The idea of inserting an extra director very close to the Driven Element has been independently discovered several times. One of the first to specifically recognise that this extra director can help
biggest easier with a edges That tradeoff isn't universally true. It may well be true for HF Yagis because of the relatively small number of design variables (element lengths and spacings) that are a
That's very close - the cause of the distortion is a non-optimum load line. Most of us are familiar with the idea of drawing a 'load line' on the characteristic Va/Ia curves for a tube amplifier. Ex
by too kind The story about "molten" CATV cable sounds like someone connected it to the 115/230V AC mains. half you out of Here you go... <http://www.ifwtech.co.uk/g3sek/in-prac/best-of.htm#0904> To
Agreed. The topic here is "back of the desk grounding", and in that location a massive copper busbar is a big waste of money. Worse still, it may indicate a dangerous lack of understanding. The plac
Sure, but maybe not right now... I'm cleaning up the drips of oil from under the engine. 73 from Ian GM3SEK _______________________________________________ __________________________________________
The aim of "bonding" is to equalize the chassis potentials of several separate items of equipment, so that unwanted voltages induced along the lengths of the interconnecting cables are effectively sh
guys. It depends on which conductor was torn. A torn center conductor is usually quite dramatic: everything stops. On the other hand, a torn shield can often cause only a moderate mismatch because t
can It depends totally on where you live. The only valid generalization about driving ground rods is: "Local Mileage WILL Vary". 73 from Ian GM3SEK _______________________________________________ __
and All users should try creating a .PRO file from scratch at least once, because creating your own file gives far more insight into how HFTA actually uses its radial data. If you use only the SRTM
Insulating the elements will certainly reduce the correction for the boom and mounting plate, but does not eliminate corrections completely. There is still a proximity effect, which will obviously be
It was only an idea, but at least I can share the thinking behind it... The aim is to use a HF (20-10m) beam with insulated elements for top loading the whole tower on one or more of the LF bands, so
the My first reaction was "Go Google for it!" because there is lots of information about element length corrections on the web. However, there is surprisingly little on the web about corrections for
Yet another good alternative is hot melt glue. HMG forms a flexible, weatherproof seal onto metals, plastics and many other kinds of materials. In many years of outdoor use, in a notoriously wet clim
air deep) who Ah yes - the amazing, alarming 'Scope' soldering iron. Designed to operate directly from a car battery, the heating element was a small slug of carbon which could be pushed forward insi
THIS is a much more serious butane-fueled solder gun, with a chunky copper tip that stores the heat well. There is a built-in igniter but the heating element is catalytic so there is no naked flame a
be a rods, It isn't clear what you're aiming to achieve here, Jim. If you connect the coax shield to the boom at a point that has a low impedance down to the ground at the base of the tower, that wil
Truly balanced antennas are beyond "rare". In the real world, they don't exist at all. There is a strong ham myth that center-fed dipole antennas in some way "want" to be balanced; but that is almost
You certainly shouldn't need to do that. Let's think about this, because RF current on a rotator control cable can't just appear out of nowhere. The defining feature of current is that it must have
I never said that a Yagi doesn't *need* a balun! Using no balun at all would just be a fool's way of turning a "soft" common-mode problem into a tough one. 73 from Ian GM3SEK _______________________