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I have just installed an Aziloop and I do not get good nulls - 10 -15 dB on 50 -100-mile ground wave signals, Loop is 13' on long side, 8' on short side and PVC mast is 15 feet. Radials are on the ground below the loop elements. It is fed with about 200' of RG6 cable and the supply voltage is 12.7 volts. I have a SAL-20 antenna 40 feet north of the AZI. I can get 15-30 dB nulls with it. I have a 60 foot self-supported welded steel tower with a large 10–40-meter Mosley beam at the top 42' east of the Azi. Antennas are in the middle of a 1.5 acre lot - no other buildings or metal nearby. Ground elevation is 15 feet ASL. Could these two other antennas be affecting the poor null operation on the Azi? Any suggestions would be appreciated. 73, Bill, WA2DVU Cape May, NJ 609 425 8651

Hello from Austria, I am an enthusiastic mediumwave BC-DXer and operate a small remote station outside Salzburg, which I have built up over the last 14 years. (https://remotedx.wordpress.com/ As I don't own the land, I can't set up endless antennas there. At the moment I use a 200 metre two-wire Beverage and a K9AY (circumference of 30 meter), but it only listens to Asia and South America and is much too close to a house wall. The cows want it that way. But everything can be controlled remotely from QRO.cz, I'm very happy with it. I'm thinking about setting up the ingenious AziLoop, which I could erect a good distance from the houses. The coax there is already buried, so far everything is fine. However, I have two problems at my location: the antenna has to survive storms well, and there are often storms there. And it has to be able to be dismantled quickly, but maybe I can talk my farmer out of that. So I come to the point: I should - although the opposite would be better - erect the antenna as compactly as possible, also because I have to do everything myself. Dave specified a circumference of only 10 meters in his AziLoop manual (page 104). He wanted to cover this topic in more detail in the forthcoming manual, which will be much more comprehensive, but it has not yet been published. In an exciting (and humorous) talk at the Norfolk Amateur Radio Club, he presented the antenna and his thoughts: https://www.youtube.com/watch?v=riQnZ6su_YE&t=2161s - starts at minute 20, the more technical part begins at minute 52. In the presentation Dave showed a circumference of 15 meters, a picture is attached here. This size seems to me to be easily realisable, so my question is whether anyone here already has experience with a ‘relatively’ small AziLoop. My use is only intended from 500-1800 kHz. I have seen the perfect installation from Steve, VK5SFA, in the group - I don't know the exact size, but that seems ‘a size’ too big for me - even if I would do it exactly the same way. Then I would certainly hear AM stations from Australia better in Austria! Thanks for your opinions. 73 Christoph, OE2CRM — https://remotedx.wordpress.com

Guy Atkins <dx@...> added the photo album Azi-Loop Self-Supporting Structure for Transportable / DXpedition Use : My in-progress design uses fiberglass rods to support and tension the lower legs of the triangular loops. Screw hooks along the length of each heat-shrink tubing covered rod allows quick removal of the loop wires (Teflon-covered 20AWG), along with weatherproof connectors that will be used near each pair of 90-deg. angle brackets. I will upload more photos as the design progresses.

Christoph Ratzer <ratzer@...> added the photo album AziLoop Loop Dimension 2025 : In the presentation Dave showed a circumference of 15 meters, a picture is attached here. The following photos have been uploaded to the AziLoop Loop Dimension 2025 photo album of the [email protected] group. AziLoop_YouTube2025.jpg By: Christoph Ratzer <ratzer@...>

Hi, I have made an indoor active broadband loop for HFusing the LAMB-1B amp board from Casarain. Having now got back into amateur radio I want to know if there is anything I can build on the lead to protect against accidental transmission from my rig. If someone could point me in the right direction of a simple circuit Id be much appreciated. Thks. Adam M6RDP

If anyone needs mounting nuts for ARCO and other brands of "padder" or "trimmer" capacitors, I have some that are surplus to my needs. These are almost unobtainium.... VERY hard to find. They are size 12 and have 40 threads-per-inch, solid brass. Charlie, N0TT n0tt at Juno.com

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? Would someone please discuss the advantages of the broadband loop over a resonant one, have I missed something? Thanks JohnT

If anyone is interested in a loop amp, or a phaser, please contact me off list. everettsharp (@) aol.com Everett N4CY

Just compared 2SC5551 to 2SC3357 in an LZ1AQ amp. There is almost no difference in IP2/IP3 and frequency response. I was going to post to say the 2SC3357 are available, but looking at Digikey there are only 9 in stock. It says one week factory lead time and new product, so I assume they are still in production. -- =================================================================== Mike M

