RSGB RadCom K3 review posted on RSGB Members web page
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RSGB RadCom K3 review posted on RSGB Members web page
 
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The numbers reported below are close to what I would expect if the 2.7 kHz and
500 Hz column labels were accidentally switched. Typo maybe? Doug N0HH ========================================================================= Yes something isn´t right. This was his measurements: CLOSE-IN INTERMODULATION ON 7MHz band,500Hz bandwidth, CW preamp off 2.7 kHz roofing 1.8 kHz roofing 500 Hz roofing 2kHz +19dBm 101dB +12.5dBm 96dB +2.5dBm 88dB 3kHz +19dBm 101dB +12.5dBm 96dB +2.5dBm 88dB 5kHz +22dBm 103dB +12.5dBm 96dB +8.5dBm 92dB 7kHz +22dBm 103dB +12.5dBm 96dB +13dBm 95dB 10kHz +22dBm 103dB +12.5dBm 96dB +17.5dBm 98dB 15kHz +22dBm 103dB +12.5dBm 96dB +22dBm 101dB 20kHz +22dBm 103dB +12.5dBm 96dB +25dBm 103dB 30kHz +22dBm 103dB +12.5dBm 96dB +26.5dBm 104dB 40kHz +22dBm 103dB +12.5dBm 96dB +27dBm 104dB 50kHz +22dBm 103dB +12.5dBm 96dB +27dBm 104dB _______________________________________________ Elecraft mailing list Post to: [hidden email] 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 |
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I have Radcom in front of me. The editor has two reviews, the K3 and a new Alinco hand held. I suppose it shows the state of amateur radio in the UK that the hand held makes the front cover. The K3 reviews very well indeed.
So... to your figures. The 500Hz filter is 8 dB worse than the 2.7 kHz filter out of band but at close spacings. According to the review it suffers non-linearites not noted in the 2.7kHz stock filter nor the 8 pole INRAD the 400Hz filter. These showed odd properties with tone spacing that makes me think it was the DSP responding to the wider skirts of the 5 pole 500Hz filter but maybe that particular filter had a fault, it happens with crystals. Even so 88 dB dynamic range at 2kHz is not at all bad. I am sure the experts can explain this behaviour but for now I think it might be better to order an 8 pole 400Hz filter than a 5 pole 500Hz one - you will be able to sleep better. Mike
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Re: RSGB RadCom K3 review posted on RSGB Members web page
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Administrator
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Looks like he clearly had a bad 500 Hz filter. It does not match our
measurements here or Sherwood's. We'll make sure the customer gets a replacement. We were not contacted prior to publication so we were unable to replace it ahead of time. Also, their TX tests were incorrectly run at 120W instead of at our spec limit of 100w. TX IMD will degrade at least 5 dB at 120W. That's there for the CW guys ;-) 73, Eric WA6HHQ ---- AD6XY - Mike wrote: > So... to your figures. The 500Hz filter is 8 dB worse than the 2.7 kHz > filter out of band but at close spacings. According to the review it suffers > non-linearites not noted in the 2.7kHz stock filter nor the 8 pole INRAD the > 400Hz filter. These showed odd properties with tone spacing that makes me > think it was the DSP responding to the wider skirts of the 5 pole 500Hz > filter but maybe that particular filter had a fault, it happens with > crystals. Even so 88 dB dynamic range at 2kHz is not at all bad. > > I am sure the experts can explain this behaviour but for now I think it > might be better to order an 8 pole 400Hz filter than a 5 pole 500Hz one - > you will be able to sleep better. > > Mike > > > > > Elecraft mailing list Post to: [hidden email] 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: RSGB RadCom K3 review posted on RSGB Members web page
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At 02:44 PM 6/18/2008, Eric Swartz - WA6HHQ, Elecraft wrote:
>Looks like he clearly had a bad 500 Hz filter. It does not match our >measurements here or Sherwood's. We'll make sure the customer gets >a replacement. Just curious - do you guys check filters before shipping them? Most of us out here wouldn't have a clue if we had a bad filter - we would just suffer with poor performance without ever knowing why. Jerry W4UK _______________________________________________ Elecraft mailing list Post to: [hidden email] 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 |
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In reply to this post by AD6XY
NOT SO...G3SJX only tested the 2.7k, 1.8k and a 500...NOT a 400. He was speculating about the 400 because Sherwood and ARRL had good measurements with one (Sherwood had nearly identical IMD measurements with the 500 which I posted previously - below). There's another problem with the 1.8k data which also looks bad. Sorry but I trust Elecraft/Sherwood's published measurements of the 400/500 listed below. Peter may have had both a bad 1.8k and 500. http://mailman.qth.net/pipermail/elecraft/2008-June/091593.html http://mailman.qth.net/pipermail/elecraft/2008-June/091606.html 73, Bill |
RE: RSGB RadCom K3 review posted on RSGB Members web page
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Let's stop speculating.
