INTEREST IN TINY 440 MHz Mobile Antenna?
Fractenna
I'm trying to get a sense of how interested hams are in a mobile whip
alternative for 440 repeater work.
The antenna is a fractalized inverted F. Although the antenna is smaller than
its radome, the whole system--with magmount-- is about 4 inches long; and 1
inch by 1 inch otherwise. The gain is within 1/2 dB to a whip on a car and the
pattern is almost omni in az, with some 1-2 dB excursions from peak. The BW
covers the 440 repeaters easily. Best SWR about 1.25:1 or better.
Is there an interest in such an antenna? What's out there already that has good
440 performance in a small mobile package? Is 440 that popular these days?
Appreciate thoughts, preferably here on the NG.
Thanks.
73,
Chip N1IR
Richard Clark
Hi Chip,
All very impressive specs. You got any pictures? inverted F , fractalized much
less, means nothing to me.
How about 6 M application? I presume it scales without problem. You size this
at 4 cubic inches, does the antenna fill a volume (as opposed to lying in a
plane)?
73's
Richard Clark, KB7QHC
W6RCecilA
> The gain is within 1/2 dB to a whip on a car and the
Hey Chip, what would the pattern be like in tx? :-)
--
73, Cecil, W6RCA http://www.bigfoot.com/~w6rca
Fractenna
Yep. See the news page om:
>The inverted F , fractalized
>much
>less, means nothing to me.
>
The inverted F is a very well known professional and commercial design,
although probably unknown to most hams.
>How about 6 M application? I presume it scales without problem. You size
>this
>at 4 cubic inches, does the antenna fill a volume (as opposed to lying in a
>plane)?
>
Its essentially a co-planar design. Nope; not for 6M. The top board is made of
4003. Too expensive for a 6M version. Of course ELECTRICALLY it could be easily
done.
>73's
>Richard Clark, KB7QHC
>
73
Chip n1IR
Fractenna
>--
That IS tx Cecil. ;-)
Chip
Richard Clark
>>All very impressive specs. You got any pictures?
>
>
>Yep. See the news page om:
>
>http://www.fractenna.com.
>
> >The inverted F , fractalized
>>much
>>less, means nothing to me.
>>
>
>The inverted F is a very well known professional and commercial design,
>although probably unknown to most hams.
>
Hi Chip,
Rather a difficult matter to have to hunt for your pictures with only the URL to
the first page. A nice page otherwise (perhaps a site index would help).
However, your reference does nothing to resolve my problem. The inverted F
remains unknown to me in spite of it being so common elsewhere. Can you provide
a link to a site that does illustrate this design?
Fractenna
>remains unknown to me in spite of it being so common elsewhere. Can you
>provide
>a link to a site that does illustrate this design?
>
>73's
>Richard Clark, KB7QHC
>
>
Conventional inverted F's are too standard at this point. I suggest you go to
search engines and look. Also, any recent antenna proceedings or journals are
smack full of inverted F antennas.
BTW if you went to NEWS on the URL, you would have a problem NOT seeing it:-)
73
Chip N1IR
Richard Clark
Hi Chip,
You are right, I could have done all this without asking for help from you. I
will, as you suggest, stick with tried and true methods that provide useful
results. I thought this was to be dialog rather than an advertisement. My
error.
Fractenna
>
>You are right, I could have done all this without asking for help from you.
>I
>will, as you suggest, stick with tried and true methods that provide useful
>results. I thought this was to be dialog rather than an advertisement. My
>error.
>
>73's
>Richard Clark, KB7QHC
>
>
...and your error again.
The point is, Richard, that it is common courtesy to do a LITTLE bit of work
before asking. I am not a librarian, and neither are you.
IF you got onto google, or northern lights, or even metacrawler--and came up
empty--then I would have been quite receptive, and EVEN SENT YOU COPIES OF
ARTICLES, which AS YOU REMEMBER, I have done for you in the past.
Not with any thanks, you understand.
So there's YOUR advert. Doesn't sound too good to me.
73
Chip N1IR
Richard Clark
>So there's YOUR advert. Doesn't sound too good to me.
>
>73
>Chip N1IR
Hi Chip,
I certainly agree.
For others who would appreciate help, here are a couple of links:
http://www.users.wineasy.se/svengrahn/radioind/Antennas/antennas.htm
In case that last link gets garbled, it is simply the IBM Patent response for
searching on US05764190.
Of the avaliable drawings, the Russians appear to be the most helpful (the first
link).