I am curioues if any one tested THE lZ1aq Active Antenna Amplifier (model AAA-1C) with 3m wire loop or even longer wire? 73 Lars sm4ive

Hello everyone, a while ago there was a discussion in a german forum where forum member ArnoR proposed modifications to the original LZ1AQ circuit. The modifications seemed plausible to me but as an electronic hobbyist with little knowledge (but a lot of passion!) I had difficulties understanding them. A circuit (and later an updated version) was presented as an improvement over the original LZ1AQ design that i know has been in use for years (and has highly regarded updated versions published in this forum). Since I don’t have the experience to evaluate the design myself, I thought I’d bring it here, where the level of expertise is much higher. My goal is not to argue for or against the changes but simply to understand whether and why they might be beneficial—or if they introduce new drawbacks. Even if there is no benefit, the proposed changes are still interesting from a circuit design perspective. I would appreciate any insights you can share! (I created some LTSpice files for the proposed circuits, they do run but are not refined enough to do a proper circuit simulation. They should be seen as a starting point for experimentation. They are called Arno_V1.asc and Arno_V2.asc in the files section.) Here is a summary of the changes: 1. Output Transformer Issues Output transformer has too low an inductance (18?H, actually likely ~10.2?H). Results in too high a lower cutoff frequency (~500kHz or even 800kHz). Incorrect dimensioning limits low-frequency performance rather than the input resistance or loop inductance. 2. Base Circuit Design Issues Separate base voltage supplies used instead of a proper differential amplifier. Better approach: Connect bases directly for true base-coupled differential amplifier. Eliminates unwanted differential voltages. Improves symmetry, reduces component count, lowers noise. No issues with biasing due to resistor tolerances. Enhancement: Replace lower divider resistor with an LED for thermal compensation and power indication. 3. Emitter Circuit Design Issues Same as above: Should be a true differential amplifier. Converting saves components, improves performance, no downside. Output drive capability remains unchanged. 4. Signal Tapping at Collector Resistors Output should be collector current/voltage across resistors, not collector voltage to ground. Incorrect method introduces power supply noise into the signal. Fix: Use PNP emitter circuits or PNP differential amplifier for: Massively better power supply rejection. Eliminating the need for regulated supply voltage. Improved output drive capability and fewer components. 5. Frequency Response & Component Choice Original upper cutoff frequency: ~10MHz, due to capacitances in base/emitter circuits. Author claims flat response up to 40MHz—but only due to input VHF filter resonance. Better solution: Use 2SA1015/2SC1815 instead of 2N2222A for: Lower noise, better linearity, smaller capacitances. Higher cutoff frequency, higher slew rate. Lower input resistance → Better low-frequency response. 6. Final Circuit Comparison New design vs. original tested with 1m, 3.4mm AL loop, no VHF filter. Same input & bias currents, measured max output level. Conclusion: Much better performance with significantly less complexity. I’d love to hear your thoughts. Could they offer any advantages, or might they introduce unintended issues? Looking forward to learning from your insights! Best regards, Nils Just to be super clear: none of this is my original work, all work was done by ArnoR. I just translated his post to post it here and condensed it for clarity. For reference i include the original forum post in translated form: Proposed circuit 1 Source: https://www.mikrocontroller.net/topic/523344?page=1#6790749 Since I previously criticized LZ1AQ’s circuit without providing specifics, I now want to briefly address this to avoid the impression of baseless complaining. Let us start at the very end. The output transformer supposedly has a winding inductance of 18?H. With the output resistances of the emitter circuits (220Ω), which generate the output voltage, and the load resistor, the resulting lower cutoff frequency is around 500kHz. This means the inductance is far too low if one intends to amplify cleanly down to the longwave (LW) range. *) The core is specified with ?=1000 and core size R10. According to the Epcos catalog, this core has an AL value of 407, which, with 5 turns, results in an inductance of only 10.2?H. This would place the lower cutoff frequency at about 800kHz. Thus, the lower cutoff frequency is not limited by the input resistance of the circuit and the loop inductance but by the incorrect dimensioning of the output transformer. The two base circuits are powered by separate base voltage supplies. However, the circuit is actually supposed to amplify the differential signal between the emitters. This only works properly if there is no differential voltage between the base connections. Here, this is achieved for AC signals using bypass capacitors. A much more natural approach would be to connect the base terminals directly, thereby constructing a true