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25lc256 /1024mikeb26/08/10  03:37 pm
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bruce
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Post Number: 403
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Posted on Monday, 16 August, 2010 - 11:48 pm:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

I've long been interested in radio reception, in the sense of using radio as a link ( I'm not remotely interested in radio communication in the radio-ham sense ). I do realise that nowadays you can make a radio link with 433MHz modules, but I still want to understand the workings of superhet receivers as they used to be done for AM.
What I'm particularly interested in learning is the theory of IF transformer design ( the guts of the receiver ). I've scoured Google and there are only 2 sites which even touch on it, but the information is fragmentary and contradictory.
The next recourse is to buy a text-book. However, I've been stung many times buying text-books on Amazon only to find they're nothing that I expected. With these text-books fetching 50-70 quid, I'm not risking it.
Not many CZ users are interested in radio AFAICT,
but does anyone have any pointers or know something I dont?

Regards
bruce
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terrym
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Posted on Tuesday, 17 August, 2010 - 03:38 am:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

The best way, to my mind, of getting this information, is to get your hands on an older RSGB or ARRL Radio Handbook.

Yes this is amateur radio stuff, but they do explain, with the theory, all about superhet receivers, if's etc.

Oh, the IF transformer is not 'the guts of the receiver', it is but one part of a superhet.

I put 'if transformer design' (without quotes) into google - approx 284,000 entries. A lot have nothing to do with if transformers per se, but I found a lot more than 2 that did, so what search terms were you using?

TM
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bruce
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Post Number: 405
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Posted on Tuesday, 17 August, 2010 - 09:04 am:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

Hello Terry,
I used almost every combination imaginable of
" IF, transformer, can, strip " and so on. You do get lots of hits, but most of them are junk. I only found 2 that tackled the IF transformer in anything but a superficial way.

I like the idea of the ARRL book and I'll give it a try.

Bruce
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oz1lqb
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Posted on Tuesday, 17 August, 2010 - 12:16 pm:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

Hi Bruce..
if you need a very good book telling what goes
on in a circuit have a look at
Experimental Methods in Radio Frequency Design
it is a very nice book from ARRL.
if i remember correct i paid 35£ on ebay for a
brand new one
all the best from OZ1LQB / Claus
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atferrari
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Posted on Wednesday, 18 August, 2010 - 09:10 am:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

Since a long time now, the ARRL book just give correct definitions not going too much into details that would allow you to recognize much of what it talks about in real circuits.

I bought three of them (and put my hands on on several more) along my life as a radio ham.

Less and less they were actually involved in details.

Just for the concept, go there. But later you will ask yourself if paying dearly such a big book just to read maybe half of a page was worth it.

I have the feeling the Experimental Methods in Radio Frequency Design as suggested by Claus should give MUCH MORE of what you want.

In Spanish we use to say: El que mucho abarca, poco aprieta.

I wonder if nowadays trying to get some info from traditional manufacturers of IF trafos amongst other things (TOKO?) would help...

Not to derail this thread, I always tried to find any consistency in TOKO's scheme of numbering and naming their products. Never could find any "master" catalog and they seem to keep discontinuing their products along the time in a regular basis.

Just check any circuit using their stuff. Then try to get them just in a catalog. Hard to.
Agustín Tomás - Buenos Aires - Argentina
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bruce
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Posted on Wednesday, 18 August, 2010 - 09:24 am:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

Atferrari,
Thanks for that: I've always had a suspicion myself that the ARRL books didnt really go into the sort of fine detail I want. I'll try and locate the other book you mentioned.
Let me give you a flavour of the problem: IF transformers ( stick with 455KHz for now ) have a split primary and a secondary. Why? It's to do with BW, but the only reference to it is a Dutch site and the explanation is unfollowable. The turns ratio is, I believe, an impedance matching device. Have you seen the number of different turns-ratios out there? I want to know what's going on.
Ideally, I'd like to wind my own cans rather than rely on something designed for a totally different circuit. I need a more thorough mathematical treatment; the sort you get in 'Art of Electronics'. The available sources seem to be either mathematically trivial ( ARRL ) or degree level physics.

