Tom, the Jetstream JTM3BM is about 43" from top to bottom including the
mag-mount base. It is a 1/2 wave on 2 m and two 5/8 waves on 440. However,
if your other mag-mounts didn't work, I doubt if this one would; though,
admittedly, it out-performs my other two mag-mount antennas. Jetstream sells
one that is even better than the one I have in terms of the gain. The only
reason why I didn't purchase the other one is because it has more coils in
the whip and presents slightly more wind load, and I was afraid it might
come off the top of the van when we were traveling at high speeds on the
interstate. Here is the information on the other one I almost purchased that
has slightly better gain figures:

JETSTREAM JT7505BM
Dual band (2m/70 cm) mobile antenna with mag-mount
3.5/6.0 DB gain -- R & L price: $49.95

As you can see, it has 3.5 db gain on 2 m compared to 3 db for the one I
purchased and 6.0 db on 440 compared to 5.5 for the one I purchased. For my
purposes, I felt the lower wind load out-weighed the slightly higher gain.
So, I purchased the JTM3BM. There is a difference of $10 in the price, but
that was not a factor at all in my decision. For you, if you want every
possible db gain you can get, the JT7505BM might be a better choice for you.
It is also slightly longer, by about 1 or two inches, I believe, in case
that is a consideration.   

My suspicion is that you are just in a very poor place with too many
obstacles that are blocking and/or shielding your signal from getting out.
Evidently, you don't have a window that you can open, right? If you did, you
could jury-rigged something that would work.

Ron, K8HSY


-----Original Message-----
From: For blind ham radio operators [mailto:[log in to unmask]]
On Behalf Of Tom Behler
Sent: Friday, November 22, 2013 1:17 PM
To: [log in to unmask]
Subject: Re: Jetstream, JTM3BM,

Ron:

How long is this antenna?

I am still struggling with accessing the local 2-meter repeater in my area
from my University office.  The repeater is only about 10 miles from my
office, but my office window is facing exactly in the wrong direction. 
Furthermore, the steel in the office building, and all of the computer
electronics in my office and the offices around me are, I think, further
degrading my situation.

I've already tried a magmount antenna with a cookie sheet as a ground plane,
but no joy.

This antenna may be worth my looking at.

Tom Behler: KB8TYJ

----- Original Message -----
From: "Dr. Ronald E. Milliman" <[log in to unmask]>
To: <[log in to unmask]>
Sent: Friday, November 22, 2013 2:03 PM
Subject: Jetstream, JTM3BM,


> Colleagues, just to share with you, I received a new Jetstream, JTM3BM,
> mag-mount antenna today from R & L Electronics. This is a dual band, 2
> meter/70CM antenna rated at 3 DB gain on 2 meters and 5.5 on 70 CM. I am
> extremely impressed with this antenna. It is very well built, has an
> excellent magnet and out-performs any of my other mag-mount antennas. The 
> 2
> meter repeater is about 25 miles from me, and I can hit it easily, at full
> quieting, on 1 watt with the new Jetstream antenna. It was only $39.95 
> from
> R & L, including the antenna, base, and 16 1/2' of coax. If you are 
> looking
> for such an antenna, I highly recommend this one.
>
> Ron, K8HSY
>