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Hi All, I saw an interesting article. an amplifier using a 2N5109 at the bottom of this page. https://www.microchem.fr/ayet/atlas/hf_amplifier.html It has a 3.3V zener diode and a 3.3k resistor to make a bias voltage. It looks simple and stable, seems to work well in LTSPICE simulations. I have a question. I have never seen a direct bias style like this. Is there any problems? 73, Hisami 7L4IOU

Merry Christmas to ALL from Los Angeles, California !!!! 1). Need a Formula for designing an "L Impedance Matching Circuit" for matching 50 Ohms to an Antenna with a known Antenna Input Impedance ( Z ). Any Web Sites for referral or Formulas ? So far have not found any. 2). Question: In winding a Toroid there are many ways to get a Turns Ratio of 3:1, such as - 6 Turns to 2 Turns, 9 Turns to 3 Turns, etc. Is there a "GENERAL RULE" for determining the number of Turns that is best ?? [ I believe EACH winding on the Toroid needs to operate below it's Self Resonant Freq inorder to act as an Inductor. Maybe for a "Broad Band" Toroid, a Higher Number of Turns ( increases R ) is better because it lowers the Q = Xl / R of the Inductor ? Any Comments and Help would be APPRECIATED !!!! THANK YOU Garey Wittich

Pa0FRI has become a silent Key. Anyone using any of his loop amplifier designs or data may well want to archive or save it before the web page disappears. There is also a lot of other general useful information his page. https://www.pa0fri.com/ Henry

Thinking of getting on but am wondering what users in the US have done for an enclosure? The round shape was made to fit into 20mm electrical trunking junction boxes that are available in Europe. Could save me some time if anyone has it figured out. Thanks

I sold a bunch of multicouplers this month and still have one left. The multicoupler can power an active antenna with its internal bias-tee, and feed 1 to 4 receivers. If interested contact me at thomas.b.seeger(at)gmail.com 73 Tom /g/loopantennas/files/VE3PSZ%20Multicoupler%20General%20Notes.pdf

I want to add this post to Martin's MLA-30 thread, but it is locked. Hence, my starting this new topic. I know the MLA-30+ has been done to death where evaluation is concerned, but I can't resist jumping into the fray! So, here's the link to my eval. Thanks for reading!? 73, Chin-Leong Lim, 9W2LC.

I tested three different transistors in the Ikin Norton 9 dB circuit--2SC5551, BFU590QX, 2SC3357 (all SOT-89 package). I used Everett N4CY's PCB. All were tested at 12.0 volts supply and bias set for 70 mA. Since the 2SC3357 has a max 12 volts Vceo; this circuit with 12.0V supply and 70 mA had 10.3V emitter to collector so is running below the Vceo 12V limit. IMD tested with my standard 3/4 MHz test tones set for 0 dBm each tone at output of the preamp----2IMD checked at 1 and 7 MHz; 3IMD checked at 2 and 5 MHz. P1dB tested with 50 ohm load at 1 MHz. Gain swept with DG8SAQ VNWA--all three had fairly flat response from about 50 kHz-30 MHz. Noise figure tested on HP 8970B. 1. 2SC5551 IMD--1 MHz +93 dBm OIP2, 7 MHz +89 dBm OIP2. 2 MHz +50 dBm OIP3, 5 MHz +49.4 dBm OIP3. P1dB--0.585 watts, +27.7 dBm. 10 MHz noise figure 1.82 dB. (The transistors are from what I purchased several years ago when Rochester Electronics still had them.) 2. BFU590QX IMD--1 MHz +84.5 dBm OIP2, 7 MHz +83.5 dBm OIP2. 2 MHz +50.1 dBm OIP3, 5 MHz +49.3 dBm OIP3. P1dB 0.585 watts, +27.7 dBm. 10 MHz noise figure 1.87 dB. (I got the transistors from mouser.com, NXP made them.) 3. 2SC3357 IMD--1 MHz +89 dBm OIP2, 7 MHz +89 dBm OIP2. 2 MHz +49.9 dBm OIP3, 5 MHz +49.6 dBm OIP3. P1dB 0.63 watts, +28 dBm. 10 MHz noise figure 2.15 dB. (I got the transistors from digikey.com, EVVO (Chinese) made them.) All three transistors gave similar IMD and P1dB. 2SC5551 is no longer available but the other two are currently being made. If you're careful not to exceed the 2SC3357 Vceo 12V max, it would also be suitable. 73, Steve AA7U

The following items have been added to the Files area of the [email protected] group. /Common Mode Chokes.pdf By: Everett N4CY <everettsharp@...> Description: Common Mode sweeps of RX chokes

My balcony on the 6th floor of my condo has very poor short wave reception within the confines of the balcony. This is probably due to all the metal structures on the outside, such as steel railings and an aluminum framework meant to enclose the balcony with glass panels (which I don't use). I strung a 20 foot length of antenna wire just outside this framework and reception was much better. So I am now thinking of putting a MLA-30+ just outside this metal "cage" to go with my Tecsun-680 radio with hopes of improving the s/n even more. How sensitive are loops to nearby metal? Do I need to mount the loop a minimum distance from the metal or is just a couple inches adequate? I am concerned about stealthy-ness here because of restrictions so the closer the better from that aspect. Thank you!

