Re: Topband: Topband Digest, Vol 139, Issue 20
No guesswork Tom, sorry to dissapoint; just a little tongue in cheek. For most of us that use seperate receiving antennas the Comtek style is sufficient and is easily duplicated as a homebrew. I havent seen any in depth review of the DXE as to how it really performs for TX and RX under a wide range of site and propagation conditions. Carl KM1H - Original Message - From: "Tom W8JI" To: "Carl" ; "Mike Greenway" ; Sent: Friday, August 01, 2014 11:06 AM Subject: Re: Topband: Topband Digest, Vol 139, Issue 20 Poor guessing by Carl. The control units are entirely different. One is just a switch, and the other is a microprocessor based system that has an omni function and a hot switch lockout for relay protection. It also has a relay clean function. I this the original poster was asking about Array Solutions vs. DXE, and not Comtek. The original poster might have been asking about the phasing box??? The control head is in the house on the desk. The phasing box is out at the antenna. The various subparts of the system are very commonly called incorrect names, even by sales people. For example, the phasing box or outdoor unit is called a controller. The Q-sections that are nothing more than feedlines are called phasing lines. I never really am sure what part someone is asking about. :) Another point about guessing... The original error in hybrid 4 square design was from ignoring mutual coupling, and assuming element impedances were ~35 j0 for all four elements. The original thought was to transform the antennas to 100 ohms at the phasing box ports by using 1/4 wave 75-ohm Q sections. The 100 ohm ports were paralleled to get 50 ohms. The problem with that idea is mutual coupling changes the antenna resonance and impedance. The antennas are not even close to the correct impedance, and are reactive with different signs when phased. The elements also require equal currents, not equal power. A hybrid tries to force equal power. As far as I know, NONE of these units are true hybrids. This is because a true hybrid would have terrible F/B ratio and gain in this application. This is because: 1.) None of the elements or feedlines are 50 j0 when phased. They are all different impedances, except the center two elements. A hybrid ONLY provides the design phase when the termination is the design value, and that does not happen. 2.) None of the element groups require equal power. Equal power would result in a terrible F/B ratio. The DXE outdoor unit, besides an omni function and sophisticated controller, is much better optimized for the impedances actually presented in the working system. Rather than accidentally working through a design shortfall in hybrid, like the original system many years ago was, it is planned for the loads presented by the system. Because none of these units are really hybrids (they would not work very well if they were), they are all different. 73 Tom - Original Message - From: "Carl" To: "Mike Greenway" ; Sent: Thursday, July 31, 2014 8:00 PM Subject: Re: Topband: Topband Digest, Vol 139, Issue 20 More like a Chevy vs one thats been dolled up a bit for more money (-: - Original Message - From: "Mike Greenway" To: Sent: Thursday, July 31, 2014 2:25 PM Subject: Re: Topband: Topband Digest, Vol 139, Issue 20 Hi Paul.. I have used two Comteks for over 20 years and they have never had a problem. The DXE looks like a very nice unit and it appears to me the circuitry is about the same.. Either should work well I think... Ford versus Chevy... 73 Mike K4PI From: topband-requ...@contesting.com Sent: Thursday, July 31, 2014 12:00 PM To: topband@contesting.com Subject: Topband Digest, Vol 139, Issue 20 Send Topband mailing list submissions to topband@contesting.com To subscribe or unsubscribe via the World Wide Web, visit http://lists.contesting.com/mailman/listinfo/topband or, via email, send a message with subject or body 'help' to topband-requ...@contesting.com You can reach the person managing the list at topband-ow...@contesting.com When replying, please edit your Subject line so it is more specific than "Re: Contents of Topband digest..." Today's Topics: 1. 4-square controllers (Paul Baldock) -- Message: 1 Date: Wed, 30 Jul 2014 21:32:30 -0700 From: Paul Baldock To: Subject: Topband: 4-square controllers Message-ID: <20140731043244.b6490ac9...@mx.contesting.com> Content-Type: text/plain; charset="us-ascii"; format=flowed Does anybody have an opinion on the DX Engineering verses the Array Solutions 4 square controller? - Paul KW7Y -- Subject: Digest Footer ___ Topband mailing list Topband@contesting.com http://lists.contesting.co
