messing with a car radio
I have an 80s model delco am/fm radio. I'd like to attach an external
long wire AM antenna, an external FM antenna, and rig something up so I can listen to it with headphones at bedside. Questions: 1. What do I need to do/build the headphone connection? Can I put something together using the car radio speaker wires? 2. Is it possible to hook up the long wire antenna without getting too complicated? Can I use the antenna plug on the radio in some way, or will I have to get inside the box? I don't know a lot about electronics. I have a soldering iron and have fixed the occasional loose wire on things around the house, but not much more than that. Or should I just forget it and buy a portable receiver? I mainly want to listen to AM talk at night and a particular FM college station in the next town. I read on several posts about using a car radio because of the AM reception. I've also thought about buying a used Grundig receiver, in particular the S350. I think having the option of listening to shortwave might be fun. Does this thing put out good audio via headphones? Thanks. |
"ellisc" wrote in message m... 1. What do I need to do/build the headphone connection? Can I put something together using the car radio speaker wires? You can use the speaker wires, however, the audio used to feed the speakers will be amplified, and will probably overdrive your headphones. You'll need to find a way to match the headphones to the speaker output. 2. Is it possible to hook up the long wire antenna without getting too complicated? Can I use the antenna plug on the radio in some way, or will I have to get inside the box? I don't know a lot about electronics. I have a soldering iron and have fixed the occasional loose wire on things around the house, but not much more than that. It should be easy to connect a random wire antenna to the jack of the car radio. Just solder the plug onto the wire antenna. I think they use Motorola type plugs as a standard. However, an antenna that is good for the AM broadcast band won't necessarily be good for the FM broadcast band. However, as you stated below, you just want to listen to an FM station in the next town, so a random wire antenna will probably work OK. Or should I just forget it and buy a portable receiver? I mainly want to listen to AM talk at night and a particular FM college station in the next town. I read on several posts about using a car radio because of the AM reception. Well it all depends on if you're looking to do it easy, or if you want the challenge of making it work. If you're looking for a technical challenge then the car radio will fit the bill. You'll need to match the headphones to the speaker output, attach an antenna, and find a way to power it from 12VDC, either from a battery or power supply. It would be fairly easy to go buy a decent AM/FM radio for DXing (GE Superradio comes to mind). -- Tom Sevart N2UHC Frontenac, KS http://www.geocities.com/n2uhc |
"Tom Sevart" wrote in message ... "ellisc" wrote in message m... 1. What do I need to do/build the headphone connection? Can I put something together using the car radio speaker wires? You can use the speaker wires, however, the audio used to feed the speakers will be amplified, and will probably overdrive your headphones. You'll need to find a way to match the headphones to the speaker output. This is easily done with a resistor divider... I'd put a load for the speaker, too. This would look like an 8-ohm 20W resistor (RatShak sells 'em) across the speaker leads, with a 500ohm pot across that... your h-phones are tapped from ground to the center wiper of the pot. Adjust for taste. __ Steve KI5YG .. |
ellisc wrote:
I have an 80s model delco am/fm radio. I'd like to attach an external long wire AM antenna, an external FM antenna, and rig something up so I can listen to it with headphones at bedside. Questions: 1. What do I need to do/build the headphone connection? Can I put something together using the car radio speaker wires? 2. Is it possible to hook up the long wire antenna without getting too complicated? Can I use the antenna plug on the radio in some way, or will I have to get inside the box? I don't know a lot about electronics. I have a soldering iron and have fixed the occasional loose wire on things around the house, but not much more than that. Or should I just forget it and buy a portable receiver? I mainly want to listen to AM talk at night and a particular FM college station in the next town. I read on several posts about using a car radio because of the AM reception. I've also thought about buying a used Grundig receiver, in particular the S350. I think having the option of listening to shortwave might be fun. Does this thing put out good audio via headphones? Thanks. It would be easier to buy a normal radio. For AM a CCRadio or GE Superadio 3 would work. The best FM reciever there is is the Tivoli Audio Henry Kloss Model One, but be prepared to plunk down mucho dinero for one ($100 last time I checked) and it's not that great on AM. I'd go with a SR3, or you can try to get an SR2, which some think had better build quality, but since it's (obviously) an earlier, out of production model it's hard to find. |
tommyknocker wrote in message ...
