Re: Simrex - GLB Pre-Selector Verus
You're actually comparing two different boxes.
no6b@ wrote:
Nope - comparing GLB vs. GaAsFET/pass cavity combo
Still not the equivalent box... you're still missing
the post active-device stages.
I don't need them. But I suppose one could add a 2nd
The better skirts are mucho desired.
n...@... wrote:
As you so often like to state, it all depends on the
application - in many cases it simply isn't necessary.
And in many cases it's beneficial to have better skirts...
But there are other solutions: if you want a brute-force
window
At 8/1/2010 01:15, you wrote:
But there are other solutions: if you want a brute-force
window filter they're out there too. I have a few 5 MHz
wide 1 dB loss UHF filters sitting on the shelf here that
I acquired at the Dayton Ft. Tuthill hamfests. ~$40 each.
Seems like a good deal...
Re: Simrex - GLB Pre-Selector Pre-Amplifier
n...@... wrote:
Then we're back to the pass cavity solution. Just
saying there are other inexpensive, well-engineered
options out there.
Sure, the pass cavity is one of many possible options.
The VHF HB MVP front-end helical assembly has a
It looks like Skipp and I have found that the GLB preselector has been
successful at helping less then ideal repeaters work better. I can
think of two examples that I have had.
I had a Midland 13-509 repeater back in the late 80's on 223.72MHz. It
used a set of homebrew copper pipe
At 7/30/2010 08:31, you wrote:
Re: Simrex - GLB Pre-Selector Pre-Amplifier
Yes, but the NF is unpublished unknown. I therefore
assume it's poor, maybe 3 dB?
Once again, the NF depends on what device arrives in your
specific Simrex (aka GLB) Pre-Selector. It wouldn't hurt
or be impossible
Hello Bob,
I agree that the GLB is a space saving device, but don't you think that
the multistage helical coil stages in the preselector with beat a single
cavity in skirts and out-of-band rejection?
Joe
On 7/31/2010 9:30 AM, n...@no6b.com wrote:
A 1/4 wave bottle
will provide much more
Bob,
Some of us are geographically disadvantaged when it comes to availability of
equipment. Here in rural Australia, anything secondhand for Amateur Repeater
construction is rare, shipping of anything is expensive. From what I read on
the group, the U.S. Is overloaded with surplus equipment,
Joe wrote:
Hello Bob,
I agree that the GLB is a space saving device, but don't you think that
the multistage helical coil stages in the preselector with beat a single
cavity in skirts and out-of-band rejection?
Curves for the GLB are available here:
Re: Simrex - GLB Pre-Selector Pre-Amplifier
Jack Chomley ra...@... wrote:
Well, I have decided to buy and try a Simrex
Pre-Selector,experiment with it, test it
...whatever.
Something to never say in an airport...
Hi Jack,
Hopefully you will find the Simrex / GLB Pre-selector
That is the system on my uhf repeater. It's sensitivity is unmatched with this
setup. I'm using one moto t1500 can before my arr gasfet preamp in a nema
enclosure at 100 feet on the tower. The 9db rx only antenna sits 15 feet above
that at 110 with the TX antenna 50 feet below at about 60 feet.
Re: Simrex - GLB Pre-Selector Verus
You're actually comparing two different boxes.
n...@... wrote:
Nope - comparing GLB vs. GaAsFET/pass cavity combo
Still not the equivalent box... you're still missing
the post active-device stages.
I have measured all the original GLB
Re: Simrex - GLB Pre-Selector Pre-Amplifier
Kevin Custer kug...@... wrote:
While the skirts and OBR of the GLB might beat a
single cavity, many times it isn't necessary -
The better skirts are mucho desired.
especially if the receiver that follows is
able to cope with high out of
At 7/31/2010 06:58, you wrote:
Hello Bob,
I agree that the GLB is a space saving device, but don't you think that
the multistage helical coil stages in the preselector with beat a single
cavity in skirts and out-of-band rejection?