Bruce
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dave_squibb
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Posted on Wednesday, 18 August, 2010 - 10:41 am:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

Many years ago I worked for a company that made coils and transformers, including IF transformers.
The RF design guy was a very clever chap and a lot of what he did was regarded as a bit of a black art.
The company eventually lost most of that side of the business to the far east and when the Designer retired he was never replaced. When he died some years later all of that knowledge was lost for good..

A familiar story these days unfortunately.

I've just looked at my RSGB handbook from 1970 ish but it doesn't go into the sort of detail you are looking for.

This may help:

http://my.integritynet.com.au/purdic/if-amplifier-filters.htm

(Message edited by dave_squibb on 18 August, 2010)
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mikeb
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Posted on Wednesday, 18 August, 2010 - 11:45 am:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

I think I know what you are getting at Bruce.

I have a little booklet Coil Design and Construction Manual by B.B Babani.

It contains equations, design information and is intended for constructors. I would say about 1945 and is valve orientated, but clear and simple, with easy maths.

Probalby no more than £4 today.
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mikeb
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Posted on Wednesday, 18 August, 2010 - 11:48 am:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

oh... just noticed isbn 0-85934-050-3 £2.50.

rgds

mb
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mikeb
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Posted on Wednesday, 18 August, 2010 - 11:57 am:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

the book also refers to R E Blakey Radio and Telecommunications Design Manual) - thats a beast and may need ordering from the Library.

rgds

mb
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hackinblack
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Posted on Wednesday, 18 August, 2010 - 03:10 pm:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

either of the two books (pt1,pt2)called 'electronic servicing' by Ian Sinclair will give you the basics of receiver design,albeit in 'block' schematics.
or some of the ancient babani paperbacks on radio or coil design

i have some of clive sinclairs radio books from the mid sixties which i will be ebaying soon to lighten the load
along with a 1962 RSGB handbook,which unlike the modern copies,actually has build-it-yourself details...

the ARRL books are much more up to date and useful for data charts etc too;your local library should have(or get!)a copy,

though,last time i went,they had sold off almost all of their tech books;meaning i had more in my library than them
what an incredibly short-sighted decision
most of this information ISN'T on the web,and now never will be...
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bruce
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Posted on Wednesday, 18 August, 2010 - 04:50 pm:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

Hello everyone,
I went to the central lending library today. Predictably there were no books on RF in the library, although there were a few titles in the reference library ( different building ). None of the books was any use whatever: only one had info about the IF stages of a radio ( a simple text with block diagrams ). The rest were advanced theoretical texts about RF design and about as much use as Sanscrit.
It's a tragedy that the info is inside the heads of people who wont be here much longer. I'm amazed that the Net ( a resouce for even the most obscure info ) is bereft of such valuable stuff.
BTW, the main City library has one shelf covering 'Science'. That includes all of maths, physics, electronics, engineering. It has about 20 shelves covering 'Religion'. In the 21st Century. God, it's enough to make you weep. If you want to know what's wrong with the World, look no further.

Bruce
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ant
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Posted on Wednesday, 18 August, 2010 - 07:21 pm:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

Hello Bruce,

Try
http://www.vintage-radio.net/forum/

Also Chas Miller of Radiophile fame
01785 284696
as he seems to have some good books available at his auctions.

Regards Ant
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terrym
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Posted on Thursday, 19 August, 2010 - 02:55 am:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

Re the ARRL book, you will notice I said an older issue of the ARRL handbook.

The 1936 and 1941 issues are available as a free (legal) download as well as William Orr's 1959 Radio Handbook. You should find all the info you need in any of these.

A google search will dig them up, but they are quite large downloads. If you can't find it, let me know.

TM
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bruce
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Posted on Saturday, 21 August, 2010 - 10:48 am:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

Thanks Terry,
I downloaded the Orr book OK. Regrettably it doesnt actually answer the specific question I have ( or it might, but it's buried in the noise )
I'll try the ARRL books later.

Bruce
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alanr
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Posted on Saturday, 21 August, 2010 - 11:06 am:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

Does anybody sell the formers, cores and cans from which to assemble the transformers these days? It would be difficult without them.

