Radio antenna connector repair

[djnolan]

I had to resolder the antenna connector because the shield ground wire had broken. When I disassembled it, there were 2 small plastic inserts on the main antennal lead, which was a single strand of very thin wire. Does that thin wire need to be soldered to the plug?Or is it sufficient to just thread it through the plastic pieces.

[Monkey Wrench]

the internal wire is the antenna, the shrouding is just shielding to prevent stray hash from getting to the antenna wire. its not super critical but if you had a bad connection it might cause a crackly antenna..

at the end that pushes into the radio it's not soldered but the pug is designed to grab it snugly. you could cut and splice that wire if you needed to, then Id solder and heat shrink the wire and join the grounded shielding up.

the radio antenna is designed to receive signals so it can pick up noise from pug wires etc, maybe nearby electric cars.

an FM antenna is made to a specific length, this length relates to the wavelength the antenna is designed for. some car stereos have an adjustment behind, to tune the antenna to the radio for the strongest signal.. your radio may or may not have that antenna tuning adustment, If you have it out it may be behind the radio or if you have the right book, might describe it. or it may not even be present.

It'll work otherwise but if things are right, reception will be at its best. even with the antenna half way retracted and at the wrong length if ou have a good signal you may not notice much difference.

the radio has circuitry called automatic gain control, it evens out the loudness of a strong station so as you tune you dont have some very quiet and some very loud, particularly on AM
AM can travel far, bounce off the stratosphere, FM is pretty much line of sight from the tower. near big cities most just use FM in rural areas you may not have so much choice in FM.. optimally the FM and AM could have different antennas that are tuned to the frequency, the standard car antenna is a bit of a trade off.

I tried once to just use a piece of sticky copper foil tape, its used for stained glass work, comes in 1/4 inch width,, I ran a strip of that across near the top of the windshield, it worked. maybe not optimal but well enough for me.

technically you shouldn't make sharp bends in any of that cable. if you have extra Id try not to kink it but make loops instead. you can solder, crimp or whatever but f it's a loose connection your radio will probably crackle and annoy you.

there is really no considerable electrical potential in an antenna , its carrying signals from the sky and they are being beamed right through and around you. for AM, in general the longest and highest wire will make a good antenna. you cna put one p to a nearby tree, dont let it be grounded.. and drive a ground spike int he ground , then hook up an am radio to a good antenna and a good ground, and get far and distant stations.

If you ask someone into ham radio they can give you a lesson on antennas and the associated math that can make your head spin. basically the wavelength you are intending on receiving determines the best antenna design. there is some relationship between antenna length and wavelength.

I have a neat book that shows pictures of all these old wooden wheel cars from the 20's , they had canvas tops back then..Its a book about installing these early antennas in cars. , of course all AM or shortwave.. an AM radio then was quite a novel luxury, especially in a car !

the old cars probably interfered a lot, with the old continuous spark ignition systems. interesting book , completely outdated. they likely had to park to hear the radio very well.

new Teslas are eliminating AM radios because the motors put out so much stray hash , it messes with them. some don't like that because although its mostly talk radio some like to have access to things like traffic and weather reports, forest fire reports, or may live far away from FM towers. after 100 years they are going full circle. now the cars interfere with their own radios once again.

[djnolan]

I cut the wire off a few inches, put the antenna strand inside the red thingy and pushed the red plastic thing inside the center insulator. The 2nd red thingy i threaded the wire through and pushed it inside the metal plug. Then i soldered the shield and wrapped it with electrical tape. Wish I had a picture to show.

I guess the thing that surprised me was it wasn't like a standard coax cable, the main wire was hair thin single strand instead of a copper wire in the 12-14 gauge size you would find in a cable tv or other coax wire.

Also on the 944 there is an antenna amplifier in the circuit that has a separate power lead in the wire bundle.

[wwdwgs]

djnolan,
how thick is the antenna wire embedded in windshield glass? it's also very thin.
MW,
The length of antenna could be wave's length or 1/2, 1/4, 1/8 etc. I don't know how an impedance plays a role in antenna.

