity Phase-Locked AM Product Detector
Michael Black wrote:
HFguy ) writes: Joe Analssandrini wrote: John Plimmer wrote: There was also a long thread on this newsgroup that claimed the AOR 7030 had the best sync detector in the business, but I still punt the R8B as the 7030 sync was NOT sideband selectable, which is required for most good listening. Dear John, Contrary to what you write, the AR7030's synchronous detection circuit IS most definitely sideband-selectable and features double-sideband detection as well (so does the Drake R8B). It does not feature a "fixed" sideband selection as does the Drake R8B (or the Drake SW8/Grundig Satellit 800), but rather a "variable" one using the passband tuning. (You can tune the circuit this way as well on the Drake.) If your description (above) is technically accurate, the 7030 does not have a 'real' sideband sync' detector because it requires using the passband tuning to select the desired sideband in the double-sideband mode. The sideband sync' detector on the R8B uses phase cancellation for rejecting the unwanted sideband. This is a more effective rejection method than using only passband tuning. But are you arguing semantics, or outcome? Because the phasing method of selectable sideband reception is not as good as the filter method. A filter really knocks out the unwanted sideband, while the phasing method tends to give far less rejection of the unwanted sideband. Michael Both methods have their limits to unwanted sideband rejection. For the filtering method, no physical filter has infinitely steep sides, so closer to carrier, the unwanted sideband rejection can be poor if you do not want to also lose part of the desired sideband. For the phasing method, the unwanted sideband rejection is based upon the accuracy of the phasing network. The better the network, the better the results. So, to say one is better than the other is challenging. If you wish to say one is better than th other, you will need to describe the two specific implementations in great detail. This must include the characteristics of the filters and phasing networks over the range of interest. Deetailed measurements of unwanted sideband rejection vs. frequency would be good to see. craigm |
Sherwood SE-3 MK III D Synchronous High-Fidelity Phase-Locked AM Product Detector
In article , craigm
wrote: Michael Black wrote: HFguy ) writes: Joe Analssandrini wrote: John Plimmer wrote: There was also a long thread on this newsgroup that claimed the AOR 7030 had the best sync detector in the business, but I still punt the R8B as the 7030 sync was NOT sideband selectable, which is required for most good listening. Dear John, Contrary to what you write, the AR7030's synchronous detection circuit IS most definitely sideband-selectable and features double-sideband detection as well (so does the Drake R8B). It does not feature a "fixed" sideband selection as does the Drake R8B (or the Drake SW8/Grundig Satellit 800), but rather a "variable" one using the passband tuning. (You can tune the circuit this way as well on the Drake.) If your description (above) is technically accurate, the 7030 does not have a 'real' sideband sync' detector because it requires using the passband tuning to select the desired sideband in the double-sideband mode. The sideband sync' detector on the R8B uses phase cancellation for rejecting the unwanted sideband. This is a more effective rejection method than using only passband tuning. But are you arguing semantics, or outcome? Because the phasing method of selectable sideband reception is not as good as the filter method. A filter really knocks out the unwanted sideband, while the phasing method tends to give far less rejection of the unwanted sideband. Michael Both methods have their limits to unwanted sideband rejection. For the filtering method, no physical filter has infinitely steep sides, so closer to carrier, the unwanted sideband rejection can be poor if you do not want to also lose part of the desired sideband. For the phasing method, the unwanted sideband rejection is based upon the accuracy of the phasing network. The better the network, the better the results. So, to say one is better than the other is challenging. If you wish to say one is better than th other, you will need to describe the two specific implementations in great detail. This must include the characteristics of the filters and phasing networks over the range of interest. Deetailed measurements of unwanted sideband rejection vs. frequency would be good to see. Like any functional feature in a receiver the effectiveness varies depending on the reception situation. Sometimes shifting the passband or selecting the sideband works best. The Drake just has another tool that the AOR 7030+ does not have and sometimes it make a big difference other times not. -- Telamon Ventura, California |
Sherwood SE-3 MK III D Synchronous High-Fidelity Phase-Locked AM Product Detector
In article .com,
