ka3jjz
Wiki Admin Emeritus
We've all read the horror stories of how someone forgot to disconnect their antenna and the radio got zapped - or perhaps how static electricity fried some portable's front end
Let's face it; there are going to be times when you will forget to disconnect the antenna (and ground it away from the home, of course).
There is also the problem of too much antenna. Little portables like some of the Kaito models simply aren't designed to handle the amount of RF a 50 or 75 foot antenna can deliver, particularly on the East Coast of the US. It would be nice to be able to add a little attentuation from time to time when it's needed.
The JPEG below is a schematic of a simple box anyone can build. The parts can be had at any decent hamfest, and it's a great first timer project.
It might be necessary to replace the diodes with something like a small light bulb if you are using a good sized antenna in an area like northern NJ or NYC (my home area) where AM signals are very strong. It's just possible that the diodes could begin to rectify and cause noise and other issues.
In fact this is also a good addition for those using the Carpet Loop antenna- it can be put right into the switchbox with very little effort.
The JPEG is below...it comes from an older ICF2010 page, by the way. Adjust the input plug to whatever is needed - it's not all that critical
Mike
Let's face it; there are going to be times when you will forget to disconnect the antenna (and ground it away from the home, of course).
There is also the problem of too much antenna. Little portables like some of the Kaito models simply aren't designed to handle the amount of RF a 50 or 75 foot antenna can deliver, particularly on the East Coast of the US. It would be nice to be able to add a little attentuation from time to time when it's needed.
The JPEG below is a schematic of a simple box anyone can build. The parts can be had at any decent hamfest, and it's a great first timer project.
It might be necessary to replace the diodes with something like a small light bulb if you are using a good sized antenna in an area like northern NJ or NYC (my home area) where AM signals are very strong. It's just possible that the diodes could begin to rectify and cause noise and other issues.
In fact this is also a good addition for those using the Carpet Loop antenna- it can be put right into the switchbox with very little effort.
The JPEG is below...it comes from an older ICF2010 page, by the way. Adjust the input plug to whatever is needed - it's not all that critical
Mike
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