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General Vintage Technology Discussions For general discussions about vintage radio and other vintage electronics etc. |
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16th Sep 2021, 1:31 pm | #1 |
Triode
Join Date: Jun 2021
Location: Falaise, France
Posts: 13
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Where to buy off the shelf AM modulator?
I have finally got my Ekco CR 227 car radio working.
I am in France and MW broadcasting seems to have ceased in France. But I'd like to be able to drive along with music playing from the radio despite the absence of MW broadcasting. My question: Is there available a unit that can take an audio signal (from a CD player for example) and generate an AM signal on medium wave frequencies? Last edited by Cobaltblue; 16th Sep 2021 at 1:43 pm. Reason: Automotive removed |
16th Sep 2021, 2:04 pm | #2 |
Heptode
Join Date: May 2015
Location: Chatham, Kent, UK.
Posts: 965
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Re: Where to buy off the shelf AM modulator?
Hi not off the shelf but the minimod project https://vintage-radio.net/forum/show...hlight=minimod will do it Mick
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16th Sep 2021, 5:50 pm | #3 | |
Triode
Join Date: Jun 2021
Location: Falaise, France
Posts: 13
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Re: Where to buy off the shelf AM modulator?
Quote:
Years ago I bought a ready to use FM modulator. I suspect it was intended for pirate radio operators. I used it, fed from a Marconi low distortion oscillator, to generate a modulated FM signal that I could use to measure the frequency characteristics and distortion of FM receivers and tuners. The unit itself produced surprisingly low distortion when fed with a sinusoidal modulating signal. I don't know if an AM counterpart was available back then. |
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16th Sep 2021, 6:37 pm | #4 |
Triode
Join Date: Sep 2021
Location: Swanage, Dorset, UK.
Posts: 10
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Re: Where to buy off the shelf AM modulator?
This guy (Tony) has a couple of models of 100 mW medium wave PLL transmitters/modulators. The Hurricane is easiest to use if you like exploring different frequencies. Also you can send audio to it via bluetooth and can monitor and control it from a smartphone app (his Android one or a generic Bluetooth Terminal app with preset buttons on iPhone etc.). Or the Spitfire is cheaper if you just want to set it to one frequency and forget it. I am not associated with that company or either of those products.
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16th Sep 2021, 8:40 pm | #5 |
Moderator
Join Date: Jun 2003
Location: Oxford, UK
Posts: 27,970
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Re: Where to buy off the shelf AM modulator?
These microtransmitters are not suitable for using in a car though, at least without a fair bit of fiddling.
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17th Sep 2021, 4:45 pm | #6 |
Triode
Join Date: Jun 2021
Location: Falaise, France
Posts: 13
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Re: Where to buy off the shelf AM modulator?
Paul, could you elaborate on that? From a quick look I think the units will operate on a 12V dc supply so I'm not sure what would need to be fiddled so they could be used in a car.
Thank you David. Those units look so far as I can see suitable for what I have in mind. |
25th Sep 2021, 9:35 am | #7 |
Triode
Join Date: Jun 2021
Location: Falaise, France
Posts: 13
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Re: Where to buy off the shelf AM modulator?
It seems that in the 1960s in the USA small FM radios providing an AM output were often sold as FM adapters for use with AM only car radios. No shortage of them on Ebay.com.
https://www.ebay.com/itm/22461797562...MAAOSw-ehhOq6d One such unit is winging its way to me now and I should have it in operation soon if all goes well. |
25th Sep 2021, 10:50 am | #8 |
Dekatron
Join Date: Feb 2007
Location: Leominster, Herefordshire, UK.
Posts: 16,536
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Re: Where to buy off the shelf AM modulator?
That device should get you FM stations via your AM radio. Next you'll need an FM modulator to feed your other sources into the AM radio via the Sparkomatic
Hopefully it won't live up to its name
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25th Sep 2021, 11:12 am | #9 |
Moderator
Join Date: Jun 2003
Location: Oxford, UK
Posts: 27,970
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Re: Where to buy off the shelf AM modulator?
I only meant that physical installation in a car wouldn't be straightforward, though it could certainly be done.
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25th Sep 2021, 1:19 pm | #10 |
Nonode
Join Date: Feb 2005
Location: Worcestershire, UK.
Posts: 2,535
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Re: Where to buy off the shelf AM modulator?
There's a unit from the US known as the "Redirad". The UK dealer's site is no longer up though. I see there's still a site in the US.
I once fitted such a unit to a friend's automobile. It plugged in series with the aerial lead and provided a medium wave signal on 1000 KHz, deriving the programme material from a flylead tipped with a 3.5mm jack, which you plugged into your audio source. When you tuned to a 'real' MW station on the set, it could sense this and reverted to passing the radio signal straight through. It worked well. Steve
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