At 10/24/2007 19:46, you wrote:
>145.25 can be a real pain. We have a repeater on that frequency. It is CATV
>channel E. We always have leaks from the cable rendering the repeater
>useless in some areas until a call is made to the CATV plant. They go out
>and tighten the screws on an amplifier (le
At 10/24/2007 10:08, you wrote:
>At 10:10 AM 10/23/2007, you wrote:
>
> >No, it's not linear. First off, it doesn't satisfy the superposition
> >principle since it will produce harmonic when fed by a pure sinusoid carrier
> >(hopefully we can agree to that without added discussion), so right off t
> You have to read carefully -- I said "capable" of gain. Not
> "designed into the circuit in such a way that they EXHIBIT gain".
Thank you.
I can tune an otherwise-functional transmitter such that it takes in several
kW of DC power and gives me practically zero RF output. That doesn't make
the
We had a 1500 watt 70 MHz circulator go bad. I disassembled it to see what
failed. IIRC there were 9 capacitors and at least 3 inductors along with
the ferrite ant tuning magnets. Really makes a TV transmitter quit when the
circulator between driver and final fails. Quite a site to see the
capa
> Again, the circulator will produce intermod when external strong
> signals enter the antenna port when used as a switch for the duplexer
> and there is transmitter power also going through it. 50 Watts or
> 47dBm to -116dBm receiver sensitivity is 163dBm dynamic range. The
> device is not linear
145.25 can be a real pain. We have a repeater on that frequency. It is CATV
channel E. We always have leaks from the cable rendering the repeater
useless in some areas until a call is made to the CATV plant. They go out
and tighten the screws on an amplifier (left loose by the last tech working
Nate,
Ok,
73, ron, n9ee/r
From: Nate Duehr <[EMAIL PROTECTED]>
>Date: 2007/10/24 Wed AM 10:25:31 CDT
>To: Repeater-Builder@yahoogroups.com
>Subject: Re: [Repeater-Builder] Re: duplexer isolation and reciever noise
>
>
>On Oct 24, 2007, at 5:56 AM, R
Ron Wright wrote:
> Also if packet on VHF and repeater on UHF a simple crossband coupler
> and dual-band antenna will simplify things.
>
> 73, ron, n9ee/r
Yes-greatly!
--
Jim Barbour
WD8CHL
_
From: Repeater-Builder@yahoogroups.com
[mailto:[EMAIL PROTECTED] On Behalf Of Ken Arck
Sent: Wednesday, October 24, 2007 12:04 PM
To: Repeater-Builder@yahoogroups.com
Subject: RE: [Repeater-Builder] Re: duplexer isolation and reciever noise
budget
At 09:51 AM 10/24/2007, you wrote:
>OK,
Replace the duplexers antenna tee with a circulator. Tune the
circulator as follows: Port A to B to pass TX frequency, port B to C
to pass RX frequency. Port A to Port C isolation should be in the 20dB
range or better and it still protects the transmitter and helps with
mixing. RF from the antenna
At 10:10 AM 10/23/2007, you wrote:
I thought it was linear unless it becomes saturated. Circulators are
ferrite devices and as long as the ferrite core isn't saturated, it
remains linear.
At 10:10 AM 10/23/2007, you wrote:
>No, it's not linear. First off, it doesn't satisfy the superposition
>principle since it will produce harmonic when fed by a pure sinusoid carrier
>(hopefully we can agree to that without added discussion), so right off the
>bat it's nonlinear. Furthermore, it'
At 09:51 AM 10/24/2007, you wrote:
>OK, I have to comment,
>
>An isolator/circulator should not be used in a duplexer at the
>antenna connector when there are other strong signals floating
>around the air that can get into the isolator.
<---Uh...a couple of things here:
1) Did I miss somet
the cans on one side if possible, but it is
> looking more and more like it will not be, so I'm willing to give up
some
> space in the power electronics bay to make space for more cans.
