View Single Post
  #5 (permalink)  
Old 06-29-2018, 5:34 AM
hertzian hertzian is offline
Member
   
Join Date: May 2009
Posts: 2,328
Default

Display noise and alternate fix:

Noticed that if you hold your thumb over the display you can induce slight noise on weak AM signals, especially when listening to the speaker alone.

So don't hold your thumb over the display or do a top-pincer type hold when rotating it for least noise. It may make the peak / null harder to find - and when you let go you may not be in the best position.

You can also induce noise a little bit by holding the unit say with your left hand, and your thumb fully extending to the top just to the side of the display. Or holding it in your palm strangely by the top half only.

Seems like body capacitance near the display is not a good thing. The worst way to induce this is to hold the radio in your left hand with thumb over the display, and with the other hand, hold the bottom of the radio where the loopstick is. Normal people, even dx'ers aren't going to hold the radio this way!! But I think when listening to weak dx, your hand can provide an unwanted path between display and loopstick. Again, mostly notable when you want to pretend that this pocket radio is a handheld Drake R8B.

Ok, NOW I understand the option to disable the display entirely if you notice this issue. I didn't at first because of this workaround which seems to work just as well:

Instead of using the display-off feature, when you are listening to speaker only, plug in the headphones! You won't hear anything from them, but they seem to provide some sort of additional groundplane to the unit lowering the overall noise. It still does not seem to be an antenna for AM, distorting the pattern. That's great.

So if you are dx'ing very weak signals, with this thing, just keep your thumbs/hand away from the display, AND even if you don't listen to headphones, just leave them plugged in and tossed across the desk. A slightly lower noise floor on weak am signals is now noticeable.

I don't know exactly what's happening, but it seems to work just as well as turning the entire display off.

And now I know why some reviewers said that the display-off feature didn't do anything. That's because they were either listening to AM with headphones already, or weren't holding it abnormally forcing the noise issue by providing an easy path from display to antenna.

So now when I'm holding it and dx'ing a weak station, my thumb now rests to the left of the speaker instead of up near the display and I keep my fingers below the display as well on the back. No biggie, since I listten to mostly local stations, but occasionally I'll dx. Now I know how to get the best out of it when dx'ing.

Last edited by hertzian; 06-29-2018 at 6:03 AM.. Reason: Path from display to antenna and fix
Reply With Quote