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HF/MW/LW Equipment - For general and technical discussion of all receivers which cover the HF bands. For HF tranceiver discussion please use the Amateur Radio Equipment forum above.

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  #41 (permalink)  
Old 01-28-2018, 3:08 AM
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In answering the preceding question, I took out the 200629 and gave it a listen again. I think the issue on SW I'm seeing is internally generated... a birdie of some sort, which either I never noticed before, or has somehow appeared on SW. Just tuning across the SW spectrum, I found 11 or 12 of them. The few SW stations that are coming in well tonight are clear as a bell, except for one on 5830 that seems to be near a birdie.

Whether these birdies are RFI or an internal defect, or just something I never noticed previously I don't know. I will load batteries into the radio over the next few days and take it away from the house to make sure it isn't RFI. If it is RFI, my other radios (DX-398, which I also tuned tonight) don't pick these up. Which leads me to believe they're either birdies or a result of poorer filtering and RFI overloading the radio in some way.

Wonders never cease in the radio hobby...
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  #42 (permalink)  
Old 01-28-2018, 7:38 AM
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There's a new litter of "wonders" born every day in this hobby!
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  #43 (permalink)  
Old 01-28-2018, 1:09 PM
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To follow up: I took the radio out in the car... the strongest of these ten or so signals (9820 kHz) still came in, even with the antenna down, and the DX/Local switch set to Local. It's obviously a birdie, as are the others. Whether this is a new defect, or was always there and I just didn't remember it, I don't really know.

I'm not about to rip apart the radio to find out -- anything like that would be a microprocessor function anyway. Just live with it. Most of the HF spectrum seems unaffected, as well as MW and LW.

The radio hadn't been used in maybe a year or more. Had batteries in it, which died. No leakage, though. It's either birdies or the microprocessor acting up. I'll run it through its paces over the next few days, maybe it's a glitch that will clear up with a reset.

DXed the MW a bit with it last night. Picked up 1660 KBRE the Bear readably.

Stay tuned.
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  #44 (permalink)  
Old 01-31-2018, 12:46 AM
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Well, well, well.

Did some SWLing on my 200629 the past couple evenings / mornings. Heard a lot of stations, with very few actual 'birdies'. Then, this evening, I unplugged the headphones.

All of a sudden the radio acts like it's being utterly overloaded. When I move my hands close to the radio, there is a varying whistle noise -- almost like a Theramin -- and when I touch the radio the reception is more 'normal', but still sounding weird.

When I take my hand away from the radio, the whistle returns and there is a popping noise that happens from time to time. When I switch the DX/Local switch to Local, it abates it somewhat.

It's possible this radio was defective from the get go on SW, I just never noticed it because I do the vast amount of SWLing through headphones. Or it's a defect that sort of happened after a long period of disuse. Not sure.

Still works, though -- just have to keep the headphones plugged in. On MW and FM, it's very normal. Actually, a very good radio for those bands. The ceramic filter for MW is almost perfect for DXing vs. hearing actual fidelity, especially on headphones.
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  #45 (permalink)  
Old 02-01-2018, 5:15 AM
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I discovered something about the 200629 -- at least mine. Plugging an antenna into the SW EXT jack all the way, using a mono plug, is what is causing the theremin-like feedback.

When I pull the antenna jack outwards a bit, to where it's just engaged, it acts normal.

Weird.

The schematic shows that it seems to want a stereo plug. I don't know why.

But when I push the antenna plug in all the way, it causes some sort of feedback, and makes the radio act like it's blocking, and then when you move your hand close it's like a theremin.

Perhaps the radio is actually not defective. It might be using a mono plug in a stereo jack. Why the headphones affected it, I don't know. NOt tech savvy enough to figure that one out. But so far it seems a bit encouraging....

There are a few stations on 49 meters this morning. The Asia pipeline might be coming in this a.m.
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  #46 (permalink)  
Old 02-01-2018, 6:40 PM
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This afternoon I found a mini MONO-to-STEREO plug adapter. I attached it to my indoor SW antenna. Plugged it in all the way. The radio is completely normal.

