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8th Sep 2006, 10:28 am | #1 |
Hexode
Join Date: Mar 2003
Location: World Heritage Village of Saltaire, Shipley, West Riding of Yorkshire.
Posts: 324
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Short Wave Receiver
Hello.
Getting a bit bored with buying receivers. Have always fancied building a decent short wave receiver covering something like 0.5-30Mhz. It would obviously have to be valve, double conversion with a BFO for SSB reception as well as AM, switched band change (instead of plug in coils) and preferably home made wound coils. Does anyone have any suggestions or a decent Practical Wireless/Radio Constructor design? My favourite radio author is F.G. Rayer, would prefer one of his designs. If it took a year or 10 years to build it would not matter. Regards Paul |
8th Sep 2006, 11:53 am | #2 |
Retired Dormant Member
Join Date: May 2005
Location: Aarhus, Denmark
Posts: 281
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Re: Short Wave Receiver
Well, the classis solution would be to make a copy of one of the HBR receiver variations. Not sure though if it is band switched. That basic design comes highly praised, even today, and should be relatively simple to find parts for and get going. I have no personal experience with it though.
Please note that the previous link is to the qsl.net server, which is ridiculously overbooked these days and thus slower than frozen tar to respond to external stimuli. Google cache of the main page. Frank N. |
8th Sep 2006, 12:30 pm | #3 |
Nonode
Join Date: Jun 2005
Location: Western Lake District, Cumbria (CA20) - UK
Posts: 2,136
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Re: Short Wave Receiver
Hi Paul,
I've got a fairly comprehensive collection of RCs including several of the designs they published for comms recievers. It is an idea I have been toying with for some time. I'll have a look when I get home and if you like I can let you have photocopies (no working scanner I'm afraid) of the articles. PM me if interested. Regards,
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8th Sep 2006, 1:18 pm | #4 |
Hexode
Join Date: Mar 2003
Location: World Heritage Village of Saltaire, Shipley, West Riding of Yorkshire.
Posts: 324
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Re: Short Wave Receiver
Hello Brian.
Have sent you a PM. Regards Paul |
8th Sep 2006, 6:57 pm | #5 |
Dekatron
Join Date: Jan 2006
Location: Ramsbottom (Nr Bury) Lancs or Bexhill (Nr Hastings) Sussex.
Posts: 5,814
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Re: Short Wave Receiver
Hi Paul. Hope you got those PW photo copies ok. Re your circuit request have you already got a switched coil pack otherwise you might struggle!
A quick glance at my Radio Constructors has only brought up one Rayer so far ie B Spread 4 valve [unganged rf/osc caps] wearite coils and only 6.5-32 megs for some reason-Oct 68. There's an 11 valve D Con set that meets your spec in Nov 63 but it uses a Denco Coil Turrett. [F Baldwin]. Top of the range in July 68 "High Performance D Conversion Communications Receiver" [R Murray-Shelley BSc] but it uses an Electroniques front end. You have a lot of bits to collect for these. Have you seen the Mike Miller Site [Capstone Valley]. In his radio section he shows a picture of his 5 Valve All wave RX Radio Constructor April/69 set which he has expanded over the years, It's very interesting. He seems to have added an RF stage and then a 2nd IF and other bits but it's plug in coils I'm afraid. Cheers Dave |
8th Sep 2006, 7:22 pm | #6 |
Retired Dormant Member
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Location: Bishop's Waltham, Hants, UK.
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Re: Short Wave Receiver
Hi Paul,
you could also consider teh G2DAF design that was serialised in Radcom, and later published in, I think, the RSGBs "Radiocommunication Handbook" (older editions). Jim. |
8th Sep 2006, 7:44 pm | #7 |
Dekatron
Join Date: Jan 2006
Location: Ramsbottom (Nr Bury) Lancs or Bexhill (Nr Hastings) Sussex.
Posts: 5,814
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Re: Short Wave Receiver
There was a seperate "mini-book" about the G2DAF when I was fouteen but I've never got near one. At least you can make your own coils for this monster [ 20 valves] according to the RSGB Handbook 3rd Edition! There's also a [relatively] simple G3LOK design shown but with a 2.1 meg first IF. Dave
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8th Sep 2006, 10:41 pm | #8 | |
Rest in Peace
Join Date: Jun 2006
Location: Chard, South Somerset, UK.