[Monkey Wrench]

I put up a long wire AM antenna on my house, , to run that to the radios in the house I use coaxial cable, that is grounded and sheilds any stray electrical interference, fluorescent lights, or fridge motor for example..

to that kind of properly I got some 2:1 impedance matching transformers, plus a splittter and they were made up by a HAm that knows more about this stuff. you probably remember seeing similar little transformers hanging off the back of your TV or radio, where you connect the cablevision wire.

the impedance of the wire is I think 75 ohms and so the transformer tries to match that and as it comes out it converts it back, the splitter allows two radios to be connected.

I have a house full of old radios, I like restoring them and it's a bit of a sickness, but anyway, so why not just run my antenna to every radio?

the splitter, and you can use a similar thing and probably have, for cable vision, it will divide the signal from the antenna, you can use a gizmo to measure signal, a strength meter.

the transformers are called impedance matching transformers.

If I run the signal to two radios and split it, the signal is then a bit weaker, but normally acceptable.. a funny thing is happening here that you wouldn't expect, the signal is actually connected within the radio and all signals go there, the radio selects out just only the frequency you are "tuned into" some radios are more selective than others. the bandwidth is the widthof the station band you are receiving, it can be adjustable on some radios, it may affect the tonal response, but also , a radio that is very selective is good at picking out the station you are listening to and shutting out the neighboring station on the dial.

If I restore an AM radio I will tune the IF's these are intermediate frequency transformers, they are designed to pass only a certain wave length the most common is 455 kilohertz, or kilocycles. in some radios it is different, but the frequency of that does not change.

I will then adjust other things for example to make a station that is coming over at 600 to show as 600 and not 575 on the radio dial. there is also band-spread and if that is wrong the stations can be spread or shrunk or stretched out across the dial so the adjustments make it accurate. If a radio has a maladjusted IF or of other adjustments are off it will become less selective, commonly capacitors fail and the most common outcome is a 60 cycle hum.

Now FM is different because it is frequency modulated whereas Am is amplitude modulated. tuning an FM receiver properly is a little deeper and a bit different I dont normally work on those. but if you took an FM radio to a good radio man he may be able to make some adjustments, maybe change any bad capacitors or resistors much as I do..

i only work on tube stuff, before around 1965 where they went into IC's and transistors. and from there it went to digital electronics and got even smaller.. i quite like being able to see and touch and work on the wires and stuff.. most of what I know was basically self taught and there are a lot of holes in my knowledge but basically Id buy some old radio from the 30's maybe like the cabinetry and go about 6 months of restoring the case, refinishing it, restoring the electronics/
there is no money in it , but there are a lot of neat old radios around and it's fun to work on them.
sometimes Id get so stuck Id basically start following the wires about in some state of confusion but normally I'd win , maybe not in any speed competition just happy the dusty old ex mouse nst actually works. I can follow the signal through the radio an you can then see on a scope screen as it is an envelope and then the station is selected out and then various stages of amplification/ eventually driving the voice coil f the speaker.

the radio has coils in it, if they are connected to the antenna the coils are full of signals 24x 7 no matter if the radio is turned on or not.

in a car you can sometimes get interference, if you got a hum from the wiring you could put a transformer in the input to try to block some of the noise of the power supply that might look like a big capacitor. it might be called a noise suppressor or similar.

you can amplify the radio signals amplitude but You dont really get something for nothing , you might need to amplify the signal's amplitude to go a greater distance because the wire has some signal loss if it is very long.

old tube radios for cars, well cars only had 6 or 12 volts and that's not enough voltage to run vacuum tubes. You can transform power if it is AC but a car is DC. to get around that they would install a "vibrator" in the radio, it is like a buzzer, and makes pulsed DC, the pulsed DC can be transformed to a higher voltage much like AC can.

around 1965 or 1970 everything changed and japan got really good at making solid state electronics, that generally replaced tube radios.
If I attempted to fix a modern one I'd generally just be quite lost, but you can still replace the capacitors, and any resistor you can read you can check it's resistance to see if it has drifted out of tolerance.. If I wanted to hack at it with hopes of saving it I might try changing all the capacitors and then just hope. if you can get the schematic for your radio, that's normally where the instructions for it's alignment procedure will be. you may possibly find a label showing the circuit on a printed sheet, inside the radio.

a main part of most radios is it's tuning capacitor, that's the delicate looking thing with a bunch of fins that fold together. it has higher capacitance as more fins are engaged and that affects the frequency it is sensitive to, thus your station selection. dust in the area can affect it, that may make it scratchy or have dead spots, if those fins ever touch at all the radio is dead, no stations can be heard.. on old radios these are not tiny parts but as time progressed they made them smaller. I was just never enthusiastic about working on or soldering parts that are the size of a fly poo. but some are good at that , the stuff I am most interested in is antiquated.

