... Why are we modifying the Arrow?
... Because someone's analysis says the element length is all wrong ...
So Al Lowe's software program which he used to design these is all wrong?
Sorry to get defensive on Al's behalf. This thread just "feels" like a re-hash of an "engineer's view vs. real world results" argument. Like when I was told here - by engineers - that it mattered how I twisted my Arrow while working the sats. "Ya gotta take polarization into account, Clint - there's a 22db difference when you turn your antenna 90 degrees - a tremendous performance hit if you don't take this into account ... "
Yet in the real world of demonstrating workin' the birds, there's no such performance degradation. I have hundreds of witnesses to this fact: Capture SO-50 and AO-51 with the Arrow and operate TX and RX while twisting the antenna in different angles doesn't change the great reception and transmission quality.
If you are in the market for an Arrow, I simply suggest that you use it as offered to you. You will be pleased with its 2M and 440 amateur bands performance. And leave the modding of the elements w-a-y on the bottom of your "things to do" lists.
Clint Bradford
---------------------------------- Clint Bradford, K6LCS http://www.clintbradford.com
Oh, I agree that it works acceptably well right out of the box, and I've made contacts with it. I've also noticed little to no difference changing the polarization by rotating it. I wonder if the proximity to the ground, and the person holding it, is why the polarization doesn't seem to matter too much. I know for a fact that polarization *does* matter if you're using a Yagi up on a tower. I get better signal strength from my omni on 2 meters than from my 9-element horizontally polarized M2 Yagi when pointed at the same repeater. And at a previous job, one of my responsibilities was to aim satellite antennas, and "peak and cross-pole" them. I've seen well over 20dB difference from being on the "wrong" polarization. Theoretically, it's infinite, but due to how the feeds are made, and other factors, it's never "infinite". As for Al's software program being "wrong", it might not be the software, but how it was used. I'm not knocking Al; he's provided a great, unique product for the Amateur community. If I were better versed in the use of antenna-modeling programs, I'd measure out the antenna and check it for myself, but I'm not, so I go by what other antenna experts that I respect have said. I suppose an easy way to get a rough idea on this would be to see where the SWR is lowest in the 70cm band. My antenna analyzer doesn't go that high in frequency, so I can't do that. Britain's article was in the Summer 2006 issue of "CQ VHF", where he states that the antenna has been measured at several conferences, and has showed gains of around 4dBi at 435MHz, well short of what 7 elements should give. For example, an M2 6-element, end-mounted 70cm antenna is rated at 11dBi, and a Gulf Alpha 8-element, end-mounted 70cm is rated at 13dBi. His NEC evaluation based on the element length and spacing showed forward gain *should* peak at around 457 MHz, and that his NEC model suggested the boom correction factor for insulated vs directly mounted elements was not applied, and that the elements appeared to be about 1/2" short. And as the Arrow Antenna website states, "This Antenna has not been tested for gain. No need, it works." Can't argue with that! For the small cost of a box of 1/4" threaded spacers, I think it's worth making the elements longer. Jim KQ6EA --- On Sun, 8/16/09, Clint Bradford clintbrad4d@earthlink.net wrote:
From: Clint Bradford clintbrad4d@earthlink.net Subject: [amsat-bb] Re: Arrow Antennas To: amsat-bb@amsat.org, amsat-bb@amsat.org Date: Sunday, August 16, 2009, 1:19 PM
... Why are we modifying the Arrow?
... Because someone's analysis says the element length is all wrong ...
So Al Lowe's software program which he used to design these is all wrong?
Sorry to get defensive on Al's behalf. This thread just "feels" like a re-hash of an "engineer's view vs. real world results" argument. Like when I was told here - by engineers - that it mattered how I twisted my Arrow while working the sats. "Ya gotta take polarization into account, Clint - there's a 22db difference when you turn your antenna 90 degrees - a tremendous performance hit if you don't take this into account ... "
Yet in the real world of demonstrating workin' the birds, there's no such performance degradation. I have hundreds of witnesses to this fact: Capture SO-50 and AO-51 with the Arrow and operate TX and RX while twisting the antenna in different angles doesn't change the great reception and transmission quality.
If you are in the market for an Arrow, I simply suggest that you use it as offered to you. You will be pleased with its 2M and 440 amateur bands performance. And leave the modding of the elements w-a-y on the bottom of your "things to do" lists.