Larry Benko
This kind of childish bickering is not what amateur radio is supposed
be about. It seems recently that a significant percentage of the
postings are from people who enjoy criticizing and putting down others.
This is truely sad.
Larry, W0QE
Fractenna wrote:
>
> >Hi Chip,
> >
> >You are right, I could have done all this without asking for help from you.
> >I
> >will, as you suggest, stick with tried and true methods that provide useful
> >results. I thought this was to be dialog rather than an advertisement. My
> >error.
> >
> >73's
> >Richard Clark, KB7QHC
> >
> >
>
> ...and your error again.
>
> The point is, Richard, that it is common courtesy to do a LITTLE bit of work
> before asking. I am not a librarian, and neither are you.
>
> IF you got onto google, or northern lights, or even metacrawler--and came up
> empty--then I would have been quite receptive, and EVEN SENT YOU COPIES OF
> ARTICLES, which AS YOU REMEMBER, I have done for you in the past.
>
> Not with any thanks, you understand.
>
Fractenna
>From: Larry Benko be...@aztek-eng.com
>Date: Wed, 04 August 1999 05:13 PM EDT
>Message-id: <37A8AD16...@aztek-eng.com>
The problem is Richard has done this trick before, and I have actually spent
time and expense sending him papers, which he then summarily ignored and never
discussed.
I have sent out thousands of reprints, and hundreds of page link posts and
e-mails in the last few years, and had no problem with it. But when such
efforts are treated as OWED I do take exception.
Since Richard has obviously found links--and there are many; the InterKosmos
one is nice-- I must point out that my response was more than appropriate.
It is NOT in bad taste to expect someone to do at least a little work for
knowledge or at least be cordial when they get it.
73
Chip N1IR
Richard Clark
>
>The problem is Richard has done this trick before, and I have actually spent
>time and expense sending him papers, which he then summarily ignored and never
>discussed.
>
...
>
>It is NOT in bad taste to expect someone to do at least a little work for
>knowledge or at least be cordial when they get it.
>
>73
>Chip N1IR
Hello Chip,
You undoubtedly don't recall much of the postings I made in response to the data
you sent. Your reaction to the following reprint from 2 1/2 years ago may jog
your memory and serve as a search point in DejaNews. You thanked me at the
time....
Hi Chip,
This is in response to a long-standing review of your materials. Of
those, I've chosen to focus on the discussion of the FracVee due to
the attendance on this thread.
To establish a basis of comparison, all values are dBi.
The FracVee is tested as provided by the author, N1IR, with the
exception of my choice of ground. As such it is operated without
additional radials (all wires shown below) and is expected to perform
as a phased vertical system, over three bands.
The reference is a monopole over 10 radials (each as long as the
vertical is tall, 8.6 meters) elevated about a meter off ground.
The ground is good.
Frequency, MHz 8.45 16.85 24.4
FracVee field @ 10 deg. 0.35 -0.71 4.1
FracVee best field @ angle 2.49/23 1.38/23 4.4/15
FracVee Z, Ohms 31.3 + j2 30.6 + j.4 141 + j2
Monopole field @ 10 deg. -2.77 -0.54 -0.33
Monopole best field @ angle -0.36/25 0.8/18 4.4/47
Monopole Z, Ohms 35.7 - j7.8 1368 + j473 61 - j84
The FracVee exhibits the characteristic lobes of a phased vertical
array. These lobes are aligned to the axis of the major vertical
structures.
FracVee drive point impedance excursions are smaller and reactive
components are marginal.
For my analysis, I was concerned with return on investment. That is,
I have an existing monopole of similar height to the candidate
antenna. What do I stand to gain, literally. The answer is the
FracVee is often a stellar performer.
73's
Richard Clark, KB7QHC
p.s.
FracVee (20 ga.) Wires table follows:
0.000 0.069 0.026 0.000 0.069 0.232
-0.069 0.000 0.026 -0.069 0.000 0.232
0.000 0.069 0.232 0.000 0.155 0.000
-0.069 0.000 0.232 -0.155 0.000 0.000
0.000 0.000 0.026 0.000 0.069 0.026
0.000 0.000 0.026 -0.069 0.000 0.026
Source at 5,0
rwc
Fractenna
Thank you for posting this analysis.
In reference to your question, my opinion is that the InterKosmos satellite
discussion is the best intro to the inverted F. Search on www.google.com on
"inverted F antenna" and it will easily turn up. The inverted F shown is for
180-odd MHz.