Did anybody talk to the guy? 73, Arie PA3A _______________________________________________ Elecraft mailing list Post to: [hidden email] 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: RSGB RadCom K3 review posted on RSGB Members web page
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Administrator
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In reply to this post by Jerry Flanders
The spec difference is almost impossible to detect in normal usage. It
takes very clean lab signal generators to test. We're talking about extreme signals that might just start to cause barely noticeable IMD in the 'bad' filter. Even the 'bad' filter IMD is better than most other rigs on the market. It just looks like a one off failure. (This can happen in any xtal filter from any mfg.) 73, Eric Jerry Flanders wrote: > At 02:44 PM 6/18/2008, Eric Swartz - WA6HHQ, Elecraft wrote: >> Looks like he clearly had a bad 500 Hz filter. It does not match our >> measurements here or Sherwood's. We'll make sure the customer gets a >> replacement. > > Just curious - do you guys check filters before shipping them? Most of > us out here wouldn't have a clue if we had a bad filter - we would > just suffer with poor performance without ever knowing why. > > Jerry W4UK Elecraft mailing list Post to: [hidden email] 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 |
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In reply to this post by Bill W4ZV
The wonders of English. It depends how you read "according to the review". In any case we now know it was a flawed filter or (if you are right about the 1.8k) perhaps a problem in the IF of that particular K3. The faulty 500Hz filter at 40kHz spacing has a 3rd order intercept of +27 dBm !!!! Just what we need over here in Europe to counter the broadcast signals just above 7.1 MHz. I take Eric's point about the power measurements but I speculate most operators (but obviously excluding all elecraft owners and QRPers who would never dream of doing such a thing) tune their transmitters for maximum power in attempting to crack a pile-up or for a contest. It is a fair assessment of what it could sound like on air, in the worst hands and it is still very good. Mike |
Re: RSGB RadCom K3 review posted on RSGB Members web page
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In reply to this post by AD6XY
On Wed, 18 Jun 2008 11:14:07 -0700 (PDT), AD6XY - Mike wrote:
> > I have Radcom in front of me. The editor has two reviews, the K3 and a new > Alinco hand held. I suppose it shows the state of amateur radio in the UK > that the hand held makes the front cover. More the need for advertising revenue, I suspect... 73 Stewart G3RXQ _______________________________________________ Elecraft mailing list Post to: [hidden email] 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 |
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In reply to this post by Eric Swartz - WA6HHQ
Eric Swartz - WA6HHQ, Elecraft wrote:
>Looks like he clearly had a bad 500 Hz filter. It does not match our >measurements here or Sherwood's. We'll make sure the customer gets a >replacement. > >We were not contacted prior to publication so we were unable to replace >it ahead of time. > Like the ARRL review, this one was very much a first shot - and as we all well know, the K3 is a moving target. A few words about Radcom reviews may help put this into perspective. Availability of new models is typically several months behind the USA, and quite frequently the QST review is already in print before a reviewer in Europe can even lay hands on the hardware. This puts reviewers under intense time pressure. On receiving the equipment, the reviewer has a very short time to make some basic functional checks, just to confirm that the equipment is fit to be reviewed. More than once, I have rejected equipment at this point, and I'm sure Peter Hart has too. But once a reviewer commits himself to the magazine's production schedule, the process cannot be stopped. If subtle issues emerge from the detailed measurements, the reviewer will report whatever he sees. The issue about the 500Hz filter was one of that kind, and I don't believe it was dealt with unfairly. All parties agree that it would be extremely hard to spot by a normal user. The problem does need to be investigated - was it confined to that individual filter, or could it affect any or all of them... or is there a measurement problem? - but all that needs to be done on a much longer and more (ahem) measured timescale. The reason Elecraft didn't make the front cover seems perfectly simple - no dark conspiracy but simply that Alinco provided superb photo artwork that no editor could possibly resist. Sorry, folks, but editors of radio magazines see far too many pictures of black boxes with glowing displays... >Also, their TX tests were incorrectly run at 120W instead of at our >spec limit of 100w. TX IMD will degrade at least 5 dB at 120W. That's >there for the CW guys ;-) > Equally important would be that Peter's editorial deadline (which is the same as mine) would have been before the major firmware update that considerably improved the SSB performance. It's pretty certain that he didn't try any upgrades himself, or else he'd surely have mentioned how simple it is. All of these issues could perhaps be addressed in a "10,000 mile report" sometime down the road. (I'll be away now until Tuesday. Mike - listen out for me in Abingdon... you won't need a radio :-) -- 73 from Ian GM3SEK 'In Practice' columnist for RadCom (RSGB) http://www.ifwtech.co.uk/g3sek _______________________________________________ Elecraft mailing list Post to: [hidden email] 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: RSGB RadCom K3 review posted on RSGB Members web page
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In reply to this post by Douglas G. Bonett
Stewart I agree with you.
