JVC detachable face with auxillary input

Ideally, you need an FM antenna, which is usually a folded dipole loop, looking like a 'T' made of parallel conductor. The input impendance, symbol Z, is usually 50 ohms, so the F 750 may be
F Z50 with bottom of Z not visible.
F=Frequency modulated input
Z=Impedance
50=50 ohms impedance
The number '750' makes no sense, as the FM broadcast band frequency of 88-108 MHz is way below 750MHz (UHF), and impedance at 50R is well under 750 ohms.
Tip:
Although a proper FM antenna is recommended, in good reception areas, such as near a city, a single insulated wire stuck into one 2-pin FM socket or center-pin of a coax FM socket can give reasonable reception.

8-21-2021 FM reception across the band was degrading in sensitivity over time & now barely gets 2 very strong stations . I'm an Electrical Engineer radio designer. I intuited that the tuner's frequency synthesized oscillator could be corrupted / unstable causing a noise that degrades sensitivity. Today I confirmed that the oscillator is indeed unstable from digital noise in the synthesis mechanism. worse at the 88 mhz end than the 108 mhz end. This typical action for a synthesizer. Hope when open it up a simple degraded resisitor or capacitor component in the synthesizer will reveal irtself. Elsewhere someone reported contaminant on the PCB which is also a likely cause of degredation. Perhaps a leaky back-up memory AA battery dripped "acid" on the PCB and just needs to be cleaned ? jerry at jdm labs


8.22. I measured the the spectrum of the FM tuner's superheterodyne oscillator which should be a single pure frequency . Instead at the 2 ends of the band the spectrum plots show it has multiple frequencies spaced about 40 kiloHertz apart which becomes a 40 kilohertz "noise" interfering with the desired signal . The frequency synthesizer is a Sanyo chip LC72131 and I'm searching for the application schematic diagram of the Recepter ( only owners manual is available) to identify which components may have failed or shifted. Hopefully the chip is ok but need to figure that out too.

if there is an auxillary input on the radio you can plug it in through that, if not you need a fm transmitter to do it... you can pick em up at your local radioshack

http://resources.jvc.com/Resources/00/01/15/GET0570-001A.pdf

there isnt one on it buddy ive fitted one of these before the only way is the port in the back

are you sure you have an antenna connected to the radio?????????

I was having the same problem with a jvc kd hdr 30. I Installed it myself over a year ago and never wanted to deal with the issue. Finally, I decided to take a look at it today.
On my head unit, all wires were connected except one blue one with a tag that says "do not connect to power, for remote device or power antenna only." This unit is in a '97' MBZ E320 with no visible antenna; I think it is part of the windshield. In any case, between the wiring diagram in the manual and the harness that is part of my car, I was left with 2 blue wires to choose from, one with a white stripe and one with a gray stripe. After testing both for power or ground, I determined neither had power with key on or off. Both had high resistance ground when compared to the chassis ground. In other words, I measured between chassis and these wires. First, I took a wire and connected it to the chassis ground and connected the other end to the blue wire coming from the unit while tuned to a local am station. This simply killed all reception am or fm but did not harm the unit. Next, I connected the blue wire with gray stripe of the car harness to the blue wire of the unit and again this killed all reception. Then I connected the blue wire with white stripe of car harness to the blue wire of unit and presto magic I had great am reception.
I am guessing that this blue wire with white stripe must be part of the antenna itself or perhaps is a connection that increases antenna power. Maybe 'power antenna' on tag refers to an actual powered antenna (like as in amplified?) and not as in an antenna that rises up out of fender, as I believed.
This may not help the first person with the question, but maybe it will help someone out there who searches for these kinds of answers like I do from time to time.

If this unit worked in the past, and there have been no repairs done that would have disturbed the connections, then its quite possible that you accidentally engaged the mute feature. 
Good luck...

best thing is to pull the radio out and check the red and yellow wires red wire is the egnition switch and your yellow is the always on for your memory if you like you can connect the red and yellow wires to the yellow one that will work with engine on or off but every time you get out the car you will need to turn the radio off manually i sugest pulling the radio out and checking the 2 leeds as far as you can it could also be a fuse gone but it wouldnt work when enging is off so not sure except check the wires your engition switch doesnt play up does it like your dash clocks go off and on while driving headlights etc? need more information please

Try 0000 or 1234....