base-coupled differential amplifier. This would require only a single bias voltage divider, with changes in base currents perfectly canceling each other out. No interference voltage could be coupled between the bases, and there would be no difference in operating points due to resistor tolerances. This results in better symmetry, saves some components and power, and delivers improved performance without any drawbacks compared to separate base circuits. The frequency response remains identical to that of the separate base circuits. At the same time, the lower resistor of the divider could be replaced with an LED, which provides good thermal compensation of the operating point while also serving as an operating indicator. The same mistake as in point 2 has also been made in the emitter circuits. These, too, can be converted into a true differential amplifier without any drawbacks. This again saves several components and improves performance—without even affecting the output drive capability (large-signal behavior). The most serious error, however, is the incorrect signal tapping at the 220Ω collector resistors. The output signal of the base circuits is their collector current, or the voltage across the collector resistors—not the voltage at the collector relative to ground. If, as in LZ1AQ's circuit, the emitter circuits are driven against ground, then the supply voltage and any noise on it appear directly in the signal. Additionally, the operating point becomes highly dependent on the power supply. For these reasons, the circuit can only be operated with a stabilized supply voltage (the 10V regulator). This issue can be easily avoided by using PNP emitter circuits or a PNP differential amplifier. This improves power supply rejection by orders of magnitude compared to the original circuit, eliminating the need for supply voltage stabilization, reducing component count, and increasing output drive capability. The upper cutoff frequency of the original circuit is about 10MHz. It is determined by the effective capacitances at the collector resistance of the base circuits: the Miller capacitance of the emitter circuit, feedback and output capacitance of both the base circuit and the emitter circuit itself. The transistors are no longer suitable for these frequencies or dimensions because their capacitances are too large. According to the author, the circuit is supposed to maintain a flat frequency response up to about 40MHz. However, this is due to the input-side VHF filter introducing a resonance peak in the 10MHz–40MHz range, which compensates for the amplifier’s frequency response roll-off. I consider this an unclean approach. Much better performance can be achieved with more suitable transistors, such as the 2SA1015/2SC1815. These transistors are extremely low-noise, highly linear, have much smaller capacitances, and are very inexpensive. With these transistors, one achieves a significantly higher upper cutoff frequency, a higher slew rate, and a lower input resistance than with 2N2222A, leading to a lower cutoff frequency at the loop. Finally, I present the circuit resulting from the above considerations in the attached images and compare its characteristics with the original circuit. In both cases, the same 1m, 3.4mm AL loop was used, and the VHF input filter was omitted to focus solely on the amplifier’s characteristics. The input signal was kept the same in both setups, slightly into overdrive, to show the maximum output level. The operating currents of all stages are identical in both circuits. Conclusion: Significantly better performance despite much less effort. Proposed circuit 2: Source: https://www.mikrocontroller.net/topic/523344?page=2#7450453 Transistors T1/T2 and T5/T6 each form a composite transistor (Sziklai pair) configured as a common-base circuit. The base is clamped (via D1/C1), and the input signal is fed into the composite emitter. This composite transistor has a significantly lower emitter input resistance compared to a single transistor, which is essential since the lower cutoff frequency of the circuit is determined by the relationship: fu=re2πLf_u = \frac{r_e}{2\pi L}fu?=2πLre?? The two composite transistors operate as a base-coupled differential amplifier for the floating magnetic loop, which is connected to the two blocks at the bottom. The output signal from this input differential stage is amplified by the emitter-coupled differential stage T3/T4 and then fed via C8/C9 into a balun, which sums the output signals and provides high common-mode rejection. The resulting 50Ω output is floating (potential-free). C11 and C12 limit the upper frequency response and must be selected according to the desired bandwidth. I have used only C12 with a few picofarads. The input impedance of the circuit is 0.4Ω differentially (i.e., 0.2Ω per side), which allows for a lower cutoff frequency of approximately 20kHz (-3dB) with a 1m loop. The balun is simply a bifilar winding on a toroidal core and is connected like a standard common-mode choke, meaning both winding starts are connected to C8/C9, and the winding ends go to the output. The core must have low losses in the desired frequency range, and the winding inductance should be at least 100?H.

