Instructions on how to install a new inexpensive power antenna to work with the OEM antenna up/down switch.

When I purchased my 1972 Fairlady Z-L it only had the 8-track face plate and a loose antenna switch. The 8-track unit itself was missing. I purchased an old 8 track off ebay, 3d printed some parts to build a mock up unit. It does not play but cartridges can be inserted, the buttons work and it looks original. The up/down switch is secured and functional.

I am in the process of putting in a secret audio head unit so that I have a radio and use Bluetooth. I wanted to replace the manual antenna with a power antenna. However new antennas operate differently.

Original antenna uses two wires, power one and the unit goes up, power the other and the unit goes down.

New antennas operate like this;
up - power to both red and green wires
down - power to red wire only. (however I discovered that the antenna needs a pulse to both wires first to turn it on.)

I achieved this with the use of three bosch type relays, a capacitor (1000 microfarad) and resistor (10k Ohm) to provide a pulse to the green wire.

The capacitor/resistor powers the third relay for about 0.5 Seconds

Relay 1 and 2 for up ensure that the circuits are isolated from the down wiring. Relay 3 provides the pulse to green for down. 
 

5 hours ago, scotta said:

a new inexpensive power antenna

Problem is those antenna's are not worth looking at.. leave alone the hassle to install them.. they work a few weeks or month and break down.. those relais probably cost more than the antenna, buy a good antenna or don't do it at all..  just my 2 cents..

On a different not the fuse box cover is very interesting. what cars got that version? The parking lights switches and maybe defroster switch?

10 hours ago, Patcon said:

On a different not the fuse box cover is very interesting. what cars got that version? The parking lights switches and maybe defroster switch?

It is a 1972 Japanese domestic market fairlady z. Yes it has a rear window demister switch and the two parking light switches. Plus the  8 track radio

 

I too wanted to have my antenna work with the original switch, and replaced my antenna about two years ago with a MQ-1 semi-automatic unit.  I followed the work found here: 

http://jarvas240z.blogspot.com/2015/05/amfm-antenna-upgrade.html

So far it's been great, no complaints

 

3 hours ago, 2377kN said:

I too wanted to have my antenna work with the original switch, and replaced my antenna about two years ago with a MQ-1 semi-automatic unit.  I followed the work found here: 

http://jarvas240z.blogspot.com/2015/05/amfm-antenna-upgrade.html

So far it's been great, no complaints

 

That was my starting proposition. However because of the need to pulse power on both wires (for the antenna I had) before removing the green power to make it go down, I had to modify the circuit. 

 

On 1/5/2020 at 7:31 AM, 2377kN said:

I too wanted to have my antenna work with the original switch, and replaced my antenna about two years ago with a MQ-1 semi-automatic unit.  I followed the work found here: 

http://jarvas240z.blogspot.com/2015/05/amfm-antenna-upgrade.html

So far it's been great, no complaints

 

Patcon. the design of that circuit also uses a separate 12 V supply that would have to be routed.

I've also simplified the circuit such that it only uses the 12V coming from the original switch. i.e. no additional 12v wiring needed. This keeps it very simple to put in.