I tend to restore stuff like that as a hobby and not a serious one. when you restore a antique radio and get it working nice it's a great feeling and an accomplishment.. after that sure you can listen to talk radio but I don't really find myself very drawn to that. some collectors rebroadcast, you can do that up to 100 MW, so you can legally rebroadcast your iTunes or MP3's or whatever in your own house. then listen to them on antique radios. unless you break the law, its such a weak signal it would be gone next door.

I have a couple of things that can broadcast into a car antenna, one is an Fm receiver that is intended to fit and hide into a 60's car with a stock AM radio, you tune the radio to 800 AM and this tuner plugs into the antenna, then with the radio on at 800 on the AM dial it can receive whatever FM station you tune it to.

I have something similar that plugs into a lighter socket, that one can broadcast over FM to the car's FM radio,, there is a little plug so you can plug in an Iphone or Mp3 player etc.

there were also cassette tapes that had a little plug so you could broadcast into the tape heads if you owned a tape deck. If the FM radio in your Porsche is stock and it works that may be an OK way to be able to connect your Iphone without going to a non OEM radio..

As the law works here, if we want collectors insurance . that's insurance at a very reduced rate only for collector cars. they want the OEM radio, not something aftermarket. so the FM transmitter isn't a bad way to stay OEM and still lay your Mp3's streaming media or whatever.

mine was yanked and replaced with a pioneer CD player but the owner gave me the OEM radio with the car.

in my volvo the OEM radio/ tape went crackly, Id bump it and that would fix it, bad solder joint somewhere.. it wasn;t such a bad system, 4 speakers, sounded ok.

gee I had to really tear into the dash to get it out and I had the same one from another car so swapped it, it works but the LED dial doesn't light, that's ok, I dont need to see any numbers, It has a seek station function so I'm ok just with that. probably it has a ribbon cable for the display that somehow disconnected itself

i like old school radios with just a simple tuner and a knob, once they digitized they made everything small and more disposable. i don;t mind tape decks, you can record what you like, by now a lot are suffering from breakdown of rubber parts. I paid about 400 bucks for a car deck in about 1980, separate amplifiers, i put 6 speakers and a couple tweeters in, man the thing sounded awesome.

[djnolan]

here is the wire in the center next to some 12# and 20# fishing line for comparison.

[Monkey Wrench]

wire size wont mmattter much because the antenna is only carrying signals, basically near 0 amps.
you can crimp the thin wire under the connector , sure as long as it keeps contact.
a lot of this new garbage has thin wires, headsets, chargers and things, they cheap out on metal where they can.
if you want to splice thin wire you can take a piece of a little thicker wire, like the size of the wire in a twist tie, about like that. wrap it around a pin , like for sewing, or a needle. now you have something that resembles a spring. you can slip that over the thin wire and crimp and solder that.

any time you can use heat shrink its preferable to tape but tape works too.

I had a situation where I needed a dash light, went and found one that was about the right brightness , it had stainless steel leads, meant to pop into some proprietary socket, I just needed to solder leads to it, but thing is you can't easily solder to stainless steel.. so I did that. made a little coil slipped it over, soldered it up then it was in contact, even thought the solder didn't' stick to anything it was a mechanical connection.

have a look at this
https://en.wikipedia.org/wiki/Western_Union_splice

this is a western union splice, anytime you are joining up wires , slip some heat shrink over the wire, wrap the wires like in the pic then solder them and put the heat shrink over, I use a bic lighter to shrink it down.

