So I'm putting a new audio system into my FD, and ran into problem with the antenna wiring. Crutchfield supplied me with the correct male-to-male Motorola type antenna adapter, which allows me to plug the radio's antenna lead into the larger of the 2 antenna feeder cables under the dash, but I need an adapter that connects to that 2nd smaller diameter antenna feeder under the dash instead. Does anyone know the part specification for that connector so I can build one, or someplace that sells such a beast outright? It just looks like a miniaturized version of the standard Motorola coax connectors.

Reason I need to do this is because the car no longer has the power mast antenna - PO removed it and had the hole welded over when the car was painted, and I don't want to drill a new hole in the sexy body work just to install an antenna. So my game plan was to try to use the 2nd radio antenna Mazda provided that is embedded in the rear window glass - but that stupid non-standard antenna connector seems to have kaboshed that plan.

Cheers,
Pete

 

It's called a diversity antenna, if it helps. I've been looking around the forum, there's a lot of talk but haven't found a direct solution reference yet.

Found this solution, but not clear it works for our application: https://www.bonanza.com/listings/Div...iABEgJadvD_BwE

Might be worth a try for the price.

Here's an interesting thread about it https://www.rx7club.com/interior-ext...to-1-a-450022/

You may have compromised reception using just the glass antenna, it's the weaker of the two.

 

Nope, that particular adapter won't work in a FD application because it's not a male-to-male type adapter. FWIW, if a radio/head unit does have 2 separate antenna inputs to support the FM diversity feature, you really need two separate antennas with two separate feeder lines for the diversity feature to work properly - this adapter (and any other "Y" wire adapter) will just wire the 2 antenna feeds into one, defeating the FM diversity feature. The way FM diversity works is the tuner samples the available signal from 2 distinct antenna input channels, and uses the one that has the most favorable SNR (signal to noise ratio) at any given time. That said, if you are installing an aftermarket radio with only 1 antenna input, you don't need a "Y" adapter; you just need to connect to 1 of the 2 antennas (with appropriate gender adapter if necessary) and leave the remaining one unconnected. If I still had my mast antenna, I would just connect to that one (the female Motorola coax receptacle, which is the larger diameter of the two.).

I found that thread in my search too, I understand the window glass antenna won't work as well as the mast, but it should be good enough for most of my FM listening (< 30 miles from FM stations, minimal terrain). I never listen to AM, and FM reception isn't a big priority - most of the time I'll be listening to music streamed from my phone or USB stick. BTW, I suspect the reason Mazda uses a different connector for the glass antenna is because they needed to specify a lower loss transmission line for that antenna to be of any use, so the connector decision was driven by the cable type.

 

I wonder if you could salvage a snip some male connectors

 

This adapter plug has worked for other vehicles with diversity antennas. It should allow you to plug your standard Motorola male to male antenna line to the smaller FD female antenna connector.

SCOSCHE MDAB 1988-05 GM Micro/Delco Antenna Adapter; Tip only

 

I would give that adapter a try.

For my car I removed the antenna as well and I got an "internal" antenna. I can't find the one I got, but this one is a better one than mine -


I pretty much NEVER use my radio, have an old iPod hooked up with 40 gigs of music. But it is nice to have the option.

Dale

 

Upon closer inspection, this adapter appears to connect to an aftermarket radio with the standard Motorola antenna, allowing the smaller male Delco oem to plug in.

What you need may actually be this reverse adapter:

Scosche MDARB Reverse Antenna Adapter for 1998-05 GM Vehicles

https://www.scosche.com/ant-adp-micro-delco-rev

Features1988-up GM Micro/Delco Antenna Adapter (Reverse)

For use when replacing original factory radio

Aftermarket Antenna Female (Motorola Plug) to Factory Radio Male (Proprietary Plug)

 

That thought did occur to me, though the odds of finding one at the closest pick & pull yard are slim to none.

^Now THAT adapter looks promising; guess I'll buy one from a shop with a good return policy and try it out. I'll let you guys know how it turned out.

Same here Dale, I don't listen to FM radio much when I'm driving the 7's. If the reception with the window antenna sucks, an internal antenna might be worth a try.

 

Quick update. I tried this antenna adapter, which looked like it would fit and work - Scosche MDARB Reverse Antenna Adapter for 1998-05 GM Vehicles https://www.scosche.com/ant-adp-micro-delco-rev

Unfortunately it doesn't fit well enough to make a solid RF connection. The diameter of the center pin and shield conductor fits the factory antenna receptacle, but because of the larger diameter the plug base where it crimps on to the cable (see picture), you can't shove it far enough into the receptacle to get a good contact. As it stands now, I can pick up louder static now and maybe 1 or 2 very local FM stations.

 

Don’t give up buddy !

 

If another solution isn't readily available, can the larger diameter plug base be slit to compress further into the factory diversity antenna female connector?

It doesn't seem like other Mazda radios from the late 80's/90's use the same diversity antenna connector. Can anyone confirm?

 

Actually had a similar idea - take that new adapter plug and put the larger diameter shoulder portion of it in my cable crimpers with suitable dies to squish it down to size. Looks like that's do-able without compromising the cable or connection. I have one of those Harbor freight hydraulic crimpers that I use for battery terminal lugs; some of the smaller dies that come with it might fit. Will have to wait till I get back from another biz trip though.

 

any reason why no one is just snipping the coax and adding a new standard motorola male connector? it's coax, so you can roll-your-own to make y-cables or whatever you like. it's perhaps a little hard to reach in the dash, but could definitely be done. both coax are the same gauge too.

​​​​​​total hack job that I'm correcting, but 18 years ago I snipped the ends, stripped the wire and jammed it into the head unit's female antenna connector. I then used impatience and tape to secure it. no actual plug. it's held since 2002 until I ripped the old Deck out the other day.