73,
Chip N1IR
Fractenna
set of questions. I don't have any NG answers. Let me try again, being somewhat
more direct:
1) Is 440 used that much for repeaters, or is 2M still 10 times popular?;
2)Is there a NEED for a very small MOBILE antenna for 440 repeater use--or is
a six inch whip good enough?;
3) What else is out there that is NOT a whip? Looking for high performance, so
a 'baby' stubby is not what I wondering about.
Is this an advertisment? Certainly not! I'm trying, in part, to pull something
together for ANTENNEX magazine and a 440 construction project seems doable.
Whether this is chosen (by me) will be decided, in part by the perceived NEED,
based on NG responses. Prefer no e-mails on this, thanks.
Please; no comments like: 'what about 2M', or 'how about my 160M mobile
antenna'? I am focusing on this at the moment and appreciate relevant comments.
Thanks in advance,
73
Chip N1IR
Roy Lewallen
>
> BEFORE a few offending individuals deteriorated the thread, I had a legitimate
> set of questions. I don't have any NG answers. Let me try again, being somewhat
> more direct:
>
> 1) Is 440 used that much for repeaters, or is 2M still 10 times popular?;
2 meters is still much more popular. For actual numbers, I suggest
picking up a copy of the _ARRL Repeater Directory_ for a few dollars.
> 2)Is there a NEED for a very small MOBILE antenna for 440 repeater use--or is
> a six inch whip good enough?;
About this I have no idea. Some people might want a "stealth" antenna
for some reason.
> 3) What else is out there that is NOT a whip? Looking for high performance, so
> a 'baby' stubby is not what I wondering about.
There are collinear whips. For mobile use, an omnidirectional azimuth is
generally desirable, so "high performance" means gain by compressing the
vertical pattern. A collinear array is an obvious way to do this. The
available ones are simple and rugged; it would be interesting to see how
a fractal design would compete with regard to these important
characteristics.
I suggest getting some literature from, or looking at the web site for,
some of the manufacturers catering to the amateur VHF/UHF antenna
market. Larsen comes to mind, and I'm sure you can easily find others
advertising in the popular amateur magazines. This should give you a
good idea of what's "out there".
Roy Lewallen, W7EL
Richard Clark
Hello Chip,
Now that you've seen my posting from March of 1997, are there any other postings
that you've forgotten about? Silly question I suppose.
Well no matter, I will be posting ALL design reviews to my homepage and more. I
have a fairly complete record of my correspondence and postings and finding
fractal topics is not difficult at all. Within moments of reading your
>
>The problem is Richard has done this trick before, and I have actually spent
>time and expense sending him papers, which he then summarily ignored and never
>discussed.
>
I found the copy of the report (reposted above) you thanked me for back then
(and again above). We only ever conversed once, and that was the genesis of
your sending material, as you say, to which three weeks later I responded
directly in exactly the manner you wished. I will admit for those three weeks
you showed some agitation at my slowness(?) with your postings to the group to
"remind" me of my offer to review. You probably have also forgotten that I also
presented some 6 to 8 designs of my own in the same interval. (For which you
showed no interest except to point out how terrible they were - what was an
already admitted characteristic.) I've seen no criticism of my effort put into
this review then or now (except for the quote above to another poster). If
there's any confusion, our correspondence will be available for review - check
my page soon.
I had wanted to include this current design of yours, but it seems unlikely
except by osmosis or inference. Actually this last is all good and well, it
sort of lends itself to the guess how many jelly beans are in this small black
box. Given that the veil has descended over this latest iteration, I will be
glad to investigate if there are better designs (compared to your advertising
claims that is) that fit inside your black box. This seems unlikely, you do a
good job of crushing antennas, but it'll be fun all the same.
I have done an overhaul of many of those topics, but presentation takes its time
(more so than analysis). I've finished up the Triadic Koch Curve (I may give a
try to the Quadratic Koch, but the wish list keeps growing faster than the
presentation list). I also have the Triangle Sweep and Harter-Heightway dragon
near completion (both from that same three week period 2 1/2 years ago). Then
there is also that gasket design you've posted recently for your 2M beam.
For others following this thread for the entertainment value (and presumably
entirely numb to the claims of fractals) I will offer other designs reviewed.
Notably the Discone (yeah I can hear the sigh now - another fractal - but its
already a done deal). Maybe later the log-periodic (the sighs turn to groans -
just kidin' ... maybe).
73's
Richard Clark, KB7QHC
p.s.
Work in progress at
http://www.qsl.net/~kb7qhc
Fractenna
>sort of lends itself to the guess how many jelly beans are in this small
>black
>box. Given that the veil has descended over this latest iteration, I will be
>glad to investigate if there are better designs (compared to your advertising
>claims that is) that fit inside your black box.
