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Dual JFET Preamp?
Does anyone in the group have experience with this product:
https://www.sv1afn.com/j310preamp.html It looks to be very well constructed and suitable for a loop preamp. Steve / VE7SL |
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Re: RF Systems DX-One Pro MkII - Bi-Loop or not ?
johnnyc604
Ian,
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Did you by any chance have a Wellbrook 330S or 1530S in the past collection of antennas you could compare the RF Systems to? Thanks, John --- In loopantennas@..., <ihmeyers19@...> wrote:
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Re: 1.5-volt active loop antenna?
In loopantennas@..., <christrask@...> wrote: > I just deleted that earlier PDF file and replaced it with "Active Antenna Amplifiers for Low Voltage Operation.pdf" that has the low input impedance amplifier on the second page. This is still a work in progress. I'm thinking about building the low-input-impedance amplifier on the second page, using 2N3904 transistors and running off of 1.2 volts. Intended use is for shortwave listening and maybe MW listening. A couple of questions: 1. Are the ferrite beads necessary? 2. I'm thinking about winding the inductors and transformers as follows. All inductors will be wound on FT50-43 cores. T1: 20 turns, center-tapped. T2: 20 turns primary, 20 turns secondary, each center-tapped. L1: 20 turns. T3: 20 turns primary (center-tapped), 20 turns secondary (output). Do these values sound reasonable? 3. For Q1-Q4, what base and collector voltages should I aim for? 4. Is symmetrical physical construction important?? 5. Why can't we take the antenna output directly off of the T2 secondary, using Q3 and Q4 only and eliminating Q1 and Q2? 6. I'm planning on using the coaxial cable to supply power to the antenna, using a bias tee and running +Vcc through the T2 secondary (similar to the original M0AYF design). Any problems with this approach? Thanks for any advice. |
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Re: RF Systems DX-One Pro MkII - Bi-Loop or not ?
I had a DX-One (MK2) for about two years.? It worked very well but my HOA made me take in down and I ended up selling it.
1) It is ABSOLUTELY an omni-direction vertical. 2)? It was the best vertical I had ever used and I had most of them.? I now have a DX Engineering active whip because it is lower profile.? I would say it has 80%+ of the performance of the DX-One at 25% of the price.? Where the DX-One REALLY excelled was in the LW band where reception was significantly better than with any other antenna I ever used. 3) I seem to recall that the developer (and President) of RF Systems died earlier this year.? My understanding was that the company was no longer in business though it seems Universal Radio still carries their products. 73, and Happy New Year, Ian Meyers Boynton Beach, Flroida |
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File - Links.txt
Active AM Antenna With Twin Coil Ferrite by C. Crane Co.
JLKolb?s antenna links including the KRS AA-1 Active Antenna schematic, antenna preamplfiers, center-tapped loops, and a dual gate FET preselector. Directional Terminated MW/LW Loop by WellBroook (UK) K9AY is the Remote Controlled Variable Termination; Provides a Cardioid Reception Pattern with up to 30dB Gain Front-to-Back; Uses Two Delta Loops. Kiwa - High Performance MW Air-Core Loop Antenna High Performance MW Air-Core Loop Antenna by KIWA Palomar Engineers Loop Antennas LW-MW-SW2 Palomar's Loop Antenna gives superb performance on the AM medium-wave broadcast band. The loop rotates and tilts to give deep nulls so you can eliminate local interference. It also allows you to null out a station and listen to another one on the same frequency. The Quantum loop antennas, now V2.0 Terk AM loop at Amazon.com Here is a place you can buy yourself a TERK AM loop antenna, even some other stuff that is kind of off topic to talk about. 