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Old 24th Nov 2017, 5:55 pm   #61
astral highway
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Default Re: FM to AM Converter?

David, the more I look at it, the more I'm intrigued by the quality of your water-slide transfer! It looks amazing.

How do you do the artwork and the rest of the process? Have you put a link on your write up of this previously?

I'd love to start practicing!
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Old 24th Nov 2017, 9:11 pm   #62
Karen O
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Default Re: FM to AM Converter?

I've had a quick scan-through but I may have missed mention of Daryl Hock's FM to AM adapter. I thought I'd invented this myself but, as usual, no...

If I understand Daryl's converter correctly, it senses where the AM set is tuned to by picking up the local oscillator. It then uses this information to i. program an AM modulator to where the radio is tuned and ii. tunes an FM receiver by mapping the AM dial onto the FM band.

The result is that the FM band can be tuned using the AM radio's tuning knob!

The downside is the LO pick-up required, and the need to totally exclude all AM stations which means the radio needs a screened aerial connection.

I've no vested interest in Daryl's operation, by the way. In fact I'm a little peeved that he thought of the idea first!
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Old 24th Nov 2017, 9:15 pm   #63
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Default Re: FM to AM Converter?

Thanks from me too, David. Your work has pushed mine a few notches up my to-do list.
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Old 24th Nov 2017, 9:34 pm   #64
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Default Re: FM to AM Converter?

Quote:
Originally Posted by Karen O View Post
I've had a quick scan-through but I may have missed mention of Daryl Hock's FM to AM adapter. I thought I'd invented this myself but, as usual, no...
Sorry if I misunderstand. This sounds interesting, but don't think it is what this thread is about.

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Old 24th Nov 2017, 10:08 pm   #65
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Default Re: FM to AM Converter?

Quote:
Originally Posted by astral highway View Post
David, the more I look at it, the more I'm intrigued by the quality of your water-slide transfer! It looks amazing.

How do you do the artwork and the rest of the process? Have you put a link on your write up of this previously?

I'd love to start practicing!
It's kind of you to say so Al, but my CAD skills are very limited and the transfer I created was done by using MS Paint (which MS would like to kill off and probably will). It comes bundled with Windows. The transfer is quite basic - just a few straight lines, segments of circles at the corners, a couple of circles for the switch button hole, a coloured border and background, with some added text. I don't hold myself out to be an aficionado of water-slide transfers, I just like to make my home-brew projects look as presentable as I can.

There are countless 'PAINT' tutorials on youtube.

I also designed and created the artwork for the PCB for this project using 'PAINT' - I dislike PCB creating CAD packages such as easy-PC as the layouts tracks and pads don't lend themselves to amateur production and aren't really intended to - they're to send the artwork to a PCB Pool for commercial production. (I don't understand 'Gerber files', I don't want to and I don't need to).

I also use an ageing version 'Photoshop Elements' ('Elements 7', from 2008).

There have been several threads on the forum on creating and applying water-slide transfers (or 'decals' as they tend to be known, which is the American term for them). The paper is available in white and clear, and for ink-jet and laser printers. My experience is limited to ink-jet.

Here are a few recent threads to which I and others have contributed, which cover the creation and application of transfers, and sources of materials, which might be of interest:

https://www.vintage-radio.net/forum/...lide+Transfers

https://www.vintage-radio.net/forum/...lide+Transfers

https://www.vintage-radio.net/forum/...lide+Transfers

Hope that's of help.
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Old 25th Nov 2017, 12:54 am   #66
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Default Re: FM to AM Converter?

Quote:
Originally Posted by Philips210 View Post
Very nice work as usual David. Your projects always have that highly professional finish. Even the front panel slotted screws are set at a 45 degree angle...
Definitely!

Whether CAD skills are basic or advanced, is immaterial really... So you used MS Paint rather than Catia!

But then, a true craftsman can still produce outstanding work with basic tools!
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Old 25th Nov 2017, 1:57 pm   #67
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Default Re: FM to AM Converter?