>
>
>
> _
>
> From: Repeater-Builder@yahoogroups.com
> [mailto:[EMAIL PROTE
On Oct 24, 2007, at 5:56 AM, Ron Wright wrote:
> An active element does not have to have gain. I have designed op-
> amp circuits which had no voltage, current or power gain and these
> are most certainly active elements. The last I designed was to
> covert the roll of a B52 aircraft from
, ron, n9ee/r
>From: Jim <[EMAIL PROTECTED]>
>Date: 2007/10/24 Wed AM 09:17:56 CDT
>To: Repeater-Builder@yahoogroups.com
>Subject: Re: [Repeater-Builder] Re: duplexer isolation and reciever noise
>budget
>
>
>>> OK - Here are my requirem
>> OK - Here are my requirements for the transmit chain. minimal
>> physical space and minimal insertion loss :-) (ok - too
>> bloody obvious) Tuning simplicity is also a factor. I'm
>> combining 3 transmitters at 144.39, 145.05 +/- 0.04 and 145.25
>> Can you list out some of the other options
e devices still.
73, ron, n9ee/r
>From: Nate Duehr <[EMAIL PROTECTED]>
>Date: 2007/10/24 Wed AM 01:24:20 CDT
>To: Repeater-Builder@yahoogroups.com
>Subject: Re: [Repeater-Builder] Re: duplexer isolation and reciever noise
>
>
>On Oct 23, 2007, at 12:4
On Oct 24, 2007, at 12:37 AM, John Barrett wrote:
> Re splitting the simplex: a circulator with the radio hooked to the
> input, the transmit chain on the standard output, and the receive
> chain feeding the load port is what I was thinking – a relay would
> do the job just as well, but would
L PROTECTED] On Behalf Of Nate Duehr
Sent: Tuesday, October 23, 2007 7:52 PM
To: Repeater-Builder@yahoogroups.com
Subject: Re: [Repeater-Builder] Re: duplexer isolation and reciever noise
bud
John Barrett wrote:
> Re: selectivity and rejection: I'm looking at the Icom V-8000, which
> spec
: Repeater-Builder@yahoogroups.com
[mailto:[EMAIL PROTECTED] On Behalf Of Jeff DePolo
Sent: Tuesday, October 23, 2007 6:43 PM
To: Repeater-Builder@yahoogroups.com
Subject: RE: RE: RE: [Repeater-Builder] Re: duplexer isolation and reciever
noise budget
> If I do two antennas, the best I can do
On Oct 23, 2007, at 12:42 PM, Jeff DePolo wrote:
>> Jeff,
>>
>> A diode is most certainly an active device. Its properities
>> change with exciting voltage and follow many parameters just
>> as a transistor.
>
> A diode is NOT an active device. It's properties changing with
> applied
> voltage
means a coordinated
pair is impossible to get, and since I'm portable, I'd be a lot happier on a
backyard pair.
-Original Message-
From: Repeater-Builder@yahoogroups.com
[mailto:[EMAIL PROTECTED] On Behalf Of Nate Duehr
Sent: Tuesday, October 23, 2007 7:52 PM
To: Repeater-Builder@yaho
On Oct 23, 2007, at 9:06 PM, Kris Kirby wrote:
> On Tue, 23 Oct 2007, Nate Duehr wrote:
>> Your idea has sucked me in SLIGHTLY, however... you do know you could
>> get a FOUR port isolator, right? (Ha... that's bound to give you
>> some
>> REALLY wild ideas.) Look for "dual-stage" isolators.
On Oct 23, 2007, at 9:01 PM, [EMAIL PROTECTED] wrote:
> You're confusing "active" with "nonlinear". They are not equivalent
> terms. A diode is passive & nonlinear, while a class A amplifier
> is active
> & (hopefully) linear.
Of course...
Your Class-A amp that was designed to be linear, if
On Tue, 23 Oct 2007, Nate Duehr wrote:
> Your idea has sucked me in SLIGHTLY, however... you do know you could
> get a FOUR port isolator, right? (Ha... that's bound to give you some
> REALLY wild ideas.) Look for "dual-stage" isolators.
Four-ports are over-rated. I'm putting all my money on f
At 10/23/2007 10:59, you wrote:
>Jeff,
>
>A diode is most certainly an active device. Its properities change with
>exciting voltage and follow many parameters just as a transistor. And
>there are many ways to make a diode.