It would be easier to buy a normal radio. For AM a CCRadio or GE Superadio 3 would work. The best FM reciever there is is the Tivoli Audio Henry Kloss Model One, but be prepared to plunk down mucho dinero for one ($100 last time I checked) and it's not that great on AM. I'd go with a SR3, or you can try to get an SR2, which some think had better build quality, but since it's (obviously) an earlier, out of production model it's hard to find. The superradio isn't fm stereo, is it? I want stereo for fm listening. |
"ellisc" wrote in message m... I have an 80s model delco am/fm radio. I'd like to attach an external long wire AM antenna, an external FM antenna, and rig something up so I can listen to it with headphones at bedside. Questions: 1. What do I need to do/build the headphone connection? Can I put something together using the car radio speaker wires? 2. Is it possible to hook up the long wire antenna without getting too complicated? Can I use the antenna plug on the radio in some way, or will I have to get inside the box? I don't know a lot about electronics. I have a soldering iron and have fixed the occasional loose wire on things around the house, but not much more than that. Or should I just forget it and buy a portable receiver? I mainly want to listen to AM talk at night and a particular FM college station in the next town. I read on several posts about using a car radio because of the AM reception. I've also thought about buying a used Grundig receiver, in particular the S350. I think having the option of listening to shortwave might be fun. Does this thing put out good audio via headphones? Thanks. |
"ellisc" wrote in message m... I have an 80s model delco am/fm radio. I'd like to attach an external long wire AM antenna, an external FM antenna, and rig something up so I can listen to it with headphones at bedside. Questions: Depending on the frondend design... Early AM car radios included the antenna feedline capacitance as part of the tuned circuit; and included a trimmer to fine tune the radio tracking to match the antenna. The antenna was connected to a very high impedance point of the RF stage tank. Later designs used aperiodic frontends, and were less critical. You might loss ground using a long antenna on the set, depending on its vintage. pete |
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"ellisc" wrote in message om... The superradio isn't fm stereo, is it? I want stereo for fm listening. It's only got one large speaker, not sure if it has stereo through the headphone jack. Heck, I'm not even sure if it does have a headphone jack. Mine is stowed away in the camper & is mainly used for listening on camping trips. -- Tom Sevart N2UHC Frontenac, KS http://www.geocities.com/n2uhc |
CDE,
ANTENNA: You could try building a 'Low Noise' AM Antenna that can start at near ground level and going up to as far as you can get it and then out as far as your can make it. NOTE: This is usually called an Inverted "L" Antenna. * First install a Ground Rod and a short Heavy Ground Wire at the Base / Starting Point of the Antenna. * The Antenna Element was 100 Feet of Landscape Lighting Cable (Heavy Duty Outdoors Zip Cord). * Affixed the Two Wires of the Near-Feed-End of the Antenna Element across a TV 300 Ohm Matching Transformer and connected them one-to-one. * Secure the The Near-Feed-End of the Antenna Element and Matching Transformer using insulators to the Ground Rod. * Stripped and Twisted Together the Wires of the Far-End of the Antenna Element and covered them with electrical tape. * Ran/Routed the Antenna Element from the Ground level up to the Top of the First / Near Antenna Support. * Ran/Routed the Antenna Element from the Top of the First / Near Antenna Support to the Top of the Far Antenna Support. * Attach 50Ft to 100Ft of 75 Ohm Coax Cable to the other end of the Mounting Transformer. * Attached a short Heavy Ground Wire to the 75 Ohm Side of the Mounting Transformer. * Ran/routed the Coax Cable from the the Antenna