Re: [Elecraft] KPA-1500 wish list

Tavan Sent: 18 November 2019 17:45 To: N4ZR; Elecraft Reflector Subject: Re: [Elecraft] KPA-1500 wish list I'd love to have something like this, Pete! It's not only frequency excursions that cause output fluctuations but also warm-up. The gain of the power transistors is temperature-sensiti

Re: [Elecraft] KPA-1500 wish list

. 73 Doug EI2CN -Original Message- From: elecraft-boun...@mailman.qth.net [mailto:elecraft-boun...@mailman.qth.net] On Behalf Of Rick Tavan Sent: 18 November 2019 17:45 To: N4ZR; Elecraft Reflector Subject: Re: [Elecraft] KPA-1500 wish list I'd love to have something like

Re: [Elecraft] KPA-1500 wish list

I'd love to have something like this, Pete! It's not only frequency excursions that cause output fluctuations but also warm-up. The gain of the power transistors is temperature-sensitive. I'd like to be able to set a target output power (typically 1500w but maybe less on bands with mismatched ante

[Elecraft] KPA-1500 wish list

Here's one that I kept running into.  My K3/KPA-1500 when operating at one end of the band on 40 and 80, would work fine, but when I went to the other end  I found that often I would be running over 1500 watts, and sometimes, the result would be reflected power exceeding 200 watts, causing a fa

[Elecraft] KPA 1500 on 12 meters

Makes the impedance here in parts of Florida a moving target. Its not how high the antenna is above the ground (sand) it's how high above the water table which can vary from a few inches below the surface in July to 25 feet or more below in Dec-Mar in our dry season. Suddenly our 80 or 160 meter

Re: [Elecraft] KPA 500 glitch

I ran into this exact issue caused by cable connections, specifically the Y-cable that didn't allow the connector screws to join the cables. Getting the Y-box from N6TV solved the loose cable problem. 73, Dennis NJ6G On 10/30/2019 13:26, Jack Brindle via Elecraft wrote: Jim; Check the AUXIO

Re: [Elecraft] KPA 500 glitch

Jim; Check the AUXIO cable to make sure it connects to the K3S and the KPA500 (or KAT500) properly. This sounds like the Band1 signal may not be making proper contact. The KPA500 watches the K3S’s Band signals for its band selection when RADIO is set to K3. If doesn’t see the combination for a

Re: [Elecraft] KPA 500 glitch

Jim, I would suggest doing a Direct Frequency Entry into each of the ham bands - no guarantee, but it has a chance of setting things straight. 73, Don W3FPR On 10/30/2019 3:57 PM, Jim Sheldon wrote: Having a bit of trouble with the KPA500 following the bands out of the K3S.  For some reason,

[Elecraft] KPA 500 glitch

Having a bit of trouble with the KPA500 following the bands out of the K3S. For some reason, the other day I accidentally hit a button combination on the K3S (not sure what I hit) and the KPA500 is now thinking 7.0 MHz is 1.8 and some of the other bands aren't switching correctly either. I ca

Re: [Elecraft] KPA-1500: Widely varying drive requirement - same frequency, different antenna

This is not unusual when the loads presented by the antennas (or tuner) to the amp are different. This can even be true when the SWRs are identical if the actual +/- reactance of one is different than the other. This is most noticeable on lower freq bands where the amps gain is typically hig

Re: [Elecraft] KPA-1500: Widely varying drive requirement - same frequency, different antenna

Based on my experience, the KPA1500 is very sensitive to small changes in load impedance (SWR) with respect to power gain and current. The ATU software is much better than it started out, but still sometimes doesn't get below 1.2:1. That could result in the kind of power gain variation Pete is

Re: [Elecraft] KPA-1500: Widely varying drive requirement - same frequency, different antenna

Actually the fact that you were using the internal tuner doesn't change the chance that with the settings on the auto tuner don't tell you which direction the tuning of a certain antenna approach unity from. So there could be twice the variation allowed between the 2 antennas. So if one is coming f

