Railfan Technology > Antenna Foil

I have a magnet mount antenna that needs to have the cable replaced. If I remember correctly, once that foil on the bottom the base is cut, the antenna won't work right.

Does anybody know where I can get the foil tape at? And no, with what it cost, tossing it out is not an option.

Doug Wetherhold
Macungie, PA

It's probably a pretty specialized product developed for the application. If you want to try it, you might try the muffler tape. You can get that at Wally*World (Wal*Mart) or your favorite auto supply place. There is also some metallic duct tape you can get at Home Depot, Lowes, or whatever home / building supply stores you have in your area.

I've never opened up one of these bases. The tapes mentioned above would be good for keeping moisture out but I don't know how it's going to perform electrically.

I know you don't want to toss the old one but that may be the only option. The coax may be crimped and it may be pretty difficult to get a good connection with the new cable or it may not be possible to reach the connection without damaging the mount. It used to be that you could replace just about anything but a crimp job is cheaper than putting a screw in a mounting to hold something.

John

Is that steel or aluminum foil?

Ed

It's soldered on. I already opened it up to fix it. I just made small incisions instead of tearing it off. Mabey if it's now a little less sensitive I won't get blasted out by interference.

Doug Wetherhold
Macungie, PA

The tape is there to keep out moisture and to protect the automobile's paint.

If you want to get fancy, you can clean off the ring magnet with solvent (I like 92% isopropyl alcohol) and smear a very light coat of GE Silicone II sealant-adhesive onto the ring surface.
Take this and place it on a sheet of polyethylene which has been sprayed with "Pam." I use one side of a good-quality freezer bag. Place the lubricated polyethylene onto a flat piece of steel, your auto roof will usu sally suffice for this, and place the silicone adhesive smeared magnet onto the sheet. Allow the adhesive to cure overnight. In the morning, peel off the polyethylene and you will have a soft surface that is inherently "dry-sticky" due to the smoothness and softness of the silicone and a good seal to the roof.

When you replace your cable, you can smear a bit of synthetic grease around the bolt connection area to help delay corrosion.

Or, give the connection area a shot of clear paint like Krylon after carefully cleaning the area and de-greasing it with solvent.

If you can, use stranded center-conductor coax cable, soldered in place. Most of the solid center conductor stuff uses a copper-plated steel center conductor. If a magnet shows affinity for the center conductor, it is likely steel. The plating on these can be very thin which will quickly go away leaving the steel center to rust and eventually fail.

If crimp connectors are used in the mount, try to figure out a way to solder the coax to them. This may involve using a stainless steel "toothbrush" to clean the hardware. I've had a number of really bad experiences with crimp-on connectors. Be sure to use rosin-core lead-tin (not no-lead)
solder.

Be Well,
Tim Colbert K3HX

If you use your scanner in a variety of automobiles, this won't help, but for the record, for years I have used an On-Glass antenna (Antenna Specialists) on my personal vehicle.

I am now on the fourth vehicle - same antenna - and reception is still outstanding. You can buy a "Re-installation kit" for these which contains the adhesive, silicone sealant and other non-reusable parts and allows use of the base, cable, connector, whip and plastic shield several times.

If you move from one car to another regularly, or use rental cars, this won't help. But for the regular train-chasing flivver it's a great deal. I must concede that probably my next change of vehicles will require a new unit entirely - the blackening on the base is about gone and the threads are worn from removing it at car washes.

Bill

Chicagoboy Wrote:
-------------------------------------------------------
> If you use your scanner in a variety of
> automobiles, this won't help, but for the record,
> for years I have used an On-Glass antenna (Antenna
> Specialists) on my personal vehicle.
>
> I am now on the fourth vehicle - same antenna -
> and reception is still outstanding.

Maybe a bit off topic but I used one of these for a couple of years and thought it was great. I lost it on a two lane road when a snow-plow passed in the opposite direction. I was lucky the window didn't go with it.