Richard, this is one of hundreds of fractal designs I've investigated. I am
always a bit flabbergasted when someone refers to the Minkowski or "Chip
fractals" as some handful of things I've investigated (this is not your comment
I might add). That's silly.
Some people WANT a smaller inverted F and that's what this design is. Its about
1/8 wave by about 1/32 by about 1/64 waves.
Its by no means a wire design as you describe:-)
.
< This seems unlikely, you do
>a
>good job of crushing antennas, but it'll be fun all the same.
>
Crunch crunch:-) Love to munch:-)
>I have done an overhaul of many of those topics, but presentation takes its
>time
>(more so than analysis). I've finished up the Triadic Koch Curve (I may give
>a
>try to the Quadratic Koch, but the wish list keeps growing faster than the
>presentation list). I also have the Triangle Sweep and Harter-Heightway
>dragon
>near completion (both from that same three week period 2 1/2 years ago).
>Then
>there is also that gasket design you've posted recently for your 2M beam.
>
>For others following this thread for the entertainment value (and presumably
>entirely numb to the claims of fractals) I will offer other designs reviewed.
>Notably the Discone (yeah I can hear the sigh now - another fractal - but its
>already a done deal). Maybe later the log-periodic (the sighs turn to groans
>-
>just kidin' ... maybe).
>
>73's
>Richard Clark, KB7QHC
>
>p.s.
>
>Work in progress at
>http://www.qsl.net/~kb7qhc
>
I will look at your site after you overhaul, and assuming the results are as
expected, will link on the http://www.fractenna.com web page.
As usual, I need to remind you that the fractal antenna designs you describe
are covered by patent pending. Kindly take note of that, as there is about to
be some legalistic issues involving this on other 'ham' fractal antenna web
pages.
73,
Chip N1IR
Fractenna
>
>2 meters is still much more popular. For actual numbers, I suggest
>picking up a copy of the _ARRL Repeater Directory_ for a few dollars.
I have one--from 1995. My sense then was 440 was more a 'private' repeater
band. I take it this hasn't changed?
>
>> 2)Is there a NEED for a very small MOBILE antenna for 440 repeater use--or
>is
>> a six inch whip good enough?;
>
>About this I have no idea. Some people might want a "stealth" antenna
>for some reason.
>
Some people do; but do hams?
>> 3) What else is out there that is NOT a whip? Looking for high performance,
>so
>> a 'baby' stubby is not what I wondering about.
>
>There are collinear whips. For mobile use, an omnidirectional azimuth is
>generally desirable, so "high performance" means gain by compressing the
>vertical pattern. A collinear array is an obvious way to do this. The
>available ones are simple and rugged; it would be interesting to see how
>a fractal design would compete with regard to these important
>characteristics.
>
It does indeed. The problem is getting it into an acceptable form factor: this
is done with comcyl(R) designs.
>I suggest getting some literature from, or looking at the web site for,
>some of the manufacturers catering to the amateur VHF/UHF antenna
>market. Larsen comes to mind, and I'm sure you can easily find others
>advertising in the popular amateur magazines. This should give you a
>good idea of what's "out there".
>
This I know. What I DON'T know is if non-whips are of interest. In any case, I
found your comments helpful and I appreciate the time.
73,
Chip N1IR
>Roy Lewallen, W7EL
>
>
>
>
>
>
Dennis C. O'Connor
Yes, 2 meters is still the premier band... But, 440 is busy and growing, especially
in the big burbs where there are no open frequencies on 2 meters.... For example,
in Michigan there are no available repeater pairings on two meters in the southern
two thirds of the state, so all new repeaters have to be on 440 as the next best
choice... Certainly, a compact antenna that offers comparable performance to a 5/8
whip is going to have a market, both for fixed and mobile use...
Denny
Fractenna wrote:
> BEFORE a few offending individuals deteriorated the thread, I had a legitimate
> set of questions. I don't have any NG answers. Let me try again, being somewhat
> more direct:
>
> 1) Is 440 used that much for repeaters, or is 2M still 10 times popular?;
>
> 2)Is there a NEED for a very small MOBILE antenna for 440 repeater use--or is
> a six inch whip good enough?;
>
> 3) What else is out there that is NOT a whip? Looking for high performance, so
> a 'baby' stubby is not what I wondering about.
>
Fractenna
>whip is going to have a market, both for fixed and mobile use..
Thanks Dennis; the design I have in mind at the moment is a 1/4 wave
'replacement' but a higher (design) version will give omni gain.
