Radios that have the ability to disconnect the internal ferrite rod

[formula72]

Not sure if this is in the right forum, but I figured I'd ask. I was unable to find any topic on the matter, via a google search.

I was reading Jay Allen's review on the new Tecsun PL-330, and he stated " the PL-330’s ability to disconnect the internal ferrite rod and use an external antenna on AM makes it one of the very few modern portables to allow this option".

OK, what are the "very few modern radios" he's speaking of?

I know of only three now.
Sangean 909x ( not sure if the standard 909 has this ability also )
Tecsun PL-990X
Tecsun PL-330

 

[Schroedingers Cat]

You'd be surprised what radios you can just inductively couple to an external antenna and have the same effect. For some reason, I haven't been able to do this my Tecsun that way effectively.

 

[boombox4]

Sangean 909 does. No sure about the ATS818, as I don't have the schematic handy, but it might also.

 

[formula72]

You'd be surprised what radios you can just inductively couple to an external antenna and have the same effect. For some reason, I haven't been able to do this my Tecsun that way effectively.

Inductively coupling is pretty good, but coupling an external antenna via a wired connection gives you much better results.

Last night, I had a blast with my new PL-990X with a 20" PK HD series loop. I was hearing stations from all over the place. Up until this point, I have been doing all my MW DXing either barefoot or inductive coupling.



"For some reason, I haven't been able to do this my Tecsun that way effectively".
If you are referring to the Tecsun AN-200, I do not think the "ant out" works. Seems this is a common problem.


I'm not sure why more of these portable radio don't have this great feature. Removing/disconnecting the internal ferrite, means less noise when using a wired connection. This feature "should have" been implemented on all moderately priced ( $100 plus ) radios years ago.

Are there anymore radios we can add to the list?

 

[jim-satx]

I believe that my Sony 7600GR has this capability. When I plug a wire into the antenna port, AM reception no longer changes when I rotate the radio. I need to get myself that 20” PK HD loop or something similar.

 

[boombox4]

In my opinion, inductively coupling an external antenna is much better. #1, you just make or buy a bigger loop to DX with, and the directionality is preferable to that of a longwire, which is fixed, and a longwire can overload a portable, or zap the RF amp FET transistor if the radio has no internal diode protection. #2, by inductively coupling, you can vary the gain just by moving the loop and the radio, no need to adjust RF gain controls, which many radios (most radios, actually) do not have. Varying the distance between radio and loop also adjusts selectivity somewhat. It's also more portable to use than a longwire.

I have used longwires with some radios before, mostly on SW, but I used to do it on MW with my FRG-7 and DX-160. And yeah, I heard DX, including Hawaii and Japan. I also got lucky -- I didn't blow the RF amp on either radio. Luckily, we don't have static charge inducing weather here in Western WA very much. Ironically, I got better MW DX with a 3 ft. spiral loop and a boombox, but that's another story...

As for radios I know about that have external antenna switches or jacks that disconnect the internal loop antenna, the DX440 / Sangean 803A has a switch, the DX398/Sangean 909 has a stereo jack for the external antenna jack and a plug can be wired to disconnect the internal loopstick, and the Sangean ATS805 RS 200629 has a similar external antenna jack, with which the internal loopstick can be either overridden or disconnected. Some Grundigs (Satellites and maybe some others) have switches that switch between internal and external, and I'm guessing they may disconnect the internal loop antenna (when switched to 'external') as well.

 

[Schroedingers Cat]

I mainly used my long wires on an old 1938 Westinghouse tube radio. That allowed hearing KPMC 1560 when WQXR signed off, and XEOY 1000 when WCFL signed off on Monday Mornings. The other uses were in rural areas where there are few strong signals. I always was careful to tune the loop away from the strongest signals and turn the RF Gain down to avoid potential problems with solid state receivers.