Antenna gain is not an easy notion for a new radio operator to pick up. Some even go as far as supposing that the antenna gain shows the increase in radio power.
But is not that the actual energy radiated is increased by the better antenna, this is not allowed by the law of the conservation of energy. It is because the radiated energy is handled, shaped-formed and directed better towards you.
A look at wikipedia tells us: ” In electromagnetics, an antenna’s power gain or simply gain is a key performance number which combines the antenna’s directivity and electrical efficiency. In a transmitting antenna, the gain describes how well the antenna converts input power into radio waves headed in a specified direction. In a receiving antenna, the gain describes how well the antenna converts radio waves arriving from a specified direction into electrical power.”
Now this explanation is correct but let’s make it simpler.
Continue reading “A Practical Interpretation of Antenna Gain, donuts included.”
By a strike of luck the SurvivalComms name is used by me for this blog, and by another guy (Bret) for his YouTube channel.
It also happens that we both are focused on practical HAM radio matters for Survival and Prepping.
Bret is not only knowledgeable but also good at breaking down matters and applications into simple, layman’s terms. Among these are his DIY simple antennas.
So DO subscribe to his channel.
Building a Communications Network.
When building a communications network, one must answer 3 basic questions which form one of those dreaded decision triangles.
What is the purpose and object (what signals must be exchanged, text or e-mail maybe?)
Continue reading “Radio Communications Musings no2.”
What is Communications?
The word has obviously has to do with “Community” in the sense of Sharing. Sharing of information that is. But what kind of information?
To put it straightforward, it is about information that will allow proper decision making on all levels of involved parties, and for the task at hand.
Imagine you are in a rescue team searching for an injured hiker. What kind of information would you beam back to base once you find him?The victim status is an obvious one. Time of arrival is another, needed resources and assistance on route is another, etc.
But does the base needs to know that you have arrived at a tight spot and you will have to rig a way to pass the stretcher along a crevice? So in the process you need to judge what to pass on and what to leave out. Cos too much of data may needlessly burden and clog the command center, delaying decisions.
Continue reading “Radio Communications Musings no1.”
Ο παρακάτω πίνακας συντάχθηκε κατά την προετοιμασία της παρουσίασης για το επόμενο Σεμινάριο Ραδιοεπικοινωνιών.
Δεν είναι λίγες οι φορές που ένας νέος ραδιοερασιτέχνης ή χειριστής επιλέγει ένα κοινό ομοαξονικών καλώδιο μεταφοράς για την κεραία του, το RG-58. Αυτό βρίσκεται εύκολα, είναι σχετικά οικονομικό, εύχρηστο αλλά παρουσιάζει μεγάλες απώλειες ισχύος, ειδικά στις μεγάλες συχνότητες.
Continue reading “Μια ματιά στις Απώλειες των Ομοαξονικών Καλωδίων των Κεραιών μας”
For the purposes of the next Radio Communications Seminar I constructed 2 antennas.
The first one is a ground plane field antenna using a folding handheld radio antenna.
An SMA to chassis mount adapter is used and the radials are just solid core wire twisted through the adapter mount holes. The good thing about this method is that the antenna requires no tuning as the vertical element is already pretuned.
Continue reading “More Easy Antennas for the VHF/UHF”
The man behind the GuerillaComm Youtube Channel does wildfirefighting comms. In his new videos he loads up the deployment comms and personal gear and sets up a filed repeater. Do not miss this!
You have your first radio for some time now, you want to increase its performance in the field and also make a better radio kit for it. If you haven’t heard or read yet, the three most important words in radio communications are: Antenna, Antenna, Antenna
(which are followed by the next three: Location, Location, Location)
So, let’s see what your starter antenna options are . And that means simple, economic, easy to deploy -or even make- radio antennas for the VHF and UHF bands.
It is the antenna that uses an artificial “ground” to work. In a base antenna the “ground” is the 3 or 4 radials that extend from its base. In a mobile (car) antenna the “ground” is defined by the car’s metallic body.
So a way for a ready-made option is to take a mobile antenna (that is already pre-tuned) and create its ground yourself.
One option is to get a magnetic base antenna and nail a metal sheet on top of a pole. This can be a lid of a paint can, a cookie baking tray etc etc. Then you stick the magnetic mount antenna on top.
Continue reading “Basic Antennas for VHF-UHF Field Communications part 1”
Κατά κανόνα υπάρχουν μπαταριοθήκες ΑΑ & ΑΑΑ που αντικαθιστούν την κανονική μπαταρία για τους περισσότερους ασύρματους χειρός. Οπότε είναι καλό να έχουμε μια σαν εφεδρική πηγή ενέργειας, αλλά θα πρέπει να την δοκιμάσουμε εν λειτουργία πρώτα.
Και αυτό γιατί:
- Το βολτάζ των επαναφορτιζόμενων και των αλκαλικών μπαταριών ΑΑ είναι διαφορετικό και μπορεί ο ασύρματος μας να μη δουλεύει με έναν από τους δύο αυτούς τύπους.
- Συνήθως οι ασύρματοι χειρός κατεβάζουν ισχύ όταν χρησιμοποιούν τέτοιες μπαταρίες γιατί αυτές δεν έχουν την δύναμη να αντέξουν το φορτίο σε πλήρη ισχύ.
Διαβάστε περισσότερα στο blog μας GreekPreparedness
If there was a plan for little green Martians to conquer the earth, they would hide inside the Baofeng (UV-5R) radios and then pop out the same exact moment all around the world.
And those being so popular and cheap are two of the reasons for trashing them around the web. But are they…
Glorified FRS radios or Incentives for new HAMs?
Among the preparedness and survivalist communities the BAOs are prevalent. And I do not think there is anyone that has a second radio and it is not a UV-5R. so even the advanced HAMs among us could not resist the temptation of the cheap and “easy” radio.
Continue reading “Random Thoughts on the BAO(feng)s”