73
Chip N1IR
Tom Bruhns
Fractenna wrote:
>
> BEFORE a few offending individuals deteriorated the thread, I had a legitimate
> set of questions. I don't have any NG answers. Let me try again, being somewhat
> more direct:
>
> 1) Is 440 used that much for repeaters, or is 2M still 10 times popular?;
There are more 440 repeaters around here than 2M ones. Useage? The 2M
are used a little more, I think, but it's similar.
>
> 2)Is there a NEED for a very small MOBILE antenna for 440 repeater use--or is
> a six inch whip good enough?;
A _need_?? Considering the traffic on both 440 and 2M, I don't consider
either one to be a "need." So as far as I'm concerned, for me, there's
no "need" for a very small mobile antenna. And I'm personally happy
with a thru-glass 2M/440 antenna. One thing I don't "need" is the
hassles of putting two different antennas on my car so that I can access
both 2M and 440. I have zero interest in covering 440 without also
covering 2M, and I strongly prefer to do that in one antenna.
>
> 3) What else is out there that is NOT a whip? Looking for high performance, so
> a 'baby' stubby is not what I wondering about.
Slot antennas, for one.
As for an article: In spite of what I wrote above about my interest in
actually using such an antenna, I for sure would welcome a construction
article. I always learn a lot from such things, both theoretical and
practical. And to me, for something like this, the learning is far more
important than the application.
Cheers,
Tom
Fractenna
for 440/2M.
BTW, you just ragged on me about details on the 440 invert F . I'm trying to
WRITE such an article, as I said. So don't complain.
Chip N1IR
Brian
frac...@aol.com (Fractenna) wrote:
> Hello All--
>
> I'm trying to get a sense of how interested hams are in a mobile whip
> alternative for 440 repeater work.
>
> The antenna is a fractalized inverted F. Although the antenna is
smaller than
> its radome, the whole system--with magmount-- is about 4 inches long;
and 1
and the
> pattern is almost omni in az, with some 1-2 dB excursions from peak.
The BW
> covers the 440 repeaters easily. Best SWR about 1.25:1 or better.
>
> Is there an interest in such an antenna? What's out there already that
has good
> 440 performance in a small mobile package? Is 440 that popular these
days?
>
> Appreciate thoughts, preferably here on the NG.
>
> Thanks.
>
> 73,
>
> Chip N1IR
I was one of the last holdouts using -only- 440 in my vehicle and a
Larsen 4.5 db gain uhf antenna. At Dayton, I finally went dual-band
with 2M/440. I would suggest that most 440 users are dual-band, and
your concept for a 440 mono-band vehicular antenna won't be financially
sucessful.
Can you go dual-band with your idea?
73,
Brian
Sent via Deja.com http://www.deja.com/
Share what you know. Learn what you don't.
Fractenna
>I was one of the last holdouts using -only- 440 in my vehicle and a
>Larsen 4.5 db gain uhf antenna. At Dayton, I finally went dual-band
>with 2M/440. I would suggest that most 440 users are dual-band, and
>your concept for a 440 mono-band vehicular antenna won't be financially
>sucessful.
>
>Can you go dual-band with your idea?
>
>73,
>Brian
>
Thanks Brian--
That's quite helpful and seems to refelect the hand held market and trend. I
had expected that by 1999 most repeater work would migrate up to 440, hence
that's why I asked.
It certainly makes sense to have a smaller fractal gain antenna on 440 which
is a much reduced size antenna on 2M. Promise a surprise in the late Fall;
want to beta test?
73
Chip N1IR
Hmmmmmn
concur. All you seem do do Chip is fill this newsgroup with
advertisements - I can't remember ever seeing something you posted
which allowed me to build anything!
Now I'm off to see why my kill filter failed to work on this post.
-----------------------
Regards,
Richard VK5OO
VK5OO @ yahoo.com.au
"Nothing better than home-brew, except perhaps an absence of Spam"
Fractenna
>concur. All you seem do do Chip is fill this newsgroup with
>advertisements - I can't remember ever seeing something you posted
>which allowed me to build anything!
>
And yet, what is being sold? How much does it cost? How can you buy one? What,
pray, is being advertised here?
Funny, but I seem to recall giving a description of the fracvee and fracvert
RIGHT HERE ON THIS NG for you to build and check out. many have.
How would you suggest I describe building a Sierpinski ribbon monopole with a
fractal spiral growth spiral as a top load here. And why would any ham be
interested?
Your comments lack validity, accuracy, and relevance.
73,
Chip N1IR