Thanks for your kind comments.

There's a reason I try to attain a good standard, and it's encapsulated in one sentence:

'OK is not OK' - 'good enough is not good enough'.

That sentence goes back to a harsh lesson I learnt aged 15, more than sixty years ago when I left school and joined the world of work as a craft apprentice.

It's about pride in what we do and has no relevance to this thread, so I'll try to find a place were it might be worth elaborating on.
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Old 29th Jan 2018, 1:33 pm   #68
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Default Re: Bush DAC90A. Thank the stars I found this forum......

Could this converter be used with an AM Car Radio, specifically in this case a BL/Motorola Push-Button set made in the 1980s? I appreciate that, for in-car use, the converter may need to be built into a screened box, and the aerial input circuitry may need adaptting/modifying to suit a car aerial, which typically wil be either 50 or 150 ohms impedance and use a coaxial cable. Ideally, too, the output of the converter woul be couple directly to the AM radio via a short length of car aerial coax. cable terminated in a suitable plug, in this case the 'traditional 150 ohm type, rather thab the later ISO connector.
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Old 29th Jan 2018, 2:15 pm   #69
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Default Re: FM to AM Converter?

Just finished a third one for my son to use with his Ekco A22. As with the first two it was built on a PCB as covered in this thread and it works fine. I built it along similar lines to the second one and again, as I couldn't find a suitably sized ABS box, I made a little comb-jointed wooden one. Not really much more that I can add, but I've attached a few pics.

The first pic shows 6BA brass pillars soldered to the underside of the front panel, which was scrap double sided FR4 PCB laminate.
The second pic is the completed PCB, with the FM module soldered upside down on Veropins on the underside of the PCB. (where the push button switch is also mounted).
Third pic is the completed PCB ready to be fixed in the box.
Fourth pic shows the front panel with an ink-jet water-slide transfer label ('decal) fitted.
Fifth pic is a close-up of the PCB fitted to the stand-off pillars, correctly spaced from the front panel for the push button.

Looking back over the thread, for anyone not having PCB facilities, it's clear that a number of constructors (not forgetting Guy Fernando - the designer), have successfully built this most useful little project on strip-board. The trickiest part by far is mounting the little FM module, but as John ('60 old john') at post 15 showed, and other have since, it can be done with care. If the module is trashed, it's not the end of the world - they can be found on ebay from UK suppliers for around £2.00 each.

As to my own input to the thread, perhaps posts 40 45, 49, and 57 are the most relevant. For anyone with a laser printer but without a UV light box, the 'laser print/iron on' technique seems to be widely used with success - there's lots of videos on youtube which show how it's done. Just make sure that the image is reversed for ironing one or the PCB will come out back to front! For those who do have A UV light box, I can commend the use of the negative dry film technique (which requires a negative PCB mask). I'd reiterate that due to time constraints, I'm not able to make PCBs for others.

Guy Fernando - the designer, (forum member '14iy'), wrote a very informative post #54 which answered several queries. Guy's website, where the full original BVWS article can be found and programmed PICS can be bought for £12.95 inc Post is at this link:

http://www.i4cy.com/m0oox/fm2am/FM%2...0Converter.pdf

I hope this update might encourage a few other forum members to have a go at building one.

For anyone wishing to build a simple 'pantry transmitter' which enables any input (MP3 player, audio output from an FM or DAB radio etc) to be re-transmitted onto M.W. I can highly recommend the 'Mini-Mod', which is covered extensively in other threads.
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Old 15th Feb 2018, 12:29 pm   #70
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Default Re: FM to AM Converter?

Just to say - Take care when buying the RDA5807 module.

I got 5 for £1.25 including postage from china.

Too good to be true? Yep, only 1 worked and not very well!

(I'm using an arduino pro mini 3.3v to program it so i can have lcd RDS display too)
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Old 24th May 2018, 8:19 pm   #71
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Default Re: FM to AM Converter?

