I built the combination dual band 2meter/70cm antenna found at WA5VJB's webpages. I chose the 5 elements on UHF forward and 2 elements on VHF rear. All elements are in the same plane. I now read elsewhere that in-same-plane uhf/vhf elements can interfere with each other. I visited the Arrow website and see their LEO antennas are opposing for uhf/vhf. My question is if i made a mistake building the uni-plane version? Why did WA5VJB has such success?
Hi Jackie, Same-plane antennas work nicely, as long as they are designed with that in mind. See multi-band same-plane yagi examples in the HF world. Kent is a skilled designer who both engineers *and* pretests before publication.
Simply interlacing antenna elements for different bands without taking into account their mutual interaction invites problems. Arrow gets around that by placing different bands in different planes.
Ev, W2EV
On Sunday, February 16, 2020, 7:08:34 AM EST, Jackie Dander via AMSAT-BB [email protected] wrote:
I built the combination dual band 2meter/70cm antenna found at WA5VJB's webpages. I chose the 5 elements on UHF forward and 2 elements on VHF rear. All elements are in the same plane. I now read elsewhere that in-same-plane uhf/vhf elements can interfere with each other. I visited the Arrow website and see their LEO antennas are opposing for uhf/vhf. My question is if i made a mistake building the uni-plane version? Why did WA5VJB has such success? _______________________________________________ Sent via [email protected]. AMSAT-NA makes this open forum available to all interested persons worldwide without requiring membership. Opinions expressed are solely those of the author, and do not reflect the official views of AMSAT-NA. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: https://www.amsat.org/mailman/listinfo/amsat-bb
thanks for your reply. Yes, Kent's success is evidence that if I copied his yagi plans properly I should do well. I have used my built yagi to listen in on AO-91 and AO-92 (QSL attempts by others) as well as NOAA-18, 19 ( just signals). I noticed, by experiments, that I could pick up AO-92 with just my HT and it's rubber duck antenna better than with my yagi. Still learning......
On Sunday, February 16, 2020, Ev Tupis via AMSAT-BB [email protected] wrote:
Hi Jackie, Same-plane antennas work nicely, as long as they are designed with that in mind. See multi-band same-plane yagi examples in the HF world. Kent is a skilled designer who both engineers *and* pretests before publication.
Simply interlacing antenna elements for different bands without taking into account their mutual interaction invites problems. Arrow gets around that by placing different bands in different planes.
Ev, W2EV
On Sunday, February 16, 2020, 7:08:34 AM EST, Jackie Dander viaAMSAT-BB [email protected] wrote:
I built the combination dual band 2meter/70cm antenna found at WA5VJB's webpages. I chose the 5 elements on UHF forward and 2 elements on VHF rear. All elements are in the same plane. I now read elsewhere that in-same-plane uhf/vhf elements can interfere with each other. I visited the Arrow website and see their LEO antennas are opposing for uhf/vhf. My question is if i made a mistake building the uni-plane version? Why did WA5VJB has such success? _______________________________________________ Sent via [email protected]. AMSAT-NA makes this open forum available to all interested persons worldwide without requiring membership. Opinions expressed are solely those of the author, and do not reflect the official views of AMSAT-NA. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: https://www.amsat.org/mailman/listinfo/amsat-bb
Sent via [email protected]. AMSAT-NA makes this open forum available to all interested persons worldwide without requiring membership. Opinions expressed are solely those of the author, and do not reflect the official views of AMSAT-NA. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: https://www.amsat.org/mailman/listinfo/amsat-bb
Jackie,
I built mine10 years ago and it has served me well. I earned my VUCC Satellite with it. As someone else said, it was designed with multi bands in mind.
It's a great design. I built mine for under $20.00. the biggest expense was the shipping for the caps for the diplexer, which couldn't be sourced locally.
Get out and make some Q's
73 Rick Tejera (K7TEJ) Saguaro Astronomy Club www.saguaroastro.org Thunderbird Amateur Radio Club www.W7TBC.org
-----Original Message----- From: AMSAT-BB [email protected] On Behalf Of Jackie Dander via AMSAT-BB Sent: Sunday, February 16, 2020 5:07 AM To: [email protected] Subject: [amsat-bb] dual band vhf/uhf antenna
I built the combination dual band 2meter/70cm antenna found at WA5VJB's webpages. I chose the 5 elements on UHF forward and 2 elements on VHF rear. All elements are in the same plane. I now read elsewhere that in-same-plane uhf/vhf elements can interfere with each other. I visited the Arrow website and see their LEO antennas are opposing for uhf/vhf. My question is if i made a mistake building the uni-plane version? Why did WA5VJB has such success? _______________________________________________ Sent via [email protected]. AMSAT-NA makes this open forum available to all interested persons worldwide without requiring membership. Opinions expressed are solely those of the author, and do not reflect the official views of AMSAT-NA. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: https://www.amsat.org/mailman/listinfo/amsat-bb
If the design is good in the first place (interlaced yagis),there should be no problem.
I am using an interlaced yagi , 2m and 70cm and a *common feedpoint, *that is, no duplexer at the feedpoint a single/common element feed. All elements for both bands are in the same plane.
It was designed to be used that way. It is an EAntenna, 5 EL on 2m, 8 EL on 70cm and it works beautifully on the LEO birds. I run strictly mode B and have the antenna mounted atop a 48' tower and 15' of mast. It is vertically polarized with a fixed 15 deg upltilt (elevation), eliminating the need for an elevation rotor, as the gain at the horizon is only down 1 dB.
Judicious use of Comet duplexers or triplexers as filters works out very well. I can hear myself at an elevation of -0.5 deg easily on nearly all the LEOs. No intermod , no desense because duplexers make such good filters for satellites.
You can see my QRZ page for pictures of the antenna in place at 65' (fed with 1/2" hardline)
73, N0AN *Hasan*
On Sun, Feb 16, 2020 at 6:09 AM Jackie Dander via AMSAT-BB < [email protected]> wrote:
I built the combination dual band 2meter/70cm antenna found at WA5VJB's webpages. I chose the 5 elements on UHF forward and 2 elements on VHF rear. All elements are in the same plane. I now read elsewhere that in-same-plane uhf/vhf elements can interfere with each other. I visited the Arrow website and see their LEO antennas are opposing for uhf/vhf. My question is if i made a mistake building the uni-plane version? Why did WA5VJB has such success? _______________________________________________ Sent via [email protected]. AMSAT-NA makes this open forum available to all interested persons worldwide without requiring membership. Opinions expressed are solely those of the author, and do not reflect the official views of AMSAT-NA. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: https://www.amsat.org/mailman/listinfo/amsat-bb
participants (4)
-
Ev Tupis -
Hasan al-Basri -
Jackie Dander -
Rick Tejera