Category: Antennas

A Small, Pocketable Antenna Kit for Handheld Radios

I call it the Giveaway Antenna Kit. Because it has the capability to be adapted to any handheld radio, that is, the antenna connector style of any handheld radio. So you can have it in your larger radio kit, and give it away to anyone in need without bothering for compatibility with his radio.

The basic idea stems from this idea by Bret of Survival Comms Youtube Channel . The use of the handheld radio’s own (actually aftermarket improved) antenna on a groundplane kit. In my built, the groundplane (radials’) kit is much simpler and easier to use. You just attach the antenna kit wire to fit your HT.

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Construction

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Ενα μικρό Κιτ Εξωτερικής Αντένας για το Φορητό σας Ασύρματο

Οι φορητοί μας ασύρματοι υστερούν στην αποτελεσματικότητα τους για δύο λόγους. Έχουν μέτρια , έως κακή κεραία, και δεύτερον έχουν χαμηλή ισχύ.

Μπορούν όμως να βελτιωθούν προσθέτοντας μια καλύτερη κεραία (κάντε το οπωσδήποτε) και επίσης -αν μένουμε σταθεροί- μια κεραία βάσης.

Η ιδέα μου βασίζεται στην ιδέα του Bret από το Survival Comms. Στην ουσία μετατρέπει την βελτιωμένη κεραία του φορητού ασυρμάτου σε μια groundplane κεραία βάσης, κατασκευάζοντας ένα προσαρμογέα με radials.

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Η κατασκευή μου προχωρά παραπέρα δημιουργώντας ένα εύκολα κατασκευάσιμο κιτ radials.

Continue reading “Ενα μικρό Κιτ Εξωτερικής Αντένας για το Φορητό σας Ασύρματο”

HAMsmithing – September 2017

Just as September was ending, I spent quite some time on small HAM projects.

1. I received the connectors and cables I ordered, so I sat down making cables for each DIY antenna I have.

2. I used some leftover PVC pipe to add 2 more sections in my collapsible antenna pole. Each section is 130cm (about 1.5 yards long), the wider my car trunk will allow. That makes for about 7 yards total height, just short of what one would need to make a sloping longwire antenna.

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A Practical Interpretation of Antenna Gain, donuts included.

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.”

Μια ματιά στις Απώλειες των Ομοαξονικών Καλωδίων των Κεραιών μας

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.

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More Easy Antennas for the VHF/UHF

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.

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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”

One more DIY Groundplane Field Antenna version

Bret at the SurvivalComms Youtube channel (it is not me, just a name coincidence I did not expect) has built his own version of the Jungle Antenna (Link 1, Link 2)

He uses a ring made from ABS rods to “hang” and position the ground wires, and the handheld’s radio own antenna. From the looks of it performance can further be increased with a telescopic antenna like the Diamond RH-770.

He also has a build of a discone antenna with the same method.

DIY folding VHF / UHF Discone Antenna

Check him out!

 

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