The Mackinac Bridge is actually a pretty effective Faraday cage for MW frequencies. I've noted a distinct signal drop when crossing it, on 680 WDBC Escanaba, Michigan. But still, thinking of it as an LP just adds another dimension to its beauty. It also has two TIS stations. They give a brief history narrative, and then talk about ongoing maintenance on the bridge when there isn't a wind advisory. Scott NM8R

I just finished building an another batch of LZ1AQ loop amps that will fit directly on the Wellbrook ALA1530 loop. If there is any interest then please contact me off list at everettsharp (at) aol com everettsharp@... Everett N4CY

Hi, I am looking for a very low noise dc power supply to use with various 12 volt preamps in a bias T configuration. I would think no more then 3-5 amps would do it. Obviously would need a 130 VAC input. Does anyone have a recommendation? Preferably from a US source, but am open to any and all options. Thanks Tom

November 15, 2024 Hi all, New to this group, so I hope I am posting in the right place! If not, let me know! I am having a weird issue with my Wellbrook Imperium 1530 loop antenna. It is connected to my Drake R8B receiver and tonight while listening, the signal slowly started to disappear. At first I thought it was my Drake, but soon realized that the problem was with the Wellbrook. I noticed that if I disconnected the Antenna Interface box, and reconnected it, the signal came back to the full strength. It would operate okay until the same thing happened with the signal slowly disappearing. Any ideas? I think this box has a fuse. Is this a notice that the fuse is failing? Or is it something else? Thanks for any help you can share. Sincerely, George Santulli Lovettsville, VA

I have S9 "Static" covering BCB thru about 7 Mc being picked up on my 24 foot Vertical antenna. The antenna is Grounded to a copper water pipe. [ I verified it is NOT Common Mode Noise being picked up on the coax or coming from the House. ]. When I stand in a CERTAIN LOCATION - between the ANTENNA AND RECEIVER and 5 Ft from the Antenna the Static Noise drops to S1 or S2. Seems there is some sort of "Capactive Coupling" going on that shorts the Static out ? Still researching where the. Static Noise is coming from - using a battery powered BCB Radio. PUZZLED ?? Garey Wittich. Alhambra, Calif

My knowledge of semiconductor theory is rather basic and I was wondering whether amplifiers like the LZ1AQ could be improved by using low noise transistors like the 2N5109, rather than 2N2222 or 2SC5551. The NF of the 2N2222 is published as 5dB in datasheets but when I searched for the comparitive NF of the 2SC5551 it did not appear to be listed in the ONSemi and other datasheets. There was just an oblique reference to it being 8dB. Are the noise factors (NF) the same when used in a very low Z amplifier? Has anyone measured it for the low input Z LZ1AQ amplifier or other similar uses? Thanks John

The following items have been added to the Files area of the [email protected] group. /Good_Common_Mode_Chokes.pdf By: Everett N4CY <everettsharp@...> Description: Common Mode zChokes for LW and MW

I just built the stacked toroid loop stick antenna for the MW band as described in the files section. What would be the best way to connect it to a Drake R8A? I have the choice of 50 ohm or high imp antenna connection. Larry n0sa

Found this interesting article about changing the size of the YouLoop. http://radio-timetraveller.blogspot.com/2024/09/modding-experiments-with-youloop.html Zack N8FNR

An advantage is not having to run guy wires and more penitrations, plus the support will all come from the existing tripod. I did this to to 2 alliance rotors and an RCA over the years. Some of my other (easier) solutions were to mount the rotator UNDER ...at the bottom of the tripod! Make an insulating bearing out of PVC at the top of the tripod. Make a plate or bracket to firmly mount the rotator base, (above any possible standing water). You can always "slit" or stack one or more PVC diameters or sections, to makeup a thicker homegrowen bearing, glue 'em up, glue 'em together) to make 'em thicker, (even using hose clamps or a vice). Inserting the PVC spacer and clamp it down at the top of the tripod just enough to allow free rotation (with a little grease!). I also used hose clamps to hold the slit tripod's PVC bearings to the right diameter while loosely inserting the mast through the tripod and the rotor. Once in place, I slowly tightened everything up so the greased PVC bearing was held firmly In place by the groved indentations of the bolts... The one cavet is to not ever mount a rotator where it may sit in water! Don't set a rotator outside unless it is elevated and vertical. If your flat roof floods and water comes up to the rotator, that's bad. Sorry 'bot running on like this. I'm faithful follower here! Holmzie n2exg

I ordered a four port SMA switch from this company today and also found the upgrade for a Youloop. 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