Topband: DX Conditions

[Jim Brown]

On 12/20/2024 1:05 PM, Guy Olinger wrote:
> There is a particular type of "diversity" that I have found particularly
> useful.

BTW, as long ago as the early '80s, I was utilizing diversity reception 
professionally with wireless mics operating high band VHF TV channels 
(that is, Ch 7-13, which are above 170 MHz). These were very good 
quality commercially mfd products from a SoCal-based company called 
Cetec-Vega.

I was also doing frequency coordination for my clients (mostly local 
broadcasters, but also theatrical and sports facilities like Wrigley 
Field and Sox Park), using inter-mod-prediction software that Cetec-Vega 
provided, after modifying the source code to make the print-out more 
user friendly.

The two receivers also implemented narrowband bandpass filters to 
prevent overload and intermod from strong local stations operating on 
those high-band channels.

In those days, the radios were crystal-controlled. Within decade or two, 
the industry had migrated to UHF and implemented programmable 
synthesized frequency control. The market also became dominated by 
microphone companies like Shure, Sennheiser, Audio-Technica and 
Lectrosonics, a non-mic mfr near ABQ.

73, Jim K9YC