Saturday, February 16, 2013

The New NOAA Solar Calculator

Yesterday while checking sunrise/sunset times for a mediumwave station, I came across NOAA's (National Oceanic and Atmospheric Administration's) new solar calculator web page. It is impressive.

NOAA Solar Calculator web page

Now using the Google Maps interface, you can move a map marker over a geographic point of interest and after specifying the date and time, automatically calculate the local sunrise and sunset times for that point. The latitude and longitude coordinates can be saved to a cookie for use on a subsequent visit to the page.

Additionally, the calculator displays solar data in the form of the Equation of Time, Solar Declination, Solar Noon, Solar Elevation, and Solar Azimuth (current right ascension of the sun). The formula is highly accurate.

The old NOAA Solar Calculator is still available here.

I've added the link to the new calculator to the right sidebar above the old calculator to keep it handy. Now we have an easy and foolproof way to get sunrise/sunset data for any point of interest, and quickly. Thank you NOAA!

Monday, February 11, 2013

Field Strength Calculator One: Update 1.0050

I tweaked the Field Strength Calculator One program a little and added some new calculations figures which may be helpful for mediumwave DXers. Added are expected distance coverage for Local (2.5 mV/m), Distant (0.5 mV/m), Fringe (0.15 mV/m), and Extreme Distance (0.05 mV/m) signal levels. Also added is a Custom mV/m level which you can enter and the program will calculate the expected distance.

For those new to Field Strength Calculator One, the program returns expected received field strength in millivolts per meter and dBu (also known as dBµV/m), based on ground conductivity, earth dielectric and several other input constants. It also displays the distance to the radio horizon and the signal path loss in dB, along with several more technical parameters. The resulting output of Field Strength Calculator One should be accurate in most cases to a couple of percent in the longwave and mediumwave bands. It compares favorably to ITU program GRWAVE and currently available FCC Ground Wave Conductivity graphs.

For further information on how field strength is calculated see the Field Strength Calculations Series previously published on RADIO-TIMETRAVELLER.


To download, see the link at the top of the right sidebar under LATEST PROGRAMS. The sidebar at the top right will have the most current link in case the program is updated. The link will change in the case of an update, so I would avoid copying and pasting it into a forum or other web page. Come to the main page of this blog instead.


Install is simple. Download the .zip file and unzip. Click on the FieldStrengthCalculatorOne.exe file to run. This program makes no registry changes and saves no data to your hard drive. It has been developed and tested in Windows 7. It should work fine in Windows Vista and XP environments, and Windows 8. It is written in the old standby Visual Basic 6.

Included in the .zip is a readme.txt file. Be sure to have a look.

Click image to enlarge.

Thursday, February 7, 2013

San Francisco's KNBR-680

I was up in the San Francisco Bay area for a couple of days last week. Stayed overnight in Belmont, about 20 miles south of the city, down on the peninsula. While there, I suddenly realized that I was less than a mile from the KNBR-680 transmitter site, so jumped in the truck early one morning to check out the site. The site is at the edge of a residential area, in the boggy area next to San Francisco Bay, and just south of the San Mateo - Hayward bridge (CA 92). KNBR broadcasts with a power of 50KW.

The single broadcast tower is impressive, some 550 feet tall. It is sectionalized, an FCC type 3, and is also a nice example of top-loading. The lower section is 400 feet tall, and the upper section 150 feet. With the top hat, KNBR realizes an electrical equivalent of .520 wavelength. Just feet from San Francisco Bay, its radials literally dangle in the boggy water. It's no wonder they call KNBR "The Flamethrower".

On the air since 1922, (as KPO, originally transmitting from downtown San Francisco) KNBR has had a long history. It became an affiliate of the NBC network in 1927, and was later sold to NBC and became their flagship station on the west coast. The call sign changed from KPO to KNBC in 1946 and remained until 1962 when it was changed to KNBR after the local NBC television affiliate assumed the KNBC call.

In 1987, when NBC got out of the radio business, KNBR was sold to Susquehanna Corporation, a longtime radio station operator. Currently, KNBR broadcasts a full-time sports format, and has so since 1990. KNBR is the longtime radio home of baseball's San Francisco Giants and had been affiliated with ESPN, but on January 2, 2013 became a charter affiliate of CBS Sports Radio.

KNBR "The Sports Leader" is owned by Cumulus Media Partners, LLC, a private partnership of Cumulus Media, Bain Capital, The Blackstone Group, and Thomas H. Lee Partners. It was purchased from Susquehanna in 2005 along with other Susquehanna Radio Corporation stations.

The tower site is located at latitude 37.54722222 (N) and longitude -122.23333333 (W). If you are ever in the area, be sure to check out this impressive site.

Headed home to southwestern Arizona last Tuesday, KNBR was easily logged on the truck radio while motoring through Needles, CA and into Arizona at mid-day with good signal strength, at distances exceeding 480 miles.

Note: As of this date, the FCC database still erroneously lists KNBR as being owned by the Susquehanna Radio Corporation.

KNBR-680, San Francisco, CA

KNBR-680 upper section and top hat.