[ARC5] Radios and the Canal

Sun May 12 18:30:44 EDT 2013

The first US-made TV sets used a video IF in the 21.5 MHz range.  This was an exceedingly poor choice, because low order harmonics or spurs from multiplier stages in ham transmitters operating anywhere from 160 to 20 meters would fall right into the wide band video IF.  When the 15-meter band became available in the early 50s, it really was Katie-Bar-the-Door.  Johnny Novice with his DX-20/35-40 or whatever could take out every TV set for blocks!  I know for a fact.

This video IF was also vulnerable to Chikin Band signals on 27 MHz.  At that time the general public equated Chikin Banders with hams.  We couldn't win for losing.

Some time in the very late 50s/early 60s the video IF was shifted to the 45 MHz range; this did a lot to reduce TVI from ham signals but anybody within sight of a 40-50 MHz police or business band radio site (or mobile) still got "et up."  And more often than not, the interference was wrongly pinned on "Damn Hams!"

By the way, someone else corrected me re EDWIN Howard Armstrong, not William.... Sorry!  I should'a knowed better (and did).  I was still half asleep.

And anyone working up a bibliography on broadcasting history would be well advised to look at references to Reginald A. Fessenden, who held many of the most basic patents dealing with modern radio communications -- until they were stolen from him at the court house, by greedy investors who in turn sold them to an organization called "The Radio Trust," which in turn morphed into RCA. (I did my Master of Arts thesis in History on Fessenden's early work.... much of it was done here in NC, 1901-1902.)

73

Mike
W4DSE

--- On Sun, 5/12/13, Robert  Eleazer <releazer at earthlink.net> wrote:

