[rapido]

Apologies if this isn't the right place, but is this the original patent for the bowtie grid aerial?

http://www.google.co.uk/patents/about?id=jvdoAAAAEBAJ&dq=3373432

(US patent 3373432 by Walter E. Breneman)

I stumbled across it whilst doing research. I couldn't find any reference to Mr Breneman or this patent on any website.....

 

[stampeder]

I'd be surprised if it is the first such patent (filed in 1965) because the electromagnetic principle of phased arrays in wave propagation and reception has been known and understood since about the beginning of the 1900s!

I wonder if holl_ands and others would have a link or two to the appropriate literature about that or to prior art and patents?

Breneman also seems to have invented a "Frankfurter Cooker" circa 1942: http://www.freepatentsonline.com/2269178.html

 

[rapido]

One of the other patents that is referenced is:

http://www.google.co.uk/patents/about?id=FrhEAAAAEBAJ&dq=2869125

(2869125 by Irvine H. Bouchard)

Looks basically the same to me, but the elements are staggered rather than the connections being crossed over!

 

[300ohm]

beginning of the 1900s!

Earlier than that, heh. Oliver Lodge patented the bowtie in 1898.

http://www.coe.montana.edu/ee/rwolff/EE548/EE548-S06/UWB/History_UWB_antennas.pdf


But most important of all, he introduced the concept of "syntony", the idea that a transmitter and receiver should be tuned to the same frequency so as to maximize the received signal.
Where would we be without that concept ????

 

[JamesK]

^^^^
Back in the early days of radio, when spark gap transmitters were common, the signal was very broad. Receivers at that time weren't very selective either. This meant you'd still receive the signal, even when your receiver was tuned to a different frequency. Having both on the same frequency simply meant you heard it louder.

 

[300ohm]

Looks basically the same to me, but the elements are staggered rather than the connections being crossed over!

Yep, the middle elements are crossed and staggered using straight phasing lines instead of cross over phasing lines commonly found on a four bay bowtie.

Novel approach, but I fail to see where it would have reduced manufacturing costs.
No dimensions are given in the patent.

In his patent, he states that by eliminating the crossing of the phasing bars, he lowers the "Q" of the antenna (not sure what he means by "Q") and therefore increases the bandwidth.
A quick rough model of the antenna, using 9 over 9 dimensions and assuming the feedpoint is in the middle of the antenna, shows SWR from 6 to 2 then back up to 3. Pretty high. Net gain looks to be about the same. If the bandwidth is increased over a typical crossover type phasing line 9 over 9 bowtie, it isnt by very much, and not necessary any more with channels only going up to 51.

 

[rapido]

Definition of Q:

http://www.antenna-theory.com/definitions/q.php

Also when I mean first patent, I am talking about regarding the 4 bowties with reflector (grid aerial), not the first bowtie itself, which have obviously been around for years.

 

[300ohm]

The Q of an antenna is a measure of the bandwidth of an antenna relative to the center frequency of the bandwidth.

Kind of makes his patent statement a bit redundant, heh.

 

[300ohm]

Also when I mean first patent, I am talking about regarding the 4 bowties with reflector (grid aerial)

Well, before uhf tv existed, they had 4 bay vhf bowties and each bay had a reflector rod or two behind it. They were first introduced around the late 1940's. A mesh behind a vhf 4 bay would have been very impractical.

 

[nikiml]

Kind of makes his patent statement a bit redundant, heh.

No, that is like measuring the bandwidth in octaves.

 

[holl_ands]

The above definition of antenna "Q" is the ratio of the center frequency to the "bandwidth".
But it didn't stipulate WHAT KIND of bandwidth. Since the frequency response of most antennas
far exceeds the "acceptable" range for SWR, many times the "bandwidth" means the range of
"acceptable SWR" [say <3, <2 or perhaps <1.2 for a transmitter], rather than -3 dB Gain points:
www.kcvhfgridbandits.com/linked/yagiqfactor.pdf

However, as noted in the above article, the much more complicated "Q-Factor" is frequently
encountered when comparing high gain Yagis:
www.kcvhfgridbandits.com/linked/yagiold.pdf
In the above article, if you compare the "Boom Length and Average Gain...." ORDERED chart
to the "Average Q-Factor for Dry and Wet Yagi's" chart (SAME ORDER), you'll see that the
Q-Factor does NOT increase as the Boom Length (and hence Gain) increases (left to right)!!!

To compare the quality of Yagi's used for Earth-Moon-Earth (EME) bounces also requires
consideration of how much man-made noise is being picked up by the sidelobes, quantified
as the ratio "G/T", where G=Antenna Gain and T=Antenna Noise Temperature:
dpmc.unige.ch/dubus/8704-1.pdf

Dobricic also published fol. article proposing yet another comparison metric, "M=G^2*B/T":
www.kcvhfgridbandits.com/linked/vhfnoisetemp.pdf

 

[rapido]

Well, before uhf tv existed, they had 4 bay vhf bowties and each bay had a reflector rod or two behind it. They were first introduced around the late 1940's.

