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Components and Circuits For discussions about component types, alternatives and availability, circuit configurations and modifications etc. Discussions here should be of a general nature and not about specific sets.

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Old 15th Mar 2018, 2:59 pm   #21
merlinmaxwell
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Default Re: Silicon Chip Pantry TX & TV modulators

I went to buy the issue, it seems to be readable online only, this could upset some ISPs with a secret link etc.. I didn't go ahead because it requires you to create (yet another leaky) account, not a simple paypal type transaction.
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Old 15th Mar 2018, 3:18 pm   #22
David G4EBT
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Default Re: Silicon Chip Pantry TX & TV modulators

Quote:
Originally Posted by Boater Sam View Post
Well , I thought it was a good buy, but having explored it further it seem that the Aussies have had me over. I paid for a download copy but have received a preview copy only.
Never again.
Reading that, it looks to me as though Sam thought he was buying a copy of Silicon Chip that he could download - say as a PDF, save it to his computer, print it off or whatever. If so, he's been under a misapprehension. Silicon Chip make it clear on the website before buying that you can only view it online, which you can do as many times as you like. I'm not sure if that's what Sam considers to be a 'preview' but if so, he's got exactly what he paid for. It's made very clear on the website that there is no 'download' - there are only two options:

1) Buy a print edition, with consequent postal delays, or;
2) Pay for the online edition, which Sam seems to have done.

Those two options are made very clear before even adding it to the cart, where the 'shop window' states:

Silicon Chip Online Issue - March 2018

Online access to the March 2018 issue of Silicon Chip.

Online issues are not downloadable - see FAQ for details.

Cat No SC4557. Price: AUD $8.20 1

Add to trolley?

Here's a clip of the FAQs:

Q: Can I print pages from the online edition?
A: Unfortunately not. Flash has a print option but it doesn't seem to work after the latest security updates.
Until we find a way around this, if you want a printed copy of the magazine, please order the printed edition.

Q: Can I save the online edition to my computer as a PDF file?
A: Not currently. We would like to provide such features but are concerned that they would encourage unauthorised distribution of the magazine.

Q: Is the online edition now identical to the print edition?
A: Effectively, yes. There are only two differences:
(1) online editions will have some or all errata already fixed and;
(2) older issues may be missing some full-page ads.

Q: If I purchase an online edition of Silicon Chip, will my access to it expire?
A: No. Once you have bought an online issue, it's yours and you will continue to have access to it.

8-<

End quote.

So if by ' he only got a preview' Sam means that he can read the whole edition online, but can't download, save or print it, that's exactly what he's paid for and it's all that Silicon Chip offer.

About browser compatibility, it goes on to say:

Silicon Chip Online Website Browser Compatibility:

We recommend that you use the latest version of Mozilla Firefox to view the Silicon Chip website (but see other valid options, below). There are versions of Firefox for Windows, Mac OSX and Linux.

You will also need the Adobe Flash browser plug-in to view the issues. In addition, for the Silicon Chip website to work properly, you will need to enable cookies and JavaScript.
We have also tested the website in Microsoft Internet Explorer 9, Safari 5 and Chrome 23. We have found it to work satisfactorily using these browsers, with the following caveats:

IE9 Browser Issue - when mousing over article titles to the left of an issue, the whole title is supposed to appear but it is cut off by the Flash plug-in box to the right. This appears to be a limitation in the Internet Explorer engine which prevents DOM elements from appearing on top of a plug-in box.

Safari 5 Browser Issue - when mousing over article titles to the left of an issue, the whole title is supposed to appear but it is cut off by the Flash plug-in box to the right. This appears to be a limitation in the Safari engine which prevents DOM elements from appearing on top of a plug-in box.

Chrome 23 - no known issues.

https://www.siliconchip.com.au/Help/FAQ

Don't know if that helps to clarify things and lower the pitch of the thread an octave or two.

