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Anyone have experience with this amp? https://casarain.com/products/lamb-1b-hf-receiving-loop-amplifier Thanks!

Since MFJ has closed their doors there is no longer a source for replacement amplifiers for MFJ-1886 loop. I recently designed a LZ1AQ amplifier on the same size board as used in the MFJ loop. If there is any interested in a replacement amplifier for the MFJ loop you can contact me off list at everettsharp (at) aol com, everettsharp@... Everett N4CY

Awhile back I obtained a LZ1AQ amp board from N4CY. I am now ready to build the loop for it. I have read a lot of posts and files but can’t decide on what loop to build for it. I am mainly interested in LW and MW. I live in a noisy suburban area. I am thinking of just a simple 1/2” copper pipe 36” diameter loop or maybe a “shielded” design inside the copper tubing. Possibly multi turns inside the copper tubing. I am looking for suggestions. Thanks Larry n0sa

I ordered an SMA switch from this company today and also found this Youloop upgrade. Anyone tried this? https://elekitsorparts.com/product/youloop-balun-box-with-preamp-youloop-amplifier-with-wideband-ultra-low-noise-bias-t-youloop-upgrade/ Zack N8FNR

I just finished building 5 LZ1AQ loop amplifier boards, 4 of which I used 2SC5551 transistors. The 5th one I used BFU590QX transistors. Running sweeps on the 2 looking at both impedance and gain, one with 2SC5551s and the other using BFU590QX, I saw very little difference between the two. Both boards were supplied 3.8VDC, the 2SC5551 board ran at 142mA, the BFU590QX board ran at 130mA. I checked both boards with my SA and saw no signs of oscillation on either board. Everett N4CY

I have attached a link that gives info on my newest design of the improved LZ1AQ loop amp. It is being offered in several different configuration, including ideas for the experimenter that want a receive loop antenna. Everett N4CY https://drive.google.com/file/d/1iSsCVMf3OHZnzMIGeOVt3Q-_P-8oBD33/view?usp=sharing

I have read a lot about loops and the formulas for calculating a loop for the lowest band you would like to operate. I have a situation where I a large area to create a loop and wanted some input about whether I should cut if for 80 meters or go ahead and use the entire space available and go with as much wire as possible. I think I should have space for an 800 ft loop. So I guess my question is should I put out as much wire as possible or cut the loop for 160m (1005/mhz) and expect the harmonics to be resonate on all the bands? Lee

I was poking around on Thingverse and found a bunch of printables to help mount loops on the LZ1AQ active antenna box. Some cool stuff here. https://www.thingiverse.com/search?q=Lz1aq&page=1 Also found this printable to house the controller board. https://www.printables.com/model/116386-lz1aq-control-board-enclosure Zack N8FNR

I just finished putting together an Improved LZ1AQ Loop amplifier that I am offering in several different configurations. One of them is with coax to offer a complete loop. Also this amp could be used as a replacement for W6LVP loop amplifier. If interested please contact me off list for a copy of the info sheet. everettsharp (at) aol com everettshatp@... Everett N4CY

Before I go out to modify, in the rain no less, my test antenna I wonder if anyone has experience with the somewhat directional loop from Cross Country Wireless. Seems like an easy build. It would be most useful to have a steerable notch instead of twisting knobs on a phasing unit. Dave

Good day all, Help me out… I am only interested in reception of signals from DC to Daylight with SDR radios in my urban environment, (Not interested in transmitting.) I am also an active antenna tinker (like to build things and try them out) my theory has been toss some wire and metal together and see if it works. ? A bit of background. I study and used Smith charts 40 years ago, heck I can not tell you what they even do anymore. I have a very good understanding of radio and a basic idea of antenna Theory (I understand SWR and wave lengths know how a dipole works etc) However, I am over my deep theory days. So please in basic terms tell me why I should have an Antenna Analyzer? What will it do for me? How can it help in building the antenna that can hear a big pass gas at 1000 Km away. I have a little extra pocket money and if I can be sold on the idea of a VNA I could get one. But my ignorance is stopping me.. Thank you for your time. Tom

When using flexible conductors, we need some arrangement to keep the loop flat. Any significant torsion or twist presumably affects null depth. So just wondering if anyone has done the calculations? Small deviations from the plane are obviously the most interesting. But we can twist a loop all the way to a figure-8. Anyone up for *that* challenge hehe?

