[amsat-bb] Re: Fw: ELK or ARROW

Sun Dec 28 11:06:36 PST 2008

I guess CSVHF has already tested the Arrow at UHF - oops!

How I read Kent's data is that adding either an 8-32 nut to lenthen 
the elements #1, or insulate them #2 improves gain about 0.3 dB over 
the standard antenna #4.  I'mnot sure what torquing means other than 
maybe consistent tightening each element.  Obviously it does not show 
any difference with #4.  #6 merely shows that using the diplexer adds 
some loss which is normal for any such device, though 2.4 dB seems a 
bit high (but maybe not for its small phycial size -compare its 
insertion loss with a Comet 416 diplexer).

In my opinion it is not fair to compare diplexer loss with antenna 
gain measurements.  All diplexers have some losses as do repearer 
duplexers.  One can merely compensate Tx power for this.  Rx 
performance is harder to compensate but a preamp will help.

73, Ed - KL7UW

At 07:00 AM 12/28/2008, Gary \"Joe\" Mayfield wrote:
>http://www.csvhfs.org/ant/CSANT06.HTML
>
>Man; that is some good info.  I have nothing but respect for Kent, wa5vjb.
>Would someone please clarify some things for me?
>
>1. Arrow Antenna w/8-32 nuts on elements ~7.3
>2. Arrow Antenna w/plastic inserts on elements ~7.3
>3. Arrow Antenna w/star washers on elements ~7.1
>4. Arrow Antenna w/o Diplexer ~7.0
>5. Arrow Antenna w/"torqued" elements ~7.0
>6. Arrow Antenna w/Diplexer ~4.6
>
>I assume number 6 is the dual band Arrow "out of the box", and that number 4
>is the dual band Arrow "out of the box" bypassing the diplexer.  Is this
>correct?
>
>Does everyone else read this as insulating the elements, and/or lengthening
>the elements only buys you at most .3 dB, or were those tests run with the
>diplexer in line?
>
>It seems improving the 2.4 dB of insertion loss of the diplexer would be a
>better strategy (although not necessarily easy in the space available) than
>attempting to modify what is very mechanically sound antenna.
>
>73,
>Joe kk0sd
>
>
>
>-----Original Message-----
>From: amsat-bb-bounces at amsat.org [mailto:amsat-bb-bounces at amsat.org] On
>Behalf Of Jim Leder
>Sent: Sunday, December 28, 2008 8:06 AM
>To: Amsat
>Subject: [amsat-bb] Re: Fw: ELK or ARROW
>
>Is it really worth it for .3 DB gain? Seems you would be better served by
>not using the diplexer.
>
>Reference http://www.csvhfs.org/ant/CSANT06.HTML
>
>I continue to be amazed how people can judge by just looking at imagined
>numbers. Seems that practical hands on experience has no bearing on how good
>
>or bad the Arrow or the Elk antenna is, but just conjecture over assumed
>specifications makes them less than a 'Ford or Chevy'?
>
>  If you need a handheld satellite antenna, you have pretty much 3 choices:
>-The 'bad' Arrow
>-The equally 'bad' Elk
>-make your own Arrow clone, which according to the numbers is far superior
>(what's that they say about imitation?)
>
>I have an Arrow and have 'field tested' the Elk. I stuck with the Arrow. My
>OPINION, it's better. Others disagree. I contemplated building an Arrow
>clone, as there are several websites that tell you how. Are they better?
>Perhaps, but I got to think that a DB or 2 won't make that much difference.
>
>  Believe what you want, but I believe the Arrow works just fine the way it
>it is.
>
>      Jim Bob Buckeye
>             AKA
>   **** Jim Leder****
>     K8CXM since 1961
>  IBM retiree since 1999
>
>There are 10 types of people in this world -- those who understand binary
>and those who don't.
>
>
>
>
>----- Original Message -----
>From: "Jim Jerzycke" <kq6ea at pacbell.net>
>To: <amsat-bb at amsat.org>; "Gary Joe Mayfield" <gary_mayfield at hotmail.com>
>Sent: Saturday, December 27, 2008 11:42 PM
>Subject: [amsat-bb] Re: Fw: ELK or ARROW
>
>
> > Or you can just lengthen them 1/4" on a side with a threaded spacer....
> > Jim  KQ6EA
> >
> >
> > --- On Sat, 12/27/08, Gary "Joe" Mayfield <gary_mayfield at hotmail.com>
> > wrote:
> >
> >> From: Gary "Joe" Mayfield <gary_mayfield at hotmail.com>
> >> Subject: [amsat-bb] Re: Fw:  ELK or ARROW
> >> To: amsat-bb at amsat.org
> >> Date: Saturday, December 27, 2008, 8:17 PM
> >> Has anyone played with insulating the Arrow elements from
> >> the boom?  It
> >> shouldn't be too hard to do.
> >>
> >> 73,
> >> Joe kk0sd
> >>
> >> -----Original Message-----
> >> From: amsat-bb-bounces at amsat.org
> >> [mailto:amsat-bb-bounces at amsat.org] On
> >> Behalf Of Jim Danehy
> >> Sent: Saturday, December 27, 2008 8:33 PM
> >> To: amsat-bb at amsat.org
> >> Subject: [amsat-bb] Fw: ELK or ARROW
> >>
> >>
> >>   there is the old adage that you get what you pay for . .
> >> . why buy a
> >> poorly designed antenna that does not work very well
> >> > ?
> >> >
