I am looking for a commercial antenna that I can replace the regular
broadcast antenna on my car with, that would still service the car
broadcast radio but have bandpass/bandblock filters so that I can also use
the same antenna for my mobile 2m/70cm FM radio.

Is there such a beast?

"yea right" wrote in message
news
I am looking for a commercial antenna that I can replace the regular
broadcast antenna on my car with, that would still service the car
broadcast radio but have bandpass/bandblock filters so that I can also use
the same antenna for my mobile 2m/70cm FM radio.

Is there such a beast?

First, I couldn't find you an HF/VHF diplexer, but you can build one.
http://home.datacomm.ch/hb9abx/diplhf6m-vuhf.html

Second, do you have to have both radios functional simultaneously or are you
willing to switch one antenna between to radios? If you're hamming you
probably don't want the BCST radio playing in the background.

Here's my story:
Years ago, I developed an open shield in my van's BCST antenna and I didn't
want to tear apart the dashboard to replace the antenna, so I put a
Motorola-to-BNC adapter into the back of the car radio. From there I
dropped a short length of coax down, ran it under the floormat to a point
behind the seat and connected it to my MFJ magmount's coax. (If I'm hamming,
I disconnect the BCST radio and use the magmount as MFJ intended. I never
bothered to install a switch.)

My $15.95 (last time I bought one) MFJ Dual Band magmount works perfectly
as a substitute for the car's BCST antenna -- AM & FM just fine. BONUS: On
long inter-city trips, I swap out the stock whip for a longer, straight whip
and the BCST reception is just wonderful.