I have a working stock radio in my 73 240z along with a working power antenna in the rear. My question is, can I "splice" in another antenna (say a hidden unit under the dash cover) into the existing antenna? The goal of this would be to get good reception while leaving the power antenna retracted and when I wanted to, I could extend the antenna for giggles, and it would still be functional.

Also, can I hook up an amplifier to the stock radio and push sound through two aftermarket speakers? How would the wiring go from radio to amp?

Most antenna need to be outside of the cab as it is a faraday shield.

Out of curiosity, why don't you want to use the power antenna?

Dennis

There's a small booster amp (I got one at Pep Boys, didn't hook it up yet) that has 40 watts total IIRC, 4 channels with internal crossovers for the treble and bass, it's designed so you can hook the radio's audio frequency (speaker) wires to the inputs, should work with the stock radio according to the instructions (but maybe not as well as with radio frequency inputs). Only problem is the sensitivity and selectivity of the stock radio are kind of weak. Should be able to reduce distortion by turning the volume down on the radio and turning it up on the amp. I'm guessing I'll still have to keep messing with the tuner knob since the radio drifts off station - or maybe it's just that the push buttons don't always come back to the same place. Or both.

40 watts total must be better than the 3 watts or whatever the stock radio has. For some reason my big Sony blaster, that I sometimes run in the car off an inverter plugged into the lighter socket, picks up at least twice as many stations as the Hitachi. I doubt if a booster amp will cure that. Good experiment anyway.

Have a look at some of the antenna options available at retrosound.

RetroSoundUSA.com - RetroAntennas

If you want to attach an external amp to the stock radio's speaker output you'll need a line level converter. It'd probably sound like crap though, 1970s car audio had... a lot to be desired.

Why not look at some of the hidden radios on the market and mount it under the seat. Some of the new units can link to a smart phone to run the radio. I'd use the antenna in the car already and add a magnetic interference shield to improve the radio reception

All helpful info. The reason why I'm sticking to the stock radio is because I will barely be able to hear it anyways (v8 240z). Since my radio works and my antenna works, I want to keep them working. I'm not looking for amazing sound quality, just a small amp that will power 2 6x9's.

As for the antenna, I already have a hidden wire unit in addition to the stock motorized antenna. I want to splice the two antennas together (still haven't figured this one out yet) so that I get good reception when the stock antenna is raised or retracted (I don't want the antenna up all the time). I realize that I could just leave the stock antenna lead unplugged and still have it function (go up and down), but it'd be cool to have it functional.

So, I need a line level converter to covert the speaker wire to RCA for the AMP. What wires are the speaker wires from the stock radio?

Thanks for everyone's help so far.

It is not electrically practical to connect two different antenna's together and have them contribute "more" signal strength that either alone, especially the part about one providing more than other depending on mast position. When I pointed out the retrosound site, it was in reference specifically to the HPA1 amplified antenna systems;

RetroSoundUSA.com - HPA1 Amplified Hide-away Antenna

This device provides a hidden antenna (allowing you keep your original for looks only) that also amplifies the received signal to provide the best possible input to the radio. In the case of the stock radio, this step is critical to get the best you can from it (which ain't much to start with...)

Also, many modern ampliers have speaker level input options that don't require a device to step the signal down to RCA jack line level. It will depend on the amp, so shop carefully and talk to a knowledgable car stereo salesperson about your requirements.

However, all that aside, there is little harm in just connecting the two antenna wires together and see what happens. Each antenna cable has two internal conductors. One in the center (carries the radio signal), and a surrounding shielding sheath which is grounded at either end at the antenna and at the radio. Dig into both wire casings, expose the center conductors carefully and connect the centers of both, and the outer shields of both (keep them separate from each other!) tape it up with masking tape (used if possible) to keep the "ghetto-ness" of this process intact, and hope for the best. You never know....

And just because I can , I checked Google about antenna Y fittings, and guess who has millions of them.... You need the two female/One male version. Put your knife and masking tape away. Now.

Antenna Y Adapter | eBay

Edited September 11, 201311 yr by zKars

Here's the one I have.Kicker Car Audio DX100 2 DX Series 2 Channel 100 Watts RMS Amplifier 08DX100 2 13034041123 | eBay

They're made by Stillwater Designs, see Kicker.com. This model, DX100.2 has 40 watts per channel, it is superseded by a new one that has 60 watts/channel. They have line-level inputs for the speaker wires.

Took me a while to find one, most of the amps for cars are way bigger. If you google small auto booster amps you'll see a bunch of different brands, and some jump starters.

No idea which ones are best.

Thank you for the information. I now have a good enough understanding on how to get this to work.

Only one thing left: are the grey and grey/blue wires coming out the back of the deck into a 3 socket female connector (along with fused blue wire) the speaker wires? Anyone know which is ground and which is positive, or are they interchangeable? And is the red/blue wire for illumination?

Glad to hear we're more help than hinderance.

Blue with the fuse and noise reduction coil in-line is +12 power to turn it on, Red/blue is dash light illumination, remaining grey and grey/Black(?) are speaker - and + respectively. Radio gets ground through its metal chassis.