Posts: 7,457
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Re: Short Wave Receiver
Quote:
Building a receiver to cover the freq. range you specify with all the other "desirable attributes" - and get a good result - is no mean task! It may be better for you to buy an old well-known make of such a receiver - e.g. an Eddystone - and renovate it. By the time that various Rs and Cs have been replaced, valves checked, unit re-aligned / calibrated, performance check (sig./noise, sensitivity etc.), cabinet cleaned up - plus possible repairs to the tuning mechanics - you can have a fair bit of work on your hands! And you should end up with a receiver that satisfies your need. The biggest problems to be overcome in home-designed / built receivers are freq. drift, instability, reasonably constant sensitivity with freq. and spurious responses. And a decent tuning mechanism. All these are taken care of in a good "factory" design. BTW The G2DAF receiver is a very fine example of what the home constructor can achieve. But it is a complicated beast! NOT for the faint-hearted! Just a thought. Al. |
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9th Sep 2006, 10:05 am | #9 |
Hexode
Join Date: Mar 2003
Location: World Heritage Village of Saltaire, Shipley, West Riding of Yorkshire.
Posts: 324
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Re: Short Wave Receiver
Hi Al and Dave
I do have a number of Eddystone receivers (10 I think) but still fancy having a go at building a decent short wave receiver. I honestly think I am going past the stage of just buying old receivers, doing them up and just putting them on a shelf? Regarding the comments by you and Dave on the G2DAF, I have studied this for years, ever since I bought the fourth edition of the RSGB handbook in 1968 (just shows how long I have had this yearning). The problem is that whilst my first love has always been Amateur radio (SWL) I would probably like “My” radio to be more than just a ham band receiver (although not too sure why as I only listen to Amateurs), although Band Spread on the ham bands would be nice and to be honest the G2DAF is probably far to complex for my capabilities! I did however find someone on the Internet who had built two of them in recent times. When you see a picture of a G2DAF wouldn’t we all like to say we had built that? Regarding the G3LOK receiver, I have been studying this a lot recently, it is better than the G3RKK published in the fourth edition as this has a pre built front end (Electroniques type QP166), which is now no doubt unobtainable. Regards Paul |
9th Sep 2006, 2:38 pm | #10 |
Dekatron
Join Date: Jan 2006
Location: Ramsbottom (Nr Bury) Lancs or Bexhill (Nr Hastings) Sussex.
Posts: 5,814
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Re: Short Wave Receiver
I have seen electroniques front ends advertised quite recently [on a well known site last year]. There is a page re that company on somebody's website! I've got one in a SW Mag Rx design. [I didn't build it]. Some people get bits and pieces like that just by advertising a need although I've encountered one or two who took advantage [in my opinion] of others. It does seem that there are more people out there than you would imagine still banging out G2DAF's and the other classic designs. I admire your ambition but why not start with a front end and feed the IF into something ready built! Dave W
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9th Sep 2006, 6:00 pm | #11 |
Hexode
Join Date: Mar 2003
Location: World Heritage Village of Saltaire, Shipley, West Riding of Yorkshire.
Posts: 324
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Re: Short Wave Receiver
The G2DAF, G3LOK(3rd edition) and G3RKK(4th edition) were only described in a few pages in the RSGB Manual. Were there more detailed build information given in the RSGB magazines? I joined the RSGB in about 1967 so obviously would have missed out on these issues. Must admit to having a liking to the looks of the G3LOK, very Eddystone I think.
Regards Paul |
9th Sep 2006, 7:06 pm | #12 | |
Rest in Peace
Join Date: Jun 2006
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Re: Short Wave Receiver
Quote:
Well, if you do decide to go the whole hog on this, I wish you well! I suppose it all depends on how much time you can devote to such an advanced project. Plus the cost. Plus the test gear to set it all up properly. For myself, I simply settle for restoring / updating Eddystones plus the venerable Racal RA-17 et al. (Although I wouldn't turn away a tidy Collins KWM, or a Hallicrafters HQ180X, mind you! ). And then using them. Regards, Al. |
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9th Sep 2006, 7:17 pm | #13 | |
Rest in Peace
Join Date: Jun 2006
Location: Chard, South Somerset, UK.
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Re: Short Wave Receiver
Quote:
Your comment there sums up my viewpoint on home construction (& design) of a SW RX to meet the outline spec. you provided, plus the necessary performance that is going to be required for anything really serious. That's why I take my approach! The G2DAF and comparable receivers - e.g. the Racal, and similar USA-origin radios - are not highly complex beasts just for the sake of it! Really good performance comes with its own price. Al. Last edited by Skywave; 9th Sep 2006 at 7:18 pm. Reason: Add italicisation for effect |
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9th Sep 2006, 7:39 pm | #14 |
Retired Dormant Member
Join Date: Apr 2003
Location: Salt Spring Island, BC, Canada
Posts: 368
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Re: Short Wave Receiver
A nice feature in a home brew receiver is to use the Eddystone system of locating where you are on the highest frequency band (15-30 mcs ?) by zero beating to a 1mcs crystal, and then tuning the 1st IF over a spread of 1 mc.