Re: [Elecraft] KPA-1500: Widely varying drive requirement - same frequency, different antenna

Thanks to everyone who replied, either directly or on the list.  I'm sorry, but I forgot to mention one key fact - I was running the amp's ATU with both of these antennas.  Assuming that the amp's power output measurement is done at the input of the ATU and not the output, and that the ATU sett

[Elecraft] KPA-1500: Widely varying drive requirement - same frequency, different antenna

I have two 40M antennas, a Carolina Windom and a full-wave parasitic sloper.  I have just noticed that on any given frequency, my K3 must deliver considerably more power on one than the other, in order for the amp to produce 1500 watts.  The difference is 27 watts on one vs 42 watts on the othe

Re: [Elecraft] KPA-1500 failing on 160...AGAIN!

Folks - Looks like this thread has way drifted OT.   Let's close it for now. I also gave the original poster a call and his KPA1500 is OK. He made some new changes external to the 1500 based on list comments and the problem is no longer present. We'll stay in touch with him to make sure he does

Re: [Elecraft] KPA-1500 failing on 160...AGAIN!

On 10/1/2019 2:12 AM, David Wilcox wrote: A trip to Palomar Engineers with a description of your set up will help so they can sell you the correct EMI suppression toroid set up. NO! This company doesn't have a clue, is selling the wrong components, and for very high prices. 73, Jim K9YC _

Re: [Elecraft] KPA-1500 failing on 160...AGAIN!

You have to use the best quality connecting cables. A trip to Palomar Engineers with a description of your set up will help so they can sell you the correct EMI suppression toroid set up. And, YES, even some of Elecraft’s cables can be (or become) defective as described in this site. A friend

Re: [Elecraft] KPA-1500 failing on 160...AGAIN!

And not just antenna and feedlines, but the AC wiring in your shack, the potential EMI problems, etc. This is why I keep saying that hams badly need a tutorial -- perhaps something named, "What to Expect When You Run High Power".  There are lots of us, including me, that could learn about the ex

Re: [Elecraft] KPA-1500 failing on 160...AGAIN!

From: elecraft-boun...@mailman.qth.net on behalf of David Gilbert Sent: Friday, September 27, 2019 4:45:55 PM To: elecraft@mailman.qth.net Subject: Re: [Elecraft] KPA-1500 failing on 160...AGAIN! I've probably posted this here before, but I once had a 160m Inverted-V at 70 feet

Re: [Elecraft] KPA-1500 failing on 160...AGAIN!

I've probably posted this here before, but I once had a 160m Inverted-V at 70 feet that didn't have a DC ground.  As a thunderstorm approached (but was still several miles away) I reached down to short the coax end in the shack and drew a heavy blue 2 inch long arc that traveled from the end

Re: [Elecraft] KPA-1500 failing on 160...AGAIN!

It's from my head.  I have a BVT - it's DC so the 4K is a DC claim.  I BVT cables used here in the shack as a fast way to ensure I don't have some microscopic wire or filing or whatever down in a connector - stuff like that is a nightmare to troubleshoot. At one point I tried to use a PL259 fo

Re: [Elecraft] KPA-1500 failing on 160...AGAIN!

For those with insulated verticals, the potential gradient is about 100 V/meter. That varies with humidity and altitude. But, you get the picture. In dry climates like here in NM, this is a big deal for commercial broadcast AM antennas. Even with the transmitter shut down, unless there is a "D

Re: [Elecraft] KPA-1500 failing on 160...AGAIN!

Few of us can guarantee dry air for our antenna connections. Where is this data from? For the question “Has anyone tested them?”, I expect that Amphenol tests to the published specs. Those tests would be over the entire temperature range in the data sheet. If you visit the data sheets I linked

Re: [Elecraft] KPA-1500 failing on 160...AGAIN!

