Re: Fw: Re: [Repeater-Builder] Frequency Spacing?
Ian; I do not think you suppled enough info for us to answer that. While isolators are always a good idea at sites where there are multiple transmitters, the specifics of why in the preceding discussion is for specific problems due to exact offset paired repeaters in the same site working in close proximity with probable antenna coupling contributing to potential intermod as a resultisolators are probably mandatory in that case. That specific site set of conditions as was being discussed may have no relevance to you unless your pairs all have same TX-RX offset, and the transmitters are capable of cross coupling energy among themselves and thus create intermod for your receiver(s). 70 Mhz isolators will not be cheap... so I would not jump there without proper diagnostics... You did not tell us what your receive frequencies are, or are these simplex stations??? 70 mhz is not a repeater band we recognize here, I am unaware of your licensing schemes for this band in Australia Same question applies for your uhf... specifics would be helpful for analysis of your exact inputs and outputs...at 470 here we use 3 mhz offset... at 450 we use 5 mhz offset... Rules vary by locale Doug KD8B At 01:03 PM 4/5/2006, you wrote: I have several repeaters on one tower .2 uhf commercial 473.575 and 489.10mhz and 3 VHF 70meg repeaters 70.300mhz,70.5875,70.725mhz and i am having desense issues on both 70.5875mhz and also 473.575.Would i also require installing isolators on each of these repeaters..any thoughts? Thank You, Ian Wells, Kerinvale Comaudio, http://www.kerinvalecomaudio.com.au/www.kerinvalecomaudio.com.au ---Original Message--- From: mailto:[EMAIL PROTECTED][EMAIL PROTECTED] Date: 04/06/06 01:32:28 To: mailto:Repeater-Builder@yahoogroups.comRepeater-Builder@yahoogroups.com Subject: Re: [Repeater-Builder] Frequency Spacing? At 4/5/2006 07:27, you wrote: How close, frequency spacing wise, can a couple of VHF (2 meter) repeaters in the same equipment room on the same short tower be made to work well without much trouble or extra expense? How does 45 Kc. with same 600 Kc. offset sound? What will work this close and what won't? If the offset is the same, closer is actually better since the duplexer of each repeater will protect each RX from both TXs, both in RX notching of TX TX noise suppression at the RX freq. However, isolators on both TXs are a MUST, otherwise you will 2A-B mix in both TXs end up TXing 45 kHz above below your two outputs. Try to keep the two antennas as far apart as possible. If you can't separate the antennas much, you might need dual isolators on both TXs. I've seen two TXs 20 kHz apart at the same site mix strong enough to be heard 10 miles away, even though both systems had single isolators. When dealing with close-freq. TX spacing, equipment shielding seems to be more important for some reason. Stay away from converted mobiles as repeaters, or plan on using a separate RX in an RF-tight box with EMI feedthroughs. Bob NO6B Yahoo! Groups Links http://groups.yahoo.com/group/Repeater-Builder/http://groups.yahoo.com/group/Repeater-Builder/ mailto:[EMAIL PROTECTED][EMAIL PROTECTED] http://www.incredimail.com/index.asp?id=96846 FREE emoticons for your email! click Here! -- YAHOO! GROUPS LINKS * Visit your group http://groups.yahoo.com/group/Repeater-BuilderRepeater-Builder on the web. * * To unsubscribe from this group, send an email to: * mailto:[EMAIL PROTECTED][EMAIL PROTECTED] * * Your use of Yahoo! Groups is subject to the http://docs.yahoo.com/info/terms/Yahoo! Terms of Service. -- 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: Fw: Re: [Repeater-Builder] Frequency Spacing?
Sorry to the group for that nonsense on the bottom attachment in my previous reply...NOT sent intentionally.. something embedded in the reply from the first message I do not think it originated in my system, but apologize non the less... Doug At 11:25 AM 4/6/2006, you wrote: Ian; I do not think you suppled enough info for us to answer that. While isolators are always a good idea at sites where there are multiple transmitters, the specifics of why in the preceding discussion is for specific problems due to exact offset paired repeaters in the same site working in close proximity with probable antenna coupling contributing to potential intermod as a resultisolators are probably mandatory in that case. That specific site set of conditions as was being discussed 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: Fw: Re: [Repeater-Builder] Frequency Spacing?
