Re: [Elecraft] KPA500 Faulting on high SWR on power rise

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

[Elecraft] KPA500 Faulting on high SWR on power rise

Your 5KW example is RMS voltage and peak would be 707v. I am not sure how much moderate SWR effect this value but clearly the 1000v Alpha Delta discharge tube should be adequate for an Elecraft KPA-500 unless the SWR is horrible. John KK9A From: K4TAX Date: Sat Feb 24 19:46:55 EST 2018 Based

Re: [Elecraft] KPA500 Faulting on high SWR on power rise

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

Re: [Elecraft] KPA500 Faulting on high SWR on power rise

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

Re: [Elecraft] KPA500 Faulting on high SWR on power rise

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

Re: [Elecraft] KPA500 Faulting on high SWR on power rise

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.

Re: [Elecraft] KPA500 Faulting on high SWR on power rise

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

Re: [Elecraft] KPA500 Faulting on high SWR on power rise

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

Re: [Elecraft] KPA500 Faulting on high SWR on power rise

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' <elecraft@mailman.qth.net> Subject: [Elecraft]  KPA500 Faulting on high SWR on power rise I just posted almost the

Re: [Elecraft] KPA500 Faulting on high SWR on power rise

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' <elecraft@mailman.qth.net> Subject: [Elecraft]  KPA500 Faulting on high SWR on

Re: [Elecraft] KPA500 Faulting on high SWR on power rise

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

Re: [Elecraft] KPA500 Faulting on high SWR on power rise

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

Re: [Elecraft] KPA500 Faulting on high SWR on power rise

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

[Elecraft] KPA500 Faulting on high SWR on power rise

I just posted almost the exact thing. I should have read all of the posts first. It is interesting that coax has a much higher voltage rating than the connectors however Amphenol UHF connectors rarely fail even after direct lightning strikes. John KK9A K6WRU wrote: The Amphenol voltage rating

[Elecraft] KPA500 Faulting on high SWR on power rise

Really? An Amphenol UHF connector only has a 500v rating. John KK9A Bill Johnson k9yeq wrote 1000v to me could be too low for a 500W amp. You can for the time being leave the plug out, just disconnect when you are not using your equipment. I use a remote disconnect to remove the antennas at

Re: [Elecraft] KPA500 Faulting on high SWR on power rise

of Chris Hallinan [challi...@gmail.com] Sent: Saturday, February 24, 2018 10:50 AM To: donw...@embarqmail.com Cc: Wes Stewart; <elecraft@mailman.qth.net> Subject: Re: [Elecraft] KPA500 Faulting on high SWR on power rise Not sure. I pulled the plug out and Googled the numbers on it. Th

Re: [Elecraft] KPA500 Faulting on high SWR on power rise

elecraft@mailman.qth.net> > <elecraft@mailman.qth.net> > 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 think means it is a 1000V breakdown

Re: [Elecraft] KPA500 Faulting on high SWR on power rise

...@mailman.qth.net <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 <wes_n...@triconet.org>; <elecraft@mailman.qth.net> <elecraft@mailman.qth.net> Subject: Re: [Elecraft] KPA

Re: [Elecraft] KPA500 Faulting on high SWR on power rise

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

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 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,

Re: [Elecraft] KPA500 Faulting on high SWR on power rise

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

[Elecraft] KPA500 Faulting on high SWR on power rise

Great troubleshooting. After a recent Elecraft post by K9YC I purchased three of these https://www.arraysolutions.com/surge-and-rf-protection/as-303u and I will likely buy more as they look really nice. John KK9A K1AY wrote: Thanks Don, and everyone. This morning, after reading the posts, I

Re: [Elecraft] KPA500 Faulting on high SWR on power rise

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

Re: [Elecraft] KPA500 Faulting on high SWR on power rise

: Saturday, February 24, 2018 9:32 AM To: Wes Stewart Cc: <elecraft@mailman.qth.net> 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 pro

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 along. It's arcing at about 300W. Do you have a suggestion for alternatives? I live in the lightning capital of the world ;)

Re: [Elecraft] KPA500 Faulting on high SWR on power rise

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

Re: [Elecraft] KPA500 Faulting on high SWR on power rise

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!

Re: [Elecraft] KPA500 Faulting on high SWR on power rise

*/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

Re: [Elecraft] KPA500 Faulting on high SWR on power rise

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

Re: [Elecraft] KPA500 Faulting on high SWR on power rise

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

Re: [Elecraft] KPA500 Faulting on high SWR on power rise

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

Re: [Elecraft] KPA500 Faulting on high SWR on power rise

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

Re: [Elecraft] KPA500 Faulting on high SWR on power rise

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

Re: [Elecraft] KPA500 Faulting on high SWR on power rise

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

Re: [Elecraft] KPA500 Faulting on high SWR on power rise

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

Re: [Elecraft] KPA500 Faulting on high SWR on power rise

mething. > Maybe the control cable to the auto tuner? > > > 73, > Gary K9GS > Original message From: Chris Hallinan <challi...@gmail.com> > Date: 2/23/18 11:42 PM (GMT-06:00) To: "<elecraft@mailman.qth.net>" > <Elecraft@mailman.q

Re: [Elecraft] KPA500 Faulting on high SWR on power rise

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

Re: [Elecraft] KPA500 Faulting on high SWR on power rise

ailman.qth.net>" <Elecraft@mailman.qth.net> Subject: [Elecraft] KPA500 Faulting on high SWR on power rise Greetings from southwest Florida. My KPA500 is kicking out with REFL HI warning (high SWR).  But here is the strangeness. My setup is K3->KPA500->40' coax->MFJ 600W r

[Elecraft] KPA500 Faulting on high SWR on power rise

Greetings from southwest Florida. My KPA500 is kicking out with REFL HI warning (high SWR). But here is the strangeness. My setup is K3->KPA500->40' coax->MFJ 600W remote tuner -> 4:1 balun -> open wire feedline to 80-meter doublet. In words, I have a remote autotuner feeding an 80-meter