On 9/27/2019 12:00 PM, Jeff Blaine wrote: One thing I can say from personal experience is that if you have a tall or long antenna, you definitely need a static bleed on that bad boy. YES! After experiencing multiple shorts of Polyphaser arrestors on high wires, I've switched to the arrestors t

Re: [Elecraft] KPA-1500 failing on 160...AGAIN!

I'm going to partially disagree with Jim :) I agree on good quality connectors, when you have them. I can honestly say I have yet to have a none-Amphenol fail since I learned to solder them in 1972. I can also honestly say I have had a connector fail when I did not assembly it correctly. This

Re: [Elecraft] KPA-1500 failing on 160...AGAIN!

I don't doubt the AMP connector is great but doubt this issue is due to a connector. One thing I can say from personal experience is that if you have a tall or long antenna, you definitely need a static bleed on that bad boy.  Never really gave those stories much credence but a number of years

Re: [Elecraft] KPA-1500 failing on 160...AGAIN!

On 9/27/2019 11:01 AM, j...@kk9a.com wrote: If PL-259s are failing they are either poor quality connectors or there are serious antenna issues causing excessive voltage. YES! Only first quality connectors and adapters should be used. I run legal limit to resonant antennas fed with 50 ohm and 7

Re: [Elecraft] KPA-1500 failing on 160...AGAIN!

Yes and without proper lightning protection or static build-up prevention on a feedline, a nearby strike can induce 4KV+ on the antenna and feedline.  A flash-over will likely leave a carbon trace that will be followed by a few 100 watts of RF.   It only gets worst, not better.   On more than o

Re: [Elecraft] KPA-1500 failing on 160...AGAIN!

PL259/SO239 BDV is around 4KV in dry air. 73/jeff/ac0c alpha-charlie-zero-charlie www.ac0c.com On 9/27/19 1:01 PM, j...@kk9a.com wrote: 5000 watts is 500 volts rms with a perfect antenna system. I suspect that PL-259 connectors really can withstand much more than 500 volts. Has anyone tested

Re: [Elecraft] KPA-1500 failing on 160...AGAIN!

5000 watts is 500 volts rms with a perfect antenna system. I suspect that PL-259 connectors really can withstand much more than 500 volts. Has anyone tested them? My station has a mixture of UHF, N and DIN connectors and all have worked perfectly for 1500 watts HF. If PL-259s are failing

Re: [Elecraft] KPA-1500 failing

This would be a lot easier with a public support forum, but I understand why Elecraft might not want to take that on. The mailing list is awesome, but it isn’t a very good database. wunder K6WRU Walter Underwood CM87wj http://observer.wunderwood.org/ (my blog) > On Sep 27, 2019, at 6:42 AM, Cha

Re: [Elecraft] KPA-1500 failing

I just fixed a very similar problem with my station - I could run 100 watts to my Carolina Windom all day, but it failed instantly at 1500 watts. The problem turned out to be a very nice-looking factory-installed PL-259 feeding the antenna.  Looking inside revealed carbon tracking, etc., so out

Re: [Elecraft] KPA-1500 failing on 160...AGAIN!

put in to add an SWR bridge/monitor. It looked okay, and >>> was finger tight, but when I replaced it in an A/B test, the problem went >>> away. >>>> >>>> The other time, the antenna had changed its impedance curve, but was >>> still 'okay' and th

Re: [Elecraft] KPA-1500 failing on 160...AGAIN!

; > > > 73 John N5CQ > > > > > > > > > -Original Message- > > > From: elecraft-boun...@mailman.qth.net < > elecraft-boun...@mailman.qth.net> > > On Behalf Of Jim Brown > >

Re: [Elecraft] KPA-1500 failing on 160...AGAIN!

its impedance curve, but was > still 'okay' and the tuner was trying to retune for it. > > > > 73 John N5CQ > > > > > > -Original Message- > > From: elecraft-boun...@mailman.qth.net > On Behalf Of Jim Brown > > Sent: Friday, Septemb

Re: [Elecraft] KPA-1500 failing

I would request that any solution one finds for their KPA-1500 failing, be posted on this forum, even if it's (typically like me) cockpit error. We have seen many "My KPA-1500 died" listings. These are obviously quite disconcerting to us potential buyers (again like me). Often, the original post