I tried several years ago and drew a blank, and gave up on the idea. Toko coils are ready made, reasonably cheap, and I cannot remember who sells them ;-)

Alan
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bruce
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Posted on Saturday, 21 August, 2010 - 12:34 pm:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

Alan,
A while back I got some discarded transceivers; ex Police or Ambulance IIRC. From these I got some nifty cans. They are larger than the 10mm Toko type, but size isnt important for everyone! I reckon these would be easy to hand-wind ( it's only about 150 turns of very thin wire, say from a 12V relay ).
As I understand it, coils have 2 functions:
1. the split primary improves the Q of the coil and restricts its BW
2.The secondary feeds the next stage and the coil ratio is designed to match impedances.

There exists a bewildering number of ways in which the primary is split. Unless you know what Q and BW you want, how would you choose? And how would you decide which part of the split coil to make the collector load?
If the coil ratio matches collector load to transistor input, why not use a FET ( cheap as dirt nowadays ) and discard the secondary?
If God made Eve from Adam's ribs, what did he make Adam from?
Some of us arent afraid to ask the difficult questions.

Bruce
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alec_t
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Posted on Saturday, 21 August, 2010 - 12:51 pm:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

Hi,
This any help (I googled 'making if transformer')?
http://www.angelfire.com/electronic/funwithtubes/IF_Can-1.html

IIRC the IF trannies in MW/LW radios have a centre frequency in the 450-470kHz range and consist of a primary winding of a dozen or so turns of around 28swg wire on a ~3/16" od tubular paxolin former with a threaded iron-dust tuning slug inside. The primary has a parallel polystyrene cap of a few tens of pF. The secondary has more turns than the primary. The whole caboodle is in a screening can.

HTH. Regards, Alec
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mikeb
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Posted on Saturday, 21 August, 2010 - 01:41 pm:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

I guess you need to think about what you want to get out of your research.

If you want to learn by 'a bit of theory and doing' (the way that I love), you need a little test rig so you can compare your results. I would say a sweep generator and scope (notice how anglefire did it in that link). Stewart of Reading has some old kit that might help.

I have some home made Weather Satellite stuff and I built my own front end and mixer.

For the IF experimented with a simple FET follwer and a TOKO coil (in those days available from Maplin)and played around on a breadboard until I got some reasonable gain (more hiss).

Then I transferred three of them to a pcb - it worked ok.

Perhaps a simple single stage using TOKO might be a good place to start, then get deeper if you want to.

rgds

mb
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mikeb
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Posted on Saturday, 21 August, 2010 - 01:45 pm:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

I could not recall the name - a comapny called Q-Max used to make large coils for valves that included IFs for valve work.

I think they have stopped now.

rgds

mb
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bruce
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Posted on Saturday, 21 August, 2010 - 01:47 pm:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

Hello Alec,
Yes, I've seen that link and many more like it.
There seems to be a Secret Society of old-timers around the Globe who made valve radios in the 1940s and are still doing it. There are lots of differeces between what they do and what I want to do. The Angelfire link is very odd; each IF transformer is the size of a baked-beans tin.

I dont know the maths that underpins what he does, but it's a World away from the Toko-type cans I'm interested in. The primary isnt just a few turns; it's 150-200 usually. The capacitor is routinely 180pF. And the secondary is smaller than the primary; less than 10t .

Bruce
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bruce
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Posted on Saturday, 21 August, 2010 - 01:51 pm:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

Mike,
Yes, I would agree about your approach, BUT unless I can answer the 2 questions I posed above, then I wont know what I'm doing or why. The test-rig and wobbulator and so on come later.

Bruce
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alec_t
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Posted on Saturday, 21 August, 2010 - 02:03 pm:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

@bruce
I obviously didn't recall correctly. Or assumed the winding with more turns was the secondary!

Cheers, Alec
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bruce
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Posted on Saturday, 21 August, 2010 - 02:39 pm:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

Au Contraire Blackadder:
The input impedance of the next stage ( if it's a transistor ) is 500R approx. The output impedance I dont know. I'm at a loss to discover how you calculate it. What I do know is that the turns ratio is about 20:1; you'll remember that the primary impedance is 'relected' and comes to 20 squared ( 400 ) times the input impedance. The value is quoted in the datasheets and is often around 50K. Clearly you want more turns on the primary or you will be in trouble; the only station you'll get will be Radio Tehran. But what is the significance of the 50K?

