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Re: PTT selection in QMX+
Yes, with red face shamefully slinking off into the QRM... On Tue, May 27, 2025 at 6:20?AM Fred M via <dl4zao=[email protected]> wrote:
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Ken - K4XL BoatAnchor Manual Archive BAMA - |
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Re: LZ1AQ / Orthogonal Plane / Cooper Loop - Poor Performance
Sean, Some of the issues I had with dipole mode was due to Common Mode noise. So, those ferrite torroids helped! If I remember correctly the only jumper (on amplifier board) I changed was the one that enables the power. Nothing else. My configuration is also different. I have same plane dual loop setup. I'm not sure how well dipole mode works with orthogonal loops and some counterpoise... Non-orthogonal setup should be better for dipole mode. But in noisy urban environment (my case) dipole mode is usually still worse than loop mode (in my case at least). This is my setup (on rotator):? ?Making an offset for the CAT cable also helps in dipole mode (little bit) - that was also one of the recommendations from Chavdar. Regards, Simon On Sun, May 18, 2025 at 12:24?PM sean via <sean=[email protected]> wrote:
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Re: LZ1AQ / Orthogonal Plane / Cooper Loop - Poor Performance
On Mon, May 19, 2025 at 05:41 AM, rfsam wrote:
KM6MUL Hi Simon,
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Thanks for the info. There is a lot to learn about noise, much of which I simply don't have the tools or instruments to do any real science with, however taking advice and applying some logic, and doing practical tests and checks from folks smarter than me in RF seems to working out :-)
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I also am referring to this article: which seems to make sense too, and I also think I am too hung up on the FTP cable being shielded, as it really doesn't seem to make a lot, if not any, difference to noise levels. (something else to experiment with)
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My other issue with dipole mode, is even with an (made for the KiwiSDR) , there are MW artifacts / reflections all through the bands, so I think my loops are possibly too large for that much gain, I am also not running a ground at this point, which seems to be a requirement for Dipole loops.
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Many thanks
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Sean |
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Re: LZ1AQ / Orthogonal Plane / Cooper Loop - Poor Performance
Hi Sean, I went through similar issues last year. I also have AAA-1 from Chavdar. Here is one of the posts with Chavdar's recommendations: I use CAT8 patch cable (stranded vs solid). That helps with winding on torroids. My recommendation would be to use a stack of 2-3 FT240-31. That helps if you cannot do too many turns (which is hard with shielded CAT cable). I did that next to LZ1AQ amp and next to the switch box. Also on control cable and coax cable. Just do it even if it may not make a huge difference. I didn't cut CAT8's external shield, just passed it through torroids. Here is the picture of my amp: You can see a stack of two FT240-31 with maybe 6 (max I could do) turns of CAT8. Next I was thinking about using many mix31 and mix75 clip-ons along the cable length. Not as good as Torroids with lots of windings but every bit helps when dealing with local man maid noise. Let me know of you have any questions! Regards, Simon KM6MUL On Sat, May 17, 2025 at 12:29?AM sean via <sean=[email protected]> wrote:
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Re: LZ1AQ / Orthogonal Plane / Cooper Loop - Poor Performance
Sean,
all used lines must be wound on the ferrite toroid, or must be choked with separate toroids.? It is not enough to have a common-mode choke in the RF-Feedline only. In this case common-mode currents are bypassed via the DC-power supply lines.
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regards
Fred |
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Re: LZ1AQ / Orthogonal Plane / Cooper Loop - Poor Performance
What you might do is run just one loop for testing, then you can null out the strongest noise offenders with a simple azimuth change. The loop configured as you have it isn't going to be able to null out much of anything, as it is now more or less omnidirectional. The ability to null is just about the loops greatest selling point far as I am concerned. It would be nice to have either a rotatable loop or two fixed loops that could be selected at whim to enhance sigstrength and/or to reduce qrm/n. Also make sure there's no noise being sent up the line to the antenna from the home because that can happen, a ferrite core or two at each end of the line should take care of noise along the line. A buried line should have little to no noise on it for obvious reasons (moles, earthworms, and grubs are stealing wifi from it).