Re: [Elecraft] KPA-1500 failing on 160...AGAIN!

gt; Behalf Of Jim Brown > Sent: Friday, September 27, 2019 4:19 AM > To: elecraft@mailman.qth.net > Subject: Re: [Elecraft] KPA-1500 failing on 160...AGAIN! > >> On 9/26/2019 10:26 PM, Peter Dougherty wrote: >> Any idea where to s

Re: [Elecraft] KPA-1500 failing on 160...AGAIN!

On Behalf Of Jim Brown Sent: Friday, September 27, 2019 4:19 AM To: elecraft@mailman.qth.net Subject: Re: [Elecraft] KPA-1500 failing on 160...AGAIN! On 9/26/2019 10:26 PM, Peter Dougherty wrote: > Any idea where to start looking here? And if it's a vertical, what about the radial sys

Re: [Elecraft] KPA-1500 failing on 160...AGAIN!

On 9/26/2019 10:26 PM, Peter Dougherty wrote: Any idea where to start looking here? And if it's a vertical, what about the radial system? 73, Jim K9YC __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Hel

Re: [Elecraft] KPA-1500 failing on 160...AGAIN!

On 9/26/2019 10:26 PM, Peter Dougherty wrote: Any idea where to start looking here? What is the antenna? The feedline? Is the antenna resonant? Is there a serious common mode choke at the feedpoint? (See http://k9yc.com/2018Cookbook.pdf ) Is it matched to the feedline at the frequency (ies)

Re: [Elecraft] KPA-1500 failing on 160...AGAIN!

What happens with a dummy load? If it doesn’t fail, then the problem is in the antenna. The KPA may be more sensitive to a short period of high SWR than the K3. Victor 4X6GP > On 27 Sep 2019, at 8:26, Peter Dougherty wrote: > > My KPA is once again repeatedly failing on 160m. I haven't used

[Elecraft] KPA-1500 failing on 160...AGAIN!

My KPA is once again repeatedly failing on 160m. I haven't used it on Topband since about the end of March, when it was fine. My antenna is checking out fine on my AA-230 ZOOM analyzer, and I can run 100W into the antenna from the K3s with no problem. I'm getting FAULT: PWR REFL on every keydown

[Elecraft] Elecraft KPA 500 and Kat 500

The Elecraft KPA 500 and KAT 500 have been sold and shipped. __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by

Re: [Elecraft] KPA 500 Attenuated Receive Signals

...@mailman.qth.net] On Behalf Of Barry Simpson Sent: Sunday, September 8, 2019 1:34 AM To: Elecraft Mailing List Subject: [Elecraft] KPA 500 Attenuated Receive Signals My KPA 500, which is several years old, has just developed an issue which so far I have been unable to resolve. What has happened is that when I

Re: [Elecraft] KPA 500 Attenuated Receive Signals

Simpson Sent: Sunday, September 8, 2019 8:22 AM To: donw...@embarqmail.com Cc: Elecraft Mailing List Subject: Re: [Elecraft] KPA 500 Attenuated Receive Signals Thanks Don That's what I thought. I will email them tomorrow. 73 Barry VK2BJ On Sun, 8 Sep 2019 at 21:36, Don Wilhelm wrote: &g

Re: [Elecraft] KPA 500 Attenuated Receive Signals

Thanks Don That's what I thought. I will email them tomorrow. 73 Barry VK2BJ On Sun, 8 Sep 2019 at 21:36, Don Wilhelm wrote: > Barry, > > I think you may find a problem in the KPA500 T/R switch area. > Email supp...@elecraft.com for further checks and resolution. > > 73, > Don W3FPR > > On 9/

Re: [Elecraft] KPA 500 Attenuated Receive Signals

Barry, I think you may find a problem in the KPA500 T/R switch area. Email supp...@elecraft.com for further checks and resolution. 73, Don W3FPR On 9/8/2019 2:34 AM, Barry Simpson wrote: My KPA 500, which is several years old, has just developed an issue which so far I have been unable to reso

