Re: [Repeater-Builder] isolation

Eric, and list... Kevin, I agree with your conclusions- provided that the exciter meets your expected performance. I would never assume that I could automatically subtract 22 dB from the proposed isolation, merely because it was a PLL exciter, without knowing for certain that its

Re: [Repeater-Builder] isolation

Gary wrote: Dan Kagabine, the chief engineer at TX-RX systems use to always say that once you have enough isolation to overcome any desense, then any more is a waste of money as it does nothing for you. If you only need 70 db then a 100 db duplexer does nothing more for you than a 70 db

Re: [Repeater-Builder] isolation

conditions, you may be unhappy when something moves a bit out of tolerance. Chuck WB2EDV - Original Message - From: Kevin Custer To: Repeater-Builder@yahoogroups.com Sent: Sunday, August 23, 2009 9:30 AM Subject: Re: [Repeater-Builder] isolation Gary wrote: Dan

RE: [Repeater-Builder] isolation

While I'll agree that more isolation, then what is needed to insure no desense is a waste; if this gentleman is suggesting that isolation in reserve is a waste, I strongly disagree. Why? Operating conditions can change - snow and especially ice on the repeater antenna can detune the

Re: [Repeater-Builder] isolation

I'll second what Kevin said and add: What if you want to upgrade? If you only purchased what you needed before, it may no longer be adequate for your new system which may have more power or a higher sensitivity receiver. Better to buy extra isolation now and not need it than to buy less and

Re: [Repeater-Builder] isolation

At 06:45 AM 08/23/09, you wrote: I agree with Kevin. You need a little headroom built in for conditions that could change. Equipment ages and changes it's operating characteristics. Temperature swings cause the same issues. Does one need to go overboard? Probably not. But if you happen to be

RE: [Repeater-Builder] isolation

...@yahoogroups.com] On Behalf Of Chuck Kelsey Sent: Sunday, August 23, 2009 8:45 AM To: Repeater-Builder@yahoogroups.com Subject: Re: [Repeater-Builder] isolation I agree with Kevin. You need a little headroom built in for conditions that could change. Equipment ages and changes it's operating

Re: [Repeater-Builder] isolation

Hi You didn, say Freq. I picked 146.94-146.34 punched in your figures and Got 94.4 Wesley AB8KD - Original Message - From: kj4si To: Repeater-Builder@yahoogroups.com Sent: Saturday, August 22, 2009 9:54 AM Subject: [Repeater-Builder] isolation Hope someone may have

RE: [Repeater-Builder] isolation

My CommShop calculates 99.65 dB is required. I'd definitely be looking at a six-cavity BpBr duplexer for this station. 73, Eric Lemmon WB6FLY -Original Message- From: Repeater-Builder@yahoogroups.com [mailto:repeater-buil...@yahoogroups.com] On Behalf Of kj4si Sent: Saturday, August

Re: [Repeater-Builder] isolation

Repeater-Builder@yahoogroups.com Sent: Sat Aug 22 10:22:36 2009 Subject: RE: [Repeater-Builder] isolation My CommShop calculates 99.65 dB is required. I'd definitely be looking at a six-cavity BpBr duplexer for this station. 73, Eric Lemmon WB6FLY -Original Message- From: Repeater

Re: [Repeater-Builder] isolation

-Builder%40yahoogroups.com Repeater-Builder@yahoogroups.com mailto:Repeater-Builder%40yahoogroups.com Sent: Sat Aug 22 10:22:36 2009 Subject: RE: [Repeater-Builder] isolation My CommShop calculates 99.65 dB is required. I'd definitely be looking at a six-cavity BpBr duplexer

RE: [Repeater-Builder] isolation

Of Tony KT9AC Sent: Saturday, August 22, 2009 10:07 AM To: Repeater-Builder@yahoogroups.com Subject: Re: [Repeater-Builder] isolation Other than ordering the software, is there an old-school formula that can be used for this? I been using the decibel-wheel to convert from microvolts to dbm

Re: [Repeater-Builder] isolation

Eric, Are you sure about your six-cavity recommendation? The MASTR II PLL exciter has 22 dB less side-band noise than a typical multiplier exciter - using 600 kHz TX to RX separation. Assuming his preamp isn't driven into a non-linear region (it shouldn't be), a good 4 cavity duplexer, like

RE: [Repeater-Builder] isolation

: Repeater-Builder@yahoogroups.com [mailto:repeater-buil...@yahoogroups.com] On Behalf Of Kevin Custer Sent: Saturday, August 22, 2009 12:52 PM To: Repeater-Builder@yahoogroups.com Subject: Re: [Repeater-Builder] isolation Eric, Are you sure about your six-cavity recommendation? The MASTR II PLL

Re: [Repeater-Builder] isolation

22, 2009 12:52 PM To: Repeater-Builder@yahoogroups.com Subject: Re: [Repeater-Builder] isolation Eric, Are you sure about your six-cavity recommendation? The MASTR II PLL exciter has 22 dB less side-band noise than a typical multiplier exciter - using 600 kHz TX to RX separation. Assuming

RE: [Repeater-Builder] isolation

To: Repeater-Builder@yahoogroups.com mailto:Repeater-Builder@yahoogroups.com Subject: Re: [Repeater-Builder] isolation Eric, Are you sure about your six-cavity recommendation? The MASTR II PLL exciter has 22 dB less side-band noise

RE: [Repeater-Builder] isolation

K4FMX _ From: Repeater-Builder@yahoogroups.com [mailto:repeater-buil...@yahoogroups.com] On Behalf Of Kevin Custer Sent: Saturday, August 22, 2009 5:38 PM To: Repeater-Builder@yahoogroups.com Subject: Re: [Repeater-Builder] isolation Eric, You may have missed the point. While

RE: [Repeater-Builder] Isolation Curves

Chris, I use a great software package, CommShop for Windows, which includes a program to calculate rough isolation requirements. Such programs can only provide a ballpark figure, because the results can vary a lot due to broadband noise from the PA or the degree of selectivity in the receiver,

Re: [Repeater-Builder] isolation curves

You were probably looking at the link below: http://www.repeater-builder.com/antenna/separation.html Vertically, for 50 dB of isolation is roughly 100' at 40 Mhz per the sheet. Horizontally, it's 800' for 50 dB, 2500' for 60 dB and 8000' for 70 dB of isolation at 50 MHz per the sheet. Classic