You're confusing "active" with "nonlinear". They are not equivalent
te
John Barrett wrote:
> Re: selectivity and rejection: I’m looking at the Icom V-8000, which
> specs 75db for all of spurious/image/rejection. I have no data on
> dynamic range or 3^rd order intercept. (haven’t seen data like that on
> any of the radios I’ve been considering for this system)
>
>
> If I do two antennas, the best I can do is about 30db
> isolation (30ft separation, 6db multi-bay folded dipole
> antenna on bottom, 9db 2m/440 base station antenna on top),
If you can get 30 feet of separation, you'll get more than 30 dB of
isolation. More like 50 dB on VHF, 60 dB or more o
der@yahoogroups.com
Subject: RE: RE: RE: [Repeater-Builder] Re: duplexer isolation and reciever
noise budget
> OK - Here are my requirements for the transmit chain. minimal
> physical space and minimal insertion loss :-) (ok - too
> bloody obvious) Tuning simplicity is also a factor.
> OK - Here are my requirements for the transmit chain. minimal
> physical space and minimal insertion loss :-) (ok - too
> bloody obvious) Tuning simplicity is also a factor. I'm
> combining 3 transmitters at 144.39, 145.05 +/- 0.04 and 145.25
Before we get to what hardware to use, we still ne
- Original Message -
From: John Barrett <mailto:[EMAIL PROTECTED]>
To: Repeater-Builder@ <mailto:Repeater-Builder@yahoogroups.com> yahoogroups.com
Sent: Tuesday, October 23, 2007 11:39 AM
Subject: RE: RE: RE: RE: [Repeater-Builder] Re: duplexer isolation and reciever
noise
: John Barrett
To: Repeater-Builder@yahoogroups.com
Sent: Tuesday, October 23, 2007 11:39 AM
Subject: RE: RE: RE: RE: [Repeater-Builder] Re: duplexer isolation and
reciever noise bud
I’m trying to understand your figures, and I got lost some place.
From the transmitters… I’m max 50w
> Jeff,
>
> A diode is most certainly an active device. Its properities
> change with exciting voltage and follow many parameters just
> as a transistor.
A diode is NOT an active device. It's properties changing with applied
voltage do not define whether or not it's active. Whether or not it
onto my trailer ??
_
From: Repeater-Builder@yahoogroups.com
[mailto:[EMAIL PROTECTED] On Behalf Of Jeff DePolo
Sent: Monday, October 22, 2007 9:41 PM
To: Repeater-Builder@yahoogroups.com
Subject: RE: RE: RE: [Repeater-Builder] Re: duplexer isolation and reciever
noise budget
> Commer
/r
>From: Jeff DePolo <[EMAIL PROTECTED]>
>Date: 2007/10/23 Tue PM 12:10:33 CDT
>To: Repeater-Builder@yahoogroups.com
>Subject: RE: RE: RE: RE: [Repeater-Builder] Re: duplexer isolation and
>reciever noise bud
>
>> An isolator is linear except w
s :-)
_
From: Repeater-Builder@yahoogroups.com
[mailto:[EMAIL PROTECTED] On Behalf Of Jeff DePolo
Sent: Tuesday, October 23, 2007 12:05 PM
To: Repeater-Builder@yahoogroups.com
Subject: RE: RE: RE: RE: [Repeater-Builder] Re: duplexer isolation and
reciever noise bud
> Total isolati
> Not sure why isolator cause harmonics for it has no
> non-linear components. It might cause tx to generate
> harmonics. Isolators are on the output of many repeater
> transmitters including my UHF Micor and it is built to work
> directly into an antenna although most applications use a
> dup
> An isolator is linear except with frequency just as a cap or
> inductor or feedline are.
No, it's not linear. First off, it doesn't satisfy the superposition
principle since it will produce harmonic when fed by a pure sinusoid carrier
(hopefully we can agree to that without added discussion),
> Total isolation = 97 to 127db (as good or better than most
> stock duplexer setups)
That's for carrier attenuation only. Aside from the passive losses in the
system, you've done nothing to attenuate transmitter noise, which is going
to be a bigger enemy in your close-spaced frequency assignmen
use ??
_
From: Repeater-Builder@yahoogroups.com [mailto:[EMAIL PROTECTED] On Behalf Of
Ron Wright
Sent: Tuesday, October 23, 2007 6:31 AM
To: Repeater-Builder@yahoogroups.com
Subject: Re: RE: RE: RE: [Repeater-Builder] Re: duplexer isolation and reciever
noise bud
There will
-9460
[EMAIL PROTECTED]
-Original Message-
From: Repeater-Builder@yahoogroups.com
[mailto:[EMAIL PROTECTED] On Behalf Of John Barrett
Sent: Monday, October 22, 2007 7:47 PM
To: Repeater-Builder@yahoogroups.com
Subject: RE: RE: RE: [Repeater-Builder] Re: duplexer isolation and reciever
noise b
smoke (another
discussion).
