A plan for HF Log Periodic Antenna working 10-20 meters band by VA2PHI
Log Periodic Antenna for 10-20 meters bands
Element spacing for a Log Periodic Antenna for 10-20 meters bands
20m Log Periodic Antenna SWR
17m Log Periodic Antenna SWR
15m Log Periodic Antenna SWR
12m Log Periodic Antenna SWR
10m Log Periodic Antenna SWR
Here you are the YOTA 2015 Team while their daily trip to Firenze today.
Yesterday I’ve been in visit to Marina di Massa for the YOTA 2015, Youngster on the air an International Event by IARU R1.
A total of 76 young hams coming from 22 countries where present
Countries represented, includes Belgium (UBA), Great Britain (RSGB), Poland (PZK), Czech Republic (CRC), Tunisia (ARAT), Croatia (HRS), Spain (URE), Netherlands (VERON ), Sweden (SSA), Austria (OeVsV), Serbia (SRS), Estonia (ERAU), Slovakia (SARA), Hungary (MRASZ), Finland (SRAL), Montenegro (MARP), Bosnia-Herzegovina (ARABiH), Oman (Roars), Ireland (IRTS), Bulgaria (BFRA), South Africa (SARL) in addition to the hosting country Italy (ARI).
It has been a nice experience, and really make pleasure to see so many youngs still interested into ham radio.
Read more about YOTA 2015
This article documents the modification of 2 typesof Hewlett Packard switching power supplies to enable their use as power sources for ham radio equipment.
Obsolete server power modules can be bought from online dealers at very good prices due to the massive replacement of older network servers; typical prices for a unit are as low as $10 including shipping.
Most of them have multiple outputs, typically delivering +12v, -12v and +5v. Some of them are capable of over 20 amperes continuous output at +12v.
This makes them suitable for powering the typical HF amateur rig, which requires 20-22 amperes at full power output.
HP-280127
Yet, such power supplies were not widely adopted due to the fact that they typically don’t work “out of the box”, requiring modifications to make them start upon connection to the mains. Also, there is no techn
ical documentation available for these units, which makes experimentation very difficult.
The present article is intended to provide experimenters with the information necessary to modify successfully the following types of power supply:
These units were chosen because they have +12v as their main output, derivated from a separate, dedicated converter (unlike typical computer AT or ATX supplies which derive all voltages from the same converter).
HP-194989
They are capable of over 20 amperes, and are very plentiful and cheap (dozens of dealers offer them used at very low prices). Their median time to failure is in the tens of thousands of hours; the engineering, the quality of the components as well as the assembly work are outstanding.
Designed for use in highly critical business machines (network servers), they are ultracompact, lightweight, very conservatively rated and feature several layers of protection to overvoltage and overcurrent. Isolation from the mains is excellent.
The units have internationally recognized safety certification (TUV, CE).
Unlike most power supplies for amateur radio use on the market, the HP units offer power factor correction and have the added advantage of working from any mains voltage between 100-240 VAC, 50 or 60 Hz, thus can be used in Europe without any modification.
The main difficulty in making these power supplies work outside the environment that they were designed for lies in identifying a) the pinout for the output connector and b) the control signals that start/stop the 12v converter.
Rather than proceeding by trial and error, I have approached this problem by
a) studying the documentation for the power factor controller/pulse width modulation IC’s that control the operation of the whole unit;
b) studying the architecture of similar power supplies for which documentation was available (none was available from HP) and c) acquiring and studying the modules that the HP power units are connected to in the HP Proliant servers, the power distribution units, or PDU.
These modules serve as an interface between the power supply and the server motherboard, they contain DC/DC converters supplying 2.5v or 3.3v to the Intel Xeon processor in the server and are also easily available for a total cost of under $10.
Tracing the signals from the power supply through the power distribution/conversion module, I wasable to identify how the HP supplies operate in their native environment.
While the 5v section is always “on”, the 12v section starts upon completion of the following procedure:
-Interlocking circuits are established on the PDU and PSU through each other’s PCB (each unit ensures that the other is “present”) – the PS_ENABLE signal generated by the PSU is pulled low (LOW=YES) on the PDU by circuitry associated to either the server’s “power on” switch or the presence and fault status of the other, redundant PSU’s -The PS_KILL signal, generated by the power supply in response to PS_ENABLE is pulled low (LOW=NO) by fault sensing circuitry on the PDU.