I also tried a factory-made external SW antenna that came with my Panasonic RF-B45. It has a mono plug. I used it on my 200629, plugged it in all the way, and got feedback. So it wasn't the way I wired my antenna plug -- it's something with the radio; it need a stereo plug in the EXT ANT jack. Or -- just push your mono plug in part-way.

My conclusion is that the Radio Shack 200629 (and undoubtedly the newer ATS-505's) need a stereo plug on external SW antennas. Otherwise, they will feed back.

Or -- it may be a glitch in my own radio.

But it was working fine earlier this afternoon. Heard RNZI on 19 meters, and Japan to Vietnam on the 21 meter band (13650 kHz) and it was crystal clear, no feedback, no theremin like symptoms, even when I unplugged the headphones -- all was completely normal.

Relief....

And now I stare at the schematic and scratch my head, wondering why a mono plug in a radio's stereo EXT SW Antenna jack would cause feedback....

If any other 200629/ATS-505 owners have this issue -- use a stereo plug on your external SW antenna. It will stop the feedback.
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  #47 (permalink)  
Old 02-02-2018, 12:49 PM
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Quote:
Originally Posted by Boombox View Post
This afternoon I found a mini MONO-to-STEREO plug adapter. I attached it to my indoor SW antenna. Plugged it in all the way. The radio is completely normal.

I also tried a factory-made external SW antenna that came with my Panasonic RF-B45. It has a mono plug. I used it on my 200629, plugged it in all the way, and got feedback. So it wasn't the way I wired my antenna plug -- it's something with the radio; it need a stereo plug in the EXT ANT jack. Or -- just push your mono plug in part-way.

My conclusion is that the Radio Shack 200629 (and undoubtedly the newer ATS-505's) need a stereo plug on external SW antennas. Otherwise, they will feed back.

Or -- it may be a glitch in my own radio.

But it was working fine earlier this afternoon. Heard RNZI on 19 meters, and Japan to Vietnam on the 21 meter band (13650 kHz) and it was crystal clear, no feedback, no theremin like symptoms, even when I unplugged the headphones -- all was completely normal.

Relief....

And now I stare at the schematic and scratch my head, wondering why a mono plug in a radio's stereo EXT SW Antenna jack would cause feedback....

If any other 200629/ATS-505 owners have this issue -- use a stereo plug on your external SW antenna. It will stop the feedback.
Which connection, on the stereo connector?

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  #48 (permalink)  
Old 02-03-2018, 12:15 AM
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Quote:
Originally Posted by krokus View Post
Which connection, on the stereo connector?
The tip of the External Antenna plug is the part that connects the Antenna to the circuitry of the radio.

If you use a Mono-To-Stereo adapter, or if you just push the mono plug in partways, you won't have the issue. The radio will act completely normal.

I have noticed no issues just using the whip.

This problem MAY just be my own radio -- Sangean's portable antennas have mono plugs.

But if anyone else has this issue with their Radio Shack 200629, just use a mono-to-stereo adapter (or shove your mono plug in part way) and you'll be fine.

I've been using mine with the mono-to-stereo adapter the past couple evenings and mornings, and it seems to be acting normal -- no feedback or extra oscillation issues.
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  #49 (permalink)  
Old 09-22-2018, 5:29 AM
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Quote:
Originally Posted by Boombox View Post
The tip of the External Antenna plug is the part that connects the Antenna to the circuitry of the radio.

If you use a Mono-To-Stereo adapter, or if you just push the mono plug in partways, you won't have the issue. The radio will act completely normal.

I have noticed no issues just using the whip.

This problem MAY just be my own radio -- Sangean's portable antennas have mono plugs.

But if anyone else has this issue with their Radio Shack 200629, just use a mono-to-stereo adapter (or shove your mono plug in part way) and you'll be fine.

I've been using mine with the mono-to-stereo adapter the past couple evenings and mornings, and it seems to be acting normal -- no feedback or extra oscillation issues.
I stumbled across this page, which is about the 909, but I presume fits the 505, too.

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