...@hotmail.com
Date: Fri, 6 Feb 2009 04:47:11 +
Subject: [Repeater-Builder] Re: Hamtronics Helical Resonator Preamp
or Advanced Research Preamp
--- In
mailto:Repeater-Builder@yahoogroups.comRepeater-Builder@yahoogroups.com,
Joe Burkleo
joeburk...@... wrote:
If for example the site has
a higher
On Feb 4, 2009, at 9:16 PM, Bob Ricci wrote:
My only thought that was as a preselector the Hamtronics might have
something to offer. As I said, the Angle Linear is on the top of the
list, but the piggy bank is getting low. The Decibel Product DB-4002
with a 10dB preamp will do for now.
If
-Builder@yahoogroups.com
Subject: RE: [Repeater-Builder] Re: Hamtronics Helical Resonator Preamp or
Advanced Research Preamp
At 2/5/2009 15:03, you wrote:
With that short of a run I would be more concerned with the repeater being
in the near field of the antenna.
-Kevin
I've read other similar
Ralph S. Turk wrote:
I have never seen or used a Hamtronics preamp. I don't know
anything about their specs or how truthfull they are. Maybe some
one out there in the great bits might have an answer. Skip? Eric? anyone??
I've been using one of their Gaasfet UHF preamps on UHF ham repeaters
n...@no6b.com wrote:
At 2/4/2009 21:19, you wrote:
The Vertex has a .20uV measured and the rest of the specs are just as
good.
You do not need a preamp. The RX might still need an extra pass cavity,
but I'd go ahead try it with just the duplexer if there isn't much RF in
your
[mailto:repeater-buil...@yahoogroups.com] On Behalf Of Barry
Sent: Thursday, February 05, 2009 11:52 PM
To: repeater-builder@yahoogroups.com
Subject: RE: [Repeater-Builder] Re: Hamtronics Helical Resonator Preamp or
Advanced Research Preamp
What he is saying is , a lower gain preamp aplifies less noise
Again, 20 ft. of 7/8 for 2 meters is an unnecessary expense.
20 ft. of
RG-214 has only 0.5 dB of loss @ 146 MHz - quite acceptable for a
first-rate system, and it won't cost you that much even if
you have to buy
it @ retail $$.
Bob NO6B
If your repeater cabinet and the antenna are
I agree. I recently moved a 2 meter repeater to a temporary location
with approx. 25 feet of coax and have problems. I had to move the
repeater cabinet around until I got rid of the desense. A better site
is in the planning, but we need to get rid of some snow first.
73, Joe, K1ike
If your
: RE: [Repeater-Builder] Re: Hamtronics Helical Resonator Preamp or
Advanced Research Preamp
Again, 20 ft. of 7/8 for 2 meters is an unnecessary expense.
20 ft. of
RG-214 has only 0.5 dB of loss @ 146 MHz - quite acceptable for a
first-rate system, and it won't cost you that much even
there, move antenna further away and check again.
Chuck
WB2EDV
- Original Message -
From: Joe k1ike_m...@snet.net
To: Repeater-Builder@yahoogroups.com
Sent: Thursday, February 05, 2009 9:48 AM
Subject: Re: [Repeater-Builder] Re: Hamtronics Helical Resonator Preamp or
Advanced Research Preamp
I
Hi All -- Here is my take on the preamp vs no preamp situation -- and with
Vertex repeaters --
First -- Preamps are not the solution to most of our troubles, in fact it
has been my experience over the years that they are more trouble than they
are helpful
I agree with Skipp and others when it is
With that short of a run I would be more concerned with the repeater being
in the near field of the antenna.
-Kevin
I am blessed with my location and yes, noise can be high. I'll
try without the preamp first and see where I'm at, and the use of the
proper antenna will help. I've spent so much
At 2/5/2009 15:03, you wrote:
With that short of a run I would be more concerned with the repeater being
in the near field of the antenna.
-Kevin
I've read other similar comments. Guess I've been lucky: the last 2 meter
system I set up has the antenna barely 15 ft directly above the
repeater.
