[Lf] history question

[Frank Gentges]

Hal,

I think you have a pretty good summary on LF here.  I don't know of any 
military interest in LF skywave as it is seen as too unrealiable.

Frank


On Tue, 1 Feb 2000, hal wrote:

> Hi Frank,
> 
> I've heard that the pionering work on LF was done by Marconi and his original
> ship-shore
> Marconi Wireless company.  So, seeing a good thing, copies were made of this
> basic
> design by naval forces of different countries, including US.  Since the
> existance of the
> Heavyside layers was not yet known,  improvements were made to Marconi's
> model:
> more power and larger antennas to increase reliability.  I surmise that this
> could
> explain many of the original maritime and naval allocations in the LF region
> prior
> to the cold war.  I suspect interest in LF began to wane when the merits of
> high frequency
> became known.  The established martime ship to shore infrastructure probably
> was
> kept in place and operated in parallel (using 500Khz as a calling frequency)
> while
> use of the new HF allocations grew.   A second generation of LF system dates
> post WW II,
> primarily as post- and trans-nuclear attack communications systems.
> 
> Are there conventional propagation modes in LF that maintain military
> interest?
> 
> I have a self published book
> called QTC  "A seagoing radio officers scrapbook"  that talks about the early
> days.
> Perhaps this has some LF history in it.
> --H.
> Frank Gentges wrote:
> 
> > Hal,
> >
> > Good questions.  I went for my copy of NRL's "Evolution of Naval
> > Radio-Electronics and Contributions of the Naval Research Laboratory"
> > written in 1979 and written as a technical report in a hard-back binding
> > by Louis A. Gerhard who spent over 58 years there.  I'll try to get some
> > answers to your questions as follows....
> >
> > On Tue, 1 Feb 2000, hal wrote:
> >
> > >
> > >
> > > On the original uses of lf can anyone tell me if these facts are true?
> > >
> > > 1) It was the German Navy prior to 1940 who began using LF to
> > > communicate with
> > > the submarine fleet?   If so, what year was it that they began?
> > >
> > > 2) Radio Luxemburg was the first international LF broadcast station?  I
> > > recall
> > > reading that some British engineers were involved with its design and
> > > construction.
> > > Anyone know the year.  This was pre-WWII, in the late 1920's or early
> > > 1930's.
> > >
> > > 3). The frequency of Hertz's spark resonator?   Was it LF?
> >
> > No.  His experiments are listed as 31.3 to 1250 mHz.
> > >
> > > 4). Marconi's first transmitters, did these operate on LF or higher up?
> > > What about
> > > the famous transatlantic (Europe to Canada) transmission?
> >
> > Marconi's famous transatlantic test on 12 Dec, 1901 from Poldhu, England
> > to Saint Johns, Newfoundland used a frequency of approx 313 kHz.
> >
> > The standard frequency of Navy spark transmission was first 938 kHz (320
> > meters wavelength) and then expanded to cover 300 to 500 kHz.
> > >
> > > 5) How did NDB find themselves clustered around 200Khz and up?  When did
> > > this start.
> >
> > Today all we have are NDBs (non-directional beacons) but in the 30s there
> > were directional beacons which could be heard as morse "n"s or "a"s if
> > you were off the beam and a steady tone when on the beam.  The antenna
> > was directional and switched its lobes to create the dit-dah and dah-dit
> > sound.
> >
> > > NDB began before
> > WWII along short hop flight routes in the US and > elsewhere. Why LF and
> > > why there?  Is there an international convention where this was first
> > > recognized?
> > >
> > > 6)The first US Navy transmitter that used long wave operated from Ft
> > > Meyer in Arlington VA (?)
> >
> > No much went on before Arlington.  The first shore sites were at the
> > Washington Navy Yard and at the Naval Academy at Annapolis in the fall of
> > 1902.  Arlington was outfitted in 1912 with a 100 kw synchronous rotary
> > spark-gap transmitter at 120 kHz.  Earlier work may very well have been
> > done there.  The book lists Arlington as the "Navy's Primary Radio
> > Station" from 1913 to 1956.
> >
> > > Were other nations were also operating LF transmitters for their naval
> > > forces?  Does anyone
> > > know of a reference to early US Navy communications experiments?
> >
> > The Germans were using VLF/LF during WWII.  They had shortages of copper
> > wire so built a VLF antenna out of steel wire that work remarkably well.
> > It was named the "Goliath" and the US subsequently used the basic design
> > on almost all VLF stations since building Cutler Maine.
> >
> > I have this NRL book and a similar NBS book on radio history that may be
> > more useful in your hands for now.  There is a wealth of information
> > here. I'll try to get them to you.
> >
> > Frank
> >
> > > > --Hal > >
> > > _______________________________________________
> > > lf mailing list
> > > lf at amrad.org
> > > http://www.amrad.org/mailman/listinfo/lf
> > >
>