Clint Bradford
---------------------------------- Clint Bradford, K6LCS http://www.clintbradford.com _______________________________________________ Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
I will say that I can improve my 437 reception by rotating the beam...I also have gotten better signals by aiming the beam at a point on the ground 100 feet away...
Why criticize? Everyone else can do anything they want to their antennas without me getting upset...afterall, it's not MY antenna.
Now if someone wants to point me toward scientific theory, antenna modeling programs, propagation theory...then I can stand up and listen...until then, my best signal is most important to me.
Roger WA1KAT
Roger WA1KAT ----- Original Message ----- From: "Clint Bradford" clintbrad4d@earthlink.net To: amsat-bb@amsat.org; amsat-bb@amsat.org Sent: Sunday, August 16, 2009 4:19 PM Subject: [amsat-bb] Re: Arrow Antennas
... Why are we modifying the Arrow?
... Because someone's analysis says the element length is all wrong ...
So Al Lowe's software program which he used to design these is all wrong?
Sorry to get defensive on Al's behalf. This thread just "feels" like a
re-hash of an "engineer's view vs. real world results" argument. Like when I was told here - by engineers - that it mattered how I twisted my Arrow while working the sats. "Ya gotta take polarization into account, Clint - there's a 22db difference when you turn your antenna 90 degrees - a tremendous performance hit if you don't take this into account ... "
Yet in the real world of demonstrating workin' the birds, there's no such
performance degradation. I have hundreds of witnesses to this fact: Capture SO-50 and AO-51 with the Arrow and operate TX and RX while twisting the antenna in different angles doesn't change the great reception and transmission quality.
If you are in the market for an Arrow, I simply suggest that you use it as
offered to you. You will be pleased with its 2M and 440 amateur bands performance. And leave the modding of the elements w-a-y on the bottom of your "things to do" lists.
Clint Bradford
Clint Bradford, K6LCS http://www.clintbradford.com _______________________________________________ Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
I will say that I can improve my 437 reception by rotating the beam...I also have gotten better signals by aiming the beam at a point on the ground 100 feet away...
Why criticize? Everyone else can do anything they want to their antennas without me getting upset...afterall, it's not MY antenna.
Now if someone wants to point me toward scientific theory, antenna modeling programs, propagation theory...then I can stand up and listen...until then, my best signal is most important to me.
Roger WA1KAT
Roger WA1KAT ----- Original Message ----- From: "Clint Bradford" clintbrad4d@earthlink.net To: amsat-bb@amsat.org; amsat-bb@amsat.org Sent: Sunday, August 16, 2009 4:19 PM Subject: [amsat-bb] Re: Arrow Antennas
... Why are we modifying the Arrow?
... Because someone's analysis says the element length is all wrong ...
So Al Lowe's software program which he used to design these is all wrong?
Sorry to get defensive on Al's behalf. This thread just "feels" like a
re-hash of an "engineer's view vs. real world results" argument. Like when I was told here - by engineers - that it mattered how I twisted my Arrow while working the sats. "Ya gotta take polarization into account, Clint - there's a 22db difference when you turn your antenna 90 degrees - a tremendous performance hit if you don't take this into account ... "
Yet in the real world of demonstrating workin' the birds, there's no such
performance degradation. I have hundreds of witnesses to this fact: Capture SO-50 and AO-51 with the Arrow and operate TX and RX while twisting the antenna in different angles doesn't change the great reception and transmission quality.
If you are in the market for an Arrow, I simply suggest that you use it as
offered to you. You will be pleased with its 2M and 440 amateur bands performance. And leave the modding of the elements w-a-y on the bottom of your "things to do" lists.
Clint Bradford
Clint Bradford, K6LCS http://www.clintbradford.com _______________________________________________ Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
Hi all, I think we need some clarification.
Which satellite(s)are we talking about, when receiving with the ARROWS antenna ? The ARROW antenna are linearly polarised.
What latitude is your QTH ?
Regarding satellites - some have linear polarisation - some have circular polarisation. AO-51 has Right Hand Circular Polarisation on the "normal" repeater downlink (435.300 MHz), SO-50 has linear polarisation - the same applies to AO-27.
The satellites attitude are stabilised with permanet magnets. This may give different results depending upon where you are.
Here in Copenhagen it is a great advantage to "twist" the ARROWS antenna to improve the downlink signal from AO-27. We are close to the North Pole (hi)
Everyone may be right :-)
73 OZ1MY Ib ----- Original Message ----- From: "Roger Kolakowski" rogerkola@aol.com To: "Clint Bradford" clintbrad4d@earthlink.net; amsat-bb@amsat.org Sent: Sunday, August 16, 2009 11:34 PM Subject: [amsat-bb] Re: Arrow Antennas
I will say that I can improve my 437 reception by rotating the beam...I
also
have gotten better signals by aiming the beam at a point on the ground 100 feet away...