In fact, PS_KILL makes and breaks the cathode to ground circuit of the LED in the optocoupler driving the power MOSFET’s of the 12 volt supply.
Therefore the PSU can be started connecting together the interlock inputs and outputs and grounding PS_ENABLE and PS_KILL.
The rest of the circuitry on the output connector, being dedicated to automatic power management (APM) functions on the motherboard and/or BIOS monitoring functions (via A/D converters in the PDU) may be left unconnected.The output connectors for both supplies are PCB blades with gold-plated “fingers”.
For HP 280127, there are no interlocks.
The pinout for the “top” side of the PCB is as follows:
1, 10Â Â Â ground
2,9Â Â Â Â +12v
3Â Â Â Â Â Â +3.3v
4Â Â Â Â Â Â +5v
5Â Â Â Â Â Â PS_KILLÂ Â Â Â Â Â Â Â Â Â Â Â Â Â Connect to ground
6Â Â Â Â Â Â -12v
7Â Â Â Â Â Â PS_ENABLEÂ Â Â Â Â Â Â Â Â Â Â Connect to ground
8Â Â Â Â Â Â +7v
The “bottom” side contains supplementary +12v and GND outputs (easily identifiable being parallel to and as wide as the top side outputs) and also APM/BIOSÂ signals that should remain unconnected.
In the HP 194989, the “top” side of the blade has just the high current +12 volt output (center) and g
round (sides). The “bottom” (Fig. 2) contains the start and interlock circuits. The pinout is as follows:
1, 13Â Â Â GND
3Â Â Â Â Â Â -12v
4Â Â Â Â Â Â +5v
5Â Â Â Â Â Â PS_KILLÂ Â Â Â Â Â Connect to GND
2,6,7,8,12 NC
9Â Â Â Â Â Â PS_ENABLEÂ Â Â Connect to GND
10Â Â Â Â Â INTERLOCK 1Â Connect to +12v on other side
11Â Â Â Â Â INTERLOCK 2Â Connect to GND
All necessary connections can be done without disassembling the power supply.
If the modification is successfully done, the green LED on the front panel of the unit will light up upon connection to the AC mains.
The output voltage will be very close to 12v (12.1-12.3 without a load).
Regulation is outstanding with 100-150 mV drop in output voltage between RX and TX at full power on a typical HF ham rig.
Voltage can be set to as much as 12.8v from an internal trimpot, but this involves disassembling the power supply and the experimenter should be aware that lethal voltages are present in the unit during operation, as well as for a short time after the unit has been disconnected from the mains.
Do not attempt working on the unit while mains power is present.
Do not connect the unit to an ungrounded power receptacle.
Use a certified, desktop-computer type power cord.
The ultra-compact 280127, unlike the 194989, does not have an internal fan.
While it should be possible to operate it at low output current or low duty cycle without one, this is not recommended.
Removing the handle and installing (e.g. glueing) a 40 mm fan next to the mains input receptacle is a satisfactory solution.
The fan can be powered from the 12v output (or any of the other outputs depending on the fan voltage rating).
For best results, the outputs of the power supply should be connected to a heavy duty 12v power strip by soldering at least 6Â 20AWG wires (280127) and at least 8 (194989) to each +12v and GND.
Like all switching power supplies, the HP server supplies generate some RF noise.
The noise is most prominent in the immediate vicinity of the power supply and can be minimized by adequate shielding andgrounding of the receiver, by the use of ferrite snap-on or balun chokes and most importantly by using a coaxial or shielded bifilar antenna feeder.
A long wire connected to a tuner inside the shack is the most likely to pick up the PSU noise.
Article by AC8DP orignally availbale at http://ohiopacket.org
This article originally appeared in the National Contest Journal.
Why am I here? Listen to all these signals. Who are they? Wonder what they are doing? All this CW sure sounds nice. What should I do with this keyer paddle? Should I push this button? I can turn this big knob but what does it mean? Why am I here? There must be some reason, if only I could remember.
It is the 1981 CQ WW CW Contest and my first real attempt at single op DX contesting from the station of N5AU. Sunrise on Sunday morning is only minutes away. I remember waking up, sitting in front of the radio, and experiencing a disorienting state of confusion and wonder. Later, I learn from N5AU’s mother that I sat there for over 15 minutes without moving. Finally, slowly, I was able to understand what I was doing and why. The “sleep drunkenness” abated and I returned to the rhythm of the contest.