> >> > If you have a 5 element  yagi that only produces 4 dbi
> >> you are not getting
> >>
> >> > what you paid for . . . most 2 element yagis would out
> >> perform that
> >> > statistic . . . a 5 element yagi should be at least 9
> >> db + or 10 db dbd
> >> > (dipole ) not isotropic  . . . . there is something
> >> that is called
> >> > MERCHANTABILITY . . .i.e., an IMPLIED WARRANTY  that
> >> you are getting at
> >> > least the minimum for your money . . .
> >> > 4 dbi for an Arrow is way off base . . .  so it is not
> >> just ; you can not
> >> > afford a Cadillac but you are not even getting a Ford
> >> or Chevy  . .  i.e.,
> >>
> >> > the gain of a 5 element yagi on 435 mhz . . .  that is
> >> the issue, not cost
> >>
> >> > alone . . . . . . same comments apply to the ELK but I
> >> have attempted to
> >> > make the point that there is a minimum performance for
> >> a certain number of
> >>
> >> > elements that is pretty OBJECTIVE and when it is not
> >> met  . . . . well
> >> > that is my point . . . these two antennas have shown
> >> to some testers that
> >> > they do not measure up to the minimum EXPECTATIONS . .
> >> .unfortunately that
> >>
> >> > is acceptable to some  . . . . then it becomes
> >> acceptable to many . . .
> >> > and objectivity is abandoned . . .
> >> >
> >> > Jim W9VNE
> >> >
> >> >
> >> > ----- Original Message -----
> >> > From: "Trey Brown"
> >> <palintheus at gmail.com>
> >> > To: "Jim Danehy"
> >> <jdanehy at cinci.rr.com>
> >> > Sent: Saturday, December 27, 2008 6:39 PM
> >> > Subject: Re: [amsat-bb] ELK or ARROW
> >> >
> >> >
> >> >> Thanks for the comments. Realize, though, that not
> >> everyone wants or
> >> >> can afford to have the Cadillac.
> >> >>
> >> >>
> >> >> On Sat, Dec 27, 2008 at 4:06 PM, Jim Danehy
> >> <jdanehy at cinci.rr.com> wrote:
> >> >>> the Arrow antenna has been critiqued by Kent
> >> Britain, WA5VJB
> >> >>>
> >> >>>
> >> http://wa5vjb.com/references/Cheap%20Antennas-LEOs.pdf
> >> >>>
> >> >>> he says that some have measured the Arrow for
> >> gain on 435 mhz @ 4 dbi
> >> >>> (isotropic) . . . . and that further analysis
> >> showed that for the
> >> >>> element lengths used on 435 mhz that it peaks
> >> at 457 mhz and not 435 mhz
> >>
> >> >>> . . . Kent is a well respected VHF/UHF antenna
> >> person who has plenty of
> >> >>> credibility . . .
> >> >>>
> >> >>> Kent opines that the Arrow, as built does not
> >> have its elements
> >> >>> insulated from the boom. It uses dimensions
> >> for insulated elements . . .
> >>
> >> >>> so much for the Arrow . . . .
> >> >>>
> >> >>> Now for the ELK  : a local friend of mine owns
> >> an Arrow and he uses it
> >> >>> successfully. He bought an ELK and attempted
> >> to compare the Arrow and
> >> >>> the ELK . . . . he could not make an across
> >> town QSO on 435 mhz from his
> >>
> >> >>> second story window with the ELK , so he sent
> >> the ELK back for a refund
> >> >>> .
> >> >>>
> >> >>> I have worked and exchanged QSLs with several
> >> hundred satellite users .
> >> >>> . .the majority of the folks that have worked
> >> and QSLed me (close to 250
> >>
> >> >>> + ) have been using either the Arrow or ELK
> >> based upon the information
> >> >>> on their cards. So they are popular. Are they
> >> optimum ? A lot of
> >> >>> anecdotal information would seem to say NO . .
> >> .
> >> >>>
> >> >>> Thirty-five years ago I worked Oscar 6 with a
> >> homebrew 2 mtr yagi that
> >> >>> probably was worse than either the Arrow or
> >> Elk but I worked YV and KL7
> >> >>> from Indiana on CW with about 15 watts to the
> >> 3 elements which my XYL
> >> >>> waved around at my directions . . . not any
> >> more . . .what do I use
> >> >>> these days : a pair of circular polarity yagis
> >> on 10 foot booms
> >> >>> manufactured by M Square . . . .
> >> >>>
> >> >>> Folks ask what should they buy ? Maybe a Ford
> >> or maybe a Chevy . . .
> >> >>> neither is a Cadillac . . . .
> >> >>>
> >> >>> Jim W9VNE
> >> >>>
> >> _______________________________________________
> >> >>> Sent via AMSAT-BB at amsat.org. Opinions
> >> expressed are those of the author.
> >> >>> Not an AMSAT-NA member? Join now to support
> >> the amateur satellite
> >> >>> program!
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> >> >>>
> >> >>
> >> >>
> >> >>
> >> >> --
> >> >> Trey -- N5THX
> >> >>
> >> >> They who can give up essential liberty to obtain a
> >> little temporary
> >> >> safety, deserve neither liberty nor safety.
> >> >> - Benjamin Franklin
> >> >>
> >> >
> >>
> >> _______________________________________________
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> >>
> >> _______________________________________________
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