Ok Doug The frequency pairs are TX 473.575 RX 478.775MHZ TX 489.100 RX 483.900MHZ TX 70.300 RX 72.800 MHZ TX 70.5875 RX 72.0875 MHZ TX 70.725 RX 73.225MHZ Thank You, Ian Wells, Kerinvale Comaudio, www.kerinvalecomaudio.com.au ---Original Message--- From: Doug Bade Date: 04/07/06 01:24:28 To: Repeater-Builder@yahoogroups.com Subject: Re: Fw: Re: [Repeater-Builder] Frequency Spacing? Ian; I do not think you suppled enough info for us to answer that. While isolators are always a good idea at sites where there are multiple transmitters, the specifics of why in the preceding discussion is for specific problems due to exact offset paired repeaters in the same site working in close proximity with probable antenna coupling contributing to potential intermod as a resultisolators are probably mandatory in that case. That specific site set of conditions as was being discussed may have no relevance to you unless your pairs all have same TX-RX offset, and the transmitters are capable of cross coupling energy among themselves and thus create intermod for your receiver(s). 70 Mhz isolators will not be cheap... so I would not jump there without proper diagnostics... You did not tell us what your receive frequencies are, or are these simplex stations??? 70 mhz is not a repeater band we recognize here, I am unaware of your licensing schemes for this band in Australia Same question applies for your uhf... specifics would be helpful for analysis of your exact inputs and outputs...at 470 here we use 3 mhz offset... at 450 we use 5 mhz offset... Rules vary by locale Doug KD8B At 01:03 PM 4/5/2006, you wrote: I have several repeaters on one tower .2 uhf commercial 473.575 and 489.10mhz and 3 VHF 70meg repeaters70.300mhz,70.5875,70.725mhz and i am having desense issues on both70.5875mhz and also 473.575.Would i also require installing isolators on each of these repeaters..any thoughts? Thank You, Ian Wells, Kerinvale Comaudio, http://www.kerinvalecomaudio.com.au/www.kerinvalecomaudio.com.au ---Original Message--- From: mailto:[EMAIL PROTECTED]gt;[EMAIL PROTECTED] Date: 04/06/06 01:32:28 To: mailto:Repeater-Builder@yahoogroups.comgt;Repeater-Builder@yahoogroups.com Subject: Re: [Repeater-Builder] Frequency Spacing? At 4/5/2006 07:27, you wrote: How close, frequency spacing wise, can a couple of VHF (2 meter) repeaters in the same equipment room on the same short tower be made to work well without much trouble or extra expense? How does 45 Kc. with same 600 Kc. offset sound? What will work this close and what won't? If the offset is the same, closer is actually better since the duplexer of each repeater will protect each RX from both TXs, both in RX notching of TX TX noise suppression at the RX freq.However, isolators on both TXs are a MUST, otherwise you will 2A-B mix in both TXs end up TXing 45 kHz above below your two outputs.Try to keep the two antennas as far apart as possible.If you can't separate the antennas much, you might need dual isolators on both TXs.I've seen two TXs 20 kHz apart at the same site mix strong enough to be heard 10 miles away, even though both systems had single isolators. When dealing with close-freq. TX spacing, equipment shielding seems to be more important for some reason.Stay away from converted mobiles as repeaters, or plan on using a separate RX in an RF-tight box with EMI feedthroughs. Bob NO6B Yahoo! Groups Links http://groups.yahoo.com/group/Repeater-Builder/http://groups.yahoo.com/group/Repeater-Builder/ mailto:[EMAIL PROTECTED]gt;[EMAIL PROTECTED] http://www.incredimail.com/index.asp?id=96846 FREE emoticons for your email! click Here! -- YAHOO! GROUPS LINKS *Visit your group "http://groups.yahoo.com/group/Repeater-BuilderRepeater-Builder" on the web. * *To unsubscribe from this group, send an email to: * mailto:[EMAIL PROTECTED]gt;[EMAIL PROTECTED] * *Your use of Yahoo! Groups is subject to the http://docs.yahoo.com/info/terms/Yahoo! Terms of Service. -- 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/ YAHOO! GROUPS LINKS Visit your group "Repeater-Builder" on the web. To unsubscribe from this group, send an email to:[EMAIL PROTECTED] Your use of Yahoo! Groups is subject to the Yahoo! Terms of Service.
[Repeater-Builder] Frequency Spacing?
How close, frequency spacing wise, can a couple of VHF (2 meter) repeaters in the same equipment room on the same short tower be made to work well without much trouble or extra expense? How does 45 Kc. with same 600 Kc. offset sound? What will work this close and what won't? Comments please and thanks, Scott YAHOO! GROUPS LINKS Visit your group "Repeater-Builder" on the web. To unsubscribe from this group, send an email to:[EMAIL PROTECTED] Your use of Yahoo! Groups is subject to the Yahoo! Terms of Service.
Re: [Repeater-Builder] Frequency Spacing?