That way you know your freqency accurately. John. |
9th Sep 2006, 11:42 pm | #15 | |
Hexode
Join Date: Mar 2003
Location: World Heritage Village of Saltaire, Shipley, West Riding of Yorkshire.
Posts: 324
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Re: Short Wave Receiver
Quote:
Regards Paul |
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10th Sep 2006, 8:25 am | #16 |
Retired Dormant Member
Join Date: May 2005
Location: Aarhus, Denmark
Posts: 281
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Re: Short Wave Receiver
Paul,
Maybe I missread your first posting, seems from your later comments that I did. I was reading 'ham band receiver', where you apparently want 0.5-30MHz general coverage. Just goes to show what happens when you look at the world through the haze of your own ideas. But - to my knowledge - there is no cookie cutter DIY design out there for a general coverage shortwave valve receiver, assuming it should have decent performance. So either you will have to reverse engineer one of the commercial designs, like the RA-17 just mentioned, or perhaps the American R-390[a]. The design, component requirements and test equipment needed to replicate a GC receiver is simply daunting to a degree, where it would make little sense to publish an article on such a monster. Few DIYers would be able to replicate it, much less getting it to work properly. Hope someone will prove me wrong on this though. Frank N. |
10th Sep 2006, 9:10 am | #17 | |
Rest in Peace
Join Date: Jun 2006
Location: Chard, South Somerset, UK.
Posts: 7,457
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Re: Short Wave Receiver
Quote:
I feel that I must respond to some of that. 1. Agreed: with the proviso that what you are "listening to " doesn't become irritating because of all the inevitable short-comings and annoying "idiosyncracies" that could arise! 2. Nice to know that you have so much "time to kill"! 3. The comment by YC-156: "The design, component requirements and test equipment needed to replicate a GC receiver is simply daunting to a degree, where it would make little sense to publish an article on such a monster. Few DIYers would be able to replicate it, much less getting it to work properly". That says it all. Further comment not needed. 4. Restoration is only "easy" in comparison. It is not necessarily "easy" within itself. 5. Agreed - although there are some of us who are still very keen on building / designing our own kit, and occasionally do. Again, time is a significant factor here. However, I wish you luck in your venture! As it proceeds, please let us know how you get on. Regards, Al. |
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10th Sep 2006, 12:29 pm | #18 |
Dekatron
Join Date: Jan 2006
Location: Ramsbottom (Nr Bury) Lancs or Bexhill (Nr Hastings) Sussex.
Posts: 5,814
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Re: Short Wave Receiver
Paul-further to your question at 6pm yesterday [I don't know how to highlight it and bring it forward I'm afraid] I thought it very likely that the Bulletin had published what you suggested. A quick trawl has brought up
the G3RKK Receiver Mk 2 March 1966 and the original which was July 63. I shall look further but up until Jan 64 the Bulletin cover was adverts rather than the more helpfull picture of a major constructional feature which was the practise for quite a few years and which makes searching a bit easier. I'll look at the SWM's as well. I have been interested to read the comments of our technical contributors. Whilst I'm very interested in the literature and history of receiver design and have been reading it up for years my actual constructional experience and level of technical knowledge is low so don't assume I'm on a par with your other, obviously very experienced, contributors please. Dave. |
10th Sep 2006, 1:43 pm | #19 |
Dekatron
Join Date: Feb 2005
Location: St.Ippolyts, Hitchin, Hertfordshire QRA IO91UW
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Re: Short Wave Receiver
Might be worth studying the Denco hf rx circuit - the theory is that this RX covers all HF bands.
Sadly designed using Denco coils, which will cost a small fortune to get the full set needed for a proper dual conversion design..... Cheers Sean
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10th Sep 2006, 4:04 pm | #20 |
Nonode
Join Date: Jun 2005
Location: Western Lake District, Cumbria (CA20) - UK
Posts: 2,136
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Re: Short Wave Receiver
I've sorted through the RCs and found half a dozen or so useful designs including some by the inimitable Mr Rayer.
Paul, I've e-mailed a list and basic details so let me know if you like the look of any of them. I can send the list to anyone else who wants it if you PM me. I really must get a working scanner one of these days! Regards,
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Brian |