While all the "facts" about the voltage ratings of the gas discharge
protectors are correct - that is only true if those devices are new and
have not 'squashed' a number of events.
Please consider that this ham's problem with the Alpha-Delta protector
may be simply that the gas-discharge devic
Rick and all,
Whether that is true or not depends on the length of the radiator and
feedline relative to the frequency. Read my "Antennas" article on my
website www.w3fpr.com.
There is good reason that the Elecraft BL2 is switchable between 1:1 and
4:1.
73,
Don W3FPR
On 2/24/2018 10:53 P
There are a lot of factors that determine what the best choice of Balun is.
Unless it is a resonant antenna, the impedance is not purely resistive,
usually far from it. It can be almost anything. The feedline length will
affect what the impedance is at the tuner. The tuner, if you have one, will
se
In my case, the 4:1 was shown as correct by comparing to a 1:1 (for me). I was
able to find more usable bands with the 4:1 (meaning closer matches).
If the dipole is single band only, using a 75 ohm feed (choke at the transition
from feed to antenna) is best. A resonant dipole is closer to 7
Yes and in years past AM legal limit PEP power was about 3KW. PL-259's were
used on these transmitters and Johnson KW Matchbox type equipment.
Bob, K4TAX
Sent from my iPhone
> On Feb 24, 2018, at 8:59 PM, Jim Brown wrote:
>
> Someone should tell the electrons. UHF connectors have been stan
I question the 4:1 balun being the correct nor best choice. Typical of that
antenna the feed Z of the radiator is more likely 25 to 35 ohms. The 4:1 balun
is presenting something like 10 ohms to the tuner. Worst case for high current
and hi loss in the tuner causing heating. A 1:1 balun would
Someone should tell the electrons. UHF connectors have been standard on
legal limit power amps for as long as I've been a ham.
73, Jim K9YC
On 2/24/2018 1:46 PM, Walter Underwood wrote:
The Amphenol voltage rating for UHF connectors is 500 V peak. So the connectors
could be another weak point
I've observed many times an arc occur from the center pin to shell with
an unterminated line during a thunder storm. No damage to the
connector occurred however. Makes for an eerie dang sound too.
73
Bob K4TAX
On 2/24/2018 8:29 PM, GaryK9GS wrote:
I have never seen a properly installed
I have never seen a properly installed UHF connector, in a matched system, arc.
73,
Gary K9GS
Original message From: j...@kk9a.com Date: 2/24/18 5:14 PM
(GMT-06:00) To: 'Elecraft Reflector' Subject:
[Elecraft] KPA500 Faulting on high SWR on power rise
I just posted almost
10:1 SWR implies that the impedance is 500 ohms resistive at the maximum
point on the line.
E = sqrt(P*R) = sqrt (500w * 500ohms) = 500 Vrms, which is 707 Vpk.
So if the UHF connector happened to be located at a voltage maximum on
the line it would see more than its rated 500V peak.
Alan N1A
In this case, the lightning protection is on the antenna side of the matching
unit, so it isn’t at 1:1 SWR or 50 Ohms. At 10:1 VSWR, we would see 500 V peak
at 500 W.
wunder
K6WRU
Walter Underwood
CM87wj
http://observer.wunderwood.org/ (my blog)
> On Feb 24, 2018, at 4:46 PM, Bob McGraw K4TAX
Based on the specification of 500 volts peak, 5KW at 50 ohms = 500
volts. It would seem the PL-259 is adequate for ham radio applications
per specification to 0.3 GHZ or 300 MHz without issues. Of course
one is dealing with 50 ohms, which implies essentially a 1:1 SWR.
73
Bob, K4TAX
Chris Hallinan [challi...@gmail.com]
Sent: Saturday, February 24, 2018 10:50 AM
To: donw...@embarqmail.com
Cc: Wes Stewart;
Subject: Re: [Elecraft] KPA500 Faulting on high SWR on power rise
Not sure. I pulled the plug out and Googled the numbers on it. The plug
is labeled CG2 1000, which I
-Original Message-
> From: elecraft-boun...@mailman.qth.net On
> Behalf Of Chris Hallinan
> Sent: Saturday, February 24, 2018 10:51 AM
> To: donw...@embarqmail.com
> Cc: Wes Stewart ;
>
> Subject: Re: [Elecraft] KPA500 Faulting on high SWR on power rise
>
> No
...@mailman.qth.net On
Behalf Of Chris Hallinan
Sent: Saturday, February 24, 2018 10:51 AM
To: donw...@embarqmail.com
Cc: Wes Stewart ;
Subject: Re: [Elecraft] KPA500 Faulting on high SWR on power rise
Not sure. I pulled the plug out and Googled the numbers on it. The plug is
labeled CG2 1000
MFJ tuners that use switched tapped air inductors often fail to allow
sufficient spacing between each tap and the adjacent turns of the coil, and
either heat expansion or high-voltage arcing can cause shorts between the
tap and an adjacent turn, completely changing the effective tuner settings,
as
Not sure. I pulled the plug out and Googled the numbers on it. The plug
is labeled CG2 1000, which I think means it is a 1000V breakdown voltage.