At 4/5/2006 07:27, you wrote: How close, frequency spacing wise, can a couple of VHF (2 meter) repeaters in the same equipment room on the same short tower be made to work well without much trouble or extra expense? How does 45 Kc. with same 600 Kc. offset sound? What will work this close and what won't? If the offset is the same, closer is actually better since the duplexer of each repeater will protect each RX from both TXs, both in RX notching of TX TX noise suppression at the RX freq. However, isolators on both TXs are a MUST, otherwise you will 2A-B mix in both TXs end up TXing 45 kHz above below your two outputs. Try to keep the two antennas as far apart as possible. If you can't separate the antennas much, you might need dual isolators on both TXs. I've seen two TXs 20 kHz apart at the same site mix strong enough to be heard 10 miles away, even though both systems had single isolators. When dealing with close-freq. TX spacing, equipment shielding seems to be more important for some reason. Stay away from converted mobiles as repeaters, or plan on using a separate RX in an RF-tight box with EMI feedthroughs. Bob NO6B 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] Frequency Spacing?
There is a magic number where the output of one repeater will not bother the input of the other and vice versa. I would want the two repeaters to be as close as possible to each other's frequency. You can use ONE duplexer for both repeaters if they are very close to each other, say less than 75 khz or so. Use a hybrid combiner and isolators to combine the two close spaced transmitters, and a receiver pre-amp / splitter to feed the two receivers. I have 3 repeaters in 460 using one duplexer with a cavity combiner, and receiver preamp / splitter combination. The repeaters are within a 150 khz window and the system works well. The repeaters are 110 Watt Johnson VX series running narrow band FM. Steve NU5D On 4/5/06, [EMAIL PROTECTED] [EMAIL PROTECTED] wrote: At 4/5/2006 07:27, you wrote:How close, frequency spacing wise, can a couple of VHF (2 meter) repeaters in the same equipment room on the same short tower be made to work wellwithout much trouble or extra expense? How does 45 Kc. with same 600 Kc.offset sound? What will work this close and what won't? If the offset is the same, closer is actually better since the duplexer ofeach repeater will protect each RX from both TXs, both in RX notching of TX TX noise suppression at the RX freq.However, isolators on both TXs are a MUST, otherwise you will 2A-B mix in both TXs end up TXing 45 kHz above below your two outputs.Try to keep the two antennas as far apart aspossible.If you can't separate the antennas much, you might need dual isolators on both TXs.I've seen two TXs 20 kHz apart at the same site mixstrong enough to be heard 10 miles away, even though both systems hadsingle isolators.When dealing with close-freq. TX spacing, equipment shielding seems to be more important for some reason.Stay away from converted mobiles asrepeaters, or plan on using a separate RX in an RF-tight box with EMIfeedthroughs.Bob NO6BYahoo! 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/-- DE NU5D - Promote Amateur Radio YAHOO! GROUPS LINKS Visit your group "Repeater-Builder" on the web. To unsubscribe from this group, send an email to:[EMAIL PROTECTED] Your use of Yahoo! Groups is subject to the Yahoo! Terms of Service.
Fw: Re: [Repeater-Builder] Frequency Spacing?
I have several repeaters on one tower .2 uhf commercial 473.575 and 489.10mhz and 3 VHF 70meg repeaters 70.300mhz,70.5875,70.725mhz and i am having desense issues on both 70.5875mhz and also 473.575.Would i also require installing isolators on each of these repeaters..any thoughts? Thank You, Ian Wells, Kerinvale Comaudio, www.kerinvalecomaudio.com.au ---Original Message--- From: [EMAIL PROTECTED] Date: 04/06/06 01:32:28 To: Repeater-Builder@yahoogroups.com Subject: Re: [Repeater-Builder] Frequency Spacing? At 4/5/2006 07:27, you wrote: How close, frequency spacing wise, can a couple of VHF (2 meter) repeaters in the same equipment room on the same short tower be made to work well without much trouble or extra expense? How does 45 Kc. with same 600 Kc. offset sound? What will work this close and what won't? If the offset is the same, closer is actually better since the duplexer of each repeater will protect each RX from both TXs, both in RX notching of TX TX noise suppression at the RX freq.However, isolators on both TXs are a MUST, otherwise you will 2A-B mix in both TXs end up TXing 45 kHz above below your two outputs.Try to keep the two antennas as far apart as possible.If you can't separate the antennas much, you might need dual isolators on both TXs.I've seen two TXs 20 kHz apart at the same site mix strong enough to be heard 10 miles away, even though both systems had single isolators. When dealing with close-freq. TX spacing, equipment shielding seems to be more important for some reason.Stay away from converted mobiles as repeaters, or plan on using a separate RX in an RF-tight box with EMI feedthroughs. Bob NO6B 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/ YAHOO! GROUPS LINKS Visit your group "Repeater-Builder" on the web. To unsubscribe from this group, send an email to:[EMAIL PROTECTED] Your use of Yahoo! Groups is subject to the Yahoo! Terms of Service.
