It looks like I am able to post here again. Don't know what happened.
This subject was examined a little about a month ago. You can search for my
comments back then but I will state again similar to what I said then.
Some transmitters do not like to see any reactive load on them. They will
cut ba
You are full quieting.
Chuck
WB2EDV
- Original Message -
From: "Gary Schafer" <[EMAIL PROTECTED]>
To:
Sent: Saturday, June 30, 2007 8:23 PM
Subject: [Repeater-Builder] test
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> Yahoo! Groups Links
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I was thinking the same thing. I was wondering how the connection at the
transmitter looked. My bet would be that this is where the real problem is.
Chuck
WB2EDV
- Original Message -
From: "Jeff DePolo" <[EMAIL PROTECTED]>
To:
Sent: Saturday, June 30, 2007 6:22 PM
Subject: RE: [Repeat
> Can't argue with your analysis. My only point is that if you
> are intent on dealing with a
> TX to duplexer mismatch, a half wave cable replicates what
> ever mismatch exists. A
> random length cable can mask the real world condition by
> making the apparent mismatch
> better or worse than i
Skip: Most of this is pure speculation on my part. Lunar electronics was
run by WB6NMT Louis Anciaux when he was in Calif. I always heard he was in
the military and Lunar was a side business that he closed when he
transferred elsewhere. My speculation is that Louis and Chip had a deal
where Chip
Can't argue with your analysis. My only point is that if you are intent on
dealing with a
TX to duplexer mismatch, a half wave cable replicates what ever mismatch
exists. A
random length cable can mask the real world condition by making the apparent
mismatch
better or worse than it really
> Jeff
>
> You make some excellent points. Thanks!
>
> Bruce K7IJ
Yer welcome, and thank you for bringing up some issues for discussion that
frequently get confused by even many seasoned techs.
--- Jeff
This may be helpful:
http://www.txrx.com/products/pdf/Duplexer_Problems_and_Remedies.pdf
Chuck
WB2EDV
- Original Message -
From: "Steve S. Bosshard (NU5D)" <[EMAIL PROTECTED]>
To:
Sent: Saturday, June 30, 2007 3:45 PM
Subject: [Repeater-Builder] The real secret cable formula at the
> I don't think I ever suggested otherwise. I never said that
> using a half wave cable would improve
> anything. What I did say was that a half wave cable would
> repeat the prevailing condition neither
> making it better or worse and I further said that using any
> variation from a half wave c
http://www.antennex.com/preview/vswr.htm
--
Ham Radio Spoken Here !!!
EM11ma - South Mountain, Texas
begin:vcard
fn:Steve Bosshard
n:Bosshard;Steve
adr:;;503 B. South 25th. Street;Temple;Texas;76504;USA
email;internet:[EMAIL PROTECTED]
tel;work:254-773-1102
tel;fax:254-773-1174
tel;home:254-770
Jeff
You make some excellent points. Thanks!
Bruce K7IJ
** See what's free at http://www.aol.com.
I don't think I ever suggested otherwise. I never said that using a half
wave cable would improve
anything. What I did say was that a half wave cable would repeat the
prevailing condition neither
making it better or worse and I further said that using any variation from a
half wave cable co
Do you recall if the leakage you observed was on channel or whether it was
broadband noise?
In a message dated 6/30/2007 3:53:42 A.M. Pacific Daylight Time,
[EMAIL PROTECTED] writes:
The cable leakage stopped when the z matcher was removed and the cable
length was altered for optimum
Line stretchers/shrinkers were also built by Kings Connectors (I have five
of them) but I don't see them in their catalog any longer. They modified a
female N barrel to mate with the shoulder of a male UG-21 that permits the
barrel to thread in and out of the UG-21, effectively varying the
>
> While the receive-side jumper may work well at any random
> jumper length, the
> transmit-side jumper is a different matter.
My experience has been just the opposite. Unless you sweep-tune a receiver
front end that uses helical resonators, the chance of having a Z even
remotely close to 5
> OK so you have a reel of cable and two connectors to make up
> the jumper between transmitter and duplexer.
>
> The duplexer is tuned using 50 ohm test gear and the
> transmitter has been optimised into a 50 ohm load.
>
> Unfortunatley the output impedance of the transmitter is not
> 50 oh
> I don't think the cable cares whether the source and load
> impedances are 50 ohms
> resistive. I think the cable is indifferent to whether the
> load and source values are
> resistive or whether they present a complex impedance
> involving +/- J. as long as the
> composite value looks like
I whole heartedly agree, Glenn, but with one say 100 Watt pa feeding a
cavity duplexer, there is no phase delay issue, just a minor mis-match, that
I doubt would ever be seen or heard outside the transmitter shack. The
advice I was given on duplexers is once they are tuned properly, leave them
al
WE also use a line stretcher in TV. When you have two UHF PAs that are fed
to a combiner, it is very important that the phasing of the signals be
correct. We use a line stretcher in the output of the exciter to the
closest PA to effectively place the PAs at the same electrical distance
from the
> However, the load impedance of most PAs
> will vary
> significantly with the drive level,
I think you meant source impedance.
> and the input impedance
> of a duplexer
> cavity is always reactive
Not necessarily. You can tune a duplexer very close to 50+j0 at the pass
frequency. It's a
OK,
There was a long and detailed thread about z matchers on this group abou a year
ago?
Lots of interesting stuff about line matching emerged.. dont take my word for
it have a look in the archives...
I can only describe what I measure and that is cable leakage from a jumper
between the transmi
Ian, I owe you an apology for my comment about striped tower paint in
response to your 'Line Stretcher' post. I never thought of using such a
tool on a short line between a transmitter and duplexer. I was thinking
such was used in AM broadcast delay lines with phased towers, and never
though of u
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