AMband.org » Technical

KNSN nee KSON gets new tower after 2004 Collapse

Ted — Tue, 13 Jan 2009 14:54:35 +0000

From CGC Communicator – The new KSON(AM) tower was
completed and activated today at about 4:30 p.m. according
to Joel Saxberg who performed the RF matching. The tower is
grounded at its base and skirted to permit RF to be induced
onto the structure.

Actually, two stations are diplexed onto the tower, each
with its own set of tuning skirts. The stations are KSON(AM)
on 1240 kHz, now KNSN with its recent call sign change (“K North
South North” as we call it); and KURS on 1040 kHz. The remaining
portion of the old tower structure will soon be dismantled and
the RF matching to the new tower will be checked after that
(there is obviously some mutual coupling between the towers).
Both stations are currently operating at full power.

Congratulations to all parties involved and particularly
to Eric Schecter, KSON’s former Director of Engineering, who
performed a large part of the planning, and to Bill Eisenhamer
who was involved in this project from the beginning and still
has a large number of finish-up details to tidy up.

Following is a December 10, 2008 photo showing the remains
of the old tower (left) and the new tower structure. The new
tower was just about completed at the time of the photo but
still had a gin pole on top:

http://earthsignals.com/add_CGC/Images/KSON/kson_DAWN_sm.jpg

Here are some photos shortly after the collapse.

Are your tower lights on?

Ted — Tue, 09 Dec 2008 16:11:48 +0000

Tower Lighting

The FCC has issued waivers of the requirement to visually check tower lights annually instead of every three months when using a high tech monitoring system. Flash Technology’s ArgusON monitors have won the confidence of regulators to let broadcasters cut back on these visual inspections.

This is partcularly valuable when the tower site is remote, or difficult to reach during winter.

After 20 Years the FCC Acts!

Ted — Tue, 30 Sep 2008 13:51:47 +0000

Consultants and Station Owners have been asking for twenty years for relief on burdensome rules to prove the performance of directional antennas for AM stations.

Last week the shoe finally dropped, and the Commission approved as a notice of proposed rulemaking, the analysis of directional antennas using Method-Of-Moments and rigorous monitoring standards to verify that AM antennas actually perform as they should. The new rules only apply to series fed, non-toploaded, non sectionalized towers.

For stations meeting the specifications, it means a substantial decrease in cost to commission or rebuild an AM directional array. The labor intensive and sometimes dangerous and always problematic field measurements may be dispensed with.

For those who choose, the old way remains available. Several safeguards have been added – regular calibration of the entire sample system, and external measurement reference points. The good thing about this is that it all encourages regular rational maintenance of antenna systems, instead of inhibiting repairs to ailing systems.

Stations with series fed simple radiators and solid sampling systems may want to consider going through the effort of changing over to the new regulatory scheme, especially if the system needs a good cleanup.

The complete Report and Order is available at the FCC website. This is now at the Notice of Proposed Rulemaking stage, with a comment and reply comment period, and publication period before the final rules are in place. There could still be a hitch if someone files comments that cause serious reconsideration.

First Mexican HD Stations on the Air

Ted — Mon, 23 Jun 2008 18:09:44 +0000

Radio Currents reports that the first two Mexican stations have started broadcasting in HD Radio.

XEEZ 970 Radio Palacios is broadcasting an AM HD Radio signal from the U.S./Mexico border town of Caborca, Sonora, using a Broadcast Electronics transmission system.

XHTY-FM 94.5 in Tijuana on the FM Side has installed a Nautel V10 HD Radio transmitter. The station is operated by Uniradio.

Radio-Locator Decoded

Ted — Thu, 19 Jun 2008 14:47:51 +0000

I have received a lot of questions about the contours shown on the Radio-Locator maps. For AM they are:

Red – 3.0 mV/m – Generally the Sellable area of the station
Purple – 0.5 mV/m – Rural protected service area, but nobody would buy ads.
Blue – 0.1 mV/m – You might still get it on a car radio

For FM they are:

Red – 60 db/uV or 1.0 mV/m – Protected service area for Class A and C stations
Purple – 50 db/uv or 0.316 mV/m – A pretty weak Signal, nobody would buy ads.
Blue – 40 db/uv or 0.1 mV/m – You won’t pick it up, except in rural areas

I determined this by comparing the plots of sample stations in Radiosoft’s Comstudy with their Radio-Locator maps. Hopefully this clears a few things up!

Mexico Approves HD Radio

Ted — Thu, 22 May 2008 14:55:58 +0000

The agency that regulates broadcasting in Mexico, CoFeTel has approved the use of HD Radio for both AM and FM stations withing 320 km of the US Border. The news reports did not mention whether night operation by AM stations was authorized.

Official statement (translated):

“Considering the extent of the development and implementation of the IBOC system in the United States of America, Mexico is required to take decisive action so that [the country's AM and FM radio stations] in the zone located within 320 kilometers of the northern border of Mexico can transmit at the same technological level so that they can provide the benefits of quality service to the radio listening public.”

Crawford Broadcasting opens Copper Theft Forum

Ted — Wed, 19 Mar 2008 14:49:15 +0000

Crawford Broadcasting has started a forum to investigate means of combating the rash of copper thefts from ground systems. You can look for ideas and add your two cents at The Copper Capers forum. If you have a theft, please post the details here so that we can understand the risks.

KFI Tower falls Again!

Ted — Wed, 19 Mar 2008 14:34:37 +0000

The historic KFI tower fell in December 2004 when a private aircraft hit the tower. After three years of seeking approval to rebuild the 684 foot structure, the new tower construction was underway Tuesday, 19 March 2008 when the partially constructed tower collapsed. For a full story see Dino’s Website with pictures of the falling tower.

ITU approves Digital Radio Mondale for Tropical Bands

Ted — Wed, 05 Dec 2007 21:32:02 +0000

According to Radio Magazine, the ITU gave the green light for DRM digital broadcasting in the tropical bands. Although not strictly an AMBand issue, it is creeping close, since the tropical bands are just above the high end of the US AM band. You can read the full article here.

NRSC issues revised standards, deletes NRSC-3

Ted — Wed, 03 Oct 2007 18:23:47 +0000

The National Radio Systems Committee has issued two revised AM standards and deleted the NRSC-3 receiver specifications standard as obsolete on September 26. The revised standards are NRSC-1-A and NRSC-2-A. NRSC-1-A specifies the preemphasis and deemphasis curves and bandwidth limitations for AM transmission, while NRSC-2-A sets the standards for RF emissions from AM stations. The NRSC intends to publish the revised standards as soon as a procedural review is completed, in about four weeks.

The NRSC also adopted a guideline for recommended bandwidth for AM transmission. NRSC-G100 provides guidance for operators who would like to decrease first adjacent channel interference by operating with bandwidth narrower than the 10 kHz limit. Using the full 10 kHz bandwidth is lost on most receivers, as nearly all receiver IF filters limit audio response to much less than 10 kHz. Benefits from this technique are limited to cases where the licensees mutually agree to bandwidth reduction of stations that interfere with each other.