One key element in paging is that it should cover a great geographical area with simultaneous transmission so that transmitters won't block or cancel each other. This technique was in use in the commercial paging network where some of the equipment used in our system originate, but we were dumb enough to discard all the material, equipment or even knowledge available when we got the transmitters. We were just looking at great PA's for 144 MHz, not actually paging transmitters where we ended up using them after a decade :)
The simulcasting technology is known and we know how we should do it, but as the infrastructure design differs quite much from the original network which was apparently synchronous till certain level, we need to do transmitter synchronizing differently. To enable simulcast, ie. multiple transmitters transmitting simultaneously on the same frequency, we need to achieve synchronization between the transmitters. Again, Hessu OH7LZB has done great job programming a PLL to the Arduino POCSAG encoder interfacing the actual POCSAG transceiver to the host controller computer. The PLL will lock to the master transmitter's special preamble sequence to achieve phase lock with it and then send out the messages in synchronous manner. This design is planned geocraphically so that there is a master transmitter in the middle, surrounded by slave transmitters.
Last week at Kauniainen Radio Club weekly club meeting, the PLL was tested initially and results were promising, the PLL locked to the test transmitter as expected.
February 28, 2011
February 12, 2011
Operating ham radio remotely
One of my long-time interrests has been remote controlling ham radio equipment remotely, and I've been doing a lot of research on that side while helping Martti OH2BH with hes project of operating the contest station in Pusula from home in Espoo. The project has lasted over ten years and several different approaches to remote control has been crawled through.
Few years back, reading the swedish QTC magazine I found an article (or an advertisement) about new innovation, self-contained devices to be placed to control location and the remote radio location, which then would stretch the audio paths, PTT/CW signalling and control head data over IP network. I immediately ordered a pair of these RemoteRig boxes to play with. When they arrived, I was very convinced that they were the ultimate solution for Martti's remote.
CCF / OHDXF had a cruise meeting in January 2011, where I held a presentation about Martti's remote project. RemoteRig devices were there and Mike SM20, the author for the Remoterig devices held also a presentation about the technology and innovation of the RemoteRig devices. RemoteRig devices were demonstrated controlling a remote Yaesu FT-DX5000 at Arcala OH8X superstation with a local Yaesu FT-DX5000. Ultimate innovation by RemoteRig is that two Yaesu radio's can be remoted so that the control radio actually controls the remote radio by every knob and button, and remote S-meter and frequency/function display is showed in the local radio's display. Very cool!
Yours trulu here giving the speech about Martti's remote station. The presentation is downloadable here. Below is a short video from the meeting, Martti operating OH8X remotely (docked to Stockholm harbour)
Few years back, reading the swedish QTC magazine I found an article (or an advertisement) about new innovation, self-contained devices to be placed to control location and the remote radio location, which then would stretch the audio paths, PTT/CW signalling and control head data over IP network. I immediately ordered a pair of these RemoteRig boxes to play with. When they arrived, I was very convinced that they were the ultimate solution for Martti's remote.
CCF / OHDXF had a cruise meeting in January 2011, where I held a presentation about Martti's remote project. RemoteRig devices were there and Mike SM20, the author for the Remoterig devices held also a presentation about the technology and innovation of the RemoteRig devices. RemoteRig devices were demonstrated controlling a remote Yaesu FT-DX5000 at Arcala OH8X superstation with a local Yaesu FT-DX5000. Ultimate innovation by RemoteRig is that two Yaesu radio's can be remoted so that the control radio actually controls the remote radio by every knob and button, and remote S-meter and frequency/function display is showed in the local radio's display. Very cool!
Yours trulu here giving the speech about Martti's remote station. The presentation is downloadable here. Below is a short video from the meeting, Martti operating OH8X remotely (docked to Stockholm harbour)
February 10, 2011
And some D-STAR stuff again!
A good time ago I received a Icom ID-RP1D/VS package from Jim N5MIJ to play with, and I have had it in my lab for a good time set up for some future interrest. Recently, a bunch of Icom ID-1 23cm D-STAR radios were offered for sale for a reasonable price, and I convinced fellow D-STAR entusiasts here that we need some radios as we do have a repeater. Only issue was to find a proper location for the repeater. The first generation repeater stuff is not packaged so that they would suffer in an outdoor cabined, although they are packed in a weather-proof looking chassis.
We took the radio's off the chassis to inspect how to re-build the setup so that we could fit everything important in to a (really) weatherproof casing and locate the repeater system to a high tower downtown Helsinki.
Finally I managed to start the recabling work on the radio units of the 23cm DV repeater (two boxes, TX and RX) and the 23cm DD data access point.
We took the radio's off the chassis to inspect how to re-build the setup so that we could fit everything important in to a (really) weatherproof casing and locate the repeater system to a high tower downtown Helsinki.
Finally I managed to start the recabling work on the radio units of the 23cm DV repeater (two boxes, TX and RX) and the 23cm DD data access point.
Here's the 23cm DV repeater TX unit with new SMA antenna connector in place, replacing the lossy pigtail cable which originally fed the N-connector on the chassis. Also the service connector cables and Control I/O cables are now terminated to a D9 connector, much easier for maintenance and cabling in the cabinet.
More details on this work will follow as it moves on. Next job is to modify the DV RX unit and DD accesspoint units accordingly and start planning how to fit them to the cabinet.
Quiet...
It's been quiet here. I haven't died or vanished :) I've just had too much to do and not had any interresting to write about. That might be false and I'm just lazy as lots of things have happened since may when I last reported our trip to the Nordic VHF-meeting in Denmark. The trip went well, as usual I took a lot of pictures;
Over the summer there was also the BIG event in Friedrichshafen, where from I planned to write something also but failed on that too. Sorry, as I had a great time and propably would have had something interresting to tell about the latest findings in the amateur world.
However, I took a lot ot pictures there also :)
The finnish annual meeting was held in June. It was very hot and we had a great meeting. I was not able to attend the meeting fully, but I visited few times. First time was to build up the temporary repeaters for the meeting and second time was to give a speech about them :) Setup being temporary is quite massive, as you can see!Here's the setup:
2m / 70cm / 23cm FM repeaters controlled by TheLinkBox linux repeater controller. All repeaters were linked to the national IP radio network R.Net. That time, R.Net had the following coverage with 7 linked repeaters. Currently there's even few more active repeaters in the west coast, and more is coming
Later in the autumn, I visited the RSGB National Hamfest near Lincoln. It was truly an interresting trip. I flew to Manchester, rented a car and drove about 150 km to Lincoln in the nighttime to get to my guesthouse. First time ever in a car with right-side steering!
So there I was. At the wrong side of the car, at the wrong side of the road, and it was dark. I managed to reach my destination, an excellent Bed-And-Breakfast house only ten minutes drive from the showground. I highly recommend The Gables Guesthouse if you happen to be around. Excellent and kind owners ready to help with even strange questions (You wouldn't have a spare UK mains plug? :) ), nice rooms and very good breakfast.
And of course, some pictures from the trip;
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