...@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
I expect that two voted receivers is part of the solution. I have
decided to either track down the commercial tower owner up the street
whose tower is not registered with the FCC and put the repeater there,
or move the antenna to the other side of the house and push it up 60
feet. In this case
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 Ralph,
Ralph w7...@... wrote:
I have never seen or used a Hamtronics preamp. I don't
know anything about their specs or how truthful they
are. Maybe some one out there in the great bits might
have an answer. Skipp? Eric? anyone??
I'll answer up to the anyone label...
Through the
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
--- In Repeater-Builder@yahoogroups.com, Joe Burkleo
joeburk...@... wrote:
If for example the site has
a higher than normal noise floor a lower gain preamp will often times
amplify more of the signal and less of the extra site noise, where a
higher gain preamp may amplify both the noise and
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
--- In Repeater-Builder@yahoogroups.com, Bob Ricci b...@... wrote:
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 one of the other antennas is better.
Bob, are/were you using three radios connected
Maybe a bit of both. The antennas are side by side. I am more than
familiar with diversity from my audio engineering days. I'll put the
antennas on a switch and try this and that. I suspect that a 6dB gain
antenna will yield the best all around performance. But then again
maybe just a 3dB
--- In Repeater-Builder@yahoogroups.com, Barry ate...@... wrote:
What he is saying is , a lower gain preamp aplifies less noise in
relation to the signal so the audio sounds better
Not trying to be superpicky here, but this is something I need to
understand better... Why, and how, would
@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
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 remain teachable.
Those that don't know, ask...
--- In Repeater-Builder@yahoogroups.com, Ralph S. Turk w7...@...
wrote:
You would still
-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
of the front end of the RX.
Ralph
- Original Message -
From: Bob Ricci b...@...
To: Repeater-Builder@yahoogroups.com
Sent: Wednesday, February 4, 2009 3:25:14 PM GMT -07:00 U.S.
Mountain Time (Arizona)
Subject: [Repeater-Builder] Re: Hamtronics Helical Resonator Preamp
or Advanced
@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
Bob,
Which preamp you use to work properly in your situation depends on
several details.
We need a lot more information from you to make any firm
recommendations. There are cases where a lower gain preamp will
actually produce more measurable results. If for example the site has
a higher than
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
Thanks for asking for details so that you may provide a better answer.
First, the site is currently my home at 6300 feet over-looking all of
southern California but is not a repeater site. There is a commercial
site up the street and one two doors down, but neither currently
affects me in the
--- 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
An Angle Linear is on the list, but out of the budget at the moment.
--- In Repeater-Builder@yahoogroups.com, n...@... wrote:
At 2/4/2009 13:08, you wrote:
Hamtronics has a preamp with a helical resonator with a 18dB
preamp. I
am at a high elevation with noise all around me. Advanced
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
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. As I said, the Angle Linear is on the top of the
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
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.
Some say yes; others say no.
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
The Vertex has a .20uV measured and the rest of the specs are just as
good. 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 alreqady that a few more
buckis for 7/8
Bob,
I think I have to agree with Kevin on this one.
Do yourself a big favor and invest in a piece of heliax, before you
spend money on a preamp. It is a much better investment.
I use heliax, even if the run to the antenna is only 20'.
I also use 1/4 superflex for cabling between the duplexer
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 one of the other antennas
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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