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Good morning, I wanted to tell you about a problem I'm having with the BFU590s (assuming they are) with which I made a replica of the ALA1530. The one I've used so far has always worked well but it uses PN2222. I then made a second version but with BFUs instead of PNs. The BFUs are marked "S59 W42" and I got them on the Italian TME ecommerce platform (www.tme.eu) and not on Aliexpress or some China page on Ebay. In practice it is impossible to calibrate the 100 ohm trimmer to 0 volts, the absorption always tends to rise, sometimes 140 mA, then it goes to 170 or worse, sometimes then it drops to 160-150 then rise again... and in any case the amplifier doesn't work. There is no point in trying to calibrate it even finely, sometimes I see the voltmeter pointer vary on its own (self-oscillations?). The rest of the circuit is built exactly like the version with PNs, same values ??and everything has already been verified several times. If you have any suggestions for me, I would be grateful. Greetings, F.

Hi, I have scanned and uploaded my collection of (historical?) Wellbrook price lists and data sheets from 1999, 2004 and 2007. Hopefully that may help people trying to date the various products and the development. /g/loopantennas/files/wellbrook_datasheets Also worth mentioning that the polarity of the antenna interface connector changed from +ve to -ve inner at some point, and maybe changed back again on later models? I have some from 2007 that are -ve inner that came with LFL1010 loops and the instruction manuals reflect this. 73 Nick

Hi - I am trying to calculate a small transmitting loop from LMR400 using the Pacific 66 calculator site. Does anyone know the actual diameter of the LMR400 shield once the black insulator is removed? The actual diameter size is required form accurate calculation. Appreciateyour help. John - W3JED

I just finished building another batch of LZ1AQ loop amps to fit the Wekkbrook ALA1530 loop. If interested please contact me off lis tat everettsharp@... everettsharo (at) aol com Everett N4CY

Hi All - Does anyone here use the W2LI magnetic loop from TriCountyRadio.org? They used to sell direct, more recently they sell through eBay. I have read the eHam reviews and it sounds like in addition to the advertised 20, 30, and 40 meter transmit, they also can transmit on 17 meters with workable SWR. I was just curious if anyone has used one of these and can also verify if they work for 17 meters. I have an Alpha Antenna 100W mag loop and its great across these bands, but the W2LI looks a bit more compact/portable when broken down and definitely less expensive to take in the field than the Alphaloop (which I leave set up and use at home). If you have experience with the W2LI, I would greatly appreciate your inputs. Many thanks, John - W3JED

Hi All, Today's amusing fact. The Chinese MLA-30 loop, that I reverse engineered some time ago, and then put my version of the circuit on my website, has been cloned by the Chinese :-) The original PCB had no component designators, but one of the clones I have seen photo's of has, and they are the same as I used in my circuit diagram. You couldn't make it up... Regards, Martin

Mostly by dumb luck I've managed to build a SW loop that seems to work well. It's made of 1/2" OD copper tubing, about 34" across, with a 10" x 7 1/2" coupling loop made from 8 AWG copper wire about 1/16" (the thickness of a ty-wrap) from the main loop. The coupling loop is connected to a dual banana female socket with banana connectors. On the other end a 15' length of RG-58 goes from the BNC to the back of my radio. The antenna has prominent nulls and is very directional. Combining that with an old 3-section variable capacitor allows me to tune from ~4500 kHz to ~18000 kHz. The only reason I went into the above is that I'm always looking for suggestions to make it even better. If anyone sees anything I'm missing here I'd certainly appreciate hearing about it... thanks! Earl

Given my off topic thread won't die, it's clear I'm not up to be a moderator on this group. Meaning well isn't enough in life and I demonstrated an atrocious failure in judgment by starting the eterna-thread, a failure of judgment that demonstrates I'm not suited to be a moderator. I hope the remaining moderators can continue to act as weed killers and kill each and every post regarding MJ growhouses. I've enjoyed being a member of this group, learned a lot, I'd like to thank Martin for confirming a goniometer is less then optimal for electronically steering the aim point of two cross phased loops and I'd like to thank Everett N4CY for offering high performance loop at an extremely reasonable price. This would turn into something the length of War and Peace if I tried to thank everyone who has helped me understand the subtleties of loop antennas, so a bit thank you to the entire group. I've learned more about loops in the few years I was a member of the Loop Antennas IO Group, but I believe it is time for me to leave the group. Good luck to group members and, to those offended by my eterna-post, I'm sorry. Accepting responsibility means accepting rational outcomes.