I have had similar results with one batch I bought, and had to remove them. This one works very well, thought you might like to see my take on it using the PCB originally designed by David Taylor and made with the Laser Printer technique. The photo shows it working a DAC90 with NO trailing AM wire. There is a socket on the side for an external wire if needed for a radio that need an external aerial. The top PCB is a 40" aerial!


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Old 25th May 2018, 10:45 am   #72
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Default Re: FM to AM Converter?

I've recently bought another batch from China. To date, I've just used one and it's fine, so hopefully the rest will be. I've only had one that didn't work, but the module didn't fail - I did! That was my first attempt and was due to the difficulty of soldering to what is a surface mount device with the solder pads on the underside - not on the top. Hence, my decision to mount the module 'upside down' on Veropins beneath the PCB, with the solder pads visible.

Clearly it's possible to successfully solder wires into the ten slots on the module and to use strip-board and that's what the Guy Fernando the designer did, and others have also successfully done, even though the pitch of the notches differs from the 2.5mm spacing of strip-board, so it calls for some dexterity, a steady hand and a good eye.

When I look these remarkable little modules - less than half the size of a postage stamp - it puts into perspective what a monumental achievement it was that almost half a century ago, with such relatively primitive, heavy and bulky electronics and limited computing capacity they had, that they were able to land astronauts on the moon and get them back safely to earth.
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Old 14th Jun 2018, 11:06 am   #73
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Default Re: FM to AM Converter?

This Chinese vendor is selling the RDA5807 module for just 29p including P&P. How do they do it?

Guy
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Old 14th Jun 2018, 2:22 pm   #74
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Default Re: FM to AM Converter?

I was lucky enough to get one of Davids pre made populated circuit boards , all i`ve done is fitted it into a project box and used an telescopic aerial for the fm signal (neater than a trailing wire) it works superbly in the Bush tr series plugged into the aerial socket ,especially the valved mb60 version.
Regards, Tim.
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Old 15th Jun 2018, 8:26 pm   #75
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Default Re: FM to AM Converter?

Glad that the converter is performing well Tim.

The little modules themselves, which are at the heart of the converter, are just 11mm square, and the RDA5807 chip itself is just 3mm square. Apart from the chip, on the module there's just a crystal and a couple of tiny SMD component which may be caps. Mind boggling to consider what it does, and at such low cost. Guy's ingenious design certainly fills a niche and the converter is especially useful for live chassis AM radios such as the DAC90A to which no direct connection is necessary, as shown by John in post #71 above.

Also, it's very useful in adding FM facility to AM transistor radios such as Roberts and the like.
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Old 8th Jul 2018, 3:10 pm   #76
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Default Re: FM to AM Converter?

Hi, Just to let ye know that I have just got a complete FM to am converter from 60 oldJohn. I am thrilled with it with lots of stations coming in loud and clear. Thanks again John. Regards, Dick.
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Old 12th Sep 2018, 5:04 pm   #77
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Default Re: FM to AM Converter?

Having been rather stopped in my tracks from early June for a few weeks due to a knee replacement operation (from which I’m well on the way to recovery), not able to get out much, not able to drive for eight weeks, or mow the lawns or walk very far, I turned my mind to light tasks that I could do sat at a desk or bench. I decided to make a few FM/AM converter PCBs, then came across some rather nice ABS project boxes, which – at 10cms x 6.5 cms x 5cms (4” x 2.75” x 2”) - were a little too small for the PCB that I designed back in July last year.

I therefore re-designed the PCB to reduce its size from the original 10.5cms x 4.5 cms, down to 8cms x 3.5cms, which fits neatly into the ABS box. I mounted the PCB to the underside of the lid on spacers and designed a waterslide ‘decal’ (transfer) to fit the lid. The height of the spacers depends on the type of tactile push-button ‘momentary’ switch used. The switches that I use are fairly generic on ebay, entitled ‘Tactile Switch PCB Push Button Momentary with Coloured Caps 12 x12x 7.3mm’. To correctly space the PCB from the lid when using this type of switch requires four 5mm diam x 10.5mm long spacers, which I tapped 6BA. The push button requires a 12mm diam hole, which I drilled using a step drill (AKA ‘cone drill’). Two 1mm holes are required in the end of the lid for the wire FM & AM aerials - just short lengths of wire.