Re: Topband: Topband Digest, Vol 139, Issue 20
Poor guessing by Carl. The control units are entirely different. One is just a switch, and the other is a microprocessor based system that has an omni function and a hot switch lockout for relay protection. It also has a relay clean function. I this the original poster was asking about Array Solutions vs. DXE, and not Comtek. The original poster might have been asking about the phasing box??? The control head is in the house on the desk. The phasing box is out at the antenna. The various subparts of the system are very commonly called incorrect names, even by sales people. For example, the phasing box or outdoor unit is called a controller. The Q-sections that are nothing more than feedlines are called phasing lines. I never really am sure what part someone is asking about. :) Another point about guessing... The original error in hybrid 4 square design was from ignoring mutual coupling, and assuming element impedances were ~35 j0 for all four elements. The original thought was to transform the antennas to 100 ohms at the phasing box ports by using 1/4 wave 75-ohm Q sections. The 100 ohm ports were paralleled to get 50 ohms. The problem with that idea is mutual coupling changes the antenna resonance and impedance. The antennas are not even close to the correct impedance, and are reactive with different signs when phased. The elements also require equal currents, not equal power. A hybrid tries to force equal power. As far as I know, NONE of these units are true hybrids. This is because a true hybrid would have terrible F/B ratio and gain in this application. This is because: 1.) None of the elements or feedlines are 50 j0 when phased. They are all different impedances, except the center two elements. A hybrid ONLY provides the design phase when the termination is the design value, and that does not happen. 2.) None of the element groups require equal power. Equal power would result in a terrible F/B ratio. The DXE outdoor unit, besides an omni function and sophisticated controller, is much better optimized for the impedances actually presented in the working system. Rather than accidentally working through a design shortfall in hybrid, like the original system many years ago was, it is planned for the loads presented by the system. Because none of these units are really hybrids (they would not work very well if they were), they are all different. 73 Tom - Original Message - From: "Carl" To: "Mike Greenway" ; Sent: Thursday, July 31, 2014 8:00 PM Subject: Re: Topband: Topband Digest, Vol 139, Issue 20 More like a Chevy vs one thats been dolled up a bit for more money (-: - Original Message - From: "Mike Greenway" To: Sent: Thursday, July 31, 2014 2:25 PM Subject: Re: Topband: Topband Digest, Vol 139, Issue 20 Hi Paul.. I have used two Comteks for over 20 years and they have never had a problem. The DXE looks like a very nice unit and it appears to me the circuitry is about the same.. Either should work well I think... Ford versus Chevy... 73 Mike K4PI From: topband-requ...@contesting.com Sent: Thursday, July 31, 2014 12:00 PM To: topband@contesting.com Subject: Topband Digest, Vol 139, Issue 20 Send Topband mailing list submissions to topband@contesting.com To subscribe or unsubscribe via the World Wide Web, visit http://lists.contesting.com/mailman/listinfo/topband or, via email, send a message with subject or body 'help' to topband-requ...@contesting.com You can reach the person managing the list at topband-ow...@contesting.com When replying, please edit your Subject line so it is more specific than "Re: Contents of Topband digest..." Today's Topics: 1. 4-square controllers (Paul Baldock) -- Message: 1 Date: Wed, 30 Jul 2014 21:32:30 -0700 From: Paul Baldock To: Subject: Topband: 4-square controllers Message-ID: <20140731043244.b6490ac9...