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KHOG RF Combiner

1 September, 2002 (17:00) | DTV, HDTV, Projects

Since a new tower had been erected in 1997 with HDTV in mind, it already featured a broadband RFS panel antenna used to broadcast the analog channel 29 and was capable of accommodating the future DTV channel on UHF 15. The trick after expanding the building and installing the HDTV transmitter was to combine the output of the two transmitters into the common antenna. This may be very common in the top 10 markets, but it is not something common in this market, so we called in people smarter than me to help make it happen.

We were lucky in that we had a standby antenna on a shorter tower normally used solely for our microwave links. The work would take several days of cutting and welding pipe to make the sections needed to couple the output of two transmitters through the RFS combiner and then through the RFS switchframe to the dual-fed panel antenna. We used the output of our diplexer to feed directly into the standby antenna while the new transmission line sections were being fabricated and fitted by the crew on site.

The KHOG panel antenna DTV combiner and switchframe

Diamond TX close up.
On the morning of August 23rd we plumbed the last pipe into place and effectively combined the two transmitters together 3 minutes into the 6am morning show (Whew!). On the 30th we had the wiring in place and the systems tested well enough to begin regular DTV/HDTV broadcasts.

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