I’ve made six boxed converters and tested them using the PIC from my own converter, and along with four of the original size built and tested PCBs I’ll be offering them for sale in the appropriate section. I’ve enjoyed building them while I’ve been ‘grounded’ but when life gets back to ‘normal’ it’s surprising how little time there is for hobbies. No wonder I have so many half-completed projects!

By far the simplest way of building the project is with the strip-board layout which featured in the BVWS Bulletin in Summer 2017, but for anyone who might wish to build their own converter and make a PCB for it, the PCB artwork, circuit, component layout and a couple of pictures of the completed PCB are attached. The positive artwork can be used for either positive resist coated UV PCB laminate or the ‘laser printer iron-on’ technique which obviates the need for a UV light box and developer.

The converter is a great little project which performs really well, enabling FM stations to be received on a medium wave AM radio with no connections to the radio, so it's especially ideal for AC/DC 'live chassis' radios such as the Bush DAC90A. All credit to the original designer, Guy Fernando! (Forum member ‘i4cy’). Guy has confirmed to me that he’s still able to supply the programmed PIC necessary to complete the project, from the link below, where the original Summer 2017 BVWS Bulletin article can also be found. The article has full details of the original stripboard layout for those who aren’t geared up for PCB making:

http://www.i4cy.com/m0oox/fm2am/FM%2...0Converter.pdf

All of the components can be readily found on ebay from UK and overseas suppliers, including the RDA5807M FM receiver module.

The first pic below shows the component overlay and the reversed positive PCB artwork. If printed onto glossy paper on a laser printer, then ironed onto PCB laminate, it will be the correct way around. There's lots of information on youtube atc about the 'iron-on' technique.

The second pic is of the underside of the PCB showing the correct orientation of the FM module, mounted on solder pins. It also shows the switch and spacers.

The third pic shows the top of the PCB with all the components in place except the programmed PIC from Guy.

The fourth pic shows the PCB mounted inside the lid of the ABS box, and the AM & FM 'aerials' in place - each just 15" or so of wire - red for the AM aerial - black for FM.

The last pic is an angled view of the completed converter.

I hope this might encourage a few more to have a go at building the converter.

I'll add a few more pics in a second post.
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Old 12th Sep 2018, 5:44 pm   #78
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Default Re: FM to AM Converter?

Following on from my previous post, here are a few more pics.

The first pic shows the underside of the FM module, which - being an SMD device - has solder pads on the underside, but not on the top. Thus, it's much easier to solder it to the pins with the underside showing.

The second pic shows the upperside of the FM module, to illustrate that if it were mounted on top of the PCB as with the other components, there's little to solder to.

The third pic is the negative mask for the UV dry film process.

The fourth pic is an etched and drilled PCB. The sharp-eyed may notice that towards the RH end of the PCB, when it came to drilling the holes for the 8-pin DIL socket for the PIC, the drill bit was throwing up a slight burr, whereas all of the holes to the left of the PCB are cleanly drilled. As soon as a bit starts to throw up a burr it's time to bin it or you risk it skidding and wrecking the board. 0.8mm HSS drill bits are only 16p each from China so it's just not worth trying to make them last, or to re-sharpen them. Sure, you can get tungsten carbide drills which are more expensive and last longer, but I'm content with HSS.

The last pic is the decal I designed for the front of the ABS box to finish it off.

As there isn't much space for text, it only gives basic information, but really, once set up, there's little to know. Once you know where to find the converter's signal on the MW dial, to use the converter, you just press the scanning button in sequence till you find the station you wish to listen to. If you have a favourite station you want to be the default, you press and hold the button for ten seconds. It automatically switches off after 2 hours.

Hope that's of interest.
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