I haven't completely read the RSGB K3 review yet. But I think I will trust the ARRL results, Bob Sherwood's and those of Elecraft more than those of the 'RSGB'. 73 Rob G3RCE --------------------- Stewart G3RXQ said: More the need for advertising revenue, I suspect... --------------------- _______________________________________________ Elecraft mailing list Post to: [hidden email] 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 |
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In reply to this post by gm3sek
Ian and All,
While I agree with much of what you say, and I sympathize with the various issues, I can't quite agree that it necessarily is a "good reason" for everything. First of all, U.K. stations had the same access to K3's as U.S. stations did. Indeed, many U.K. bound units were included in the early shipments. But Elecraft's production delays does make it extremely complex to get a unit on any kind of a predictable timeline. If Radcom intended to review the K3 (and I would assume they should have been interested from day 1), they should have probably been quicker off the mark to get a unit in the "Que", unless they were willing to delay review until they had proper time to do it right. I'm not saying Peter did it wrong--indeed his review may be quite accurate based on the radio he had--but saying he didn't have enough time suggests a hurried review. It seems to me that any committment to make such a review should be predicated on having sufficient time to do it properly. If Radcom wants it done earlier, they should insure access to a unit on a timely basis. The timing should not be the sole responsibility of the author. I also don't understand why any review (QST, Radcom, or otherwise) would be done without allowing sufficient time for communication with the manufacturer in case problems arise. Now, if the manufacturer doesn't cooperate, so be it. But I assume Elecraft, or any manufacturer, would want to be consulted about any claimed specifications not achieved. The need to work with the manufuacturer should be disclosed, as it says something about the status of "production units", but the long term benefit of the review really depends on disclosing whether or not claimed specifications are achievable, and what it took to get there. After all, the problem could possibly be on either end. In short, I think any review that is "rushed" due to time constraints is of limited value. I'm not being naive' about deadlines, but deadlines must be imposed reasonably. I also think that a review should be something that is updatable. If issues occur, which are subsequently resolved, I think it's good practice to disclose them on a timely basis in a subsequent issue, including how it was achieved. Buyers rely heavily on such reviews, and I would think it is in everyone's interest to do them as completely as possible. And they shouldn't "pull any punches" either. I hate it when reviewers seem to "gloss" around certain issues. If it doesn't perform as advertised, say so!!! Dave W7AQK ----- Original Message ----- From: "Ian White GM3SEK" <[hidden email]> To: <[hidden email]> Sent: Thursday, June 19, 2008 12:21 AM Subject: Re: [Elecraft] RSGB RadCom K3 review posted on RSGB Members web page >> > Like the ARRL review, this one was very much a first shot - and as we all > well know, the K3 is a moving target. > > A few words about Radcom reviews may help put this into perspective. > Availability of new models is typically several months behind the USA, and > quite frequently the QST review is already in print before a reviewer in > Europe can even lay hands on the hardware. This puts reviewers under > intense time pressure. > > On receiving the equipment, the reviewer has a very short time to make > some basic functional checks, just to confirm that the equipment is fit to > be reviewed. More than once, I have rejected equipment at this point, and > I'm sure Peter Hart has too. But once a reviewer commits himself to the > magazine's production schedule, the process cannot be stopped. If subtle > issues emerge from the detailed measurements, the reviewer will report > whatever he sees. > 73 from Ian GM3SEK 'In Practice' columnist for RadCom (RSGB) > http://www.ifwtech.co.uk/g3sek > _______________________________________________ > Elecraft mailing list > Post to: [hidden email] > 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: [hidden email] 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: RSGB RadCom K3 review posted on RSGB Members web page
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Overall I am very pleased with the review that Peter produced.