BTW, Mike,
I looked up that book on coil construction from Babani. On Amazon the new ones fetch 100 quid! Second-hand 60 quid. How do they make a profit?
Bruce
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mikeb
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Posted on Saturday, 21 August, 2010 - 03:28 pm:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

Have you had a good look around that anglefire site - he has quite a bit on IF transformer design.

rgds

mb
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mikeb
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Posted on Tuesday, 24 August, 2010 - 01:02 pm:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

I forgot to throw in another facility available to us - simulation.

I now always check my digital designs before building and I always catch silly mistakes.

I know analog work is a bit more tricky, but I have still learned a lot using LTSpice. I designed a lawn mower ignition system (to avoid the £70!! replacement cost) and the results from the high voltage coil/capacitor combination were exactly as predicted by LTSpice.
rgds

mb
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bruce
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Posted on Tuesday, 24 August, 2010 - 01:42 pm:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

Hello Mike,
I'm all for a bit of stimulation myself. I've never messed with Spice except for a brief period in the 1970s when I sprayed it on my stubble. I dont know what it did to women, but it certainly repelled me.
Maybe I'll have a bash with it some time.
BTW, nobody mentioned it, which was a puzzle, and I never thought about it, but EPE has a radio bygones CZ which I intend to try later. I got some useful links by persevering with Google. Ironically, the search terms: IF superhet and so on, were a bit hopeless, but when I put other terms in ( such as wobbulator - available from Anne Summers ) I got some good contacts.

Bruce
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mikeb
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Posted on Tuesday, 24 August, 2010 - 07:08 pm:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

hahahahahaah .....
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terrym
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Posted on Wednesday, 25 August, 2010 - 02:40 am:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

Radio Bygones , as a general rule does'nt go into theory. If you download the sample issue though, there is a wobbulator design in it.

TM
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bruce
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Posted on Wednesday, 25 August, 2010 - 09:52 am:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

Radio Bygones , as a general rule does'nt go into theory

Well they jolly well should. It uses less solder.

Thanks for the link Terry.

Bruce
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terrym
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Posted on Wednesday, 25 August, 2010 - 01:17 pm:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

The only problem with theory is it never works in practice.

TM
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bruce
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Posted on Thursday, 26 August, 2010 - 11:37 am:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

Hello Terry,
I have never looked at Spice simulation software. As you get older you start to believe that a lot of fancy new things are the Emperor's New Clothes. Just goes to show. I downloaded the LT Spice and started to, basically, meddle with things I dont understand. Just to see if this stuff actually did anything a pencil and paper wouldnt, I drew a 555 oscillator ( I made one for an el cheapo SMPS and the waveform on my scope was not quite as predicted by the formula ).
It took me ages to work out what I was doing, but today I finally got a set of traces for the oscillator. I couldnt believe how short-sighted I'd been; this Spice stuff is miraculous ( I was told to say that by my agent ).
I'm going to try some speculative stuff with the IF transformers. It's really astounding ( well it is to me ). Now I can test some simple circuits without having to make them first and presumably you can see if the design has some horrible error before you start soldering. One other thing struck me: if the real circuit doesnt work, but the Spice says it should, then the troubleshooting process is made easier because you know before you start theres a wiring error and not a design srror. Clever.
Thanks for the nudge in the right direction.

Bruce
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mikeb
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Posted on Thursday, 26 August, 2010 - 01:10 pm:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

I'm really glad that you have discovered this stuff. There are some demos on the web that will help your understanding and improve your designs and useage.

rgds

mb
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bruce
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Posted on Thursday, 26 August, 2010 - 01:20 pm:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

Hello Mike,
Thanks again for your help re the Spice thingy. And apologies for getting you and Terry muddled!

Bruce
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mikeb
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Posted on Thursday, 26 August, 2010 - 03:33 pm:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

Well done Bruce - it took me some time to get valid results from LT Spice, so you are progressing fast.

mb
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bruce
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Posted on Thursday, 26 August, 2010 - 04:00 pm:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

Mike,
I'll tell you something about the 555 astable: first, the two reference points arent 1/3 and 2/3 of Vcc. And the trace takes about 20-30 cycles before it stabilises ( well, it does on the simulation.)
Amswers on a post-card......