I'm not sure when the ALA1530LN version was first introduced. I've saved this Wellbrook ad of April 2021 which talks about an improved version with higher gain--note the ad does not mention comparing it with his earlier ALA1530 (now WellGood version): -------------------------------------------------------------------------- "A new version of the world famous Wellbrook Active Loop ALA1530 50kHz-30MHz 1m dia. Aluminium Loop---- As of April 2021 the amplifier gain has been increased to +28dB. This Balanced low impedance Magnetic loop has enhanced performance compared to shielded and Moebius loop types. The new JFET design affords a considerable reduction of noise compared to low cost loops using MMIC (Monolithic MicrowaveIntegrated Circuit). MMICs are designed for Microwave use and therefore are unsuitable for LF to HF loops. Furthermore, MMICs use integrated resistor feedback, which limits the noise figure to a minimum 3dB at HF. At Medium Frequencies loops using MMICamplifiers can have a Noise Figure as high as 8dB plus high IMD (Intermodulation Distortion). Compared to the W6LVP loop, the ALA1530LN affords a much lower noise floor with an average of 6-8dB higher gain with much lower IMD. The ALA1530LN has a noise figure of approximately 0.2dB which give a noise floor that is 13dB lower compared to a similar gain loop amp with a noise figure of 3dB. This antenna and its big brother, the ALA1530LN Pro Imperium are the only 1m dia. Active loops in production to use an ultra low noise JFET design. The loop has recently had a significant design change to improve LW/MW and SW reception. The ALA1530LN has been engineered to increase the LW and MW signal to noise ratio s/n by up to 10dB and provide an increased s/n on the HF bands. The LW and MW 3rd order IMD is now approx. 20dB lower. This being a combination of reducing the gain a little and the lower IMD of the JFETs. The new ALA1530LN is the second generation of this antenna and uses 8 very high gain JFETs in parallel push-pull with a Bipolar transistor cascode stage for extended bandwidth. A very low amplifier noise floor is achieved by dynamically decreasing the JFET Source resistance to a fraction of an Ohm. This is achieved using a proven technique developed in the 1980s by coupling the FET Gate to the Source with a phase inverting transformer. The loop works by designing the amplifier so that the very low noise of the loop's real resistance is mismatched to the input impedance of the low noise amplifier. Hence, reducing the amplifier noise floor by up to 13dB compared to more conventional low noise amplifiers.Also JFETs are less noisy at low frequencies compared to Bipolar transistors. The amplifier also has a rising input impedance versus frequency to match the loop's reactance; this together with Ultra low noise JFET design is a technological breakthrough. The mechanical design is now improved to afford increased reliability and to facilitate ease of servicing. The amplifier is now housed in a separate module, thus isolating the electronics from the mechanical stress caused by wind loading on the loop. The amplifier to loop wire terminations use tin plated silicone insulated wire and crimp terminals rated down to –40 Celsius. The module sits on top of the loop box and is secured by stainless steel screws. The base of the loop is now reinforced with an acetal rod to minimise damage due to weather extremities. The amplifier module can be easily replaced in the unlikely event of a failure, without the customer having to purchase a new loop antenna with the associated higher shipping costs. A resettable fuse and a power-on LED are now fitted to the Antenna Interface. Additionally a power limiter is fitted to reduce overload of receivers co-located with transmitters." ------------------------------------------------------------------------------- I would say the jfet version has a little higher gain than the bipolar version, and has a lower noise figure. Obviously with 8 jfets it's quite a bit more complex. But my own tests have not really shown much actual difference in

I'm building a medium wave antenna, 24" x 24" box loop, 20 AWG wire, 365 pf air gap variable capacitor (at least that's what I'm starting with). I'd certainly appreciate suggestions on the best design for a coupling loop for such an antenna, thanks! Earl

Kits and Parts has been my go to source for ferrites and other RF odds and ends. A friend just told me Dieter "Diz" Gentzow, W8DIZ, lost his battle with his illness yesterday, March 3rd, 2024. I have no idea how long Kits and Parts will continue, so it might be a good idea to think about parts they have that you will need and get that order in pronto.