73 WL1030 by the late Maartenhagg. Plans placed on this website by his friends in his honor. C Crane Company They sell the Justice AM Loop Antenna, Select A Tenna, Terk AM 1000 Kiwa Electronics Kwia makes the best products for you and your radio equipment, and also improves things that needed improvement a long time ago. Stormwise Ferrite Rods Get some huge ferrite rods and a converter to go along with its, heck it even comes with project book. Universal Radio Company They sell all sorts of loops big and small for LW/MW/SW and VLF also 10 kHz to 15 MHz ALA-1530 Find the best UK LF/MF antenna here. AOR This is the site that sells the AOR loop Kiwa Electronics The maker of the air core loop antenna and other useful items that you may want on your wish list. LF Engineering Company A group of engineers, who make products for VLF/LF listening even ELF loops! Select A Tenna by Intensitronics Corp The maker of the select A tenna, a great AM loop antenna that is a little bigger than the terk discontinued Terk Technolegies The maker of the best sold AM and I use also called the AM-1000 AM loop antenna, there is also technical information on how it works. Torus Tuner Loop Company A very specially made loop that is almost as big as a hula hoop discontinued GRAHN (Germany) Specialized Loop Antennas for MW and SW Reception Contributed by radiohighfreq Grahn offers both Ferrite Rod Antennas and Shielded Loop Antennas. Translated from the Gremany Language Webpages here is the "Grahn Specialized Loop Antennas for MW and SW Reception" ULR Address: Use the Google Translate a web Page Tool to convert these webpages to English. When considering AM Loop Antennas . . . - - - It all comes down to Time? & Money? How much Time? Are you going to be 'using' the Loop Antenna for DXing or simply for "Better" AM Radio Reception (Sports/Talk Radio Loop). How Much Money? Are you willing to spend for a Loop Antenna to get the kind of better reception you want. TBL: Time and Money translates to the AM Loop Antenna's Value to You. The average radio listener (97%), who wants better AM Radio Reception, can spend $100 or less and get an AM Loop Antenna that meets their needs. Here is a brief list of the more common AM Loop Antennas for $100 or less. * Twin Coil Ferrite AM Loop Antenna (Active) - - - * Torus Tuner 27" Loop Antenna (Passive) - - - discontinued * Select-A-Tenna Model #541M (Passive) - - - discontinued * Terk AM Advantage Loop Antenna (Passive) - - - * RadioShack AM Loop Antanna # 15-1853 (Passive) - - - Discontinued (Find 'used' on eBay) * MTM Scientific AM Radio Loop Antenna (Passive) * - - - Starter Kit, Deluxe Kit or Finished Antenna! * * * Home made 'Box' AM Loop Antennas - Usually 20" to 24" in size - - Generally a simple Passive antenna - - - Can be made Active with an add-on amplifier #1. * Justice AM Loop Antenna (Active) - - - discontinued#2. * Torus Tuner 27" Loop Antenna (Passive) - - - website gone#3. * Select-A-Tenna Model #541M (Passive) - - - website gone#4. * Terk AM Advantage Loop Antenna (Passive) - - -#5. * RadioShack AM Loop Antanna # 15-1853 (Passive) - - - Discontinued (Find 'used' on eBay) #1.a. Kiwa MW Air Loop Antenna #1.b. Quantum Loop Antennas . . . #3. Palomar Loop Antenna Basic Wire Back Yard Loop Antennas Full-wave loops are very popular antennas. They are especially useful on 80 and 40 meters where they perform well at modest heights. These are closed loops that are one full wavelength long. Horizontal loops may be fed at any convenient spot. For best performance, make your horizontal loop into a square, especially if it is to be used on several bands. K9AY: How to Build the K9AY Loop Receiving Antenna AY Technologies Antennas by K9AY. Excellent Antenna for Medium Wave Frequency DXing. Six Foot Square by Six Turn Loop Antenna New Mid-Size Loop Antenna by Graham Maynard with Matching Balanced Amplifier: Frequency Range 50KHz - 5000KHz. Ten Foot Receiveing Loop for Low-Frequency DXing A Page out of VE7SL's Note Book. This 10 Ft. Air-Core Receiving Loop was originally designed and constructed for NDB DXing and now is used for LOWFER DX work. Dave's HomeMade Loop Antennas This is the loop antenna my dad built in 1958. Although I was only 8 years old at the time, I knew what this was for and how it worked. WebSite/Pages produced by Dave Schmarder Page Contributed by radiohighfreq 4 Foot Box loop antenna Heres a 4 foot loop project by Bruce ATL-3 Loop Antenna by Graham Maynard (UK) Loop & Amp Project: ATL-3 Loop Windings are in the Shape of a Five 26" Sided Spiral Alt-Azimuth Wooden "HOOP LOOP" Antenna by Linus The Great Pumpkin" Speaks on "How To Make" a Loop Antenna from a Wooden Embroidery Hoop. Read the Exciting Saga of his journey in to the Kingdom of Hooppy-Looppy-Dom presented by RadioIntel.Com. DXers Tool Box - DIY - Tuned Loop Antenna The DXers Tool Box "How To Build" a Tuned Loop Antenna = How can you vastly improve your Medium Wave reception? The antenna consists of an LC (tuning) circuit formed by the air-core loop and a tuning capacitor. Embrodary Loops While