wrote: Telamon wrote: In article , (Michael Black) wrote: HFguy ) writes: Joe Analssandrini wrote: John Plimmer wrote: There was also a long thread on this newsgroup that claimed the AOR 7030 had the best sync detector in the business, but I still punt the R8B as the 7030 sync was NOT sideband selectable, which is required for most good listening. Dear John, Contrary to what you write, the AR7030's synchronous detection circuit IS most definitely sideband-selectable and features double-sideband detection as well (so does the Drake R8B). It does not feature a "fixed" sideband selection as does the Drake R8B (or the Drake SW8/Grundig Satellit 800), but rather a "variable" one using the passband tuning. (You can tune the circuit this way as well on the Drake.) If your description (above) is technically accurate, the 7030 does not have a 'real' sideband sync' detector because it requires using the passband tuning to select the desired sideband in the double-sideband mode. The sideband sync' detector on the R8B uses phase cancellation for rejecting the unwanted sideband. This is a more effective rejection method than using only passband tuning. But are you arguing semantics, or outcome? Because the phasing method of selectable sideband reception is not as good as the filter method. A filter really knocks out the unwanted sideband, while the phasing method tends to give far less rejection of the unwanted sideband. It is not a semantics argument. On the R8B you can pick the side band to listen to and tweak the passband. Often if I am bother by a heterodyne or splash from an adjacent channel I can pick the opposite sideband and the interference is GONE. The AOR7030+ can't do that. When you go for one sideband, you need to select a narrower filter (technically half the bandwidth). This works just fine on the 7030+, used with passband tuning. Also, the 7030 VFO is so steady you can pick USB or LSB, then zero beat it. This works on shortwave, but seems to add a flutter to AM BCB. The Sherwood for sale on ebay may not be functional or in good working shape as it is being sold from a drop off site rather than the user. I have no problem passing on this sale. Usually the passband tuning is all I need to get rid of adjacent channel interference and the AOR7030+ and Drake R8B both have this ability. A neat thing the AOR can do is auto notch a heterodyne tone. Additionally the AOR will track this tone and keep it notched out if it drifts. The Drake has a manual notch that is pretty sharp. I usually don't have to do this because moving the passband usually solves the problem but I have had the situation where I have splash on one side a heterodyne tone from another station on the other sideband so both functions are needed. The AOR 7030+ can auto tune itself to a station and maintains lock on it without intervention and it has the auto notch feature the Drake does not have where the Drake has the sideband selectable sync. Every radio has its pluses and minuses and will work better in some situations, is easier to use, or sound better than other radios. -- Telamon Ventura, California |
Sherwood SE-3 MK III D Synchronous High-Fidelity Phase-Locked AM Product Detector
Telamon wrote: In article .com, wrote: Telamon wrote: In article , (Michael Black) wrote: HFguy ) writes: Joe Analssandrini wrote: John Plimmer wrote: There was also a long thread on this newsgroup that claimed the AOR 7030 had the best sync detector in the business, but I still punt the R8B as the 7030 sync was NOT sideband selectable, which is required for most good listening. Dear John, Contrary to what you write, the AR7030's synchronous detection circuit IS most definitely sideband-selectable and features double-sideband detection as well (so does the Drake R8B). It does not feature a "fixed" sideband selection as does the Drake R8B (or the Drake SW8/Grundig Satellit 800), but rather a "variable" one using the passband tuning. (You can tune the circuit this way as well on the Drake.) If your description (above) is technically accurate, the 7030 does not have a 'real' sideband sync' detector because it requires using the passband tuning to select the desired sideband in the double-sideband mode. The sideband sync' detector on the R8B uses phase cancellation for rejecting the unwanted sideband. This is a more effective rejection method than using only passband tuning. But are you arguing semantics, or outcome? Because the phasing method of selectable sideband reception is not as good as the filter method. A filter really knocks out the unwanted sideband, while the phasing method tends to give far less rejection of the unwanted sideband. It is not a semantics argument. On the R8B you can pick the side band to listen to and tweak the passband. Often if I am bother by a heterodyne or splash from an adjacent channel I can pick the opposite sideband and the interference is GONE. The AOR7030+ can't do that. When you go for one sideband, you need to select a narrower filter (technically half the bandwidth). This works just fine on the 7030+, used with passband tuning. Also, the 7030 VFO is so steady you can pick USB or LSB, then zero beat it. This works on shortwave, but seems to add a flutter to AM BCB. The Sherwood for sale on ebay may not be functional or in good working shape as it is being sold from a drop off site rather than the user. I have no problem passing on this sale. Usually the passband tuning is all I need to get rid of adjacent channel interference and the AOR7030+ and Drake R8B both have this ability. A neat thing the AOR can do is auto notch a heterodyne tone. Additionally the AOR will track this tone and keep it notched out if it drifts. The Drake has a manual notch that is pretty sharp. I usually don't have to do this because moving the passband usually solves the problem but I have had the situation where I have splash on one side a heterodyne tone from another station on the other sideband so both functions are needed. The AOR 7030+ can auto tune itself to a station and maintains lock on it without intervention and it has the auto notch feature the Drake does not have where the Drake has the sideband selectable sync. Every radio has its pluses and minuses and will work better in some situations, is easier to use, or sound better than other radios. -- Telamon Ventura, California I use the notch filter quite often, but unless things have changed, it was an option on the radio. By the time you outfit a 7030 with all the goodies, it costs much more than the Drake R8B did. I never found the noise blanker to be all that useful on the 7030, but it might just be me. |