when you pul out your solder iron or solder gun, heat it up, take a little wet cloth and wipe the tip when it's hot and melted then load the tip with fresh solder, do that every time, or multiple ties if it's not all shiny. if you do not then youll be there trying to heat up wires and having trouble because your soldering iron tip is dirty. with a clean tip it only takes a moment to melt the solder and see it flow.

if you are soldering up near connectors, like the common prongs for relays and such, be careful not to overheat them if you do you will remove the temper and they will loose their ability to be springy.

if you heat copper or brass and quench it in water, it will aneal it, it will then be very soft, let your solder cool slowly on its own. you can protect parts by using a heat sink small vice grips or whatever, to suck the heat away from anything critical.

as long as you follow that when joining up car wiring you'll never have a problem with bad connections..

even with the typical crimp on connectors, i throw the plastic cover away, slip heat shrink over the wire, squeeze the connector up over the wire and solder it then slip the heat shrink over it.

when you strip wire, it helps to have a decent wire stripper tool, sure you can use a knife in a pinch, try not to nick the wire or loose any strands, use the knife along the wre not around it and cause a weak spot.
then you wont create a weak spot by necking down the thickness of the wire. a good and proper connection won't act like a fuse and blow if the wire is pushed to its limit. i you drop some wires from the twist it will reduce its current carrying ability, a chain is only as strong as its weakest link.

since the wire is thin and causing you trouble Id just solder a bit larger wire to it, something easier to see and work with. if that tip is chromed or you cant solder to it you can always make a few extra wraps that way, to assure it stays connected. the antenna will never challenge the wire thickness because its not enough amps to ever blow the wire or anything like that so the manufacturer saves bout a hundredth of a cent.. that's just how cheap a lot of this new junk is.

on car wiring the wire size usually relates to the current the wire needs to carry, so if its a headlight wire it needs to be a bit thicker. your dash lights could run off wire the size of a thread but the manufacturer didn't cheap out to that extent. as we go further into the future the manufacturers try to save copper where they can, its called a race to the bottom, whoever makes the cheapest garbage wins the contract to make parts. the problem is when you go to fix it, then the wire can be so thin, its like trying to solder human hairs together.. I think that's the issue here so just solder on a wire that's easier to see and work with, if that's the case.
i just bought a new antenna for my volvo I bet its made like that, the OEM one was extendable with a motor, I just stuck a run of the mill pull out one on it, the car is just a runner.

my other volvo had the same thing , antenna was snapped off. I found I could get just the antenna for it and it was so easy to change all I had to do was make it extend until it came out. stick the new one in and make it retract, took under 5 minutes. only cost about 12 bucks or so. if you want you can take a retractable antenna from an old volvo

I put a cheap car cover on my porsche just to keep the pitch off, the antenna doesnt; retract all the way.. so it has to poke out through the car cover.. im not near it but just thinking maybe it could have a volvo retractable one, I think I have a spare. if there is room for the gizmo where its mounted. the motor takes a little space.

it goes up when I turn on the radio down , it uses a timer relay, retracts after about 15 seconds when I park. kind of a nice feature. I initially thought oh it wont be worth fixing, but the extendable antenna alone is on "the rock place" not very much money and so easy to switch, I was pleasantly surprised.

[djnolan]

The repaired connection seems to be OK but hard to say for sure. My Blaupunkt radio went bad so I swapped in an Aiwa. During the swap is when the connector broke. The Aiwa seems to be getting an OK signal but the reason for getting the Blaupunkt was flaky FM reception with the Aiwa. The Blaupunkt was great while it lasted, it even had a fm signal strength indicator. I made sure the antenna booster is getting energized by the Aiwa (blue power antenna wire) but the signal is still not that stable on FM. Is there a way to check the antenna with a multi meter?

Both radios are vintage (20-30 years old) and have removable faceplates to complicate the situation.

