RE: [Repeater-Builder] Re: Best broadband VHF antenna
I would agree the Sinclair Antennas are well built and very broadband, but I had a horible time with a number of 4 bay vhf broadband units installed (and removed) in 2005. We bought a large number of VHF SLR-235 units new. The part number has changed but the antenna is the same current 4 dipole current model. The performance stank, with wild patterns and imd generation from all the brand new antennas we bought and installed at different locations. What a let down vs the good performance of other Sinclair antennas we've purchased in the past. Geez Skipp, that's pretty unusual. I've never had anything but good luck with Sinclair's dipole arrays, both on highband and UHF. I'm not a big fan of their whitesticks though. As I'm sure you know, most of their antennas are available in low PIM versions, though I've never had any IM problems with even their older, standard models. I figured it might be something we did, so I had a number of people check everything at least twice over. Yes we checked the harness phasing, element spacing yadda, yadda. But the same problem with 6 brand new antennas at 3 different locations? The only thing that comes to mind is maybe a quality control issue at the factory that resulted in one or more of the dipoles being assembled upside-down resulting in severe cancellation. I know they usually mark one side of each element with a band of red tape to ensure they are properly phased, but somebody could have screwed this process up (or maybe they marked them after assembly instead of before). If you have nothing else to do (hi), maybe you could do some tests to ascertain whether or not this is the case, perhaps by transmitting a few hundred mW into the input and using a scope to look at the relative phase between elements (i.e. check to see that the upper side of the feedpoint is in-phase between each of the elements). --- Jeff -- No virus found in this outgoing message. Checked by AVG Free Edition. Version: 7.1.375 / Virus Database: 268.0.0/267 - Release Date: 2/22/2006 Yahoo! Groups Links * To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater-Builder/ * To unsubscribe from this group, send an email to: [EMAIL PROTECTED] * Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
Re: [Repeater-Builder] Re: Best broadband VHF antenna
I've always heard and seen good performance from Sinclair, except for the SRL-222 and SRL-224. Those two were problematic. Chuck WB2EDV Jeff DePolo WN3A wrote: I would agree the Sinclair Antennas are well built and very broadband, but I had a horible time with a number of 4 bay vhf broadband units installed (and removed) in 2005. We bought a large number of VHF SLR-235 units new. The part number has changed but the antenna is the same current 4 dipole current model. The performance stank, with wild patterns and imd generation from all the brand new antennas we bought and installed at different locations. What a let down vs the good performance of other Sinclair antennas we've purchased in the past. Geez Skipp, that's pretty unusual. I've never had anything but good luck with Sinclair's dipole arrays, both on highband and UHF. I'm not a big fan of their whitesticks though. As I'm sure you know, most of their antennas are available in low PIM versions, though I've never had any IM problems with even their older, standard models. I figured it might be something we did, so I had a number of people check everything at least twice over. Yes we checked the harness phasing, element spacing yadda, yadda. But the same problem with 6 brand new antennas at 3 different locations? The only thing that comes to mind is maybe a quality control issue at the factory that resulted in one or more of the dipoles being assembled upside-down resulting in severe cancellation. I know they usually mark one side of each element with a band of red tape to ensure they are properly phased, but somebody could have screwed this process up (or maybe they marked them after assembly instead of before). If you have nothing else to do (hi), maybe you could do some tests to ascertain whether or not this is the case, perhaps by transmitting a few hundred mW into the input and using a scope to look at the relative phase between elements (i.e. check to see that the upper side of the feedpoint is in-phase between each of the elements). --- Jeff Yahoo! Groups Links * To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater-Builder/ * To unsubscribe from this group, send an email to: [EMAIL PROTECTED] * Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
Re: [Repeater-Builder] Re: Best broadband VHF antenna
Nope, the 235 is in the same family as the 210. The 210 family is a good line. The 222/224 does not have a boom that holds the element away from the mast. Instead, the element is attached right at the mounting mast and has some sort of funky hairpin type matching configuration. Chuck WB2EDV skipp025 wrote: Which are the same family as the 235's I have. Jeff... I've done all the feed point and phase testing you mentioned. No cigar... the dipoles are in phase, the harness is right and the antennas are still poop. skipp Yahoo! Groups Links * To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater-Builder/ * To unsubscribe from this group, send an email to: [EMAIL PROTECTED] * Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
Re: [Repeater-Builder] Re: Best broadband VHF antenna
The SRL235 series with its double dipoles side by side on each side of the mast doesn't have any connection with the SRL210 series unless it is in the way that the feedline is terminated at the element (the picture I see in their catalogue looks like an internal termination like the 210 dipole). I would not trust any antenna with the side by side dipoles to give a good smooth pattern. Our experience with SRL210 and 310 antennas has been excellant. The SRL222/224 lines appear to be a cheap version to compete with the dB 222/224 antennas. Burt VE2BMQ Chuck Kelsey wrote: Nope, the 235 is in the same family as the 210. The 210 family is a good line. The 222/224 does not have a boom that holds the element away from the mast. Instead, the element is attached right at the mounting mast and has some sort of funky hairpin type matching configuration. Chuck WB2EDV Yahoo! Groups Links * To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater-Builder/ * To unsubscribe from this group, send an email to: [EMAIL PROTECTED] * Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
Re: [Repeater-Builder] Re: Best broadband VHF antenna
Yes, Burt, that's what I guess I was getting at -- the same style element and enclosed harness attachment. Chuck WB2EDV Burt Lang wrote: The SRL235 series with its double dipoles side by side on each side of the mast doesn't have any connection with the SRL210 series unless it is in the way that the feedline is terminated at the element (the picture I see in their catalogue looks like an internal termination like the 210 dipole). I would not trust any antenna with the side by side dipoles to give a good smooth pattern. Our experience with SRL210 and 310 antennas has been excellant. The SRL222/224 lines appear to be a cheap version to compete with the dB 222/224 antennas. Burt VE2BMQ Chuck Kelsey wrote: Nope, the 235 is in the same family as the 210. The 210 family is a good line. The 222/224 does not have a boom that holds the element away from the mast. Instead, the element is attached right at the mounting mast and has some sort of funky hairpin type matching configuration. Chuck WB2EDV Yahoo! Groups Links Yahoo! Groups Links * To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater-Builder/ * To unsubscribe from this group, send an email to: [EMAIL PROTECTED] * Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