Hi group! If you're interested, I just uploaded the file "The Growing FLAG", which is a building instruction for my Rotable FLAG-antenna, which is somewhat smaller than traditional FLAG-antennas. I have been using this small antenna since the beginning of October 2024 on the MW Broadcast band, with surprisingly good results (conditions permitting). 73's Hans / LB6GG Sola, Norway

I just saw this RCA rotor on sale, I don't know that is is precise enough, because it is programmable for every 10 degrees. I haven't read the manual far enough to see if you can precisely set direction to null your noise sources or if you can fool it to ever 5degrees by only turning 180 degrees. It is $89 on sale with rebate. $14 shipping, at least to me in Fl. https://www.menards.com/main/electrical/electronics/antennas/rca-outdoor-digital-tv-antenna-auto-rotator-with-remote/vh226f/p-1544513354915-c-1454940301502.htm Here's the manual, https://www.rcaantennas.net/docs/common/VH226E/VH226E_OM.pdf Mikek

Good Afternoon all, After years of chasing MW DX with "real" hardware, I'd like to try SDR and would appreciate recommendations about what I need to get started. In particular: (1) Are any of the inexpensive USB dongles suitable for MW, or are they "toys" and I should look at more expensive hardware? (2) At the entry level, whose hardware is generally accepted as being good, which should I avoid? (3) Is a frequency upconverter required to receive MW Thanks for any comments or recomm

Found this on another group and thought it might interest someone here, but not for the budget minded: https://www.netsandmore.com/products/fishing-accessories/fiberglass-hoops

There has been interest in my improved LZ1AQ with a relay added. The new design has an added relay on the board that, when off, (NO POWER) the relay contacts short both loop legs to ground. If there is any interest, please contact me off list at everettsharp (at) aol com. Everett N4CY

Hi Folks, I recently built the PA0FRI active loop receiving antenna for HF (shortwave) use. The reception results have been highly impressive, especially considering the extremely constrained space where the antenna is installed. I have made the entire project open at the following URL: https://github.com/kholia/DDX/tree/master/Active-Antenna Total cost: Roughly 10 dollars (including professional PCB, BOM, IP65 casing, aluminum loop and all). I hope this work is useful for you. Feedback is welcome! Cheers, Dhiru (VU3CER + WQ6W)

I tried to follow recommendation from Chavdar's app note in regards to feed cable location (for vertical dual loop configuration). Here is a picture: https://photos.app.goo.gl/P1vSAeefdMkj4WYc8 Although in the notes Chavdar recommends 1-2m offset for the cable behind the loop's plane. I only have ~60-70cm (2ft) due to some space restrictions. I noticed that in Dipole mode I see about 5dB drop in AM BC station images in the lower 80m band. That's due to CM issues in dipole mode. Not sure if that was worth the hassle as loop mode is still superior in my noisy environment (semi-urban location). I also noticed that top loop (Loop A) usually provides better s/n ratio compared to lower loop (loop B) and cross-parallel connection of both loops. I see that on most HF bands. Sometimes LoopA=A+B but usually I just use loopA. I was wondering if that's due to the cable that was hanging right across the lower loop. New cable placement improved things a bit but I still see LoopA normally being better or equal to A+B configuration. LoopB is still normally worse than other two configs (A, or A+B). Next I may try to put more clip on ferrites along the portion of the cable that hangs below LoopB. Maybe mix31 and mix75 clip-ons combined on the length of 1-3m up to the point where cable comes to the wall. I already have a stack of two FT240-31 with ~6 turns of CAT before cable leaves the amplifier box and a stack of three FT240-31 with 6 turns before it enters control switch box. That actually helped a lot but I wanted to improve things even more. I wonder if Loop A is better simply because it's higher in the air and further away from my "shack" that's 2-3m away from the antenna physically. Also may try to place Yaesu GS-050 mast bearing a bit lower. Right now it sits right below the lower loop. Wonder if that can create any un-balance issues. Regards, Simon KM6MUL

I am thinking of making a VLF loop out of a 10 ft piece of PEX pipe with many turns of wire inside the PEX and a plastic junction box on the bottom. I have read several articles about doing the same thing with copper pipe as the shield and making a gap in the top center of the pipe. The purpose of the gap is to shield the windings from electrical noise and allowing the magnetic waves inside the pipe. There are several articles on how to shield VLF antennas ie; Ferrite Rods, from electrical noise. Making copper pipe loops and metal electrical boxes at the bottom and cutting a gap in the pipe at the top is basically the same as shielding the Ferrite Rod with aluminum and leaving an air gap for the magnetic waves. Pex is a different animal as if you cut a gap in the top of a PEX loop, you lose the round loop. So my question is this. What if I keep the round loop attached to the plastic electrical box and shield the entire round loop with #80 copper mesh and not the box, would I have the same shielding as an the copper pipe loop? Fred N4CLA

The following items have been added to the Files area of the [email protected] group. /BD3OLH.rar By: 钱志豪 <qianzhihao2002@...> Description: 我设计了一个分裂定子蝴蝶电容，有需要的可以看看