these loop are for crafts, they can be a craft of art for improved AM radio reception! Hard Core DXing Here's what nordic dx has to offer in their discription of loops in this website K5DKZ - Three Foot Box Loop Antenna Kit Complete Parts and Plans for a 3 Ft Box Loop Antenna "Kit" ~$85+SH KIT -by- MTM Scientific, Inc. -for- AM Radio DX Loop Antenna KIT =//= Designed to Build an AM/MW Radio DX Loop Antenna =//= Offered by MTM Scientific =//= Deluxe Loop Antenna Kit: Includes ALL the Hardware for Building this AM/MW Radio DX Loop Antenna. Long LoopStick Antenna for MW DXing Wound on a Three (3) Foot Length of PVC pipe, the "Long LoopStick Antenna" was an experiment to try to improve AM radio reception without using a long wire or ground. TL Loop Receiving Antenna 10 KHz - 30 MHz The principle of operation is that an rf voltage appears across the terminals of a loop when it is placed in an electromagnetic field. The voltage is proportional to frequency for a given field strength and so at Very Low Frequencies the voltage is very small and requires greater amplification but it is not quite as simple as that. The new TL Loop uses a unique feedback system to optimise the amplification/noise factor over a much wider range than has been possible hitherto. W2BRI Xmit Loops Contributed by n3hkn Ham Radio xmitting loops. Detailed plans and reports from Hams experiences. Typical cost is $50 for pipe, capacitor, motor. "AM Loop Antenna Calculator" - by Bruce Carter Here is a Great Tool for those Loop Antenna => "What Ifs...." "Loop Antennas 101" Read This First Minnesota DX Club's Loop Antenna's web page that is a 'Must Read' =Says It All= A Starting Point Class 101- - - TOPICS: Principles of the Loop Antenna - What is a Loop and Why Use It - Construction Principles - What Can I Use a Loop For - Loops Another Look - Pictures of Home Built PVC loops - Loop Links * NEW => 2002 AM Loop Antenna Construction "Tips" by Bruce Carter Introduction / Why Another Loop Antenna Page? / Mathematics of Rectangular Loop Antennas / Construction Articles / Loop Antenna (and Related) Links Loop Antennas at Hard Core DX TABLE: Number of Turns -v- Size of Loop in the Middle of this webpage. Loops and Rods =&= The Ferrite Rod Antenna Theory / Formulas / Drawings = The use of a small Magnetic Loop as an antenna. The ferrite has the effect of intensifying the magnetic field inside the loop. Modify the common AM Radio Loop Antenna Hard-Core DX & Nordic DX = Topics: Install Larger Ferrite Rod - Fix External Antenna -Add a Long Wire - Or a Loop - Construct it - Connect it - Add an Amplifier. Presented by Bruce Carter Sensitivity of Multi Turn Receiving Loops LWCA - Multi turn wire loops are often used as low frequency receiving antennas. Basic electromagnetic theory is developed here as it relates to electrically small multi-turn loops at low frequencies. - Presented by William E. Payne, N4YWK Using the Small Loop Antenna by Joe Carr DXing.Com presents Joe Carr's Radio Tech Notes: Eight Page PDF Document provided by Universal-Radio.Com How to Get Better AM Radio Reception Features Loop Antennas and much more. The Antenna is 90% of Your Radio. Still Need More Signal? Try a Better Antenna. Introduction to Broadcast Band AM/BCB/MW DXing The International Radio Club of America (IRCA) WebPages ** Radio-Antenna-PRO ** H.Hertz-Forum Remember you may need some Russian Text software for this groupThe international forum for radioengineers, scientists and hams. All about radioelectronics, radiocommunications, radiophysics, electrodynamics. About 250 members from 20 countries. In Russian language. Very active. Lot of interesting researches and discussions. Radio DXing with The Interference Problem This is great for that annoying problem you have with your loop antenna, and you may think its the loop, think again it could be that messed up street light, next doors dimmer switch, and other something else you can't probably solve with just a loop antenna. "3805er" 80-Meter balanced coax loop Small shielded rx only loop for 80 meters Magnetic Loop Antennas Receiving - by W8JI This WebPage's Topic Are: - Small Receiving Loops - Loop Antenna Fields - Dipole Antenna Fields - Radiation - Loop Shielding and Balance - by W8JI Radiation and Fields (Magnetic Loop Antennas) - by W8JI This WebPage's Topic Are: - Electric Field - Magnetic Field - ElectroMagnetic Field - Near the Antenna - Losses - Near Field - Fresnel Zone - Farfield - Summary - by W8JI Shielded-Loop Receiving Antenna by N5FC Shielded-Loop