@mx.contesting.com> Content-Type: text/plain; charset="us-ascii"; format=flowed Does anybody have an opinion on the DX Engineering verses the Array Solutions 4 square controller? - Paul KW7Y -- Subject: Digest Footer ___ Topband mailing list Topband@contesting.com http://lists.contesting.com/mailman/listinfo/topband -- End of Topband Digest, Vol 139, Issue 20 _ Topband Reflector Archives - http://www.contesting.com/_topband - No virus found in this message. Checked by AVG - www.avg.com Version: 2014.0.4716 / Virus Database: 3986/7954 - Release Date: 07/31/14 _ Topband Reflector Archives - http://www.contesting.com/_topband - No virus found in this message. Checked by AVG - www.avg.com Version: 2014.0.4716 / Virus Database: 39
Re: Topband: Topband Digest, Vol 139, Issue 20
More like a Chevy vs one thats been dolled up a bit for more money (-: - Original Message - From: "Mike Greenway" To: Sent: Thursday, July 31, 2014 2:25 PM Subject: Re: Topband: Topband Digest, Vol 139, Issue 20 Hi Paul.. I have used two Comteks for over 20 years and they have never had a problem. The DXE looks like a very nice unit and it appears to me the circuitry is about the same.. Either should work well I think... Ford versus Chevy... 73 Mike K4PI From: topband-requ...@contesting.com Sent: Thursday, July 31, 2014 12:00 PM To: topband@contesting.com Subject: Topband Digest, Vol 139, Issue 20 Send Topband mailing list submissions to topband@contesting.com To subscribe or unsubscribe via the World Wide Web, visit http://lists.contesting.com/mailman/listinfo/topband or, via email, send a message with subject or body 'help' to topband-requ...@contesting.com You can reach the person managing the list at topband-ow...@contesting.com When replying, please edit your Subject line so it is more specific than "Re: Contents of Topband digest..." Today's Topics: 1. 4-square controllers (Paul Baldock) -- Message: 1 Date: Wed, 30 Jul 2014 21:32:30 -0700 From: Paul Baldock To: Subject: Topband: 4-square controllers Message-ID: <20140731043244.b6490ac9...@mx.contesting.com> Content-Type: text/plain; charset="us-ascii"; format=flowed Does anybody have an opinion on the DX Engineering verses the Array Solutions 4 square controller? - Paul KW7Y -- Subject: Digest Footer ___ Topband mailing list Topband@contesting.com http://lists.contesting.com/mailman/listinfo/topband -- End of Topband Digest, Vol 139, Issue 20 _ Topband Reflector Archives - http://www.contesting.com/_topband - No virus found in this message. Checked by AVG - www.avg.com Version: 2014.0.4716 / Virus Database: 3986/7954 - Release Date: 07/31/14 _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Topband Digest, Vol 139, Issue 20
Hi Paul.. I have used two Comteks for over 20 years and they have never had a problem. The DXE looks like a very nice unit and it appears to me the circuitry is about the same.. Either should work well I think... Ford versus Chevy... 73 Mike K4PI From: topband-requ...@contesting.com Sent: Thursday, July 31, 2014 12:00 PM To: topband@contesting.com Subject: Topband Digest, Vol 139, Issue 20 Send Topband mailing list submissions to topband@contesting.com To subscribe or unsubscribe via the World Wide Web, visit http://lists.contesting.com/mailman/listinfo/topband or, via email, send a message with subject or body 'help' to topband-requ...@contesting.com You can reach the person managing the list at topband-ow...@contesting.com When replying, please edit your Subject line so it is more specific than "Re: Contents of Topband digest..." Today's Topics: 1. 4-square controllers (Paul Baldock) -- Message: 1 Date: Wed, 30 Jul 2014 21:32:30 -0700 From: Paul Baldock To: Subject: Topband: 4-square controllers Message-ID: <20140731043244.b6490ac9...@mx.contesting.com> Content-Type: text/plain; charset="us-ascii"; format=flowed Does anybody have an opinion on the DX Engineering verses the Array Solutions 4 square controller? - Paul KW7Y -- Subject: Digest Footer ___ Topband mailing list Topband@contesting.com http://lists.contesting.com/mailman/listinfo/topband -- End of Topband Digest, Vol 139, Issue 20 _ Topband Reflector Archives - http://www.contesting.com/_topband