Sherwood SE-3 MK III D Synchronous High-Fidelity Phase-Locked AM Product Detector
In article . com,
wrote: Telamon wrote: In article .com, wrote: Telamon wrote: In article , (Michael Black) wrote: HFguy ) writes: Joe Analssandrini wrote: John Plimmer wrote: There was also a long thread on this newsgroup that claimed the AOR 7030 had the best sync detector in the business, but I still punt the R8B as the 7030 sync was NOT sideband selectable, which is required for most good listening. Dear John, Contrary to what you write, the AR7030's synchronous detection circuit IS most definitely sideband-selectable and features double-sideband detection as well (so does the Drake R8B). It does not feature a "fixed" sideband selection as does the Drake R8B (or the Drake SW8/Grundig Satellit 800), but rather a "variable" one using the passband tuning. (You can tune the circuit this way as well on the Drake.) If your description (above) is technically accurate, the 7030 does not have a 'real' sideband sync' detector because it requires using the passband tuning to select the desired sideband in the double-sideband mode. The sideband sync' detector on the R8B uses phase cancellation for rejecting the unwanted sideband. This is a more effective rejection method than using only passband tuning. But are you arguing semantics, or outcome? Because the phasing method of selectable sideband reception is not as good as the filter method. A filter really knocks out the unwanted sideband, while the phasing method tends to give far less rejection of the unwanted sideband. It is not a semantics argument. On the R8B you can pick the side band to listen to and tweak the passband. Often if I am bother by a heterodyne or splash from an adjacent channel I can pick the opposite sideband and the interference is GONE. The AOR7030+ can't do that. When you go for one sideband, you need to select a narrower filter (technically half the bandwidth). This works just fine on the 7030+, used with passband tuning. Also, the 7030 VFO is so steady you can pick USB or LSB, then zero beat it. This works on shortwave, but seems to add a flutter to AM BCB. The Sherwood for sale on ebay may not be functional or in good working shape as it is being sold from a drop off site rather than the user. I have no problem passing on this sale. Usually the passband tuning is all I need to get rid of adjacent channel interference and the AOR7030+ and Drake R8B both have this ability. A neat thing the AOR can do is auto notch a heterodyne tone. Additionally the AOR will track this tone and keep it notched out if it drifts. The Drake has a manual notch that is pretty sharp. I usually don't have to do this because moving the passband usually solves the problem but I have had the situation where I have splash on one side a heterodyne tone from another station on the other sideband so both functions are needed. The AOR 7030+ can auto tune itself to a station and maintains lock on it without intervention and it has the auto notch feature the Drake does not have where the Drake has the sideband selectable sync. Every radio has its pluses and minuses and will work better in some situations, is easier to use, or sound better than other radios. -- Telamon Ventura, California I use the notch filter quite often, but unless things have changed, it was an option on the radio. By the time you outfit a 7030 with all the goodies, it costs much more than the Drake R8B did. I never found the noise blanker to be all that useful on the 7030, but it might just be me. I bought the AOR7030+ plus with options and it cost more than the Drake R8B. -- Telamon Ventura, California |
Sherwood SE-3 MK III D Synchronous High-Fidelity Phase-Locked AM Product Detector
craigm wrote: Michael Black wrote: HFguy ) writes: Joe Analssandrini wrote: John Plimmer wrote: There was also a long thread on this newsgroup that claimed the AOR 7030 had the best sync detector in the business, but I still punt the R8B as the 7030 sync was NOT sideband selectable, which is required for most good listening. Dear John, Contrary to what you write, the AR7030's synchronous detection circuit IS most definitely sideband-selectable and features double-sideband detection as well (so does the Drake R8B). It does not feature a "fixed" sideband selection as does the Drake R8B (or the Drake SW8/Grundig Satellit 800), but rather a "variable" one using the passband tuning. (You can tune the circuit this way as well on the Drake.) If your description (above) is technically accurate, the 7030 does not have a 'real' sideband sync' detector because it requires using the passband tuning to select the desired sideband in the double-sideband mode. The sideband sync' detector on the R8B uses phase cancellation for rejecting the unwanted sideband. This is a more effective rejection method than using only passband tuning. But are you arguing semantics, or outcome? Because the phasing method of selectable sideband reception is not as good as the filter method. A filter really knocks out the