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Transferring a handheld radio into a antique style radio box

  1. May 24, 2016 #1
    I'm pretty darn new to engineering, so I'm just diving in and hoping all goes well. I've got roughly 6 months to finish this project as it's a Christmas gift in the making. My current plan is to carve a large spruce log into the shape of an old cathedral style antique radio, make a cabinet, knobs etc and insert a handheld radio into it which the knobs will somehow control. I should be able to make the cabinet look decent enough as I've got a little practice with woodwork. It's the electronics and setup that I'll be guessing over.
    My main question is if I modify a larger speaker and a stronger antenna onto the portable radio, will I also need to modify the battery box to accept more than 2AA batteries, or would this power output still be enough to power everything including the LED indicator?

    Also, is there a way of replacing/increasing the strength of an Am receiver?
     
  2. jcsd
  3. May 24, 2016 #2

    phinds

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    The power will depend on the specs for everything but one potential problem I can see is that the knobs on the new radio are very likely connected directly (mechanically) to components (e.g. a potentiometer) and you'll have to pull that off and solder wires onto the circuit board over to the new knobs.
     
  4. May 25, 2016 #3
    I'll custom make a battery box and hopefully 3AA batteries will work.
    I'm assuming the radio I've ordered will be similiar to this standard handheld layout http://www.madehow.com/images/hpm_0000_0007_0_img0089.jpg
    Routing the components over to the radio face seems like a good idea.

    Thank you :^)
     
  5. May 25, 2016 #4

    Baluncore

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    There will be a problem with weak stations on AM. Switching power supplies are everywhere and are very noisy in the AM broadcast band. You might consider eliminating some of that noise by using an external antenna. That may require a small coupling loop be wound onto the ferrite rod of the radio.

    To increase the audio output power you could use an amplified speaker from an old computer audio system. You should select a heavy old plug-pack for the power since it will be a transformer supply rather than a switching power supply. That might also power the radio.
     
  6. May 25, 2016 #5
    The radio I bought is this exact one > http://img.dxcdn.com/productimages/sku_241705_1.jpg It's guts are what I'm modifying/strengthening if possible.
    And the cabinet/body I'm going to make looks similar to this old model here > http://www.radiolaguy.com/images/wood/Philco90.jpg but with one less knob.
    The am receiver could be connected over to it's antenna for a boost, but it'll definitely need a longer rod to make it up and out of the top.
    I'm planning to get a brighter led than the little red/green one that is likely on the handheld to show it's on behind the tuner read out.


    Thanks for your input guys. If I succeed with this one I'll post pictures of it finished.
     
  7. May 25, 2016 #6

    Baluncore

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    That is an AM / FM radio. The telescopic whip antenna is for FM. It needs to be extended for reception. It does not necessarily need to be extended to full length. FM will happily travel through the walls of a wooden box.

    I expect there is a small internal ferrite rod antenna wound with coils for the AM band. When you open the case you will see if it is there. Reception is best when that rod is side on to the AM transmitter site. Turn the radio to find the dip in signal strength when end on. You may need to rotate the radio inside the new case to pick up some AM stations. Car radios do not have the internal ferrite rod antenna because they use the external whip antenna with the body of the car for AM.
     
  8. May 25, 2016 #7

    Nidum

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    I'd build the radio as well . Not too difficult and many published plans .

    A traditional 5 valve superhet would be nice .

    or

    Use a ready made tuner/preamp module or single chip radio and add your own chunky controls and a valve output stage .
     
  9. Jun 25, 2016 #8
    Update time ^^

    So I just got the radio (Took a long time coming from china)
    And I went at it last night doing some tests after I got it all apart.

    I turned on the radio and it really was as cheap as it's 7$ price, hardly any reception at all. I did however decide that this one would be for experimenting on, and to get a better one down the road.
    Anyways-
    I have 2, 15 inch antennas which I hooked with alligator clips to the existing antenna.
    Then I turned on the radio and heard a clear but faint talking. So I thought to myself, if I added just one more AA to it's power supply, maybe that would give it enough strength. So I did. And a deep low hum grew and faded into a clear radio station that sounded like it was from a different state from what I could hear them talking about. And then 45 seconds later, the whole thing went dead. So I'm assuming that a capacitor blew.

    Here's it's innards http://imgur.com/a/AjJx8
    It seems like the knobs won't be too hard to manage.

    So I guess it's question time.

    1 Would 3 antennas in a fanned out position increase the FM signal or change it to a different band?
    2 If I was using a radio with an AC adapter, would a larger antenna and multiple speakers pick up the power they need regardless?

    Thanks :)
     
  10. Jun 25, 2016 #9

    Baluncore

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    What was the part number and codes printed on the IC in the picture ?
    Were you experimenting with AM or FM reception ?
    Does the radio have a short ferrite rod antenna for AM behind the PCB ?
     
  11. Jun 25, 2016 #10
    CD9088CB Is the number on the chip, and it was FM.
    It has one about 1.5 inches long behind the board.
    The capacitors on the back are pretty small, but that's probably expected for the size of the device. http://imgur.com/8yTWRhm
     
  12. Jun 26, 2016 #11

    Baluncore

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  13. Jun 27, 2016 #12

    Tom.G

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  14. Jun 28, 2016 #13
    Doesn't seem like I blew it out, must have been a capacitor.

    So, I decided the next radio will actually be a tecsun R9012. which isn't a bad little radio from all the video reviews I've seen, and I'll have it on Dc so as not to explode it lol.
    Would it be possible to run something like this > http://www.ebay.com/itm/LM1036-NE5532-Stereo-Preamp-Preamplifier-Tone-Board-DIY-Amplifier-Board-J1D4/272224752991?_trksid=p2047675.c100009.m1982&_trkparms=aid=777000&algo=ABA.MBE&ao=1&asc=20131227121020&meid=70195f1080d24f38a6523c3ef475ab1b&pid=100009&rk=1&rkt=1&sd=141678106811
    to it's existing speaker for further control? That circuit description says it doesn't drive the speaker at all, but only adds control, so I don't know how that works.
    Seems like something cool to put in as it makes it further like the older radios that had treble/bass controls in the back.

    Thanks alot for the feedback btw, this is the only forum so far that actually seems interested in responding.
     
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