[Milsurplus] Base Carrier Current ( Milsurplus Vol 132, Issue 4 )

[Clare Owens]

We had carrier current at Clarkson College in 1958 and at the Univ. of
Buffalo for at least several years after that.  I engineered at both
stations.  UB also had an RCA 1KW monaural FM station in that 1959-1965
time frame.  Now stereo, of course.  The chief engineer at UB made me climb
the antenna mast on the top of the tallest dorm to chip the ice off of the
single loop FM antenna after I blew (literally) the doorknob cap in the
Xmtr antenna matching unit by repeatedly trying to fire up the transmitter
one day after an ice storm :-)

The problem with sending carrier current over a large installation is that
the distribution transformers will not pass the AM broadcast frequencies
and so you have to provide networks to pass the BC band freq's around each
transformer.

Ah, the good old days...

Clare

On Fri, Apr 10, 2015 at 4:59 PM, Ray Fantini <RAFANTINI at salisbury.edu>
wrote:

> AM carrier current was once a widely used technology that the military and
> educational institutions used. I was involved in the seventies and eighties
> with systems at college and later servicing and repairing systems for other
> schools. A company called LPB manufactured most of the equipment that would
> allow you to connect the output of a AM broadcast transmitter to the AC
> distribution system of a building  or complex of buildings that provided a
> method for people to listen to the programing without having to broadcast
> over the air or have a FCC license. In colleges and universities we would
> usually have a transmitter located in each of the dorms connected to the AC
> distribution in that building with all the transmitters connected by dry
> pair phone lines. The transmitters were in the neighborhood of 25 to 35
> watts and for the most part anywhere in the dorms or just outside the
> building you would be able to receive the signal but you were not supposed
> to have it radiate beyond
>  the boundaries of the intuition.
> Have been told and assume it to be true that the military also used this
> same system only on a large scale for entertainment. That the difference
> would be that the distribution on an military installation would consist of
> a large transmitter that feeds from a central point where the power came in
> or was distributed on base.
> All of this is now a somewhat dead technology today being that now we have
> web base streaming and also a ton of LPFM, 100 watt and below educational
> allocations that are used by colleges and universities. Would speculate
> that the kids today have no idea what AM radio is or would have any
> interest in attempting to listen.
>
> Ray F
>
> -----Original Message-----
> From: Milsurplus [mailto:milsurplus-bounces at mailman.qth.net] On Behalf Of
> Hue Miller
> Sent: Friday, April 10, 2015 4:37 PM
> To: milsurplus at mailman.qth.net
> Subject: Re: [Milsurplus] Base Carrier Current ( Milsurplus Vol 132, Issue
> 4 )
>
> Ray, what years approx are we talking about here, the base carrier current
> stations?
> Did they use call letters, made-up or real?
> That's news to me; I'd never heard of them before.
> Interesting that you say, 1 kW level. This was also the standard level of
> the AFRS stations, the ones with the four-letter  WX-- calls. Also the
> power level of the Mobile Broadcasting units that traveled with the U.S.
> forces in Europe WWII.
>
> As a youngster I walked the long halls of the wooden building hospital
> complex at Ft. Lawton, Seattle, with a radio in hand, trying to find
> station "KURE", which I'd noticed some sign about. I could never find
> anything like that, and I think I finally decided it was some kind on
> intercom wired-broadcast.
> -Hue Miller
>
>
> >Date: Fri, 10 Apr 2015 20:10:58 +0000
> From: Ray Fantini <RAFANTINI at salisbury.edu> Often wonder what happened to
> all the old RCA AM carrier current transmitters that were once in military
> service as broadcast systems for military establishments?
>
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