Thanks - yes, the Yagi will get a standard amp like this:
I’d like to get a reasonable signal BEFORE amplification, so the next stage, I think, is to use the VNA to optimise the antenna/balun., assuming I’m aiming for 75 ohm impedance at the centre frequency. Should I just hook them together...
As you can see, I’m a bit stuck. I’m not getting an answer to this question:
Not sure if it’s the wrong question, or if there’s a tacit feeling that I should find out for myself. I would like to get the antenna up and running, but at the moment, the TV signal strength meter is not registering...
I take it I need a 75 - 50 ohm adapter, one end like this:
And the other a male SMA.
The antenna was put to use today - repairing a 433 MHz car key fob and testing the buttons. I rigged up the antenna to a simple TV signal meter (just LEDs from 50-80 dBuV) and fired the fob at it. Worked a...
Yes, it’s easy to enough to understand on a basic level, as the reading on the dial to minimise, but what I mean is, the initialism ‘SWR’ is not first expanded. In a chapter called ‘Basics’. Just one example, but that, and other things, are telling me I’ve skipped over the introductory course.
To add to the above:
I’m going to have to admit that the ARRL book is a bit beyond me. It’s a vast collection of knowledge, written by lots of very clever, very technical people. It’s a reference book, not a teaching book.
For example, the first chapter, ‘Antenna Basics’, talks of SWR without...
Thanks. Both of these antenna projects have been on the back burner, as life is getting in the way a bit.
As far as I can see from the schematic in post #5, the radio antenna socket is unbalanced, having the lower side connected to mains-earth-ground. I assume I should therefore keep the single...
The balun was designed by the software, based on that particular Yagi design and with RG6 specified as the cable. Maybe it’s a compromise, to get the impedances close rather than matching?
By using 50 ohm cable, am I not just pushing the problem down the line? The amplifier and TV socket are 75...
As I understand it, a handheld taser has two ‘stabbing’ prongs for delivering the shock, branching off from which are two smaller prongs closer together.
When the unit is activated, but not applied to a baddie, the arc is allowed to jump across the smaller prongs. This snapping arc acts as a...
6-18 MHz. I’ve found huge lists of SW transmissions, all at different time slots, and it’s quite difficult to work out what’s what with the time differences. I’ll make a rotary stand for the antenna, now I know it works.
Looking at your diagram in post #25, would you simply connect a twisted...
I’ve had a chance to build the loop as per post #25 by @Baluncore using twinax cable. Even in the daytime, it was receiving some pretty strong overseas signals. Will try later on tonight. One small problem is, the stations don’t seem to announce what/where they are.
Right, some progress, but some confusion.
Standard copper pipe standoffs allow the elements to be raised into the plane of the dipole, and have a useful centre rib for alignment.
Balun cobbled together as per the design software.
I expect there will be some comments on this, and how the VNA...
Apparently, fresh water RF comms are feasible, eg:
http://eprints.gla.ac.uk/194214/7/194214.pdf
Regarding seawater, an example formula is here (page 317)...
In conductive media like seawater, EM waves experience attenuation related to their frequency. The skin depth formula calculates the depth at which ##e^{-1}## attenuation is reached. The skin depth is inversely proportional to frequency.
In practical terms, only extremely low frequencies (eg 80...
^ and there lies the rub. Domestic electrics will work if you simply hook up L/N, ignoring wire sizes, cable runs, breaker specs, and the most basic protection against fire/shock - the earth/ground wire.