Made from Available Aluminum Conduit, this Antenna will Not Disappoint
Ken Holland, K9FV
Edited by Brian Levy, W2BRI
It all starts with my friend Leon, K5BUL. Well, he’s a new ham of about 3 years who lives in Aberdeen, MS. He got into ham radio because he wanted to use it as part of cruising on his 35’ Fantasia sailboat. His life took a different turn after he bought a new ’99 Goldwing motorcycle. He’s now a biker. He has even mounted a screwdriver antenna to his bike and has worked HF using his ICOM 706MKIIG on the motorcycle.
I’ve myself have been a ham since the mid-70’s (’75 I think) with the original call of WA4UBD, which I kept until a couple of years ago when I got the vanity call K9FV. I’ve used ham radio on my sailboat for years. In ’99 when the XYL and I took an extended honeymoon for 6 months to the Bahamian Islands, ham radio stood us in good stead.
We had been in the Islands only a few weeks when Hurricane Dennis decided to visit. We found a protected place and rode out the hurricane. The first night out after Dennis, we headed out of the cove. We decided we wanted some something good for supper so we dove for lobsters. What was most unfortunate, however, is that while I was cleaning lobster, my XYL took a shower, slipped, and broke her pelvic bone! The next morning as the Intercoastal Waterway Net came on I reported my emergency traffic. Dr Jim of Miami came on the air and discussed my wife’s symptoms with me. We agreed that it did in fact sound like a broken bone, and she would surely need more medical attention. Needless to say, we needed more medical support than the island could provide. Another ham got on the air and did a phone patch, we were still anchored out, to my insurance company and to DAN (Divers Alert Network). I then upped anchor to the closest marina where we could access the island’s nurse and a pay phone. DAN’s staff doctor talked to the local nurse at the island, then the DAN doctor talked to my insurance company. The insurance company authorized a Lear jet ambulance to transport us to Fort Lauderdale for medical treatment.
Since that fateful experience, my XLY does not complain about any radio purchases I make. These days I just say “It’s for safety on the boatâ€. She even bothered getting her Technician license – KG4TIN.
From time to time, I also install a screwdriver antenna on my motorcycle. It’s an old ’92 goldwing and it works just fine for HF mobile.
Let’s get back to the topic of Magnetic Loops. Leon and I both share an enjoyment for building things, and antennas are certainly included. Since I live on a 40’ sailboat, and he has the land for antennas – we do most of our antenna work at his QTH. After reading Brain’s post (W2BRI) on QRZ and eham.net, I visited his webpage and liked what I read. I spoke to Leon and sold him on the idea of a magnetic antenna before Christmas of 2002. By Christmas Leon had the basic loop built using electrical 3 inch aluminum conduit. This is a fairly heavy walled soft aluminum pipe that bends easy. Leon constructed the loop using “factory 90’s.†These are pre threaded pipe which is bent into a 90 degree pieces. The loop is a 10 foot by 10 foot square with a 3 inch gap at the top of one side – like we saw in Brian’s antenna plans on this site.
Leon and I got the Magnetic loop tuned and tested Dec 30th, 2002. Leon had the loop all made up and ready to be completed when I got there on Monday morning. We hung the 10 ft square loop from a tree limb putting the bottom about three feet off the ground. We added the feed and the capacitor and got the loop tuned up to forty meters.
We turned on the radio, and got ready to do our on the air comparison. We were located just north of Columbus, MS. We were able to test the antenna with a station in Talladega, Alabama against Leon’s permanent forty meter full wave loop at 30 feet. The gentleman in Talladega was located about 200 miles ESE of our location. WA4FMR near Knoxsville, TN was our second contact, who was located perhaps 400 miles NE of us. Both stations gave good reports on the magnetic loop, but did say the full wave 40 meter loop was better by about 1 or 2 S units. That was about the same results we saw on the S-meter when receiving the two test stations. This performance confirms what Brian had expressed to me earlier on the phone. The one major advantage with the loop however, is its small size. Leon liked the loop so much, he is now planning a 20 meter version. He hopes to compare it to his 20 meter bazooka one day.
Ken Holland, K9FV
By Neil Lowson, GM4XRF
Parts List:
Getting Started:Â
Assembly first starts with the capacitor and motor, this is the important part of the magnetic loop. Get the strip of paxolin and mount the capacitor at one end (top). Fit the insulated coupling to the capacitor shaft and then fit the reduction gear. The brackets will need to be made from 4mm aluminium. Then make up a bracket for the 2 micro switches.
