[BC] 26 Mhz RPU/IFB

[Dave Hultsman]

If you are thinking about the use of CB radios which was common with the older direct crystal controlled CB radios of 35 years ago you probably will have a problem.  Even though the 25-26 mHz. RPU frequencies have wider bandwidths and used to be able to use either AM or FM modulation they now are required to have a manufacturers Type Notification filing number.   I would image the Johnson business band FM radios at 30 mHz. could be modified but they probably were not typed for the FCC.
 
In my past we had a General Electric 26 mHz. base station at WRR-AM-FM in Dallas that was 50 Watts and had blowers on the final tubes,  The antenna was a coaxial antenna with a skirt on the bottom that was approximately 15 feet long side mounted at 400' on our FM tower.  We could talk to our 60 Watt mobiles out forty miles.  We could hear the base station at the football stadium pressbox next the Casa Mana in Fort Worth  40 miles away.  We used a Motorola PT-200 series solid state 5 Watt Portable for receiving cues and scores from the studios in Dallas. The antenna was a loaded whip about 40" which we opened up in the pressbox. They could not hear use with out 5 Watts but we could receive cues from the studios.  We also had  four Motorola HT=220 on 26 mHz. which worked very well.  The 60 Watt Motorola Mobile units were used for news and interviews until we purchase our first Marti Unit about 1965.  The modified mobile units had a toggle switch which keyed up the mobile unit using a solid state pre-amp on an Electrovoice 655 Microphone with about 15 feet of cable attached. A small box had a remote transmitter switch and an earphone jack to monitor the AM radio or the 2-way receiver. Also there was a 50' extension cord in each car to extend the microphone, cue and control away from the car.
 
We still used the 26 mHz. system for cueing after we got the good quality Marti Units.
 
I understand that there are several TV and radio stations presently using the 25=26 mHz. RPU frequencies full time for IFB.  I believe it has been discussed on this forum a couple of years back.
 
In  Atlanta, Dallas-Ft. Worth and Miami there are 450 and 455 mHz. frequencies operating full time with TV audio with IFB for remote trucks and cueing.  Really interesting to listen in drive time and afternoon news times.  NBC Miamis director forget their PL when punched up to the remote carries all their profanity.
 
Dave Hultsman 
 
>I was just going to say. There's got to be some old RF hats around here who can mod a CB down to that frequency. I wouldn't think it'd be that hard with the older models that used crystals for tuning.

>--
>Alex Hartman