Mobile AM dx antenna mod?

[BostonB]

Hi everyone,
Brand new to the site, and have a question I haven't been able to find any info about. I picked up a Sangean DT-400W pocket radio for use while backpacking in the mountains of New England. I'm hoping to be able to pick up AM transmissions of baseball games in the evenings, and am hoping that skywave propagation will make it down into the canyons. Problem is, though, while the radio is small, due to the built-in ferrite core antenna, it is heavy. If any of you backpack, you know how important it is to reduce weight. So, my thought was to remove the ferrite core antenna, and substitute a home-made wire antenna, like the comm wire antennas we used to make when I was in the Corps. I haven't been able to find anything on portable antenna design for AM radios, however, just HF, FM, etc. Any suggestions as to patterns, length, etc? Thank you very much!

 

[Wire Weasel]

Yep,

No more than 25 feet of small wire, say stranded 20 or 18 gauge with insulation. Solder an alligator clip to one end. Attach the clip to the wire or connection on the radio where you are removing the ferrite core antenna. Then stretch the wire out and hang in a tree branch at the campsite. Roll up around your hand and tie with a twist tie when not in use. Small and lightweight.

Any much longer wire and it will be picking up too much signal which tends to overload and distort the reception on the little portable radios.

Good luck

 

[Captain Kilowatt]

A ferrite AM antenna is actually a transformer and I don't recommend removing it. It weighs all of what, a few ounces, and that won't be an issue backpacking trust me.It provides a tuned circuit on the front end of the radio and helps filter out of band signals.Connecting a wire directly to where the ferrite bar antenna was wired too is asking for front end overload with no selectivity of out of band signals. I would suggest either using a long piece of wire and wrapping one end around the radio itself thus coupling the RF into the ferrite bar inside or better yet modifying it as seen in the link below.

Modify that AM*antenna -- on hard-core-dx.com

 

[VA3ES]

Removing that ferrite antenna may be the last thing you want to do. Some ferrite antennas are bifilar wound, with one winding being the antenna, and the other winding being the local oscillator coil. Remove the ferrite antenna, and the radio may stop working.