Bruce
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terrym
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Posted on Friday, 27 August, 2010 - 03:24 am:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

See, told you theory and practice don't mix.

Would actually like the know the answer, as the 555 (National semi) datasheet shows the reference string to be a set of 3 5k resistors.So, all things being equal, the junctions should be at 1/3 and 2/3 of Vcc.

I've downloaded LT Spice but never used it. Maybe it's time to give it a try.

TM
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alec_t
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Posted on Friday, 27 August, 2010 - 09:34 am:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

@terrym
I've also downloaded LT Spice and not used it yet! I was put off by reading somewhere (the documentation perhaps?) that the simulation runs produce umpteen Gigabytes of output file. Unfortunately my laptop drive and external drive are already fairly full (I know; buy another drive! ). I'd be interested to hear how you get on.

@bruce
How big an output file does the 555 simulation produce?

Regards, Alec
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bruce
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Posted on Friday, 27 August, 2010 - 10:10 am:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

Well, well, well, I never thought a newbie like me would suddenly become the fount of all wisdom!
The National Semiconductor website is all lies. Lies I tell you! Or not, as the case may be. That's the funny thing about simulation software; is it right that the triangular waveform doesnt sit exactly at 1/3V and 2/3V or is the software a bit wafty. The error is piffling, but we need to know; lives may depend on it. It wasnt the waveform that struck me, it was the way it took about 20 to 30 cycles to warm up to its final shape. Like a capacitor charging up! Maybe we should ask Linear technology for an explanation. The next simulation I'm going for is a simple boost SMPS. Now that should be a lot more interesting as the way I have been doing it ( by trial and error) obviously takes forever.
Luckily I never saw the bit about output files so I wasnt pout off. I'm not sure I can answer the question. You draw the circuit and then ( after you decide what type of analysis you want, and some are scarily complicated ) you just press 'Run'. I chose a simple analysis and I got a graph of waveforms at various points on the circuit. I didnt bother saving any of this data because I didnt want it. However, my guess is that the analysis must have been stored in RAM while I was working. I've got 1GB RAM, so I suspect ( though I dont know ) that the situation may not be as serious as you believed.
The Jury is still out on this stuff, I guess.

Bruce
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mikeb
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Posted on Friday, 27 August, 2010 - 12:16 pm:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

Are you sure there is not a start up time in real life - all oscillators have a 'take off' time. Normally, we dont notice, or treat it as start up noise.

mb
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bruce
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Posted on Friday, 27 August, 2010 - 01:43 pm:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

Mike,
No I'm not sure of anything. You could well be right. In fact, if the simulation is right, then I'm very impressed with simulation software. Just think what nasties lurk underneath our circuits that we never know about!

Bruce
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alec_t
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Posted on Friday, 27 August, 2010 - 03:46 pm:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

The 20-30 cycle warm-up shown by Spice sounds reasonable. I have written elementary simulation software in Basic, and it shows a similar result for various simple circuits involving an L or a C.
Bear in mind that at switch-on the voltages at most circuit nodes have to start from zero and reach a steady state value (or cyclic range of values). There tends to be some overshoot before the steady state is reached.

Alec
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alan_stepney
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Posted on Friday, 27 August, 2010 - 11:15 pm:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

To get back to the original question, I believe that before getting into the detail of IFT design, one should have a good grounding in the basics.

Start with "Scroggie", Foundations of Wireless, as many of us did "way back".
Then the Radio Designers Handbook (that one can be found on the internet).

There are dozens, nay probaby hundreds, of books that were common reading, and can still be found.

As one example, I recently cleared the entire collection from a deceased engineer. Some fascinating and informative books, that were THE textbooks for the last generation, but none will sell for "50-70 quid" as quoted in the OP.
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bruce
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Posted on Wednesday, 01 September, 2010 - 10:38 am:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

Thanks for all the input, people.

Bruce
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zeitghost
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Posted on Thursday, 02 September, 2010 - 11:34 am:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

I'll have a look in the Fred Terman books I have on my bookshelves at home.

