Re: NEC-LIST: Edmond Bruce questions

Dear Alexandre:
    I regret the delay in responding to your cogent message. Thank you for
continuing to have an interest.

    First: the conversion into English that resulted in "the regretted John
D. Kraus" results in an impression that you did not intend. My learned
mentor, John D. Kraus, was not regretted by anyone. Even in his last years,
he was highly regarded by his neighbors, many of whom did not know his fame.

Second: Your quotation is a useful contribution. Indeed, even with what is
now known about rhombics and our ability to reduce (slightly) their side
lobes, Jansky picked the right antenna for the time.

It may be of interest to note that the measurements of planetary emissions
at about 25 MHz (at NRAO) used V beams, which are closely related to rhombic
antennas.

    The second person in radio astronomy, Grote Reber, built (and this
continues to amaze me for I have seen the antenna) a rotatable dish antenna
having low side lobes. He then proceeded (on his own without funding) to
make the first detailed radio map of space. I have heard Otto Strube (Sigma
3 - the last of his family to be an astronomer) in person tell the story of
Grote's submission of the map. (Otto was then the editor) Who was this
person? The IRE (sadly gone, but not forgotten) said he was a member, but
nothing else was known. (Remember, Jansky was the sickly one of a famous
family and had much more easy access to publication.) The map was
published. It found its way to the Nederland's just before they fell and
the interned astronomers studied it - and the rest is more modern history.

    Within a year or so, the world lost both Grote and 8JK. They were great
friends and an inspiration to many. I tell my students that their Kraus
number is 2.

    I am still gathering bits and pieces on the early history of "gain"
antennas. Those who know about the RCA A and RCA B etc. are long gone. The
existing references must be missing some critical pieces of information as I
fail to see how they worked.

    Warm regards to all from cold Michigan. Mac

J. Mc Laughlin; Michigan U.S.A.
Home: JCM_at_Power-Net.Net

"Alexandre Kampouris" <ak_at_Radio-BIP.qc.ca> writes:
> Hi everyone,
>
> At 04:48 29.12.2003, J. Mc Laughlin wrote:
>
> > A few quick notes: The Bruce array, a form of which was used by
> >Jansky to start radio astronomy, is, as you know, quite a different
> >animal from the rhombic. See US 1,910,147 of May 23, 1933 (Filed March
> >9, 1927). See also US 1,947,247.
>
>
> Even though this topic is now one year old, I would like to cite the
> following testimony on this matter from the regretted John D. Kraus in [1,
> pp. 57-70] which I think could be of interest to NEC-LIST readers.
>
> << At about this time [1935] Edmond Bruce was developing some long-wire
> antennas for beaming short waves and these were called "rhombics" because
> of their geometry -- diamond shaped. They soon began to replace the Bruce
> antennas for radio telephone circuits. I recall that on a visit to the
Bell
> Laboratories in those days I discussed this trend with Edmond Bruce who
> reflected wryly that although it was nice to have his name associated with
> an antenna, it would have been nicer if the type were not one which might
> soon have only historical interest. The Bruce's were going out, the
> rhombics were coming in. Well, I could add that even though historical,
> what a great history, because it was with a Bruce-beam antenna that Jansky
> discovered radio waves of extra-terrestrial origin. Actually, Bruce's
later
> development, the rhombic, would have been less well-suited for Jansky's
> purpose because it would have to have been bigger in size, more unwieldy,
> and it had horrendously big sidelobes which would have made interpretation
> very difficult. >> [1, from page 58 to page 59]
>
> Happy 2005 everyone,
>
> Alexandre
>
> [1] K. Kellermann, B. Sheets (editors) : "Serendipitous Discoveries in
> Radio Astronomy -- Honoring the 50th Anniversary Announcing the Discovery
> of Cosmic Radio Waves by Karl. G. Jansky on May 5, 1933", Proceedings of a
> Workshop held at the NRAO, Green Bank WV on May 4-6, 1983
>

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