antennas have some nice properties that make them desirable as portable receiving antennas. Antique Electronic Supply A sorts of older variable tuning capacitors for your loop antenna that needs one bad. Fair Radio Sales A wide variety of electronic components, radios, and variable capacitors for your loop antenna Ocean State Electronics Rhode Island's best selection for a wide variety of the best tuning capacitors for reasonable price, tell them that electronicdx (Adam Ebel) sent you. The Crystal Set Society Here are some capacitor available from a club that devotes to Crystal Set Radio The Surplus Sales of Nebraska This surplus store based in the state of Nebraska, has the one you might need, but they have minumim order policy Dan Small Parts and Kits Dan's wide selection from Canada. American Science and Surplus A big spool of wire here just about for AM DigiKey.com For ribbon cable and other sorts of wire. Femco Magnet Wire Femco Magnet Wire is a joint venture company that has been supplying round insulated copper magnet (winding) wire to the transplant market since 1988. Litz-Wire,com Welcome to Litz-Wire.com! MCM electronics They do sell wire and magnet wire here MWS Industries A place for all sorts of wire for business and industry Magnet Wire from Radio Shack This is what I use often Mouser Electronics Mouser has the biggest spools here for a great price, that makes sense Ocean State Electronics magnet wire at a good price WIRE "Flex-Weave" Antenna Wire "Flex-Weave" is a hybrid aerial wire that consists of 168 strands of woven #36 solid copper wires that provide high strength and extreme flexibility. The most popular version of "Flex-Weave" is the 'equivalent' of #14 AWG wire size. It can be 'used' for unsupported spans up to 200 ft (100-150 ft in areas with high ice and wind loading). WIRE "QuietFlex" Antenna Wire by Antennas & More: Insulated, Strong, Flexible and Durable "QuietFlex" Antenna Wire by Antennas & More: "QuietFlex" #14 AWG Wire has more than 41 Strands tightly twisted together under its Flexible Insulation making it both Strong, Flexible and Durable. Scanning, Ham Radio and Public Safety Resources - Links to the various webpages with resources for the Ham Radio Operator and Scanning Enthusiast. Resources such as; Monitoring Police and Fire Communications, What Antennas to use, Secret Scanner Frequencies, Radio Programming Software, Radio Mods and Operating Tips, Professional resources for Public Safety Management, Guidance and Self-Help. Amidon Ferrite rods, bars, plates, and tubes. Bytemark Ferrite rods, bars, plates, and tubes. |
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File - UploadingFilesLinksPhotos.txt
If you have a link relevant to the group, please post it in the Links section. If you just put it in a message, it will get lost in the shuffle after a few days. The coverage of the list is pretty broad.
All members can upload Links, Files, and Photos. A few guidelines: Try to place them in the proper folder, if it exists. If not, you can either just put it in the root folder and eventually I'll move it into the proper place, or create a folder. When creating a folder or uploading a file or photo, please don't use spaces or punctuation. You can either use caps for the first letter of each word, or use underscore as a space. Like this: "4x8Loop" or "4x8_loop" or "Steves_4x8_Loop" Not like this: "Steve's 4 x 8 Loop." That goes for Folder names and File names. A special note about the Photos section: Please crop in to the important parts. For photos, JPG saves smaller and looks better, for line drawings GIF is smaller and looks better. Please do not use TIFF/TIF or BMP files, the file size is way too big and I may delete without notice. Feel free to ask if you need help figuring out how to crop and resample. Irfanview is a fairly easy to use program that loads just about any file, you can crop and resample from there: Or for more complex stuff, another free program is GIMP: Attachments are now allowed, but please use judiciously. Rather than going out with the messages, they will be stored on the list but you'll get a link with the message. A last note: if you see something in any folder or in the messages that looks like spam or simply inappropriate, don't post on the list- email me directly and tell me about it and I'll take care of it with a minimum of fuss. loopantennas-owner@... Thanks, Steve Greenfield |
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Re: RF Systems DX-One Pro MkII - Bi-Loop or not ?