I'm always highly impressed with Silicon Chip projects, which - as is known, appear in EPE magazine some months later, but the parts and PCBs generally have to be sourced from Oz from S.C. Jaycar or whoever, with the attendant complications of import duty etc if over a certain price. For the few simple projects, the drawback of not being able to print from the online version means that if it's a simple PCB (rarely - usually high quality double sided screen printed PTH), you can't download the artwork for the PCB. I did however build an S.C./EPE 10V Voltage Reference project for which I etched my own PCB back in 2012.

Without S.C. and their excellent projects, EPE would have no practical content. Not a criticism, just a fact of life.
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Old 15th Mar 2018, 4:14 pm   #23
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Default Re: Silicon Chip Pantry TX & TV modulators

I have not purchased to view the full document but if it is anything like the preview then it seems a waste of money to do so. It is too small to read the text and when zoomed there seems to be no option to move around the page to view different parts.
Maybe Silicon Chip can find a better way to present their online tec magazine as I will not pay to view it in this form.

Mike
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Old 15th Mar 2018, 5:20 pm   #24
David G4EBT
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Default Re: Silicon Chip Pantry TX & TV modulators

I've just clicked on the 'preview' and at the bottom left hand corner, it gives the option of 'Full Screen'.

When I click on that, it comes up to A4 size and is perfectly readable, so I'd have thought that likewise, the full online version of the magazine would be too.

I'm not interested in buying the copy or building the transmitter, but for anyone who might wish to, in looking at the items available from the shop to build the kit, they seem very reasonably priced. For example, the double side, plated through, screen printed, solder masked PCB (122 x 55.5mm - near enough 2" x 4") is only $7.50AUS - at the present exchange rate, $1.00AUS is 56p, so the PCB would be 4.20 GBP. That includes free front panel artwork, which - without the PCB - would be $3.00. The PCB artwork for homebrew etching of a PCB is $3.00 AUS (1.68) but the PCB is so cheap that it would make no sense to make one. The MC1496 I.C. is $2.50 - (1.40).

Looks a great project:

Tunes 650kHz - 1,500kHz (460 - 200 Metres)
Adjustable tuning plus fine tuning,
Modulation depth adjustment
Carrier balance adjustment
Supply voltage 9 - 24V DC (Draws mA at 12 V).

I think our Antipodean Chums are well served by S.C and by Jaycar.

What do we have?

Maplin going bust and 'Practical Wireless', which is neither practical nor about wireless.

Luckily, we do at least have EPE, clinging to the coat-tails of Silicon Chip.

Oh well, as others have said, maybe the thread has run its distance - it's generated more heat than light and that's not what we're about.

It wold be nice to see a thread from someone who has built the project, with an appraisal.
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Old 15th Mar 2018, 5:53 pm   #25
crackle
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Default Re: Silicon Chip Pantry TX & TV modulators

Sorry I still find it difficult to read even at "full screen" which indecently on my monitor is exactly the same size as the original view. The image is prevented from occupying full screen by the menu down the left side.
Maybe if one has a very wide monitor it could display better but on a standard 1280x1024 the quality is just not good enough to read.
You would think that when you "zoom in" you would be able to drag the view around so that persons with eyesight less than perfect could read the rest of the screen.
Maybe there is something wrong with my PC but I dont feel that site has made it friendly for persons with less than perfect vision.
Anyway as you say there has been enough said.

Mike
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Last edited by crackle; 15th Mar 2018 at 6:00 pm.
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Old 15th Mar 2018, 10:35 pm   #26
David G4EBT
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Default Re: Silicon Chip Pantry TX & TV modulators

Interesting to discover that the design appears to be an update of the 'Little Jim' transmitter which featured in issued 208 of Silicon Chip way back in January 2006. The component placement appears to be identical, but the original had what appears to be a home-brew PCB with a ground plane on the top side and the tracks on the underside, rather than the professional PTH screen printed PCB of the updated version.

A description and picture of the 'Little Jim' from issue 208 can be seen at the Silicon Chip legacy site here:

http://archive.siliconchip.com.au/cm...5/article.html

Neat!
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Old 15th Mar 2018, 11:40 pm   #27
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Default Re: Silicon Chip Pantry TX & TV modulators

When I saw that S/C had used the MC1496 IC in their current and previous Pantry Tx design I was delighted. This is by far and away my favorite transistor array. I first saw this IC back in the late 70's used in color camera encoders and some color TV pattern generators like the Philips PM5519. I've used them myself in all my pantry TX's since the 1980's.