Let's talk about rotators for loop antennas. I hope it's not too much of an off topic? Just got my cross parallel loop installed on cheap RCA rotator designed for TV antennas (VH226e). My antenna is not too heavy but it's quite long and I feel that it's a bit too top heavy for this rotator bearings. I can see quite a bit of a shaft play when I shake it by hand. So, I either need to reinforce it or buy something else. I'd appreciate any recommendations for that matter. Quick video: https://youtube.com/shorts/t8GWAMoo0x4?si=0t4zgHlfWvQ5BMcs Thank you, Simon KM6MUL

Some thoughts on cases for exterior loop antenna amplifiers. This equally applies to any electronics in exterior service. The top of the line cases are polycarbonate, Hammond probably manufactures the best as a mix of price, function, availability. Durable like they are designed for combat. Look up "Hammond Water-Tight ABS & Polycarbonate Enclosures" I've never been able to locate polycarbonate wire glands but black Nylon is probably as durable and UV resistant and readily available on Amazon. For controlled ventilation, the "Hylec vent" is probably the gold standard. This vent allows air flow but blocks humidity. This is what Cross Country Wireless used in my dual polarity horizontal and vertical active dipole. Sadly they come from England and have insanely long delivery times. Honeywell makes one that might be as good, I'll let you know in a year or so. https://www.digikey.com/en/products/detail/amphenol-ltw/VENT-PS1NBK-N8001/7898283 I built a PA0RDT mini-whip for a friend on a tight budget. I drilled a 1/4" hole in the bottom and used Gortex repair tape on the inside and outside. It's been in service for 2 years now and given we've had temperatures ranging from 98F to -10F, over a foot of water, 2 feet of snow (spread out over 2 winters), I suspect the crude Gortext double seal works just fine. However I still do not trust it for anything serious. Given how inexpensive the Honeywell vents are, I'll spring for one and replace the Gortex. Hammond polycarbonate cases are the ultimate and priced accordingly. PVC cases are much more affordable. I use Carlon electrical utility boxes for less serious projects. These feature a neoprene gasket that provides a reasonably good seal and stainless steel screws. I've found Carlon cases to be suitable for many exterior projects and for cases for interior projects. The walls are reasonably thick, the cases reasonably strong, and, the price several years ago was very reasonable [I ended up with oodles when an electrician friend hung up his tools.] A catalog is available at https://carlonsales.com/electrical.php Lowe's used to carry these but appear to have shifted to Cantex. Cantex is similar but uses zinc plated screws, which are guarantied to rust here in Kentucky. I have no experience with the quality of the weather seal in the Contex units. The Carlon utility box is just starting to show some wear from the weather. Our POTS (Plain Old Telephone System) landline NID/DSL filter is in a PVC box. It's sheltered from direct sunlight being on the north side of our home. The phone company supplied the box and internal frame and NID, I added a DSL filter and Cat 5 wiring in the fading dream Windscream, er sorry, Windstream will extend DSL out to where we are and I can give up a Consumer Cellular phone based WiFi hotspot. Oddly enough the local electrical inspector approved Cat 5 wiring from the Windstream NID to inside our home with no comments about "You need transient protectors." I guess the Tii belcore lightning transient in the NID qualifies. https://tiitech.com/wp-content/uploads/datasheets/surge-arresters/356.pdf They meet UL 497 and Telcordia GR-1361 Core protection requirements. They also installed a NID case more suited to an 8 dwelling apartment building, too bad I can't legally do anything with the spare space. The installation tech allowed me to install the DSL filter. Nice of her. The GTE PVC box at my parents home was at least 40 years old when we sold the home and still in good shape and it was on the south east side of the house and received hours of direct sunlight. So PVC might be OK for extended service. I'll continue to use PVC for casual projects but for my CCW dual polarity H/V antenna and my N4CY loop amps, I'll go with the Hammon polycarbonate cases even though the PVC cases I've used for the N4CY looks have held up nicely. OK a bit of theory here. I suspect we have water ingress because the changing temperature, cooler, sucks in moisture laden air, by having a vent that allows air but blocks all humidity, we don't get condensation. A life time ago when I went for

Hi everyone I wondered what schematic design software other members use. I've tried one or two free downloads but struggled to get good results and so I wondered if there was some free or very low cost design software that members could recommend that doesn't have too steep a learning curve. Thanks in advance Chris Sentance

