STL Antenna got a llonger antenna
mast
so we have to increase the cable length!
Arriving at the new transmitter site
New antenna mast
and the ground staff
STL cable needs to be connected!
Old transmitter site
The antenna needs to be tuned to te frequency
and its length to be adjusted
All 4 Antennas!
The antenna is on top of the antenna mast, much higher than before!
All studio staff is helping to put in the new power cable
The new 2000Watts power amplifier
Protos is putting the 4 amplifier modules each producing 500 Watts of RF
Switching everything on
On air on 97.6 MHz with 2000 Watts full stereo!
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Workreport
Iringa Radio Furaha
On Monday 4rth of March we set off to drive to Iringa. We spend the night in Morogoro
Junior seminary and left for Ininga early in the morning. We arrived in Iringa around 4:30
in the afternoon. Protos, the station manager of Radio Furaha wellcomed us at the Lutheran
Guest house, where had made the booking for us already.
Back in the diocese he showed me the new Power amplifier for the transmitter, and we
brought it up imeadetly to the transmitter site.
The next oring we were very busy to extend the cable of the STL at the diocese, since
Fundi Macha had helped to increase the length of the antenna pipe of the STL.
After getting the STL on air again we drove up to the tansmitter side again in the
afternoon. We had to connect the STL receiver cable here as well and complete the antenna
earthing. Fundi Macha had already moved tho hole of antenna structure from the other
antenna mast to the now one of TTCL. He also had moved all the antenna cables and mounted
een the STL receiving antenna nicely on the new antenna mast.
Then we continued inside the transmitter shelter. Radio Furaha is sharing it with the
microwave links of TTCL, the GSM phone, some Internet providers and another 2 radio
stations. They have rented their space plus electricity even with diesel back up in case
it fails.
We connected the ground using a thicker earth cable. The STL antenna cable and the
transmission cable got grounded outside the building. Inside the cables got grounded again
together with the power stabilizer, the UPS and transmitter/ amplifier.
We also replaced the 1.5mm electricity cable with a 6 square one to carry the new 6 kW
load.
Then we assemled the power amplifier and connected everything placing all in their rack.
The amplifier had to be adapted for the transmitter. We fed the transmitter with the
multiplex signal to ensure real stereo operation and set the transmitter to receive the
signal correctly. Then the level had to be properly adjusted.
Unfortunaltely the antenna system did not work. So we returned the next days trouble
shooting. We checked the antenna cable with a dummy load. We checked each antenna one
after another. All behaved similar bad giving an SWR higher than 3. We measured the
frequency response courve of the top antenna, which is really free and far from any mast
construction. But the response had been bad all over the FM band. We swithced off the
other FM station operating close by. But no change! Then we realized that the antenna had
not been tuned at all the first time when it got installed by Samueli.
It was still in its packing condition! After adjusing according to its instructions it
gave a perfect match! Connecting again all newly tuned antennas using the combiner gave a
good picture again. Then we checked the frequency response of the cavity filter.
Unfortunately it was a bit off the frequency, but we had not been able to adjust it,
because the adjusting screwa had been to tight. So we just left it and tested the hole
antenna system again. And- it worked well!!
The SWR could even be lower if the cavity filter could be adjusted a little bit, but as it
is it is fine as well!
We adjusted the maximum power for 2000 Watts and the drive power to 70 Watts as given in
the manual.
It had a real moving moment when we listened to the German Choir singing in the big
Cathedral "Lets Thank God ..." (This was Radio Furahas only very wide stere CD )
On Friday I continued to help with Radio Furahas internet and generator trouble.
In the Evening we were invited home of the general secretary of the diocese together with
the staff of Radio Furaha for the dinner celebrating the new chance on air with 2000
Watts.
We got reports as far as Chimala of listerners listening to the station. Evaluation of all
programmes was planned for the next week after getting feedback from the listerners.
I thank Radio Furaha paying for my accomodation in the Lutheran Centre.
On Sunday morning we continued our joirny to Morogoro.
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