 
They have to be set as to use the flexible coupling with a long 4mm screw in one of the holes for switching at min/max capacitance, see photo and wiring diagram. Next the 100mm /300mm plastic drain pipe (length to suit cap/motor) fits the bottom section of top plug with pvc. Glue and drill 2* 25 mm + holes 30mm down from top of pipe with the holes opposite one another for the 25mm copper pipe to be inserted in about 25mm. Then bolt cap/motor assembly into pipe. Connect capacitor to copper pipe with coax braiding and 6nmm brass bolts. Get the bottom plug fit the 25 mm coupling and the din socket connect to motor and fit with self-tapping screws and sealant on main pipe. Assembly of capacitor is now complete. Fit broom handle to coupling, I use this as the mast, also to attach the coupling loop with cable ties.
Assembly of the Loop:
4*1.5 mtrs 22mm copper pipe. Take 1 length cut 30mm of the length the pipet in half — this is the top portion of the loop. Clean the pipe and bends with wire wool and add flux. Then fit bends to pipe. Do this on flat surface and fix bends with self-tapping screws till you solder. You now have a square loop. Paint if required.
Coupling the Loop:
Coupling loop should be about a 1/5th size of main loop made from RG58U COAX but I always make it bigger. Then trim it by 15mm at each end till you get a 1-1 match (see photo). Then solder And seal with rubber tape.
Power supply:
I use small power supply unit you can buy for calculators/portable radios 3/4.5/6/9/12/volt at 1 amp — they are ideal for the small 12V motor. I built mine into a small box with the switches and the LEDs work well. There are more sophisticated control circuits that can be used but this was the easiest.
This article was available at http://www.standpipe.com/w2bri/article2.htm
An interesting article by W2BRI you should read if you want to home made your own magnetic loop antenna
MC-60A vs 590 S Dynamic microphone
TS-590 the K3 killer …. ???
It could be possible, but to demonstrate who is the killer we need facts and features palpable, not noise. I would like to explain my point of view on the above subject. Please excuse me if I may sound “aggressive†but we have to put light on same specific points to make real comparisons. K3 does not need a violin fiddler…
For a comparison we do need tests that can avoid personal interest or love … First test could be the comparison of TS590 and K3 circuit diagram, looking at the receiver path, although we should look at the TX area for reduction of spuries emitted. Second test, an independent review like the ones made by Peter Hart, G3SJX, and published in RadCom (RSGB). Peter is a gentleman and does not usually “offend†the manufacturers but reports his reviews quite clearly, although he does not write as much as he was doing in the past century. If you look properly at Peter’s measurement tables, you will understand the quality of equipments from the “measurements†point of you. K3 Review has been already published with good reports, see RadCom July 2008.
Sardine Can Antenna. is a BiQuad or Bi circle – wire length each side (8 x 1/4 waves ) 31 mm
Sardine cans have quite standard dimensions around the world, although the oval one shown here is lightweight aluminium & does seem (perhaps by chance ?)to have enhanced directivity compared with more normal steel Canadian “Brunswicks ” etc. It’s an ex. Latvian RICHTER “Smoked RIGA SPRATS” & perhaps first received publicity in the Nov. 2002 Australian “Silicon Chip” monthly ( author Stan. SWAN => s.t.swan@massey.ac.nz ), when it was first called a “Kipper Can”. ( For those readers who don’t recall Monty Python, Kippers are smoked herrings http://www.deliaonline.com/ingredients/ingredientsatoz/i_0000000135.asp. See refs & further construction dimensions/views/insights => http://www.manuka.orcon.net.nz <= Even an old CD can act as the reflector, exploiting the metalised layer of course, but the sardine version prooved far superior, no doubt due to the focusing side walls.
The hot melt glue shown here is not really needed if a rigid N connector is used, although a recent enhancement has been to form the radiating bow tie as tracks on a small PCB secured via nylon spacers. Gain is great -typically 10dB ( links to 10km LOS made & typically 2km more normal built up areas !).
Need a quickee antenna ? Got 10 minutes & simple tools ? You won’t get a simpler, cheaper or more compact design. The unit can be neatly hidden in a pencil case or plastic bag beside your road warrior notebook so it’s not intimidating for field use. It’s directional enough to even pin point the signal location ( using NetStumbler etc )in a multilevel building. RECOMMENDED !
Originally publihed at http://www.seattlewireless.net/SardineCanAntenna