Hi Fraser ? just once more browsing thru DX-one threads...: apparently you are in possession of Xrays! Could you please forward copies to my email address ulrich.ruch@.... My headamplifier has been laying around defective for more than one year, and all my queries at RFS remained unanswered. I would therefore ?like to have it repaired by some local - but for this I need to know how to get access to the amplifier?resp. how disassembly is made without causing any damage to the rest of the antenna stub. ? Looking forward with keen interest to Hearing from you. ? 73s and happy New Year Ulrich Ruch Hinterester 13 CH 8184 Bachenb¨¹lach |
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Re: Butterfly Capacitors from copper stock?
Andy Gardner
Yes. If I was doing one in brass, I'd be silver-plating all the components before final assembly, then using silver solder. That would give you a nice high-q capacitor.
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On 29/12/2013, at 5:49 AM, <gnuarm.2006@...> <gnuarm.2006@...> wrote:
Considering that the starting point was Aluminum and the change to copper was to improve the conductivity, then yes, Brass has a lower conductivity and *will* make a difference. The resistivity of these materials in nOhm m are |
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Re: Best cheap multimeter for capacitance
John Sterkeson
¿ªÔÆÌåÓýI built the L-C meter kit from :?
electronics-diy.com?? .? Very accurate for most
purposes.? Cost about..... $70.00
?
John
KC9ZYT
?
?
? From: jeff@...
Sent: Saturday, December 28, 2013 2:15 PM
To: loopantennas@...
Subject: [loopantennas] RE: Best cheap multimeter for
capacitance ?
?
I use both the SmartTweezers ($350, but really slick) and the AADE Model iIB
($99 kit).? The AADE will measure L and C very stably and I carry it to
hamfest tailgates.? Get the 3/4 inch binding post spacing option - it fits
standard banana jack spacing.? See it at www.aade.com. ? The SmartTweezer also gives you Q and ESR.? It's a bit more precise, but the AADE's 1 to 2% is fine for most of the stuff I do :) ? Jeff
W3HVU |
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Re: Best cheap multimeter for capacitance
I use both the SmartTweezers ($350, but really slick) and the AADE Model iIB ($99 kit).? The AADE will measure L and C very stably and I carry it to hamfest tailgates.? Get the 3/4 inch binding post spacing option - it fits standard banana jack spacing.? See it at www.aade.com. The SmartTweezer also gives you Q and ESR.? It's a bit more precise, but the AADE's 1 to 2% is fine for most of the stuff I do :) Jeff W3HVU |
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Re: Butterfly Capacitors from copper stock?
---In loopantennas@{{emailDomain}}, <brian@...> wrote:
~Anyone looked at making butterfly capacitor kits from copper. The weld that MFJ used to attach their butterfly capacitor to their aluminum loop is a great concept but we all know that copper is better conductor, and if we could braze/solder the connection of the butterfly loop directly to the copper loop (Homebrew) this would be a lot more efficient. ? Copper is quite soft, easily bent, and difficult to de-burr. I would use thin brass for capacitor plates for its easier working and polishing//de-burring properties. It solders very easily, and I suspect that its conductivity is so close to copper that ¡°there¡¯s not enough difference to make a difference¡±. ? Cheers, ? Brian Burns? Ex: W5BRO, K6UCD ? ? See my website:? www.lessonsinlutherie.com Considering that the starting
point was Aluminum and the change to copper was to improve the
conductivity, then yes, Brass has a lower conductivity and *will* make a
difference.? The resistivity of these materials in nOhm m are Cu - 17.1? Al - 26.5 Brass - 64 Of course the composition of Brass varies a bit and so will the resistivity, but it won't change enough to alter these relative amounts.? In
changing from Aluminum to Copper, I would question the resistance of
the soldered connection compared to the solid body of the Copper.?? It
may well be that the added resistance of the welded Aluminum is less
than that of the soldered joints.? Solder is *much* better than mechanical connections, but I expect a weld is significantly better yet.? However the devil is in the details... just how good a solder joint you get.? Anyone have an idea of the relative resistance of the antenna materials to the radiation resistance?? Wouldn't? that be what determines when you have reached a point of diminishing returns in optimizing the material resistance? Rick |
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Re: Butterfly Capacitors from copper stock?