> From: Robert  Eleazer <releazer at earthlink.net>
> Subject: Re: [ARC5] Radios and the Canal
> To: "Mike Everette" <radiocompass at yahoo.com>
> Date: Sunday, May 12, 2013, 9:24 AM
> The reason our current TVs use a
> 45MHZ IF is that they just added a VHF converter stage ahead
> of the pre-war receivers.  The first to do that were
> the British radar guys, given the pre-war TV freqs to use
> and also using modified TV sets as radar receivers. 
> Then, finding 45 MHZ was not good enough discrimination for
> airborne radar, they added a VHF converter stage. The
> postwar TV people picked up after them, doing the same
> thing.
> 
> Wayne
> ----- Original Message ----- From: "Mike Everette" <radiocompass at yahoo.com>
> To: "Jim Haynes" <jhhaynes at earthlink.net>;
> "Roy Morgan" <k1lky at earthlink.net>;
> "Richard Knoppow" <1oldlens1 at ix.netcom.com>
> Cc: <arc5 at mailman.qth.net>;
> "Robert Eleazer" <releazer at earthlink.net>
> Sent: Sunday, May 12, 2013 9:17 AM
> Subject: Re: [ARC5] Radios and the Canal
> 
> 
> The "additional military model" was the RBK.
> 
> All the S-27/36 versions were designated RBK-1 through
> RBK-16 depending upon date of manufacture; and there were
> circuit differences among most.  Some RBKs had outputs
> for panadapters, some did not.  The early versions
> (probably S-27s) had binding posts for the antenna; later
> ones had coax connectors of one type or another, either
> SO-239, BNC, or the "Navy" connector used on many other
> shipboard receivers.  Some had different antenna
> connectors for each band; some had only one.  There is
> a chart on line some place, maybe BAMA, which compares all
> the models.
> 
> Last of the line was the RBK-16, manufactured on a 1952 (!!)
> contract.  This one, I am pretty sure, had the
> "radiation suppressor" -- aka 'signal suppressor"--
> stage.  Best thing to do there, is bypass it.  The
> RBK-16 is not plentiful; if you see one, and want a "Halli
> UHF receiver," don't pass it up because the RBK-16 is VERY
> well made.  It has many mechanical improvements over
> the early models.  I had one years ago (wish I'd kept
> it) and the audio really is excellent.
> 
> Sensitivity in all models isn't stellar, but for their day
> it was probably not bad.  In mil service they were used
> for monitoring mainly radar transmissions which tend to be
> rather strong.
> 
> The S-37 is rather a different receiver from the
> S-27/36/RBK.  It covers 130-210 MHz in one band only,
> 15 MHz IF, no BFO.
> 
> The various S-27 models (A,B,C) have somewhat different
> ranges.  The 36-165 MHz version was originally aimed at
> the FM Broadcast Relay market, when program links were
> established among stations in early networks such as William
> Howard Armstrong's "Yankee Network" in the Northeast,
> anchored by W2XMN (yes, that's a broadcast station call, an
> "experimental") in New Jersey.  The Yankee Network
> cranked up in 1939-40, using the old prewar FM broadcast
> band of 42-50 MHz.  Ever wonder why many early 2-way
> radio systems, such as Link, had a 30-42 MHz range? 
> That's the reason... avoiding the broadcast band.  And,
> I think that when there wTV Channel 1 (never actually
> licensed though), that 42-50 was the frequency range
> therefor.
> 
> The band was moved after the war to 88-108, for protection
> against DX interference.  Many also suspected, probably
> rightly, that RCA was behind the move as well because RCA
> wanted to protect its investment in AM.  They didn't
> own the necessary patents for the superior FM
> technology.  The move caused a lot of FM station owners
> to lose a lot of money because new antennas and transmitters
> were required.  It stunted the growth of FM for almost
> 30 years, until the late 60s-early 70s when car radios began
> to appear with FM coverage.  That, and "rock album"
> formats, made FM really take off!  Today, as we all
> know, AM is all dead but stinkin' -- and much of it is
> beginning to smell real bad.
> 
> During the 1970s especially, communications for the NC SHP
> were often "covered up" by long-skip TV signals from West
> Germany which blanketed our 42 MHz frequencies.
> 
> 73
> 
> Mike
> W4DSE
> 
> --- On Sat, 5/11/13, Richard Knoppow <1oldlens1 at ix.netcom.com>
> wrote:
> 
> > From: Richard Knoppow <1oldlens1 at ix.netcom.com>
> > Subject: Re: [ARC5] Radios and the Canal
> > To: "Jim Haynes" <jhhaynes at earthlink.net>,
> "Roy Morgan" <k1lky at earthlink.net>
> > Cc: arc5 at mailman.qth.net,
> "Robert Eleazer" <releazer at earthlink.net>
> > Date: Saturday, May 11, 2013, 11:23 PM
> > 
> > ----- Original Message ----- From: "Jim Haynes" <jhhaynes at earthlink.net>
> > To: "Roy Morgan" <k1lky at earthlink.net>
> > Cc: <arc5 at mailman.qth.net>;
> > "Robert Eleazer" <releazer at earthlink.net>
> > Sent: Saturday, May 11, 2013 7:06 PM
> > Subject: Re: [ARC5] Radios and the Canal
> > 
> > 
> > > On Sat, 11 May 2013, Roy Morgan wrote:
> > >
> > >> I "collected" an October, 1944 copy of QST*.
> > It has two articles that show or tell of the SX-28 in
> use,
> > in one case by the (early version of ) the FCC
> > >
> > > There was another Hallicrafters set, the S-27
> "UHF"
> > receiver, that was
> > > apparently built for monitoring frequencies above
> where
> > the SX-28 would
> > > go. I was given one and passed it on to a friend
> > who restores stuff
> > > like that.
> > >
> > I recently saw a photo of a console at the
> > FCC monitoring station at Grand Island Neb. It
> > featured several S-27 or possibly S-36 receivers along
> with
> > a couple of Super-Pros. I can't find it and am not sure
> if
> > it was on the web or in an ancient QST I was reading in
> the
> > can. While searching around the web for it I found:
> > 
> > http://www.royalsignals.org.uk/photos/S27/s27.html
> > 
> > Hallicrafters sold a commercial receiver about like
> this
> > following the war as the S-37 covering 130 to 210 Mhz.
> I
> > also discovered that there were two versions of the
> S-27,
> > the S-27A covering 27.8 to 143 Mhz and the S-27B from
> 36 to
> > 165 Mhz. The S-27C shown in the web site above looks
> > more like the S-37.
> > BTW, I have an S-36, former U.S.Navy,
> > which I am in the processes of repairing at the moment.
> In
> > addition to the standard model the military also had a
> > modified version with an additional RF stage to
> prevent
> > radiation of the LO. I don't remember the model number
> > but I think there is a handbook for it at BAMA.
> > Hallicrafters sure was a funny company, in
> > some ways they were right at the cutting edge and in
> other
> > ways didn't quite make it.
> > 
> > 
> > --
> > Richard Knoppow
> > Los Angeles
> > WB6KBL
> > dickburk at ix.netcom.com
> > 
> >
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