At 3/10/2010 02:42, you wrote:
>On Mar 9, 2010, at 8:37 PM, n...@no6b.com wrote:
>
> > t most certainly does. Try random length cables from the cavities to the
> > T instead of 1/4 wavelength (like one local did several years ago) & watch
> > your sensitivity drop by over 20 dB if you're unlucky (
At 3/10/2010 11:16, you wrote:
>Actually, Gary, you are 180 degrees out. On a pass cavity, off frequency
>signals see a very high impedence path, an open not a short. If your
>version were true you could never use pass cans as a duplexer since both
>sets of cans together would show a "short" t
> When I say the notch presents a "short" it is not really a
> short but a very low impedance of say a few ohms. But by
> having the unwanted source impedance high rather than at 50
> ohms it is much easier to pull the high impedance down with
> the "few ohms" short circuit than it would be if
Well yes the T is sort of a magical device that makes the OTHER SIDE of the
T disappear electrically. Actually it is not the T itself that does the job
(that is just where IT happens) but it is the quarter wave length cables
that perform the magic!
Without the quarter wave length cables betwe
Good point. Yes loop length needs to be considered. Usually the velocity
factor of the loop is that of air so it needs to be calculated seperatly
from the cable and added.
Probably easiest to ask the cavity manufacturer.
73
Gary K4FMX
> -Original Message-
> From: Repeater-Builder@yahoo
to
high vswr.
73
Gary K4FMX
> -Original Message-
> From: Repeater-Builder@yahoogroups.com [mailto:Repeater-
> buil...@yahoogroups.com] On Behalf Of Nate Duehr
> Sent: Wednesday, March 10, 2010 5:42 AM
> To: Repeater-Builder@yahoogroups.com
> Subject: Re: [Repeater-Builder] Re:
On Mar 9, 2010, at 8:37 PM, n...@no6b.com wrote:
> t most certainly does. Try random length cables from the cavities to the
> T instead of 1/4 wavelength (like one local did several years ago) & watch
> your sensitivity drop by over 20 dB if you're unlucky (as he was). That
> mistake literally
Ross Johnson wrote:
> Thanks for the reply’s everyone. That cleared it up for sure. I will go
> ahead and build the T to cavity cables to one electrical wave length for
> the other band. And is that ¼ wave plus velocity factor of cable? Which
> will be FSJ1.
Actually, it's 1/4-wave times the velo
Thanks for the replys everyone. That cleared it up for sure. I will go
ahead and build the T to cavity cables to one electrical wave length for
the other band. And is that ¼ wave plus velocity factor of cable? Which
will be FSJ1.
Here is some more detail on the system. It will go in stages. The
At 3/9/2010 16:29, you wrote:
> > Here's the idea. This is a remote RX site. The idea is
> > to run something like a beefed up X500 dualbander at tower
> > top, then 7/8 hardline 100 feet down to the receivers.
> > Both receivers will have one or two bandpass cavities
> > inline before the T. Woul
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