unwanted sideband, while the phasing method tends to give far less rejection of the unwanted sideband. Michael Both methods have their limits to unwanted sideband rejection. For the filtering method, no physical filter has infinitely steep sides, so closer to carrier, the unwanted sideband rejection can be poor if you do not want to also lose part of the desired sideband. For the phasing method, the unwanted sideband rejection is based upon the accuracy of the phasing network. The better the network, the better the results. So, to say one is better than the other is challenging. If you wish to say one is better than th other, you will need to describe the two specific implementations in great detail. This must include the characteristics of the filters and phasing networks over the range of interest. Deetailed measurements of unwanted sideband rejection vs. frequency would be good to see. craigm One question here is how do you know the Drake is using quadrature techniques to kill the other sideband. You may be selecting a sideband, but again, how do you know how it is selected. I've designed Hilbert transformers for narrow data applications. Getting a good Hilbert transformer for voice grade isn't as easy. The sideband cancelation will only be as good as the Hilbert transformer allows. |
Sherwood SE-3 MK III D Synchronous High-Fidelity Phase-Locked AM Product Detector
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Sherwood SE-3 MK III D Synchronous High-Fidelity Phase-LockedAM Product Detector
craigm wrote:
Michael Black wrote: [...] If your description (above) is technically accurate, the 7030 does not have a 'real' sideband sync' detector because it requires using the passband tuning to select the desired sideband in the double-sideband mode. The sideband sync' detector on the R8B uses phase cancellation for rejecting the unwanted sideband. This is a more effective rejection method than using only passband tuning. But are you arguing semantics, or outcome? Because the phasing method of selectable sideband reception is not as good as the filter method. A filter really knocks out the unwanted sideband, while the phasing method tends to give far less rejection of the unwanted sideband. Michael Both methods have their limits to unwanted sideband rejection. For the filtering method, no physical filter has infinitely steep sides, so closer to carrier, the unwanted sideband rejection can be poor if you do not want to also lose part of the desired sideband. For the phasing method, the unwanted sideband rejection is based upon the accuracy of the phasing network. The better the network, the better the results. So, to say one is better than the other is challenging. If you wish to say one is better than th other, you will need to describe the two specific implementations in great detail. This must include the characteristics of the filters and phasing networks over the range of interest. Deetailed measurements of unwanted sideband rejection vs. frequency would be good to see. craigm With modern circuitry, the phasing networks are near-perfect, with far better effective shape factors than what one gets with even the most expensive physical IF filters. Additionally, a synchronous detector using its own phase shift networks for USB or LSB interference cancellation has a 6 dB S/N advantage over using IF filtration to cancel one sideband. That is because the Q channel contains INTERFERENCE ONLY and virtually NONE of the desired station's audio. The Q channel is in an audio null for the DSB information. Therefore, the phase cancellation works on interference only, and the full phase reinforcement of the desired DSB audio gives you 6 dB stronger desired audio (yes, 6, not 3, because of phase coincidence) than one sideband alone. With all good wishes, -- Kevin Alfred Strom. News: http://www.nationalvanguard.org/ The Works of R. P. Oliver: http://www.revilo-oliver.com Personal site: http://www.kevin-strom.com |
Sherwood SE-3 MK III D Synchronous High-Fidelity Phase-Locked AM Product Detector
craigm ) writes:
But are you arguing semantics, or outcome? Because the phasing method of selectable sideband reception is not as good as the filter method. A filter really knocks out the unwanted sideband, while the phasing method tends to give far less rejection of the unwanted sideband. Michael Both methods have their limits to unwanted sideband rejection. For the filtering method, no physical filter has infinitely steep sides, so closer to carrier, the unwanted sideband rejection can be poor if you do not want to also lose part of the desired sideband. For the phasing method, the unwanted sideband rejection is based upon the accuracy of the phasing network. The better the network, the better the results. But, when the phasing method was common, ie almost fifty years ago, they were using a phasing network that would only be good enough. And I'm sure when the method is used in the less expensive shortwave receivers of today, it's for cost reasons (read simplicity and low parts count) rather than to get improved performance. Yes, in recent years people have done work on the phasing method that uses more complicated phasing networks and which pay attention to detail, but they are no longer simpler. Note that I'm arguing the point because the poster I replied to seemed to be comparing the two methods, and did say the phasing method offered better unwanted sideband rejection, or at least that's the way I read it. Michael |
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