Subject: Re: [Repeater-Builder] Quantar Simulcast Issue
Well if the transmitters are running at the same frequency but at a
different phase it is reasonable to expect that there would be some
point where the 2 transmitters are at close to the same power level,
but 180 degrees out of phase
Jeff DePolo wrote:
To get the RF phase accuracy you're implying that is required would mean
that everything in the RF path would have to guarantee that phase
relationship. That means the same length RF interconnect cables inside the
cabinet, same RF feedline length (or full-wavelength
Thanks Kevin, Now I know the reason for the offset.
tom
On 6/24/2010 4:58 PM, Kevin Custer wrote:
Jeff DePolo wrote:
To get the RF phase accuracy you're implying that is required would mean
that everything in the RF path would have to guarantee that phase
relationship. That means the
Are the cables coming from the GPS reference are the same length at both sites?
Also if these are VHF it could be that the reference frequency
(channel spacing) is 5 kHz, if that is the case a harmonic of a paging
tone might get past the audio pass band filtering 300 - 3000 Hz
typically and is
Are the cables coming from the GPS reference are the same
length at both sites?
Maybe I'm missing something here, but how the heck would the length of the
cable from the reference oscillator to the transmitter/exciter matter? It's
just the frequency reference (10 MHz or whatever) for the
Propagation delay in the coax.
Get a dual trace oscilloscope and feed it with a 10 MHz GPS, off of a
Tee and into 2 different lengths of coax.
I could see the DC offset thing if the audio was coupled with a 1uF
cap at one site and a 0.1uF at the other.
Maybe I'm missing something here, but how
wmhpowell wrote:
I'm looking for some Quantar engineering level help re: an
interesting simulcast issue.
I live in an area where I can hear several of high band our simulcast
Quantars. The whole thing was installed and set up by Motorola
including GPS stabilized time bases.
I'm monitoring
DCFluX wrote:
Are the cables coming from the GPS reference are the same length at both
sites?
This wouldn't matter at all. For frequency, it has no effect, and if the
GPS 1pps is being used for audio phase this would just offset the phase
as though the transmitter itself were moved by the
Propagation delay in the coax.
Propagation delay doesn't affect anything on the reference output side of
the GPSDO. The phase of the reference oscillator can vary -- the
synthesizer doesn't care about the phase of the reference oscillator, only
the frequency. Likewise, the VCO output isn't
Well if the transmitters are running at the same frequency but at a
different phase it is reasonable to expect that there would be some
point where the 2 transmitters are at close to the same power level,
but 180 degrees out of phase which should cancel out the receiver or
at least make
DCFluX wrote:
Well if the transmitters are running at the same frequency but at a
different phase it is reasonable to expect that there would be some
point where the 2 transmitters are at close to the same power level,
but 180 degrees out of phase which should cancel out the receiver or
at
11 matches
Mail list logo
