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Tuesday, October 25, 2005

Checkout whats on the air at SAILIN's QTH ...


All time we have been listening about a 5/8 antenna. Surprisingly we have seen it at hundred places but never recognized it. You wil find it on the roof of every police station, on every railway station, fire station, or any government offices.


Hey here is an example of 5/8 antenna. Did'nt I say you must have seen it somewhere !!!










Whats so special about this antenna?

This is an omnidirectional antenna. The wave antenna consisting of a vertical radiator which is fed at the base of the antenna. After a perfect impedance matching is done the impedance of the antenna and the below line running towards the rig, the resulting configuration is a 5/8 antenna. This type of antenna has a better gain than a normal dipole. The recorded gain is of about 1.5dB higher. It also has a small angle radiation pattern of arount 16 degrees. The gain of antenna is simply how well antenna focuses the radiation pattern. Since the 5/8 antenna used at all places has quiet short angled half power points the antenna is a awesome choice for dxing.

Considering all these facts and by valuable advice from all our seniors hams Sailin ,
a SWL from our TARA group, decided to get one 5/8 antenna. Friends our repeater in thane also have 5/8 antennae and all these are designed by our very own Mr. George, VU2GT. We call him the antenna man. Sailin , is celebrating his birthday on 25th OCTOBER 2005, TUESDAY. Just a week before his birthday he gifted himself with his this 5/8 antenna been setup at his QTH. Omkar has helped him in this. These two guys together form a perfect team.

Recently they had a good adventure while setting up the 5/8 antenna at Sailins's QTH. Both were there at the roof top of his building , hanging out holding each other to support. It was an adventure hanging on the top of a 15 storey building . They started of with it at 8.15pm , by 9.15 pm they had completed the job. Now the time was to test the coverage and sound quality. Sailin is able to listen to all the conversations clearly. He listens to the evening nets in mumbai and thane, the sound quality is awesome in ham lingo it is 59 .

Thursday, October 20, 2005

~~~~~~~~~~~~~THANE REPEATER~~~~~~~~~~~~~~~

!!THE DAY OF ACTION!!


This post is dedicate to all those who who have helped us in bringing up the repeater at Thane.

Here are the main force behind the Thane repeater atr Tarangan.

The working frequencies are 144.500 Mhz + shift. It means that the repeater would have a transmitter at 144.500 Mhz and the receiver at 145.100 Mhz. Accordingly the base stations would be at 144.500 Mhz receive and 145.100Mhz transmit. The tail is currently set at 2 sec and we have kept the 'time-out timer' at 2 min.

We have used two rigs to throw a output signal with 6W power. Since the repeater is in its testing phase we would be first carrying out tests at low power. We sincerely appreciate suggestions from all to further improve the station.

You can see Mahesh IIA doing the cabling and connections of the repeater. This guy has done a awesome job here.

The real action started on 9th october 2005, sunday morning at 11:00. VU2IIA , Mahesh came all the way from Borivilli to Thane. VU2IZO , SWLs Sailin, Omkar, Saurabh and myself (Atul) were there at the site. The work started at around 12:30. We made a little survey of the location of the antennas and the how the cabling was to be done.

It went on till around 5:oo in the evening. Mahesh and me came to my house to program the rigs as we decided after the survey. Then IZO and IIA alongwith we all SWLs did all the cabling and fixed the antennae.

We had to replace our 5/8 stack since it was broken. We now have a 5/8 with 8 radials and a one with 4 radials. The above flick shows us all in action. Thats the 8 radials 5/8 antenna. We were all set by 7:30p.m., the rigs were ready antennae were at their places and we were ready for action. IIA did all the interface connections and then tested them all.




Oh I missed some thing, here is IZO in action. All the way drilling through the wall for cabling to be done. Hats of to this guy is who worked all day without breaks.




At around 8p.m. we tested our repeater. We were able to trigger the repeater, everything seemed to be running perfect. But we needed some feebback from a distant station. We had our first QSO with Vijay Motwani(VU2VVP). VU2VVP had been on standby all the time to let us know how was the signal. With his help we were able to know how the repeater was heard at a distant location. VVP house is in the line of sight of the repeater. With his help we made fine changes to our station and all was set.

Our first test was sucessful. Here is a snap of how happy IZO was, have a look at it. Mickey was dancing on the success of first test.

All were "HAPPY HAPPY JOI JOI...". There I am happily playing with the handy and listening to the conversation that IZO and IIA had with other senior HAM's. We received a valuable feedback from VVP, OZO, SEQ, and many others who were on air, on standby, waiting for us to put up the repeater.