He went into vast detail on most of the things you need to know when designing 1930s/40s/50s wireless sets. :-)
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bruce
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Posted on Thursday, 02 September, 2010 - 11:57 am:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

OK Zeit, thanks,

Bruce
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zeitghost
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Posted on Thursday, 02 September, 2010 - 04:21 pm:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

Bear in mind that valve IFTs are generally double tuned, thus rather different from the single tuned transistor version.

I remember seeing a Mullard Outlook article from the late 50s about designing with OC44/45 that might have been interesting for you if I'd kept it.
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zeitghost
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Posted on Friday, 03 September, 2010 - 09:10 am:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

Guess wot I forgot to do last evening?

Mostly because my office was in bits after the advent of the plumbers since Tuesday.

I've now written a note to self, so maybe I'll remember.
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bruce
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Posted on Friday, 03 September, 2010 - 09:23 am:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

Zeit,
Oh dear, oh dear, oh dear. Tut, tut.
We always blame the plumber, dont we. Well, I always do and I do my own plumbing.

Bruce
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zeitghost
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Posted on Friday, 03 September, 2010 - 12:32 pm:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

Have a look at pages 517 to 523 of this:

http://www.tubebooks.org/Books/itt_ref_4.pdf

Beware: it's 13Mb.
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zeitghost
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Posted on Friday, 03 September, 2010 - 01:17 pm:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

http://www.tubebooks.org/Books/Atwood/Sturley%201943%20Radio%20Reciever%20Design%201.pdf

goes into some considerable detail chapter 7, page 288 etc.

17Mb.

(Message edited by zeitghost on 03 September, 2010)
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zeitghost
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Posted on Friday, 03 September, 2010 - 02:01 pm:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

http://www.tubebooks.org/Books/RDH4.pdf

Page 1065 (!) onwards for IF design methods.

25Mb.

(Message edited by zeitghost on 03 September, 2010)
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zeitghost
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Posted on Friday, 03 September, 2010 - 03:57 pm:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

Just found Terman's Radio Engineer's Handbook.

Not a lot on IF, but it's a good read.

http://www.4shared.com/file/68394146/2c51481b/Radio_Engineers_Handbook_-_1943_-McGraw_Hill_-Terman.html
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atferrari
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Posted on Saturday, 04 September, 2010 - 02:41 am:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

Hola Bruce,

Look how far they are gone...!

http://www.edn.com/file/25579-Architecture_combines_low_and_zero_IF_receivers_PDF.pdf
Agustín Tomás - Buenos Aires - Argentina
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bruce
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Posted on Sunday, 05 September, 2010 - 11:45 am:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

Zeit,
After I ribbed you about your dismal failure to send those book to me, you clearly got your own back by overloading my HDD. At the moment it's holding out a white flag. And I've gone a little white as well.
Thanks for all that stuff. I used to suffer from insomnia, but I think maybe I've I found the cure!
Agustin: thanks for that: I realise I'm wasting my life on old trannies, but we all have our problems. My problem is that I'm old and sick. But it beats the alternative.

Bruce
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atferrari
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Posted on Sunday, 05 September, 2010 - 12:15 pm:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

Agustin: thanks for that: I realise I'm wasting my life on old trannies, but we all have our problems. My problem is that I'm old and sick. But it beats the alternative.

Well, I've have been after a clock synchronized to WWV station but difficulties to build a 10 / 15 MHz receiver, discouraged me.

BTW some time ago, puzzled by that world, I googled for it. Imagine my surprise...!
Agustín Tomás - Buenos Aires - Argentina
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terry
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Posted on Sunday, 05 September, 2010 - 03:47 pm:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

old trannies !!!

Terry
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mikeb
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Posted on Sunday, 05 September, 2010 - 10:15 pm:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

hey ... none of that talk on this CZ ....

we are all explorers and just cant help wondering why .... and we dont get our tooties cold ...

rgds

mb
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zeitghost
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Posted on Monday, 06 September, 2010 - 08:09 am:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

Glad that you found some of that stuff of interest.

If you think a 10MHz receiver is fun, you should try the 60kHz & 77.5kHz receivers for the timecodes over here. :-)

I'm still lost in admiration for designers who can get that functionality into a plastic blob on the back of a pcb in a 6GBP clock.

And they all work better than the one I've built.

Ho hum.

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