No. There is a compromise in that although the out of band
Kevin wrote:
The problem is, like any receiver that has several
helicals in cascade before the first active stage,
the loss that precedes the active stage has a majority
role in the overall NF of the system that follows. It
matters little what the quality of the active stage is,
At 7/31/2010 07:04, you wrote:
Bob,
Some of us are geographically disadvantaged when it comes to availability
of equipment. Here in rural Australia, anything secondhand for Amateur
Repeater construction is rare, shipping of anything is expensive. From
what I read on the group, the U.S. Is
At 7/31/2010 10:02, you wrote:
Re: Simrex - GLB Pre-Selector Verus
You're actually comparing two different boxes.
n...@... wrote:
Nope - comparing GLB vs. GaAsFET/pass cavity combo
Still not the equivalent box... you're still missing
the post active-device stages.
I don't need them.
At 7/31/2010 11:28, you wrote:
Re: Simrex - GLB Pre-Selector Pre-Amplifier
Kevin Custer kug...@... wrote:
While the skirts and OBR of the GLB might beat a
single cavity, many times it isn't necessary -
The better skirts are mucho desired.
As you so often like to state, it all depends on
Bob,
Thanks for info and links:-) I see where you are coming from.. For me,
repeaters are a new deal and I am as dumb as a box of rocks, on the
subject..that's why I subscribed to the group.
My first repeater project is a portable system, so I have to make it compact
for commissioning
Re: Simrex - GLB Pre-Selector Pre-Amplifier
Yes, but the NF is unpublished unknown. I therefore
assume it's poor, maybe 3 dB?
Once again, the NF depends on what device arrives in your
specific Simrex (aka GLB) Pre-Selector. It wouldn't hurt
or be impossible to ask.
A Chip Angle
skipp025 wrote:
The less gain is related to the internal filtering stages,
not the device. I would expect the version with the GasFet
to have the typical expected NF for that device. Any other
available active devices to have Noise Figures commensurate
with their typical expected values
Well, I have decided to buy and try a Simrex Pre-Selector,experiment with it,
test it...whatever. At the very least I will learn something from my
experiences and it may end up being useful to me, anyway.
I certainly appreciate the different points of view here and have learn't of
Friday, July 30th 2010 - Duly noted on my calendar! LOL
- Original Message -
From: skipp025
To: Repeater-Builder@yahoogroups.com
Sent: Friday, July 30, 2010 6:53 PM
Subject: [Repeater-Builder] Re: Simrex - GLB Pre-Selector Pre-Amplifier
Re: Simrex - GLB Pre
Re: Simrex - GLB Pre-Selector Pre-Amplifier
The Simrex (aka GLB) units are actually amplified pre-selector
assemblies, not just plain wide-band Receive Pre-Amplifiers.
There's a reason why these units offer/spec 8dB Gain versus
the others un-protected preamps. The less obvious gain
when
At 7/29/2010 14:59, you wrote:
Re: Simrex - GLB Pre-Selector Pre-Amplifier
The Simrex (aka GLB) units are actually amplified pre-selector
assemblies, not just plain wide-band Receive Pre-Amplifiers.
There's a reason why these units offer/spec 8dB Gain versus
the others un-protected preamps. The
On Jul 30, 2010, at 9:31 AM, n...@no6b.com wrote:
At 7/29/2010 14:59, you wrote:
Re: Simrex - GLB Pre-Selector Pre-Amplifier
The Simrex (aka GLB) units are actually amplified pre-selector
assemblies, not just plain wide-band Receive Pre-Amplifiers.
There's a reason why these units
At 7/29/2010 16:52, you wrote:
Yes, but the NF is unpublished unknown. I therefore assume it's poor,
maybe 3 dB?
A Chip Angle GaAsFET @ UHF has 0.5 dB NF. Put a 1/4 wave pass cavity with
0.5 dB loops in front of it you have a narrow 1 dB NF front-end. I'll
take 1 dB NF over 3 dB NF any day.
27 matches
Mail list logo