What he is saying is , a lower gain preamp aplifies less noise in relation to
the signal so the audio sounds better
To: Repeater-Builder@yahoogroups.com
From: lar...@hotmail.com
Date: Fri, 6 Feb 2009 04:47:11 +
Subject: [Repeater-Builder] Re: Hamtronics Helical Resonator Preamp or Advanced
@yahoogroups.com
From: lar...@hotmail.com
Date: Fri, 6 Feb 2009 04:47:11 +
Subject: [Repeater-Builder] Re: Hamtronics Helical Resonator Preamp or
Advanced Research Preamp
--- In Repeater-Builder@yahoogroups.com, Joe Burkleo
joeburk...@... wrote:
If for example the site has
I expect wiki will answer it better than I but the amps are not linear so do
not increase signals at a flat rate .
To: Repeater-Builder@yahoogroups.com
From: lar...@hotmail.com
Date: Fri, 6 Feb 2009 05:16:17 +
Subject: [Repeater-Builder] Re: Hamtronics Helical Resonator Preamp or Advanced
-07:00 U.S. Mountain Time
(Arizona)
Subject: [Repeater-Builder] Re: Hamtronics Helical Resonator Preamp or Advanced
Research Preamp
The WA-COM 642 duplexer are Bp/Br cavities. The bandwidth is already
limited. Are you saying a 7th cavity adding further loss? And why
limit the gain? I
@yahoogroups.com
Sent: Wednesday, February 4, 2009 7:21:37 PM GMT -07:00 U.S. Mountain Time
(Arizona)
Subject: [Repeater-Builder] Re: Hamtronics Helical Resonator Preamp or Advanced
Research Preamp
I do have another bandpass cavity that has 55dB attenuation. Rather
than use the 24dB preamp I can
At 2/4/2009 14:25, you wrote:
The WA-COM 642 duplexer are Bp/Br cavities. The bandwidth is already
limited.
Only in-band. Out of band they pass almost everything.
Bob NO6B
--- On Wed, 2/4/09, Ralph S. Turk w7...@comcast.net wrote:
From: Ralph S. Turk w7...@comcast.net
Subject: Re: [Repeater-Builder] Re: Hamtronics Helical Resonator Preamp or
Advanced Research Preamp
To: Repeater-Builder@yahoogroups.com
Date: Wednesday, February 4, 2009, 9:11 PM
At 2/4/2009 18:21, you wrote:
I do have another bandpass cavity that has 55dB attenuation. Rather
than use the 24dB preamp I can always use the one with less gain
because I too was concerned with overloading the front-end.
The Hamtronics is a preselector helical resonator preamp, so doesn't
it
Bob Ricci wrote:
Why then a preamp? Just to recover what I can from the LMR-400 and
the cavities.
LMR-400 on a repeater. Yuck. You need to study up on that stuff in
duplex service.
The cable length is so short that hard line isn't
justified.
Oh, but a preamp is justified - because
At 2/4/2009 18:11, you wrote:
Hi Bob
All duplexers have very poor out of band attenuation. The extra cavity is
to narrow the bandwidth.
Cavity should have 2-3db of insertion loss (equates to sharp slopes).
A pass cavity shouldn't be quite that lossy. 0.5 to 1 dB is typical. The
10 diameter
At 2/4/2009 20:16, you wrote:
My thoughts as well :) I know that the Big Bear repeater uses a
Hamtronics and it does well enough but we needed far better quality
and went commercial.
My only thought that was as a preselector the Hamtronics might have
something to offer.
If we're talking about
At 2/4/2009 20:53, you wrote:
Thanks, Bob. I sincerely appreicate your experience and the polite
sharing of it. This is my first repeater and although I have an
experienced mentor, I have things to learn. Experience is often best
learned by doing and not reading. Like LMR-400 in duplex service.
At 2/4/2009 21:19, you wrote:
The Vertex has a .20uV measured and the rest of the specs are just as
good.
You do not need a preamp. The RX might still need an extra pass cavity,
but I'd go ahead try it with just the duplexer if there isn't much RF in
your neighborhood.
I am blessed with my
At 2/4/2009 22:17, you wrote:
Excellent advice, and thank you.
We are experimenting with unity gain, 3dB, 6dB, and 9dB. The results
have been quite interesting. Using three separate radios at the same
location and manual voting we can hear that at one moment unity
gain is better, while at another
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