It appears to be a Littlefuse device, according to Allied Electronics which
has the leaded version of the part for $2 ;)
Without knowing for sure, 100
Be aware that the device on the page linked presents DC blocking to your
feed line, at least the schematic indicates that.
If you are running an RCS-4 remote coax switch, (or any coax switch that
runs control voltage down the coax), you will need to get a device which
passes DC, or change swit
Chris,
What is the possibility that you have an HP suppressor body and a 200
watt Arc-Plug?
73,
Don W3FPR
On 2/24/2018 10:32 AM, Chris Hallinan wrote:
Hi Wes. Appreciate the feedback. I'm certainly not impressed by having one
marked HP that is clearly not. See my earlier post: the surge pr
Sent: Saturday, February 24, 2018 9:32 AM
To: Wes Stewart
Cc:
Subject: Re: [Elecraft] KPA500 Faulting on high SWR on power rise
Hi Wes. Appreciate the feedback. I'm certainly not impressed by having one
marked HP that is clearly not. See my earlier post: the surge protector
was my problem all al
Hi Wes. Appreciate the feedback. I'm certainly not impressed by having one
marked HP that is clearly not. See my earlier post: the surge protector
was my problem all along. It's arcing at about 300W.
Do you have a suggestion for alternatives? I live in the lightning capital
of the world ;) Li
Thanks Don, and everyone.
This morning, after reading the posts, I took an approach similar to what
Don is proposing.
I bypassed the surge protector, and voila, problem gone.
Now I have a new problem: The Alpha Delta model TT3G50 is clearly marked
HP, but it's behaving like a 200W version.
The goo
Regardless, I would get rid of those. Pity I can't post pictures here of my
examination of the two I bought and returned.
Wes N7WS
On 2/24/2018 6:36 AM, Chris Hallinan wrote:
...
I am running through a surge protectors from Alpha Delta. I will double
check is is not the 200W versions! Hmmm
*/Chris/*
You have seen several posts with good advice. If you want to do an
easy test to localize where the failure may be, you can do it with a
dummy load.
First put the dummy load at the rig. Check to see if all is OK, if
not, blame the rig.
Then check the coax - connect the dummy load at
I mentioned a spurious signal. I tested this by using a different rig. No
problem with it. Sent the K3S for repair.
Carl Yaffey K8NU
Recording studio.
cyaffeyno_s...@gmail.com
614 268 6353, Columbus OH
http://www.carl-yaffey.com
http://www.grassahol.com
http://www.bluesswing.com
__
Triage the problem...
Dummy load at the end of the tuner chain-- if it works at high power
then all is good from the dummy load back, the problem lies downstream
of the dummy load. If it fails with the dummy load there, then you have
a coax problem between the radio and the dummy load.
So f
Another possibility: There is a spurious signal on a widely different
frequency. I experienced this.
Carl Yaffey K8NU
Recording studio.
cyaffeyno_s...@gmail.com
614 268 6353, Columbus OH
http://www.carl-yaffey.com
http://www.grassahol.com
http://www.bluesswing.com
_
Chris,
You have seen several posts with good advice. If you want to do an easy
test to localize where the failure may be, you can do it with a dummy load.
First put the dummy load at the rig. Check to see if all is OK, if not,
blame the rig.
Then check the coax - connect the dummy load at the
Thanks, everyone for the helpful hints. Some additional information:
This installation is brand new. The antenna has been up only a month or
so. Tuner and Balun even less. Coax is newly run, and I've deliberately
avoided sharp bends. I purchased the KPA500 in December, so all of this
QRO is ne
Just to add to all the possibilities, there could be an arc at the
balun. Most authorities suggest a 1:1 balun with a setup like this. As
you know, the impedance seen at the balun will vary all over the map,
depending on the band and the length of the 600-ohm line.
I've calculated that the vol
Others have mentioned arcing as a possibility. We see more of than than we
would like. There are many poor UHF connectors and (especially) adapters
around. This is especially true with right angle connectors.
There is another possibility that could be happening. RF loves any wire it can
find fo
I’d guess that something is going on in the tuner. Maybe a leaky gasket and
some corrosion.
Logan
Sent from my iPhone
> On Feb 23, 2018, at 10:00 PM, GaryK9GS wrote:
>
> Hi Chris,
> Unless there is something arcing, I would guess RF getting into something.
> Maybe the control cable to the
It appears that the higher voltages at QRO are enough on return to fault the
amp. That could be an arc or the match isn’t really 1:1. Using an antenna
analyzer at the balun would be useful.
If you’re on 80M, without the tuner, you’re likely to see ~3:1 untuned at the
balun, within the range
Hi Chris,
Unless there is something arcing, I would guess RF getting into something.
Maybe the control cable to the auto tuner?
73,
Gary K9GS
Original message From: Chris Hallinan
Date: 2/23/18 11:42 PM (GMT-06:00) To: ""
Subject: [Elecraft] KPA500 Faulting on high SWR
34 matches
Mail list logo