Element to the your Car Radio's location. * Terminate the 75 Ohm Coax Cable with an Motorola Connector. * Plug the Motorola Connector into the Car Radio. TBL: The Antenna Element is a "Flat-Thin-Loop" that is Physically 100 Ft Long and Electrically 200 Ft Out-and-Back. ALTERNATE: To the Random Wire Antenna is to use a CB 104" Stainless Steel Whip Antenna mounted on a piece of 21Ft Top Rail. * A proper Antenna Insulated "Mount" is required to be used between the Whip and the Top Rail. * Use a 75 Ohm Coax Cable from the the Antenna to the Radio. * Connect the Center Wire of the Coax Cable to the Whip Antenna Element and the Outer Shield to the Top Rail. * Terminated the Coax Cable with a Motorola Plug. * The Base (Butt-End)) of this piece of Top Rail should be 3Ft-5Ft in the Ground and allow the Top Rail to be Free Standing. NOTE: The Top Rail is your Antenna and Car Radio Ground. STEREO HEADPHONES: NOTE: Since your did not ask about Hooking-Up a Pair of Stereo Speakers. I assume you know how. The simplest method of making the connection between the Car Radio's audio power amplifier Stereo Output and your Stereo Headphones is using a pair of Dropping Resisitors with a 1/8" or 1/4" Stereo Jack to match-up with your Headphones and Two Dropping Resisitors. THE HOOK-UP: The Barrel of the Stereo Jack is Ground; Center-Section is the Left-Side Stereo Sound; and the Tip is Right-Side Stereo Sound. For the Center-Section and the Tip use an Equal Value Dropping Resistor. Here is a suggested 'value' of Dropping Resistors for different basic Headphone Impedances: * 4 Ohms Headphones = One 43 Ohm One Watt Resistor per Side. * 8 Ohms Headphones = One 82 Ohm One Watt Resistor per Side. * 16 Ohms Headphones = One 160 Ohm One Watt Resistor per Side. * 32 Ohms Headphones = One 330 Ohm One Watt Resistor per Side. iane ~ RHF .. .. = = = (ellisc) = = = wrote in message om... I have an 80s model delco am/fm radio. I'd like to attach an external long wire AM antenna, an external FM antenna, and rig something up so I can listen to it with headphones at bedside. Questions: 1. What do I need to do/build the headphone connection? Can I put something together using the car radio speaker wires? 2. Is it possible to hook up the long wire antenna without getting too complicated? Can I use the antenna plug on the radio in some way, or will I have to get inside the box? I don't know a lot about electronics. I have a soldering iron and have fixed the occasional loose wire on things around the house, but not much more than that. Or should I just forget it and buy a portable receiver? I mainly want to listen to AM talk at night and a particular FM college station in the next town. I read on several posts about using a car radio because of the AM reception. I've also thought about buying a used Grundig receiver, in particular the S350. I think having the option of listening to shortwave might be fun. Does this thing put out good audio via headphones? Thanks. .. |
1. What do I need to do/build the headphone connection? Can I put
something together using the car radio speaker wires? You can use the speaker wires, however, the audio used to feed the speakers will be amplified, and will probably overdrive your headphones. You'll need to find a way to match the headphones to the speaker output. On the other hand, if you are using modern low-impedence headphones, just attaching them across the speaker wires may work well enough. Of course, you'd probably want to add a phone jack with an extra contact to cut the speaker out of the circuit when the phone plug is inserted. With a little thought, you might even be able to add a resistor or two to adsorb some of the "extra" audio that went to the speaker. --Myron. -- Five boxes preserve our freedoms: soap, ballot, witness, jury, and cartridge PhD EE (retired). "Barbershop" tenor. CDL(PTXS). W0PBV. (785) 539-4448 NRA Life Member and Certified Instructor (Home Firearm Safety, Rifle, Pistol) |
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