KNSD signed its analog channel 39 transmitter off June 26, the last of the full-power analog stations in San Diego to do so. KNSD had provided a nightlight service to viewers since the official June 12 cutoff date. In Los Angeles, KCBS channel 2 finally shutdown its nightlight service July 12.

Stations that turned off their analog transmitters reported no other major problems. KUSI now suffers the same co-channel interference on channel 18 from Los Angeles that XETV has put up with on 23, so North County viewers must be instructed to either improve their antenna systems for greater front-to-back ratios or revert to cable or satellite. KPBS shutdown channel 15 without incident.

Channel 69 analog fired up again, if temporarily. International Communications Network, the people who brought you K61GH, were kicked off 61 by a spectrum auction. They got relief on channel 9, but told the FCC their signal suffered greatly due to adjacent channel interference from incumbents KFMB 8 and KGTV 10. Going digital on 9 from Kearny Mesa didn’t help. So the FCC granted them an STA and K69JC callsign to operate from Mt. San Miguel until September 9 this year. ICN has filed for a permanent home at channel 50, and say they are awaiting spectrum coordination results from Mexico.

Over-the-air viewers of Mt. San Miguel DTV stations needed to rescan their tuners in order to continue watching KUSI or KDTF after Wednesday, June 18. KUSI changed its virtual channel number to match its physical channel 18 June 12 during the analog shutdown. But McKinnon Broadcasting VP of Engineering Richard Large said that he learned in discussions with Gordon Godfrey at the FCC that they must keep the analog channel 51 number as their VCT Main_Channel_Number, even after the analog transmitter is shutdown. The ATSC standard does state that the digital MCN must relate to the analog channel, and the FCC has reinforced the requirement to continue the identification through the DTV transition, presumably as an additional measure to keep viewer confusion to a minimum.

KUSI had changed the number in order to allow Entravision to use 51 as its virtual channel number after it obtained a special temporary authorization to operate KDTF on channel 51 as a low power DTV station. KDTF had been on channel 36 on Mt. San Miguel, but signed on Saturday, June 13 as a dual DTV outlet with Telefutura on its primary and KBNT on its secondary subchannel. KDTF is the first low power digital station in San Diego County. KDTF-LD has renumbered its virtual channel to 36 while remaining on physical channel 51.

XHDTV Channel 49 Tecate and XETV channel 6 Tijuana continue with their analog English language services from Mexico.  Low power English language UCSD-TV’s K35DG is still on from Mt. Soledad. KBOP-CA 43 beams informercials from Mt. San Miguel.

For all of southern California, from Santa Barbara to Palm Springs and south to the Mexican border, the moment of reckoning is here. This Saturday, June 6, 2009, the 2 GHz ENG band reduces in size by 35 MHz and TV stations begin using digital modes to reduce their bandwidth to 12 MHz per channel.This will give Sprint Communications valuable new spectrum for operating future generation PCS devices. They’ve been required to reimburse local stations for the replacement of all incumbent analog gear, including more linear front-end amplifiers, receivers, control devices, mobile transmitters, and training. The ultimate cost is likely to be beyond the company’s wildest estimates.

Regional independent liaison organizer Chris Neuman said Tuesday morning that he sees no remaining obstacles to the cutover this weekend. Other than some remote camera-transmitter locations, all ENG transmissions are ready. He said that Saturday he will conduct with Sprint conference calls to check on status of the switchover.

For most stations, the conversion is a simple matter of loading or switching to new bandplans in the remote site slave units in their market and making test shots.

The conversion kickoff occurred here in May of 2005. Yuma-El Centro was the first market in the US to make the transition in September of 2006.  Due to its enormous number of participants, the southern coastal California region has taken much longer to finish.

New Chapter 36 member Steve Moreen announced in May that he’s joined the RF Specialties Group as a sales representative from his office in San Diego. RF Specialties handles a large line of products including audio consoles, processing, codecs, and terminal gear as well as RF antennas, transmitters, and cable. He says they are a primary rep for the highly regarded Nautel line of radio transmitters. You can reach Steve by phone at 619-501-3936.

