I'll try to get something recorded for my youtube channel. It'll be a few days since I'm still recovering from a few surgeries.
I'll use <ham radio doctor> channel. 73, Bob
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- Youtube: N1KPR
- Youtube: Ham Radio Doctor
Engineering, where enigma meets paradox
On Saturday, January 25, 2025 at 02:59:41 PM EST, Everett N4CY via groups.io <everettsharp@...> wrote:
Bob,
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One of the major reasons to use a Broadband Loop vs a Tuned Loop, is that most people these day are using SDR? Receivers, with some being able to see up to 24MHz of bandwidth, at one time. Using a Tune Loop would greatly restrict the visible signals.
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Everett N4CY
In a message dated 1/25/2025 1:34:57 PM Central Standard Time, w8bya@... writes:
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Hi Bob, I like messing with tuned loops as well. It was with Bertha (my first multi-turn tuned loop) that I was able to hear my first LWBC transmissions after several years of trying with numerous full sized V's and verticals.
One thing that you mentioned that sparked my attention was your use of a dsp noise canceller. My only experience with them has been the canned NR on box rigs like the FT-1000, etc. I never did find any settings that I thought I could tolerate longer than a few minutes and I never really thought they did much good other than make the audio sould like it coming from outer space. Do you by chance have a short video demonstrating the effectiveness of your NR in action?? If not even a 2-3 minute cell phone video uploaded to YT or to Google drive, dropbox etc. Would love to see an effective noise canceller/reducer in action esp during distant lightning strikes at night.? 73
Gedas, W8BYA EN70JT
Light travels faster than sound.....
This is why some people appear bright until you hear them speak.
On 1/25/2025 1:58 PM, Bob, N1KPR via groups.io wrote:
After many hours of experimentation I settled on a tuned loop for the family room entertainment feed; news, traffic and weather.
I'm using an old W-J 8711 demo/loaner unit that's quite beat up, but works as expected. As I mentioned in an earlier post, I have recorded signal strengths from either an 80-meter vertical or the 160-meter wire at 35 feet. So I can gauge from the known antennas and the known AM b'casters as to what levels I should need to get. The tuned loop is about 35 feet from the house and was on a cheap rotator (now broken) and feeding a bias-tee to a variactor (BB112). With the 330uH loop and the diode tuning I can cover 500kHz thru 2MHz. I generally have the loop toward NYC which is directly SW from here. To reorient the loop I use an "Armstrong rotator." That means I need to go outside and turn it myself. East for New Haven and RI, NNE for Hartford/Boston and the SW for NYC
The tuned loop feeds me a much better diet that the Mobius or other homebrew loops. As was mentioned, the tuned loop is limited as to what the diode can cover to resonate the 330uH loop.
In the evening, I switch to the Pixel Pro for International stuff, also on a cheap rotator (this one still works).
My point is that the tuned loop is about 18dB below the 160 wire and about 22-24dB below the vertical 80, but with significantly less noise. With a preamp (LNA) I can boost the loops up to the Ham antenna's strength. But, that gets to be a feel-good situation, since the QRN/QRM is also amplified.
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Added note: A good DSP Noise Reduction device (I use BHI) can make life a lot more enjoyable, especially for long-term listening.
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gud sigs to all,
73,
Bob, N1KPR
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- Youtube: N1KPR
- Youtube: Ham Radio Doctor
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Engineering, where enigma meets paradox
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On Saturday, January 25, 2025 at 01:24:59 PM EST, Nick Hall-Patch <nhp@...> wrote: ?
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In the past, many of us heard great MW DX with a tuned loop next to the receiver.? However, such a loop now would be likely to hear only local electrical noise from house wiring, wouldn't it?? That's pretty much all that mine can hear now. If one has some property, it may be possible to put a tuned loop away from the house, but protected from the weather, and tuned with a varicap diode, which itself may affect loop Q.? But, then one loses the ability to turn the loop to null interfering stations on the chosen channel, which was another advantage of the indoor tuned loop. Others have mentioned the necessity of a wide band loop for SDR recordings, but if one can live with a single tuned channel, is there any advantage to a tuned over an untuned loop?? That is, can something be heard on one but not the other?? ?I did try a remotely tuned Kiwa loop vs. a Flag antenna on trans-Arctic signals here, and didn't find any advantage, but the testing was not exhaustive.? ?Something more to add to the list, I guess. best wishes, Nick ? On Sat, 25 Jan 2025 08:17:14 -0800, "JohnT via groups.io" <jtstein46@...> wrote: ?
Greetings.? I am a frequent "lurker" and very infrequent "poster" to this forum, my interest is primarily MW.? I usually use a 1m diameter resonant loop and am puzzled as to why resonant loops seem to be out of favor with most of the group members.? The resonant peak provides both "free", noiseless gain to the signal of interest while also rejecting signals at frequencies other than resonance, eliminating the need for high second- and third-order intercept performance.? Granted the broadband loops that are much discussed on the forum can acquire broad swaths of the RF spectrum essentially simultaneously, is this a significant advantage given the fact that the frequency of the signal of interest is known?
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Would someone please discuss the advantages of the broadband loop over a resonant one, have I missed something??
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Thanks
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JohnT
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Bob, N1KPR