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Not long ago, I ran two turns of speaker wire around a window frame inside the house to feed to a nearby Icom R75 on its hi-z input just for giggles, twisted the wires together to secure the loop and act as a twin lead feed line that was about 4 feet long. Worked great from vlf thru hf, but it did pick up qrm from the also nearby pc in the room. If a band was open, this antenna heard it. That experience is giving me motivation to roll a 1m loop in the yard up about 20ft or more, sans amplifier, but with a 3:1 balun (5 turn pri 3 turn sec on mix 77 core is close to 3:1) and some ferrites to keep rfi off the rg11 feed line, then into a distribution amp that has about 5dB gain. Aiming it to eu, the intended target, should also null out some noise from the house.
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First post and greetz to the loop.io ppls!
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de n0sya |
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Re: Added photo album Orthogonal Loop
#photo-notice
Will do,
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I'm using KiwiSDR monitor to graph SNR across a few different ranges. So I will keep track of it once I have finished tinkering (I know, there is no such thing as "finish tinkering")
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Cheers
Sean |
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Re: LZ1AQ / Orthogonal Plane / Cooper Loop - Poor Performance
Hi Simon,
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I do intend to rebuild this at some stage with a new material, as the PVC pipe is possible a bit weak as the intersection point and a fairly strong wind is like going to break it, so will do two flat facing loops.
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The Amp does have switching ability for A or B or A and B so the purpose of intersecting loops is to switch between different planes. I do however still need to finish the switch box, as I have the pins simply shorted to connected A and B currently.
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Cheers
Sean |
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Re: LZ1AQ / Orthogonal Plane / Cooper Loop - Poor Performance
Hi Martin,
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Are you suggesting winding the cat6a through a ferrite core? I'm almost certain, to achieve this, I would need a ferrite the size of a dinner plate :-D
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It is double shielded, has aluminium and copper braid. I may just try earthing the sheild?
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Cheers
Sean |
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Re: Added photo album Orthogonal Loop
#photo-notice
Keep us informed as to how well it works across it's Freq Range. ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?? Garey Wittich
On Wednesday, May 14, 2025, 02:24:19 PM PDT, Group Notification <[email protected]> wrote:
sean@... added the photo album Orthogonal Loop : My Orthoganal loop - made from 2 x 15.9mm annealed copper tube connected to an LZ1AQ - from active-antenna.eu. Its a start! |
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Re: LZ1AQ / Orthogonal Plane / Cooper Loop - Poor Performance
¿ªÔÆÌåÓýSorry Fred, The AAA-1C amplifier has two amplifiers: one low input impedance loop amplifier, and one high input impedance amplifier for dipole mode. In orthogonal configuration the two loops are interconnected. You can select between 3 loop modes: A-loop, B-loop and A+B loops, The fourth setting is the dipole (high input impedance) mode Regards, Bela ? From: [email protected] <[email protected]> On Behalf Of Fred M via groups.io
Sent: Thursday, 15 May 2025 14:29 To: [email protected] Subject: Re: [loopantennas] LZ1AQ / Orthogonal Plane / Cooper Loop - Poor Performance ? On Thu, May 15, 2025 at 12:43 PM, Simon wrote:
Simon, the AAA-1C has two independent loop amplifiers between which you can switch remotely. It is not two loops connected together. ? regards Fred |
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Re: LZ1AQ / Orthogonal Plane / Cooper Loop - Poor Performance
On Thu, May 15, 2025 at 12:43 PM, Simon wrote:
The setup shown in pic has no nulling.which is the best bit of a mag loop ( deep nulls)Simon, the AAA-1C has two independent loop amplifiers between which you can switch remotely. It is not two loops connected together. ?
regards
Fred |
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Re: LZ1AQ / Orthogonal Plane / Cooper Loop - Poor Performance
Sean
Try the loop/ a loop with just one loop, ie not 2 at 90.. That way you can adjust loop direction for best nulling of local noise ( if mainly coming from 1 direction ( or 2 if at 180 to each other.)) The setup shown in pic has no nulling.which is the best bit of a mag loop ( deep nulls) Simon g0zen |
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