¿ªÔÆÌåÓý~Anyone looked at making butterfly capacitor kits from copper. The weld that MFJ used to attach their butterfly capacitor to their aluminum loop is a great concept but we all know that copper is better conductor, and if we could braze/solder the connection of the butterfly loop directly to the copper loop (Homebrew) this would be a lot more efficient. ? Copper is quite soft, easily bent, and difficult to de-burr. I would use thin brass for capacitor plates for its easier working and polishing//de-burring properties. It solders very easily, and I suspect that its conductivity is so close to copper that ¡°there¡¯s not enough difference to make a difference¡±. ? Cheers, ? Brian Burns? Ex: W5BRO, K6UCD ? ? See my website:? www.lessonsinlutherie.com ? ?
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Re: Best cheap multimeter for capacitance
¿ªÔÆÌåÓýI now have a Honeytek A6013L?digital C meter, range: 0.1 pF to 20000 microFd bought new on ebay.? I like it, but I cannot really comment on its accuracy.? So far, for me having capacitances?read from it is better than capacitances from my old Heathkit RLC bridge.? Bill Young WD5HOH ? To: loopantennas@... From: k910dog@... Date: Sat, 28 Dec 2013 01:33:17 -0800 Subject: [loopantennas] Best cheap multimeter for capacitance ?
I know that there are several Fluke and other top quality multimeter out there that measure capacitance but is there a decent brand/model that has a good range for measuring capacitance loop building persons could buy for a reasonable price?
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Re: Best cheap multimeter for capacitance
Good question. I have quite a few DMMs with built-in capacitance measurement, including several Flukes at work. The lowest scale on all of the ones I've used only go down to the nF scale, down to one pF (0.001nF).
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I used to build and sell capacitance meters. Originally with a standard 50uA meter for the display, then I built them to use any DMM as the display on the 200mV scale. Here is a schematic, for best results us the TLC555 (CMOS version): It does require a regulated voltage. A 78L05 works fine, or pretty much any modern well-filtered switching regulator. It wasn't meant for measuring large capacitors, so the largest capacitor it will measure is 20uF on the 2uF scale when your autoranging meter switches to the 2V scale. I still have one. I built one ugly on purpose so I wouldn't/couldn't sell it. It easily resolves 0.1pF pretty stably. Keep in mind that with any measuring system, resolution is not the same as accuracy. I have a 0.1% capacitor I use to calibrate it on the 2000pF scale, and trust the tolerance of the other resistors. Steve Greenfield AE7HD --- In loopantennas@..., <k910dog@...> wrote:
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Butterfly Capacitors from copper stock?
Anyone looked at making butterfly capacitor kits from copper. The weld that MFJ used to attach their butterfly capacitor to their aluminum loop is a great concept but we all know that copper is better conductor, and if we could braze/solder the connection of the butterfly loop directly to the copper loop (Homebrew) this would be a lot more efficient.
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Best cheap multimeter for capacitance
I know that there are several Fluke and other top quality multimeter out there that measure capacitance but is there a decent brand/model that has a good range for measuring capacitance loop building persons could buy for a reasonable price?
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For Sale; Active Antenna AAA-1B by LZ1AQ
I have two of the AAA-1B active antenna amplifiers that I got from LZ1AQ
These have both been only slightly used and come with all the extra parts. They both work and look as new. The price new was about $120 shipped. I would like to get $90.00 each, shipped in the CONUSA. PayPal preferred. These are very nice active amplifiers and they work very well. I have just changed directions so I no longer use them. I used them with small copper loops and got very good performance from them. Thank You Larry Naumann n0sa |
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Covering the MFJ 1788 loop antenna
I live in a condo and wanted to purchase the MFJ 1788 loop and place it under a
plastic cover such as a BBQ cover. This way the antenna to the condo
cops looks like a BBQ. My question is has anyone done this and if so how
did it work out?
Mike VE3WDM |
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Re: HIGH VOLTAGE BUTTERFLY CAPACITOR'S KITS FOR SALE
10" OD ROTOR + 2 STATOR PLATES $ 14.00 |
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KD9SV preamplifier
Hi,
I am building up the KD9SV preamplifier using the circuit board and having loads of trouble with oscillation is the gain pot is turned much past about 30 percent.?
I'm testing it on the bench and feeding 1850 khz out of my 8640 generator into the amp and the amp is terminated with a 50 ohm load. I am looking at the output with my scope probe (10x) across the load, and the unit is oscillating in the FM broadcast band as seen with the frequency counter connected to an output of my scope.?
I tried removing the flux around the dual gate MOSFET (using NTE455) package thinking that might help but it didn't.?
Has anyone else built this, and if so did yours work initially?
Thanks!
Chris
KD4PBJ
¡ª
Sent from for iPhone |