Thursday, April 23, 2020

My Mobile Antenna

Diamond SG7500 2m / 70 cm Mobile Antenna

This Mobile Antenna is 40 inch long and has a gain of 3.5 dBi for 2m (144 Mhz band) and
6 dBi for 70 cm( 434 Mhz band). I opted for UHF SO239 socket as PL259 connectors are easily available in market. The mobile antenna is mounted on Nagoya make 3-axis mobile mount which can be adjusted in 3 different planes making it possible to mount at various sides or corners. I use 5 meter long RG58/U coaxial cable having SO239 socket at one end and PL259 mini UHF connector at other end. The performance of the SG7500 Antenna is excellent. 

 




















My Base Antenna set-up

When I shifted to an Apartment flat, I faced difficulty in mounting mast for my 2m/70 cm VHF/UHF) vertical Antenna. I don't need high mast but just reasonably high so that it should not need extra guy-wire support. So I bought empty Paint buckets from junk market. Filled it with soil. Poured water so that it becomes like mud. Then inserted the Aluminum Pipe mast into it with mounted Diamond CP22E 2m Antenna (Initially I installed homebrew Slim JIM). Two bricks kept for extra weight and support so that the pipe should not tilt. In the other bucket I first inserted a higher diameter PVC pipe, then inserted Aluminum pipe with Diamond X30A ,
2 m/ 70 cm Band Antenna. Both the Antenna installed at some good distance, as it is recommended.
The set up working fantastically good. 

Some of the images of my Antenna setup are shown for better understanding.

Homebrew 2m Slim JIM and VHF/UHF Antenna
Diamond 2m CP22E Antenna
























Later the Slim JIM antenna was replaced by Diamond CP22E 2m Antenna. 

Base for Diamond CP22E 2m Antenna mast
Base for Diamond X30A 2m/70cm Antenna mast
 
Diamond X30A 2m/70cm Antenna






Saturday, April 4, 2020

My Radio Shack in Baroda

Amateur Radio or HAM Radio

"Amateur Radio" more commonly known as "HAM Radio" is a very popular Scientific & Radio sports Hobby all over the World. 

To enjoy the HAM RADIO in India one has to obtain the Amateur Radio Station Licence from W.P.C. Wing, Ministry of Communications, Government of India, by clearing the written examination. Having obtained my Amateur Radio Station Licence with Call Sign VU2OPX in the year 1986, I made my first Crystal Radio receiver using OA-79 Diode and old Telephone Headphone. Local AM BC station was heard very clearly. Later on as time passes, added Radio Transceivers (TX/RX) to my shack. I made several contacts (QSO) on HF both from India and other (DX) countries and received QSL cards towards the conformation of the Contact (QSO) from fellow HAMs. My profile is also present in www.qrz.com and www.eQSL.cc websites. I am thankful to my mentors VU2KH OM Aloni (now silent key), VU2IG OM Khetan who guided me for the ARS examination and VU2TET OM Raja & VU2NB OM Sharan who helped and supported me in working with the Radios.

Homebrew Slim Jim Antenna for 2 M

Year 2007 Shack
Year 2008 Shack


I had a wall mounted shelf , so I mounted the 2m mobile radio under it. For microphone hanging I used small metallic hook pasted on side of the shelf. Handy also go the place to stand above the mobile radio. It was very convenient to operate the radio. The built-in speaker is provided under the radio, so the sound is heard clearly. The radio is connected to 5/8 lambda antenna through RG213/U coaxial cable. 

2m mobile Radio and 2m Handy

The new VHF/UHR dual band radio, I kept it on my table, as it has built-in speaker on the upper side of the radio for clear audio. With this VHF/UHF radio, I am using LMR400 coaxial cable with dual band antenna. 

VHF/UHF Radio, 2m Handy with desk charger and cross needle SWR meter

For short time I kept the Radios on a small wooden almirah, which has a sufficient place on the top of it. 
VHF/UHF Radio, 2m Handy, SWR meter, High gain whip for Handy and Mobile antenna

Below was special arrangement during 1st lockdown due to COVID-19 outbreak.
VHF/UHF Radio, 2m Handy on desk charger & Power supply 

As the COVID-19 lockdown extended, I shifted the Radio on my table, so that I can operate Radio while working on laptop.