martedì 2 giugno 2015

IN3AQK-246 antenna 144 Mhz, 70Mhz, 50Mhz multifunction sota - Field Radio Dipole

On my mountain activations I normally need a lightweight hamradio equipment.
The problem is that I'm not an athlete and doing a climb of 800 to 1000 meters, in Dolomiti mountains, above 2000 meters is not simple if you are not fit.

I do both HF and VHF activations but I prefer to use the altitude to try VHF and above qso.

I need a simple and re-configurable antenna able to work on 2 meters, 4 meters and 6 meters with a minimum effort, an antenna that could be used in vertical, horizontal polarization, in linear or inverted V configuration.

As you know the dipole a nearly no gain but it's surely better than the standard whip of a yaesu 817

I decided to built a strange dipole based on two 1,4 meters telescopic whips.
The dipole could be used atop a fiberglass rod.

The name is IN3AQK-246  ... the numbers are the bands :-)

Some photos are better than 1000 words



IN3AQK-246 antenna



Antenna parameters at 50.100


Front view, the ferrite beads are used as a RF cocke

Really simple!!





SWR diagram in 2 meters band



144 Mhz configuration





Two new test instruments in my shack

Two new test instruments are now ready on my shack:

I've built them from a kit of components.

  • IZ1PMX VNA vector network analyzer  from 2 Mhz to 180Mhz
  • Multifunction tester, very cheap.

IZ1PMX  Vna


Is a Vector Network Analyzer, based on a projetc of Alfredo IZ1PMX
It's based on a Atmel Processor ATmega  and a AD9951 DDS.
The instrument has a frequency range from 2Mhz to 180Mhz but test has been done to 250 Mhz.
It's a really cheap kit, has a good price to performace ratio

The reference site is:


Here you could find also a QRP HF transceiver

IZ1PMX VNA 2-180 mhz


Multifunction Tester

I needed an Electrolytic ESR meter so searching on internet ad blogs I found this little an very very cheap instrument base on an Atmel atMega processor.

The funny is that this instrument reads completely automatically also:

  • Capacity
  • Inductance
  • Resistance
  • Electrolytic ESR
Detect and give information's about:

  • Diodes
  • Transistors
  • Fet 
  • Mosfet
  • Tirystors
It's a really useful instrument especially when a component has to be tested or it's of unknown type.
The gear is electrically simple, all the operations are done by the microcontroller and the software.
It can be found on some online cinese shops.


Multifunction tester










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