The ARRL and other publications refer to the Army Loop or Patterson match.
Patterson described his antenna system at (Patterson 1967). Hams seem to call any configuration that uses only capacitors in the matching circuit a Patterson or Army loop, though they are incorrect.
The ARRL Antenna Book 21 has a nonsense circuit that cannot work.
Another ARRL example, one that does work
Above is a diagram from a much earlier ARRL and as far as I can ascertain, this is McCoy’s version the so-called ARMY Loop. (McCoy 1968) gives the middle capacitor as 500pF variable which would reduce the matching range. Continue reading The Army Loop (Patterson match)
I have been asked whether the Field strength / receive power converter can be used to solve a Eb/N0 (Eb/N0) design problem.
Eb/N0 is a method often used for specifying the relationship of signal and noise that will give adequate bit error rate in a data demodulator.
Whilst the calculator was not specifically designed for that purpose, and you cannot directly enter the desired Eb/N0, with the help of a hand calculator for simple calculations, a solution can be found. Continue reading An example of Eb/N0 design with the Field strength / receive power converter
NEC-2 and NEC-4 support a GM card to translate and rotate a structure in three dimensions.
This article gives a simple but practical example of exploitation of this often overlooked facility. Continue reading Exploitation of NEC’s GM card
Chameleon has announced a small transmitting loop, the Chameleon CHA M-LOOP. Continue reading Chameleon CHA M-LOOP
I have a bit of a soft spot for the Diamond X-50N. It is a fairly rugged vertical for 2m/70cm. Though I live in a rural setting, I resist the temptation of high gain antennas of this type as they tend to suffer fatigue problems resulting in noise in quick time, whereas the rigid one piece X-50 seems to last and last (I have another that must have had 25 years outdoor service).
The X-50N is mounted on a telescopic steel mast at 11m at its base, and fed with 10m of LDF4-50A to the antenna entrance panel, and 2m of LMR-400 to the radio. The XN50N has three short radials which are visible in the pic above, but somewhat obscured by a fan of four upwards pointing wires to discourage birds perching on the gibbert for the G5RV. Continue reading Diamond X-50N #2 at VK2OMD
This article shows use of Lou Destefano’s (VK3AQZ) VK3AQZ RF power meter (RFPM1) to adjust the output power of a low power transmitter.
Above, the test setup used. Continue reading VK3AQZ RF power meter (RFPM1) – adjust Tx power example
This article shows use of Lou Destefano’s (VK3AQZ) VK3AQZ RF power meter (RFPM1) to plot the response of a 144MHz filter.
Above, the RFPM1 as used.
Above, the test setup. The filter (DUT) is connected between a standard signal generator (SSG), and the RFPM1 connected to the filter output. A DVM recorded the DC voltage on the ‘CAL’ terminals of the RFPM1. A series of measurements was made from 140 to 148MHz and the results calculated and plotted in Excel. Continue reading VK3AQZ RF power meter (RFPM1) – filter response example
This article documents my build of Lou Destefano’s (VK3AQZ) RF Power Meter kit.
The power meter is based on probes using an AD8307 logarithmic detector.
Above, the RF Power meter with two probes. (The ferrite sleeves were not part of the kit.) Continue reading VK3AQZ RF power meter (RFPM1)
My friend Richard found himself located on the margins of coverage of the local 2m repeater where multi path reception was the main problem, a but a little lift in signal would also help.
This begs a small Yagi solution. Continue reading A compact 3 element Yagi for 2m
A reader of my article Are gamma matches as bad as all that asked whether the W5VJB dipole was a gamma match given the hint in the article that the traditional gamma tuning capacitor
is not essential to a gamma matched antenna.
Above (Britain 2006) is the subject dipole which Britain describes as a
partial folded element having a J shape which is grounded at the midpoint of the longest portion of the element. ((Duffy2010b) refers to it as a half folded half wave dipole.)
Continue reading Is the W5VJB J dipole novel