Month: September 2012

Restarting a Harris HT35 FM transmitter

This transmitter was retuned from 107.9 to 92.9 and put back into service. Retuning an HT35 transmitter is no small matter, there are 32 pages of retune instructions.  This unit is now in service as the main transmitter for WEZF, Burlington, VT.

The transmitter power output is 22,000 watts into a four bay, three around panel antenna, which gives it an ERP of 46,000 Watts at a height of 824 meters (2,703 feet) above average terrain. The tower is at the summit of Mt. Mansfield, which is 1,340 meters (4,395 feet) above sea level.

Mount Mansfield TV and FM antennas
Mount Mansfield TV and FM antennas

This is the Mt. Mansfield FM transmitter room. There are two TV stations in this building as well.

Final frames are of the WVPS Nautel NV-40 transmitter.

Wide band software defined radio (SDR)

There is some very cool stuff out there, you just have to look for it. Software defined radios are in that category. Many things come with a SDR, including a built in spectrum analyzer, continuously variable IF bandwidth and so on. Many manufactures have build SDR’s; ICOM, AOR, TENTEC, WInRadio, etc. Until recently, a SDR would set one back a pretty penny.

Then there is the Ultra Cheap Software Defined Radio based on a RTL2832 USB Television tuner.  Someone figured out that the TV tuner covers from approximately 60 MHz to 1700 MHz and it’s raw output can be used by any number of free, open source software programs.

Interface and program and be found at: http://wiki.spench.net/wiki/USRP_Interfaces

List of compatible devices can be found here: http://www.reddit.com/r/RTLSDR/comments/s6ddo/rtlsdr_compatibility_list_v2_work_in_progress/

Google discussion group: Ultra Cheap SDR

Radio software information: HDSDR, GNUradio, WinRadio

I found a Newsky TV28T USB tuner on Amazon for about $30.00.  I figured, what the heck, it is only thirty dollars.  There are some sources that have the ezcap EzTV668 on dealextreme for less than $20.00, however, I could not find that particular model.  In any case it looks like a fun project.