Andrew Ikin of Wellbrook for a short time offered a version of the ALA1530LN with an additional 9 dB gain Norton preamp in the receiver coupler--this version was called the ALA1530LNP. He developed this version which used two transformers. I've uploaded the schematic into a new folder in the Files. /g/loopantennas/files/Wellbrook%2050%20ohm%20Norton%20Preamp He used the now-discontinued ZTX 327 transistor, but any good RF transistor can be used. 73, Steve AA7U

Hi all not really a loopy question, but after a good cheap antenna analyser for future projects over winter. Have a mfj 259b but after something alittle better.. best regards Simon g0zen

Consider: 1) The DC resistance of the loop is constant. It's independent of frequency. That's one of the distinguishing characteristics of pure resistance vs. reactance. 2) The radiation resistance of the loop varies with frequency. However, it is a very small fraction of an ohm, typically around 0.001 ohms (that's a mΩ or milliohm using proper abbreviations) or less. This is what spoils tuned loops for efficiency. The DC resistance of my 0.5-inch copper tubing loop of 36-inches diameter (circumference of 113.10-inches) can be calculated. I measured 7.007 Amperes through the loop with a voltage drop across the loop of 46.3 mV (millivolts). So the DC resistance is (Ohm's Law): R = V / I = 0.0463 volts / 7.007 Amperes = 6.61 mΩ (6.61 milliohms) or 0.00661 ohms. Another measurement yielded 4.123 Amperes through the loop with a voltage drop across the loop of 29.5 mV (29.5 millivolts). Once again: R = V / I = 0.0295 volts / 4.123 Amperes = 7.17 mΩ (7.17 milliohms) or 0.00717 ohms. And for statistical significance: measured 1.60 Amperes through the loop with a voltage drop across the loop of 9.98 mV (9.98 milivolts) or 0.00998 volts. Again: R = V / I = 0.00998 volts / 1.60 Amperes = 6.24 mΩ (6.25 milliohms) or 0.00624 ohms. The numerical average of these three readings is: R AVG = [6.61 + 7.17 + 6.24] mV / 3 = 6.66 mΩ (6.67 milliohms) or 0.00667 ohms. AVG R = [ 0.00661 + 0.00717] / 2 = 6.89 mΩ (6.89 milliohms) or 0.00689 ohms. This compared to a radiation resistance of 0.001 (1 milliohm) or less ohms, I believe makes a reasonable first-order argument for constant current vs. frequency. Now we need a good measurement of radiation resistance to validate this argument. Using a VNA for such low resistances is challenging. I'll think of something. Any other ideas? I could feed a known amount of RF energy and actually measure the current induced through the loop. I have several home made current probes that I can easily calibrate. Other ideas and/or techniques are welcome along with contributions of others in measuring various parameters of SMLs. . . . Please? Dave - W?LEV

I would like to introduce you to my latest loop. Ideally, a loop should be round, but because the production costs for a round loop with a diameter of 1m are very expensive, I decided to make the loop rectangular. The surface area is slightly larger than that of a round loop with a diameter of 1m. Round 1m loop: 0.785m2 Rectangular loop 1000x800mm: 0.8m2 The loop is screwed onto a Bakelite plate, which is also very stable. The housing is IP65 and is equipped with a ventilation membrane. In terms of reception, the difference is not noticeable. Even if the loop is made of stainless steel, there is no noticeable difference to aluminum. But why stainless steel? Quite simply. It is much more durable and stable than aluminum. This is an antenna without ifs and buts. See here: [email protected] | Album

I was looking for something else and stumbled across an article on designing with new FETS. https://www.interfet.com/jfet-datasheets/audio-electronics-jfet-new-frontier1-2.pdf I know from conversation with friends deep into audio, Interfet manufactures some of the best, as in most linear and low noise, devices on the market today. While the paper is intended for AF, many of the considerations apply to audio as well. There is a new method (to me) of matching JFETS. I have no idea how much better or worse it is then the methods I currently use. Given the way webpages come and go, I'd dropped a copy in the files section as "audio-electronics-jfet-new-frontier1-2.pdf".

I just finished build another Lankford Phaser, which is for sale. It works very well with 2 loops spaces 55', or more. I am getting up to 60dB nulls on some local stations. https://share.icloud.com/photos/04e-up2ND8hyI2xFdfOLDx8zg If interested please contact me off list at everettsharp (at) aol com Everett N4CY

I was looking for something else and stumbled across an article on designing with new FETS. https://www.interfet.com/jfet-datasheets/audio-electronics-jfet-new-frontier1-2.pdf I know from corresponding with Rod Eliot Interfet manufactures some of the best, as in most linear and low noise, devices on the market today. There is a new method (to me) of matching JFETS. I have no idea how much better or worse it is then the methods I currently use. Given the way webpages come and go, I'd dropped a copy in the files section

I've uploaded to the Files a relatively simple one transistor 50 ohm preamp with +30 dBm OIP3 that can be built using common transistors and used to check your own IMD test set. I tried seven different transistors, three different types, different brands. Use a power supply you can set to 12.0 volts, as IMD is sensitive to supply voltage, to obtain the same results that I got. /g/loopantennas/files/50%20ohm%20Preamp%20with%20+30%20dBm%20OIP3 73, Steve AA7U