73, ron, n9ee/r
>From: Jeff DePolo <[EMAIL PROTECTED]>
>Date: 2007/10/22 Mon PM 09:11:21 CDT
>To: Repeater-Builder@yahoogroups.com
>Subject: RE: RE: RE: [Repeater-Builder] Re: duplexer isolation and reciever
>noise budget
>
0:47 CDT
>To: Repeater-Builder@yahoogroups.com
>Subject: RE: RE: RE: [Repeater-Builder] Re: duplexer isolation and reciever
>noise budget
>
>The danger I see with this is when your antenna goes bad (and they all do
>eventually), your receiver will be hit with the
: Repeater-Builder@yahoogroups.com
[mailto:[EMAIL PROTECTED] On Behalf Of John Barrett
Sent: Monday, October 22, 2007 7:47 PM
To: Repeater-Builder@yahoogroups.com
Subject: RE: RE: RE: [Repeater-Builder] Re: duplexer isolation and reciever
noise budget
An isolator wont cause intermod, but it may
On Oct 22, 2007, at 7:19 PM, Ron Wright wrote:
> I am not sure why an isolator would cause intermod.
The fact that they create harmonics unless filtering is done
"downstream" of the output port going toward the antenna, means that
the opportunities for external mixing are increased greatly b
At 07:41 PM 10/22/07, you wrote:
> > I'm proposing a novel application of the circulator (an
> > isolator without the dummy load on one port)..
>
>Yes, I know what you're trying to do, and it's nothing new. UHF Micor
>mobiles have an isolator in the antenna network that routes received RF
>throug
> An isolator wont cause intermod, but it may cause harmonics.
How so? What phenomenon occurs in a ferrite circulator that creates
harmonics but won't generate IMD?
> Commercial installations usually use either a harmonic filter
> and 3db hybrid coupler, or a special type of band pass cavity
> I am not sure why an isolator would cause intermod. Usually
> there are not active or non-linear components in them
An isolator IS a non-linear device.
> and
> they are often used to prevent intermod by preventing outside
> signals from coming in thru the feedline into the transmitter.
As
lder@yahoogroups.com
Subject: Re: RE: RE: [Repeater-Builder] Re: duplexer isolation and reciever
noise budget
I am not sure why an isolator would cause intermod. Usually there are not
active or non-linear components in them and they are often used to prevent
intermod by preventing outside signals f
peater-Builder] Re: duplexer isolation and reciever noise
>budget
>
>> This isn't guessing - its called RESEARCH
>
>When I said guessing, I was talking about quantifying the performance of
>your radios rather than guessing how much isolation you need. In
> This isn't guessing - its called RESEARCH
When I said guessing, I was talking about quantifying the performance of
your radios rather than guessing how much isolation you need. In other
words, make measurements to actually determine how much noise supression and
carrier attenuation you need usi
g - its called RESEARCH
_
From: Repeater-Builder@yahoogroups.com
[mailto:[EMAIL PROTECTED] On Behalf Of Jeff DePolo
Sent: Monday, October 22, 2007 3:11 PM
To: Repeater-Builder@yahoogroups.com
Subject: RE: RE: [Repeater-Builder] Re: duplexer isolation and reciever
noise budget
> Trans
> Transmit and receive paths will be separate with 30db of
> isolation (either split antennas, or a 30db isolation
> circulator just before the feed to the antenna)
I posted a followup to one of your previous messages regarding using
isolators as a makeshift way of getting more Tx to Rx isolatio
Time to reopen this subject just a little !!
I'm currently looking at Icom V-8000 radios for the simplex and repeater
radios (0.15uV sensitivity (-123dbm) and 75db spurious/image rejection)
The most any transmitter in the system will ever be running is 50 watts
(+47dbm)
Transmit and rec
I don't have a coordinated pair at this time, and someone on my local
repeater mentioned something about
uncoordinated/unprotected/test/"community" pairs in 144 and 440 bands.. so
if you know what they are, that's probably where this repeater will live
until I get coordinated (if I get coordinated
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