48-482 - Printable Version
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48-482 - falcon123 - 07-23-2022
i just sent my 48-482 to friend in maine. he was asking about how to hook it up to his dipole outside antenna. looking at the schematic it would seem that paralleling it with the cabinet loop antenna was the answer but im not really sure. also is there any way to improve on the fm antenna? using it here in my house it benefited from an outside antenna on BOTH am and fm bands but it seemed like ideally it really needed two separate antennas. he really does like that beast and i am all ears as he lives out in the ''sticks'' of brunswick and i want him to be happy
RE: 48-482 - morzh - 07-23-2022
I think that the internal loop is connected to those screw on the strip at the back side of the chassis.
I think you should disconnect the loop, which probbly has a lug, and then connect the dipole.
RE: 48-482 - RodB - 07-23-2022
I built an FM antenna using a piece of RG59 coax and followed the instructions on this video: https://www.google.com/url?sa=t&source=web&rct=j&url=https://www.youtube.com/watch%3Fv%3DKjTshXYsRss&ved=2ahUKEwiO-tfjiY_5AhXAFjQIHfIxC2QQwqsBegQIORAB&usg=AOvVaw0aW_s6E6EV5VeteAml7mOl
The two sections of dipole should come to just under 19 inches. For your friend, height and direction will be most important. It can be mounted inside plastic pipe for support.
RE: 48-482 - David - 07-23-2022
If your friend has no luck with a dipole ant adding a few pieces of wire can have a yagi ant. https://en.wikipedia.org/wiki/Yagi%E2%80%93Uda_antenna
RE: 48-482 - mikethedruid - 07-23-2022
First, what is your friend attempting to do with his di-pole antenna? Is he attempting to use it for the AM and SW bands or for the FM? Remember, the FM comes into the set through the little 4 pin jack on the chassis back, NOT through the screw terminals. I have always had very good luck with the original FM antenna setup which uses the line cord and house wiring, even here in the mountains of Tennessee. I can receive several FM stations using it. If it is the AM and SW bands, those use the screw terminals on the back of the set, and the built in loop. If you want to connect an external di-pole disconnect the internal loop, and connect both sides of the balanced feed to screw terminals 1 and 2, to which the internal loop was attached.
[Image: https://64.media.tumblr.com/6e617aa18654d8605f167b53840978eb/a691181b8e30b244-6e/s400x600/32f096fa67656fca5681351910092997e4ed790f.jpg]
RE: 48-482 - falcon123 - 07-23-2022
i am aware of the fact that the line cord clip to the plug is the fm antenna. i made one from brass. i dont know what his distances for fm are or the terrain. i do know i have an outside random wire antenna that greatly increased fm reception here as most of the fm stations are in manila which is 50 miles away. the plug was missing on the radio so i made pins gleaned from a dead octal base tube. this made it real easy to experiment. trouble with all this was i couldnt figure out a way to improve ALL the bands with ONE antenna
RE: 48-482 - mikethedruid - 07-23-2022
"trouble with all this was i couldnt figure out a way to improve ALL the bands with ONE antenna " You CAN'T... the AM and FM antennas are separate, go in to separate inputs, and to separate parts of the circuitry. If you study the part of the schematic I posted you will see that. One could make an external FM antenna from 300 ohm twin lead. Here is a site with the plan to make one.
https://www.kopn.org/about/antenna/
Or, you could order one ready made like that and wire it with 2 pins and insert them in holes 1 and 2 of the little socket. Amazon and eBay both carry them. Good luck [url=https://www.kopn.org/about/antenna/][/url]
RE: 48-482 - falcon123 - 07-24-2022
i was thinking that myself,but there are smarter than myself here so i thought i'd give it a try.
RE: 48-482 - Chas - 07-24-2022
I got curious about twin lead antennas for FM. I had measurements around somewhere but those included the velocity factor for the twin lead used, 0.86 or so.
I would assume that velocity factor applies to using the twin lead as a receptor element as much as it does for a transmission line. Therefor, the length given for the element should be multiplied by that factor for that particular station frequency in the article. Too long is not in of itself not going to work but it may work better if the correction is made...
Chas