Has anyone experimented with running a loop (Wellbrook or similar) into a modern portable (PL-880, etc.)?

ka3jjz

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I'm pretty sure I've seen folks using a PL880 with a W6LVP or similar...should work fine. You might want to construct a pigtail that goes from the male end (to plug into the 880) to a SO239 or similar. That way you don't stress the 1/8 inch ext antenna nearly as much as connecting coax directly to it.

Mike
 

ka3jjz

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I would also strongly suggest joining the PL880 reflector on groups.io. Even though the group has pretty much died out because of the H501X taking the top spot for Tecsun, you still might find someone there that has actually used an active loop with this radio Mike
 

KB2GOM

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I would also strongly suggest joining the PL880 reflector on groups.io. Even though the group has pretty much died out because of the H501X taking the top spot for Tecsun, you still might find someone there that has actually used an active loop with this radio Mike
I took your advice and posted a message there. The moderators have to approve it. We'll see if there is any response.
 

caboose101

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Hi Jock, I'm responding from SWL-ing Post. Been a member of RadioReference for several years, but not very familiar (comfortable) with the process here, so please excuse my ignorance. The full description of my most recent SW loop is attached. I've submitted it to Thomas for archiving. Regards, Bob.
 

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KB2GOM

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Hi Jock, I'm responding from SWL-ing Post. Been a member of RadioReference for several years, but not very familiar (comfortable) with the process here, so please excuse my ignorance. The full description of my most recent SW loop is attached. I've submitted it to Thomas for archiving. Regards, Bob.
Bob,

Thanks for the info; I have downloaded it and will study it, although -- truth be told -- I am not real handy at construction projects.

Did you read about my "horizontal room loop"? Is there anything that could be done to improve that?
 

caboose101

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Jock,

1. In truth, I can't recall ever having a large, horizontal, untuned loop, although, I'm sure I taped long wires around the ceiling once or twice in my time. My loops are "electrically small," i.e., a small fraction of a wavelength.
2. I can't see from your horizontal loop article where the unun comes in as mention in your recent SWLing posting. Again, I have never played with ununs or baluns. I think they must be relatively new, as I don't recall reading much about them years ago. I don't think toroids were very common. We just used impedance matching transformers. The turns ratio on the unun is not absolute. Also, the impedance match should change with frequency. I would try to experiment with that. You might wind up with 3 or 4 ununs for different bands.
Regarding locally-produced (in-house) noise, this is where a proper loop can really help. Noise is usually polarized, and the loop has to be pointed in a direction to counter it. I find that this direction changes as circumstances dictate. As an alternate approach, I would try to identify the noise sources and neutralize them if possible. For example, I have 3 or 4 of those switching "wall warts" I unplug before listening to the radio.

Bob
 

mbott

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Back when I bought my Sony 2010 in 1991, it came with two antenna connectors (as pictured below). I routinely use the one shown to connect any of my portables to my Pixel RF Pro-1B. The second connector is attached to about 75' of wire I can string out anytime I need a random wire.

--
Mike

IMG_20211015_202308076.jpg
 

caboose101

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Those original connectors are like gold to 2001/2010 aficionados. Was a time you could sell them and use the proceeds to pay off your collage loan or mortgage, then by a pair of regular phone plugs from Radio Shack for 98 cents. Hi! Hi!
 

mbott

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Those original connectors are like gold to 2001/2010 aficionados. Was a time you could sell them and use the proceeds to pay off your collage loan or mortgage, then by a pair of regular phone plugs from Radio Shack for 98 cents. Hi! Hi!
They were well made and designed right for the job. Shame they only sent two. :)

--
Mike
 

caboose101

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Please excuse me if this has been covered in the past. I post it on the chance that someone not aware may be interested in the modification, which permits direct connection of an external long wave or medium wave antenna to the PL-880. You may be aware that there is an "undocumented feature" of the PL-880 which more or less works, but is only temporary. A few years ago, a chap named Geir Laastad discovered that the external antenna jack is a stereo jack and the center (ring) terminal is not used. In short, this permits one to wrap a 5-turn transfer coil around the ferrite bar, and terminate one side of it on the unused external terminal (the other side of the coil is grounded to the circuit board). He wrote the attached article detailing the process. Subsequently, I found the trick also works on the PL-600, -660, and -680. My description for these radios, along with a couple well-known alternate approaches for attaching external LW and MW antennas is also attached.

Keep in mind, the internal ferrite antenna remains attached and functional with any of these external approaches. The end result is that any improvement when using long wires, dipoles, etc. depends on the gain of the external antenna relative to that of the internal ferrite bar. On the other hand, use of a resonant loop produces some dramatic improvement in signal strength, nulls, and noise reduction.

Also, keep in mind use of the center ring terminal on the jack requires corresponding wiring of a stereo plug on the antenna. Since many external antennas are equipped with monaural plugs with the tip hot, this requires some further modification. I worked around this by wiring up a simple, short adapter cable with a monaural jack on the antenna end and a stereo plug on the radio end. The adapter cable is then used when listening to LW or MW. For shortwave, no modification to the plug is necessary and a monaural plug will work normally without the adapter cable.

Good DXing.
Bob C.
 

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KB2GOM

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I would also strongly suggest joining the PL880 reflector on groups.io. Even though the group has pretty much died out because of the H501X taking the top spot for Tecsun, you still might find someone there that has actually used an active loop with this radio Mike
Mike, I tried to post the question on Thursday and got a response that it needs to be approved by moderator before posting. I have heard nothing since.
 
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