Hi All, Long time reader. I enjoy this group. First post. My health is lacking. I walk with a cane. I will leave it at that. Antennas must must be low to the ground as I cannot climb or put up wire antennas to any sort of height. I am very interested in setting up a broadband loop antenna to listen and log. Perhaps to use it as a second receiver. Steve, AA7U has been helpful to me and I thank him. I decided to post here and learn. I have read extensively in the files area and have looked at lots of pictures and read much about the rf amplifiers. I can make most everything I will need, and am very experienced in building manhatten or SMD (yes I can still do that! :-) with my magnifiers. I have, a scope, sig gen, DSA 815-TG, power supplys, VNWA/3E, and hako soldering equipment including the FR-301 (Handy for fixing radios!) and most all the other equipment as well. Meters, most PEAK tools (LCR DCA55,ESR70) I would like to build my own things. I read this article on top of what was posted here and was impressed with it. I would like to get your feedback on this. https://swling.com/blog/2016/03/guest-post-building-a-magnetic-loop-antenna-broadband-amplifier-for-your-sdr/ I am also interested in what Joe and Steve have done with amplifiers. I would prefer not to have to order from europe and make my own. /g/loopantennas/files/APracticalApproachToBuildingABroadbandActiveLoop.pdf Thanks for this group! 73 Guy N1GMM https://www.qrz.com/edit/N1GMM -- 73/ Guy, N1GMM Web Presence: Withywindle ( https://niggles-parish.blogspot.com/ ) tom-bombadillo ( https://tom-bombadillo.blogspot.com/ )

I wonder if anyone here has had any experience of the XG189? I recently bought one and it seems to work in a lashed up table top experiment using a sig gen and a dual channel scope.. I am particularly interested in any RF antenna experiments and findings from members here. Pete Worrall G4GJL

What happens if, instead of the 4+4 2SK715 FETs used in the schematic of the ALA1530, I will use only 2 + 2 ? I have only 5 of those FETs, so cannot build the schematic in its original form... Are modifications needed to the number of turns of T1 ? There will be a substantial degradation of the performance ? Thanks for any suggestion. 73 Alberto I2PHD

Is there a place where group owners/moderators can chat? I'm new to this (so new it's embarrassing) and there are so many things I need to learn. Like what's allowed/disallowed, is there a way to politely inform a poster "you've crossed a line, please don't again," and similar topics. We can delete this thread after it has served it's purpose. Note: I will be extremely busy from now until August 29 (more likely until September 1) with preps for and then undergoing surgery. If it's like the last time, I will be undopped August 31. I don't like opiates and they don't like me. I started PT the last time 2 days after surgery, this time it will be the day after surgery and the first few PT sessions wipe one out. Oh and I completed PT for my right knee yesterday August 13, got a nice "diploma" to hang on the wall. Note 2: If (when) you have major surgery, do not forgo the PT, it sucks bilgewater to quote a friend, but the surgeon finishes in an hour, the PT techs work with you for weeks to months. A guy at the club where we use the pool and equipment was bad mouthing my surgeon before I had surgery, I asked "Did you do PT?"" "Of course not! I don't have time for that !@#$." And he wonders why his left leg is nearly frozen. He scowls at me when I every time I went up the stairs for the last two weeks to the saunas (hey it's my wife's idea) because my right leg moves so freely. It's all I can do to not giggle at his self inflicted unhappiness.. You have perhaps 3 months to rehab major joint replacement. Oh, I am not a gym rat, I !@#%ing hate exercise, but I accept I'll live longer and healthier if I start taking care of this old body. Enough said.

Greeting to everyone. I have been a lurker/reader of this forum and finally have a contribution. Check-out ===> http://www.sonic.net/~n6gn/OSHW/ to see some of the 'kits' N6GN has developed that you can order from a Chinese FAB business. Several members of the wsprdaemon and Hamsci groups are using Glenn/N6GN hardware to great success. 73 Dick/w7wkr

On Tue, Aug 13, 2024 at 09:49 AM, wn4isx wrote: I logged into Groups IO like normal and there is a blue box with owner inside. Does this mean I've been elevated to group owner by mistake? Yes, that does mean the group's original Owner (Steve Greenfield) has selected you as one of the group's Owners. An Owner is like a super-Moderator. You have the power to create and destroy. You might recall Steve wrote that he had a recent stroke. I think he wants to make sure at least a few active group members are able to carry-on in case he can't for some reason. I think he did not do it "by mistake", but I am not him. As one of the Owners, you don't need to do anything. Just don't screw it up by deleting things that should not be deleted. And hopefully you will be with the group for a while so that you could - if needed - step in if Steve can't. The problem with some groups is that they have only one Owner, and if that Owner goes missing for any reason, the group dies and can't continue like it used to. You will probably start to receive auto-generated messages whenever anyone joins or leaves the group, and several other status messages. You can ignore them. You can even disable those messages, and act as if you are a normal member. Heck, I think you can even edit your own membership status so that you go back to being a regular member again and not an Owner, if that is what you want. If you want help knowing what you can do, I may be able to help a little with that. Andy