Local TV stations KNSD, KUSI, and KPBS on Mt. San Miguel are poised to shutdown their normal analog services June 12 with most of the rest of the nation. None of the three must change channels. KNSD’s Director of Engineering David MacKinnon says current plans have them providing “nightlight” information service on UHF channel 39 until June 26 at full power.

That will leave only low power broadcasters left on analog, along with Mexican broadcast stations like English-language XHDTV 49 Tecate and XETV 6 Tijuana.

A large number of professional broadcast engineers share a background of both listening to distant stations or playing disk jockey, or both. I certainly have.

When I got off work from playing background music at KRCO in Prineville, Oregon in 1973, I tuned across the FM dial to hear multiple signals where none normally existed. A baseball game between Spokane and Phoenix turned out to be originating from Arizona. I put up rabbit ears at home and experienced a massive influx of low-band VHF TV stations from Texas to Alberta on what I learned was the sporadic-E mode of propagation. It turns out that E-layer propagation takes place mostly in May and June, with smaller openings at other times of the year. Due to the angle of reflection, reception of a single E-layer bounce tends to take a signal somewhere in the range of 700 to 1700 miles. Multiple bounces are more rare, but can double or triple that range.

Every May and June now, I tend to log a couple dozen ham stations on the 50 MHz 6 meter band. A casual operator only, I’ve logged multi-hop contacts to Georgia, Hawaii, and a couple in Japan using my rooftop Create log-periodic and 100 watts.

A Limited Opportunity

Starting June 13, the number of full-power TV stations occupying the low-band VHF band will dwindle to a handful, and if you count only those in the E-skip zone, the number of DTV stations most likely received in San Diego will be down to 14. Obviously, these channels will eventually fill with either low-power DTV signals, or the FCC will reassign the band to other uses like the commonly discussed audio services. So I consider this a limited opportunity to enjoy relatively interference-free DXing.

Actually, the transition isn’t that simple. A number of analog stations will remain on the air for up to one month broadcasting “nightlight” service to help uninformed over-the-air viewers get the information required to transition to DTV. Many of those stations will be on low-band VHF.

Then there are the remaining TV stations in the skip zone from western Canada, central and northeastern Mexico, and low-power channels that may add enough noise to make 8VSB reception impossible during certain E-skip events. And did I mention low-band VHF analog channels 3 and 6 from Tijuana remaining on-the-air?

A listing of the 14 candidate DTV stations is below. I did not count low-power analog broadcasters, nor one 270 watt Jackson, Wyoming station with a null to the southwest. I did not list double-hop stations, but if you monitor long enough, you are likely to catch one or more. The best way to learn of sporadic-E clouds is to monitor the VHF-DX.net real-time map that accumulates the “spots” of operating hams. The MUF, or Maximum Usable Frequency, tends to rise to a peak that may never approach channel 2 VHF, but can, on occasion, extend above the FM band. I have occasionally been made aware of big openings by having our channel 6 viewers complain of big black lines and heterodyne audio tones.

If you don’t care about high definition, you can use one of the new, inexpensive DTV converters. The Zenith and Insignia (Best Buy house brand apparently also manufactured by LG Electronics) get high marks for sensitivity and allow manual channel entry. The Magnavox TB100MW9 is able to scan a single channel at a time and can freeze a frame for photographing. The Accurian HDTV receiver box can meter signal strength of a single channel even when it is below decoding threshold, which makes it very useful for DX’ing. The RCA brand is consistently criticized for its lack of sensitivity. Actually you can check the list of converters reviewed by MSTV for one with extra dBs of sensitivity, quick scanning, and easy channel ADD.

If you have a directional VHF antenna, rotator, and DTV, you should be good to go. Computer capture software or a digital camera set at 1/15 second exposure will allow record keeping.

Data for this table came from the latest FCC Table of Allocations and Hammett and Edison coverage maps. Email me with any changes.