[Monkey Wrench]

no you can't check the signal strength with a multimeter.
It is possible with a signal strength meter ( s meter) but they are normally used more for AM short wave and maybe ham bands. thing is its isn't simply how much radio waves are on the antenna but the specific frequencies you are interested in.

https://en.wikipedia.org/wiki/S_meter

probably the best way is by using another radio, you could try other FM radios just to see what difference it makes. you can also plug in an off the shelf replacement antenna to compare.
a lot of the old radios I work on have an eye tube that shows signal strength so you can zero in on the band, they are actually a little cathode ray tube, usually round with a green display that changes with signal strength. often they are displayed on some creative way , they were often a bit of "bling" a sales feature, but they do work..

Ive come across some various neat ones, I have one radio that has a "flashogaph tube" its a neon tube with one long pin and one short pin. as the station would become brighter the light would increase in length. I trued to find a replacenemt , think I even did.. but its a very rare tube, and I havent tested it. i didn't expect to ever find another.

neat but the radio is 1932 same year they went bankrupt.. made by sparks withingham or "fada"
what I did there was bought a kit to build a cascading LED signal strength meter. I glued 30 LED's in a row and connected each one so they cascaded, then I put that inside a test tube and had it sandblasted, so then it had a neat orange glow that displayed through the brass escutcheon..

many are round and green and affectionately referred to as "cats eyes" common in about 1934 until wartime era. 1939 or so when radio manufacturers stopped domestic production, for the war effort.


I have a tube ( hollow state) stereo house component style FM receiver with a really neat and somewhat unusual blue eye tube.. that is the SSR meter so it is possible to havve or add one. its main feature is so you can visually zero in on the station.

If your blaupunkt is OEM ,I'd hang on to that, working or not in case your car is ever wanted to be original.

I had a friend that was into fixing old radios, he morphed into fixing car radios, older ones that were Tube Am radios, a lot who own vintage cars want the right radio..
so instead of actually repairing them there is a kit, it uses some of the knob functions, they gut the OEM radio and hide it inside, then the radio is controlled by whatever buttons and switches are available. so the guy with the 57 chev or whatever has his OEM AM radio with the big chrome knobs for cosmetic reasons but it can "secretly" play FM.

a true car restoration would include rebuilding the radio, not mangling it. mainly changing caps, doing the alignment and tending to any weak issues, there are solid state vibrators. It's all possible. something like that could be a solution if its not worth fixing or beyond repair. in future years you might look at things a bit differently.

likely some issues are bad solder joints so you can go re - wetting solder or get it going with the covers off and try tapping it with a pencil.. sometimes you can find a fault that way, jar the part with the weak connection, maybe locate it that way if you are lucky.

often what happens with old radios is the alignment changes, then they get to be weak receivers. if you can get it on the bench of a guy that likes working on that stuff he can likely rebuild it , recap it, and align it. It might not be your cheapest alternative. likely any other 35 year old radio has drifted a little and won't perform nearly as well as it could with a bit of service and adjustment. alignment can make all the difference int he world..

If you really dig you can get info, and learn more about hte alignment procedure and if you are able to get the schematic for that radio that helps tremendously. It will have a procedure.
there were some books with published schematics, here is a link that will cover most older radios, it probably wont list anything that new on this site,

but if you research it you may find the correct one. there is a forum and there are other forums about radios, generally very helpful people. I got into fixing old radios when the internet came available, The internet newsgroups helped me find the help and information.. I found it interesting to fall down that rabbit hole and stuff half my house with them. wasn't the smartest investment ever ;-) but fun.

this link has antique radio schematics.
Nostalgia Air

this is the boat anchor manual archive.. there is a file in there for Balupunkt.

I do have one Blaupunkt from about 1964, it is tubes. great big huge impressive table radio with very good sound quality. They were miles ahead of the US radio manufacturers in technology. Blaupunkt means "blue dot"

https://bama.edebris.com/

if you even pick up an old radio and are curious or interested about rebuilding it, Id start here on " Phil's old radios" site, read about replacing capacitors first then you can try fixing up some old table radio
this is a great site,very well written, and not full of ads different collectors have different types of gear that interest them, I limit myself at transistor era stuff, some like to restore little portables, they dont fill the house up like giant wooden consoles do..
If you want to get into collecting and want space to live too, I suggest stamps ;-)


this is the entrance to the rabbit hole, after that, I warn you, you aren't in kansas anymore...

https://www.antiqueradio.org/begin.htm