The idea of the circuit with its crossed collector configuration, has an interesting history, apparently it was designed by a fellow named Jones in the early 1960's, but he didn't get much recognition for it. It got patented by Gilbert in the early 70's. Curiously prior to that, if memory serves me correctly, Nagra Kudelski used the same circuit configuration in their professional audio tape decks (Nagra MK11) as a phase detector for the capstan motor Xtal lock servo. If someone has a service manual to look at perhaps that could be confirmed.

The basic multiplier has a multitude of uses, phase detector, multiplier, modulator,mixer etc.

When the carrier is applied to the high level inputs and the modulation at the low level inputs and a DC offset at the low level input, it makes a wonderful linear amplitude modulator for Pantry Tx's. Also, the modulation doesn't affect the DC axis of the carrier at the output, so you can take the output off single ended or push pull, without a HPF. In many modulator circuits I've tried to make using long tailed pairs and modulating the emitter currents with audio, I could never get them as linear and always needed the HPF on the output.

One good way to extract the output from these IC's is with a center tapped RF output transformer. This keeps the DC collector voltage closer to the supply rail too, which can help if the available supply voltage is lower. A perfect transformer for many applications is the "Black" standard Japanese style transistor radio IF transformer, with the tuning capacitor removed, because, most of the black ones have a center tapped primary, unlike the yellow and white ones.

Also there are super high quality mil spec versions of this IC available too.

Last edited by Argus25; 15th Mar 2018 at 11:45 pm. Reason: typo
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Old 17th Mar 2018, 4:14 pm   #28
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Default Re: Silicon Chip Pantry TX & TV modulators

Quote:
Originally Posted by David G4EBT View Post

I'm always highly impressed with Silicon Chip projects, which - as is known, appear in EPE magazine some months later, but the parts and PCBs generally have to be sourced from Oz from S.C. Jaycar or whoever, with the attendant complications of import duty etc if over a certain price. For the few simple projects, the drawback of not being able to print from the online version means that if it's a simple PCB (rarely - usually high quality double sided screen printed PTH), you can't download the artwork for the PCB. I did however build an S.C./EPE 10V Voltage Reference project for which I etched my own PCB back in 2012.

Without S.C. and their excellent projects, EPE would have no practical content. Not a criticism, just a fact of life.
Hi.

I've purchased the EPE magazine each month for well over 20 years and also used to buy Practical Electronics and Everyday Electronics regularly.
I agree that Silicon Chip and EPE produce some very decent projects. The disappointing things about EPE is their policy not to show the PCB artwork, and the components list doesn't show circuit references, something that occured after the SC influence on EPE around 2006. Apart from these points it's an excellent magazine and long may it continue.

Regards
Symon.
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Old 26th Apr 2018, 12:02 am   #29
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Default Re: Silicon Chip Pantry TX & TV modulators

Bit late I know,

I appreciated the support and kind comments about EPE Magazine and can concur that without the excellent, ready-for-print (with a bit of editing) projects produced by Silicon Chip there would be no UK-published hobby electronics magazine left on British newsstands.

I hope it's not just about projects though, as we do offer plenty of home-grown editorial content, at least one column being written by a world class ex-Intel engineer and developer and another by an exceptional University tutor.

-- Alan W / EPE
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Old 26th Apr 2018, 8:52 pm   #30
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Default Re: Silicon Chip Pantry TX & TV modulators

Hi Gents, I've just chanced on this thread. I have the magazine in question that I bought when I was recently out in Oz. The circuit looks pretty good and is also available as a kit. These are often available from Jaycar by mail and are pretty good quality.
There is also an article in the same edition on building a vintage analogue TV modulator.
It looks an interesting design and uses the MC1374 as the modulator. it is again available as a kit with PCB.

Ed
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