semi automatic radio antenna

[Harlan]

does anyone know where I can get a new semi automatic electric radio antenna

I have the toggle switch to the left of the steering wheel so it seems that I can 

not use the fully automatic ones that are readily available.

Harada had a MX-1 but I can't find it anywhere

help most appreciated

thanks

Harlan

[WayneC]

This one is very similar, but 1/2" shorter in under-fender length than the MX-1:

   https://www.ebay.ca/itm/HARADA-MT-1-Triway-CB-AM-FM-Mini-Power-Antenna/163466564008?hash=item260f5dd1a8:g:7uQAAOSw2~NcLq4K:rk:7:pf:0&vxp=mtr

Have you tried Nostalgic Motorcars? Have you asked a car radio installation business if they can get one for you?

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Finding a semi-automatic antenna would be the easiest solution, but it may be possible to do some relatively minor rewiring to use a fully-automatic antenna....

Automatic antennas get their 12v signal from the radio; not all radios have the capability to send that signal. A radio repair shop can probably add it to your radio... that requires radio removal, which isn't easy, but this is the best solution for the driver.

An automatic antenna requires 12v on one terminal on the antenna to raise it and 12v to a different terminal on the antenna to lower it, with a delay before shutting antenna motor power off after having raised or lowered the antenna. That function is provided by an antenna delay relay, either housed inside the antenna assembly or in a separate relay box (but likely internal to the antenna if it is an automatic antenna).

Your Avanti already has circuitry to raise and to lower the antenna and to turn the antenna power off after the antenna is raised or lowered... that function is being performed manually by the antenna toggle switch.

If your current antenna is the MX-1, then flick the switch up to raise the antenna, down to lower it.

There should be two 12v leads at your antenna, one to raise it and one to lower it. You can check those for 12v while someone operates the switch, to find out which wire is energized when the antenna switch is raised, and which wire is energized when the antenna switch is lowered (it is possible the "lower antenna" wire is always energized, but probably not). Once you know which wire in the trunk does which, then using a fully automatic antenna should be easy.

An "automatic" antenna has a terminal in its electrical harness connector to receive 12v from the radio, and another connector to receive 12v directly from the battery. Internally, there is a relay that is energized by the 12v "raise antenna" signal from the radio to raise the antenna and keep it raised; when the "raise antenna" 12v signal is removed, power is switched to the "lower antenna" output inside the antenna and when the antenna is fully lowered, it cuts off that battery power to the antenna motor.

You can use an automatic antenna if you provide direct 12v battery "lower antenna" power to the proper terminal on the antenna harness connector, and provide the "raise antenna" signal to the antenna with a toggle switch that applies 12v to the automatic antenna's radio power terminal. The power to the switch must come from a wire that is energized only when the ignition switch is in the "on" and "accessory" positions. Then just leave the "on" knob on the radio itself always turned on. Flick the toggle switch to "on" to power the radio and raise the antenna, "off" to turn the radio off and lower the antenna. If you forget and leave the toggle switch in the "on" position, then when you turn the ignition off, the antenna will lower anyway; when you start the car next time, the radio will turn on and the antenna will rise.

 

 

Edited January 21, 2019 by WayneC
correction & clarification

[chuck]

I put a Custom Auto Sound radio in when the original failed and put an automatic antenna in also.  With a little creative wiring I was able to use the original wiring, eliminate the switch, and have the antenna go up and down when I turned the radio on or off or down when I shut the car off with the radio on and back up when I start the car if the radio is on.  It is better than having to use the switch.

chuck

RQB-3553

Edited February 3, 2019 by chuck