You certainly learn something new every day, I've never heard of these, and would love to see a photo! They certainly weren't used in the UK, that I can tell you.

 

[holl_ands]

Brenenman's 1966 Patent US3373432 described 1-Bay, 2-Bay and 4-Bay Bowties (4-Whiskers each) with
Screen Reflectors. All Feedlines were parallel, except for a cross-over to the outer bays on the 4-Bay Bowtie,
which we recognize as the unique combination of design elements used in most of today's Bowtie antennas.

The references cited in this patent included:
a) Middlemark with Back-To-Back Forward Swept Dipoles + Solid Reflector,

b) Bouchard (1959) with 4-Bay Bowties + Screen Reflector, 4-Whiskers each with INNER 2 Bowties fed from
OPPOSITE side of the NON-CROSSING FEEDLINE. ["Equivalent" to today's Crossover on OUTER Bowties.]

c) Durham (1964) 2-Bay LOOP with Screen Reflector (not really relevant),
and
d) McMullin (1967) Vertical Stack (Turnstile) of Vertical Dipoles (not really relevant).

Bouchard (1959) Patent also references his earlier (1957) Patent 2803011, which appears to be same
4-Bay Bowtie, except ALL whiskers attach as we see them today...but NO OUTER FEEDLINE CROSSOVER:
http://www.google.co.uk/patents/about?id=hTpmAAAAEBAJ&dq=2803011

FYI: Searching through antenna patents I've downloaded in the past (about 100+):
Bohm (1934) US1964190: 4-Bay Dipoles, NO FEEDLINE CROSSOVER.
Bohm (1935) US1988434: 4-Bay Dipoles, NO FEEDLINE CROSSOVER.
Gothe (1936) US2055100: 2-Bay Dipoles, FEEDLINE CROSSOVER.
Wheeler (1936) US2064774: 1-Bay Bowtie with 4-Whiskers, No Reflector.
Renatus (1937) US2095083: 5-Bay Dipoles, Alternately Connect OPPOSITE FEEDLINE (like Bouchard's 1959).
von Radinger (1939) US2163770: 3-Bay Dipoles with Plate Reflector, FEEDLINE CROSSOVERS.
Kandoian (1947) US2429629: 4-Bay Dipoles, FEEDLINE CROSSOVER on Outer (like today's 4-Bay).
White (1951) US2615005: 1/2/4-Bay (OUTLINE) Bowties. 4-Bay schematic shows Outer FEEDLINE Reversal.
Also shows OUTLINE Bowtie being used as a passive Reflector.

Bouchard's (1959) patent claimed that the opposite feedline connection for the INNER whiskers
"lowers the Q" compared to usual CROSS-OVER (presumably like Kandoian). There might be
another patent which we haven't found yet.....but if none exists, and since none were cited
as "prior art", it appears Brenenman's (1966) patent may be the earliest that describes ALL
of the unique features found in the current version 4-Bay Bowties.

 

[300ohm]

I've never heard of these, and would love to see a photo!

Actually there were lots of ads for them in Popular Science magazine.

The 138 year archive of old issues is here, search on antennas or scan through the magazines of that time period.

http://www.popsci.com/archives

Some pictures of the 4 bay fan type vhf antenna here. (part of the problem for searching is the naming of the antenna. They have gone by different names like bowtie, fan and conical.)
http://www.wtfda.org/index.php?option=com_content&task=view&id=134&Itemid=43

 

[holl_ands]

Ercolino's (1950) VHF antenna with active Forward Swept Bowtie and passive Flat Bowtie Reflector:
http://www.google.co.uk/patents/about?id=6zNWAAAAEBAJ&dq=2518297
These or a stacked version were, I think, on MOST homes in USA back in the 50's....before they
faced competition from C-M's Yagi's, W-G's Log-Yagi's & LPDA's....

As I recall, there might be a similar antenna, except using a simple Dipole Reflector and perhaps
even a Six-Whisker Bowtie in the fol. thread:
http://www.digitalhome.ca/forum/showthread.php?t=107706

 

[ScaryBob]

Ercolino's (1950) VHF antenna...

I remember seeing lot's of those in the 1960s. They were quite popular in Southern Ontario until more powerful yagi and log periodic based designs came out.

 

[rapido]

300ohm and holl_ands, many thanks for all the information, it's hugely interesting to me!

Sorry for the delay, it's taken me a couple of days to get thro' all the patents.

I love the 4 bay VHF superfan... that must be a rather large sight!!! I would have a go at building one, but sadly we only use UHF for television. That's my excuse not to build one anyway