Having chided him somewhat over the lack of a K2 review, I and others pushed him quite hard towards producing one for the K3. Given that the K3 is quite a different beast to the Far East Black Boxes he normally reviews, the end result IMHO is quite good. I don't know where, given the continual changes in the K3 development/manufacturing timeline would be a better place to conduct a review. I don't think the RadCom (RSGB) has had any interest either way in the K3 review, other than to provide an interesting read for the membership. As has been said before the RSGB does not purchase radios anonymously, the reviewer is normally loaned them by a dealer. The K3 review is very different in that this time the unit came from a user. Probably this approach is better at showing the rig, warts and all. 73 Stewart G3RXQ On Thu, 19 Jun 2008 05:49:29 -0700, David Yarnes wrote: > Ian and All, > > While I agree with much of what you say, and I sympathize with the various > issues, I can't quite agree that it necessarily is a "good reason" for > everything. > > First of all, U.K. stations had the same access to K3's as U.S. stations > did. Indeed, many U.K. bound units were included in the early shipments. > But Elecraft's production delays does make it extremely complex to get a > unit on any kind of a predictable timeline. If Radcom intended to review > the K3 (and I would assume they should have been interested from day 1), > they should have probably been quicker off the mark to get a unit in the > "Que", unless they were willing to delay review until they had proper time > to do it right. I'm not saying Peter did it wrong--indeed his review may be > quite accurate based on the radio he had--but saying he didn't have enough > time suggests a hurried review. > > It seems to me that any committment to make such a review should be > predicated on having sufficient time to do it properly. If Radcom wants it > done earlier, they should insure access to a unit on a timely basis. The > timing should not be the sole responsibility of the author. > > I also don't understand why any review (QST, Radcom, or otherwise) would be > done without allowing sufficient time for communication with the > manufacturer in case problems arise. Now, if the manufacturer doesn't > cooperate, so be it. But I assume Elecraft, or any manufacturer, would want > to be consulted about any claimed specifications not achieved. The need to > work with the manufuacturer should be disclosed, as it says something about > the status of "production units", but the long term benefit of the review > really depends on disclosing whether or not claimed specifications are > achievable, and what it took to get there. After all, the problem could > possibly be on either end. > > In short, I think any review that is "rushed" due to time constraints is of > limited value. I'm not being naive' about deadlines, but deadlines must be > imposed reasonably. I also think that a review should be something that is > updatable. If issues occur, which are subsequently resolved, I think it's > good practice to disclose them on a timely basis in a subsequent issue, > including how it was achieved. Buyers rely heavily on such reviews, and I > would think it is in everyone's interest to do them as completely as > possible. And they shouldn't "pull any punches" either. I hate it when > reviewers seem to "gloss" around certain issues. If it doesn't perform as > advertised, say so!!! > > Dave W7AQK > > ----- Original Message ----- > From: "Ian White GM3SEK" <[hidden email]> > To: <[hidden email]> > Sent: Thursday, June 19, 2008 12:21 AM > Subject: Re: [Elecraft] RSGB RadCom K3 review posted on RSGB Members web > page > > >> Like the ARRL review, this one was very much a first shot - and as we all >> well know, the K3 is a moving target. >> >> A few words about Radcom reviews may help put this into perspective. >> Availability of new models is typically several months behind the USA, and >> quite frequently the QST review is already in print before a reviewer in >> Europe can even lay hands on the hardware. This puts reviewers under >> intense time pressure. >> >> On receiving the equipment, the reviewer has a very short time to make >> some basic functional checks, just to confirm that the equipment is fit to >> be reviewed. More than once, I have rejected equipment at this point, and >> I'm sure Peter Hart has too. But once a reviewer commits himself to the >> magazine's production schedule, the process cannot be stopped. If subtle >> issues emerge from the detailed measurements, the reviewer will report >> whatever he sees. >> >> 73 from Ian GM3SEK 'In Practice' columnist for RadCom (RSGB) >> http://www.ifwtech.co.uk/g3sek >> _______________________________________________ >> Elecraft mailing list >> Post to: [hidden email] >> 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: [hidden email] > 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: [hidden email] 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 |
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