Why criticize? Everyone else can do anything they want to their antennas without me getting upset...afterall, it's not MY antenna.
Now if someone wants to point me toward scientific theory, antenna
modeling
programs, propagation theory...then I can stand up and listen...until
then,
my best signal is most important to me.
Roger WA1KAT
Roger WA1KAT ----- Original Message ----- From: "Clint Bradford" clintbrad4d@earthlink.net To: amsat-bb@amsat.org; amsat-bb@amsat.org Sent: Sunday, August 16, 2009 4:19 PM Subject: [amsat-bb] Re: Arrow Antennas
... Why are we modifying the Arrow?
... Because someone's analysis says the element length is all wrong
...
So Al Lowe's software program which he used to design these is all
wrong?
Sorry to get defensive on Al's behalf. This thread just "feels" like a
re-hash of an "engineer's view vs. real world results" argument. Like when
I
was told here - by engineers - that it mattered how I twisted my Arrow
while
working the sats. "Ya gotta take polarization into account, Clint -
there's
a 22db difference when you turn your antenna 90 degrees - a tremendous performance hit if you don't take this into account ... "
Yet in the real world of demonstrating workin' the birds, there's no
such
performance degradation. I have hundreds of witnesses to this fact:
Capture
SO-50 and AO-51 with the Arrow and operate TX and RX while twisting the antenna in different angles doesn't change the great reception and transmission quality.
If you are in the market for an Arrow, I simply suggest that you use it
as
offered to you. You will be pleased with its 2M and 440 amateur bands performance. And leave the modding of the elements w-a-y on the bottom of your "things to do" lists.
Clint Bradford
Clint Bradford, K6LCS http://www.clintbradford.com _______________________________________________ Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite
program!
Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
Gentlemen,
If you want to see some improvement from the Arrow antenna, leave it's physical dimensions alone and remove the diplexer in the handle, throw it away and replace it with one of my designs. I won't get into any of the design details however having a device with adjustable capacitors and wire wound inductors makes a world of difference. I have been using this antenna since it arrived on the market with great success. Most of my activity has been in California, Arizona and the Hawaiian Islands. I would not take any other antenna with me on my trips away from home. As Clint mentioned, there is a significant difference in the signal strength from the sats as I have to rotate my antenna at least 45 degrees during a pass.
Ron, W6ZQ SAT VUCC #99, 500+ grids confirmed SAT WAS Arrow + Icom ICw32
----- Original Message ----- From: Clint Bradfordmailto:clintbrad4d@earthlink.net To: amsat-bb@amsat.orgmailto:amsat-bb@amsat.org ; amsat-bb@amsat.orgmailto:amsat-bb@amsat.org Sent: Sunday, August 16, 2009 1:19 PM Subject: [amsat-bb] Re: Arrow Antennas
... Why are we modifying the Arrow?
... Because someone's analysis says the element length is all wrong ...
So Al Lowe's software program which he used to design these is all wrong?
Sorry to get defensive on Al's behalf. This thread just "feels" like a re-hash of an "engineer's view vs. real world results" argument. Like when I was told here - by engineers - that it mattered how I twisted my Arrow while working the sats. "Ya gotta take polarization into account, Clint - there's a 22db difference when you turn your antenna 90 degrees - a tremendous performance hit if you don't take this into account ... "
Yet in the real world of demonstrating workin' the birds, there's no such performance degradation. I have hundreds of witnesses to this fact: Capture SO-50 and AO-51 with the Arrow and operate TX and RX while twisting the antenna in different angles doesn't change the great reception and transmission quality.
If you are in the market for an Arrow, I simply suggest that you use it as offered to you. You will be pleased with its 2M and 440 amateur bands performance. And leave the modding of the elements w-a-y on the bottom of your "things to do" lists.
Clint Bradford
---------------------------------- Clint Bradford, K6LCS http://www.clintbradford.comhttp://www.clintbradford.com/ _______________________________________________ Sent via AMSAT-BB@amsat.orgmailto:AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bbhttp://amsat.org/mailman/listinfo/amsat-bb
participants (5)
-
Clint Bradford -
Jim Jerzycke -
OZ1MY -
Roger Kolakowski -
RONALD CADE