Decent HF/MW/FM Radio

[iowajm780]

What do you use for a good quality radio that does not cost a ton?. Looking for excellent AM performance especially in a portable unit. I recently found an old Radio Shack DX390 that was in bad shape. I had to disassemble it to clean out all the crap from it. The only issue is the FM tuning is off by 100 KHz which probably the 10.7 MHz IF has drifted. It's not a big deal as the MW band comes on hot. If I get around to it I may try and adjust the pots for the FM IF. That radio must be at least 25 years old. The hot MW band on it is nice to pickup a couple of distant MW stations from Chicago here in Iowa so a nice new radio would be great. There are quite a few out there and I don't believe Amazon reviews.

 

[Boombox]

Hook up a short, indoor wire to the EXT antenna jack and you can DX the HF and HF Ham bands with it. DX-390s are very usable for that sort of thing. When you next take it apart, I'd suggest soldering two back-to-back diodes between the antenna post and the negative side of the battery. Can be done with hookup wire, with the diodes shoved in the corner somewhere (if memory serves). The DX-390s didn't come from the factory with static protection.

 

[ka3jjz]

Be careful with putting back-to-back diodes like this. Under some high signal conditions, these could start to rectify and cause noise all over the place. Better to use the method detailed in this thread...

Static drain for outside long wire antenna

Up until now I've used the old tube radios I collect and restore for DXing. I use a 50' outside wire for my antenna. Static (other than lightning) isn't a problem for tube radios. But I decided I wanted to try one of the new portable radios and ordered a Tecsun PL-880, which should arrive in a...

forums.radioreference.com

Mike

 

[majoco]

The only issue is the FM tuning is off by 100 KHz which probably the 10.7 MHz IF has drifted.

I doubt very much that the IF can drift that much - especially if you can still receive signals - all of the IF transformers won't drift in unison. More likely the FM local oscillator has shifted. Just be careful going in there without some service notes and a few bits of test equipment.

 

[Boombox]

Used my radio for over 10 years with the back to back diodes, on both my DX-390 and DX-440, and never experienced any problems.

However, I also didn't have to worry as much about static discharges frying the RF amp transistor.

Also, the static drain project linked upthread, which is undoubtedly a useful appliance, won't do diddley if you walk across the carpet during the winter and happen to grab your radio and your hand touches the whip antenna, which could still conceivably fry the RF amp.

At the very least, the OP can wire 'em up, and his radio will be protected. If he does indeed get 'noise' from back-to-back diodes (which are usually included in the circuitry of later models of Sangean radios, the main difference being they are included in the antenna circuitry on the main PCB), he could always undo the mod easily.

 

[ka3jjz]

The mod also includes creating a crude RF Gain control, something many smaller portables don't have. All they generally have is a DX / local switch, and sometimes that's not enough or too much reduction. Mike

 

[Boombox]

The DX-390 has an RF gain control, so in the OP's situation, one of those really isn't needed, although if he uses a long outdoor wire, the extra protection and control could be beneficial.