[Elecraft] KPA 500 Attenuated Receive Signals

My KPA 500, which is several years old, has just developed an issue which so far I have been unable to resolve. What has happened is that when I put the amplifier into OPER, the received signal strength drops by several S units. It transmits normally and also receives normally in STBY. The issue

Re: [Elecraft] KPA-1500 on digital modes

own at 55c. Extended running of JT65 shows heatsink is a shade under 43c (lots of fans cooling things). http://www.kl7uw.com/144_1500W_PA.htm 73, Ed - KL7UW Date: Sat, 31 Aug 2019 17:04:38 -0500 From: K9MA To: elecraft@mailman.qth.net Subject: Re: [Elecraft] KPA-1500 on digital modes This is nothing

Re: [Elecraft] KPA-1500 on digital modes

FWIW, one of the things I like best about my KPA-1500 is that you can use its antenna tuner with the amp on Standby 73, Pete N4ZR Check out the Reverse Beacon Network at , now spotting RTTY activity worldwide. For spots, please use your favorite "retail" DX cluster. On

Re: [Elecraft] KPA-1500 on digital modes

On 8/31/2019 6:02 PM, Roger D Johnson wrote: Isn't this exactly the way some of the first ham linears were designed for an input of 2000 watts in SSB and 1000 watts in CW? There was a switch on the front panel for SSB/CW mode which dropped the plate voltage for CW mode so that the tubes saw

Re: [Elecraft] KPA-1500 on digital modes

Yes. :) The missing word is "NOT" satisfied. 73, Jim On 9/1/2019 5:14 AM, Wes wrote: Is this a typo? Wes  N7WS On 8/31/2019 7:45 PM, Jim Brown wrote: K6XX, one of the Elecraft engineers who works on their power amps, gave a talk to our contest club stressing the importance of providing a

Re: [Elecraft] KPA-1500 on digital modes

Is this a typo? Wes  N7WS On 8/31/2019 7:45 PM, Jim Brown wrote: K6XX, one of the Elecraft engineers who works on their power amps, gave a talk to our contest club stressing the importance of providing a matched load to the output devices, and to the output itself. He observed distortion *i

Re: [Elecraft] KPA-1500 on digital modes

Just a reminder to Canadians running the KPA1500 or any other full power amp in the contest this weekend. Max RF out is limited to 750 watts (not our usual 2250w PEP for SSB). Only CW and SSB get to go above 750 watts. Mike va3mw __ Ele

Re: [Elecraft] KPA-1500 on digital modes

On 8/31/2019 6:02 PM, Roger D Johnson wrote: If you design a different class AB amplifier for half the output of the previous amplifier don't you design it to produce the desired output into a certain load impedance? Would it not be as efficient as the first amplifier running at it's designed out

Re: [Elecraft] KPA-1500 on digital modes

On 8/31/2019 3:04 PM, K9MA wrote: This is nothing unique to the KPA1500: ALL class AB amplifiers behave this way. Even an "ideal" class AB amplifier has a maximum dissipation at around half of full output. Yep. These concepts were taught in my EE courses in the early '60s. 73, Jim K9YC __

Re: [Elecraft] KPA-1500 on digital modes

reenshots)   -larry (K8UT) -- Original Message -- From: "N4ZR" To: "Elecraft List" Sent: 2019-08-29 07:59:23 Subject: [Elecraft] KPA-1500 on digital modes Elecraft's published specs rate the KPA-1500 for 1500 watts output on all modes.  In prepping for this weeke

[Elecraft] KPA-1500 Power Output Variation

Some asked that I post results for the variable power output problem.  I now have a pretty good idea why output varies from 1350w to over 1700w at a given temperature with a fixed drive level between 7.000 and 7.050.  The problem occurs only on 40m.  The antenna SWR varies from 1.4 on 7.000 to

Re: [Elecraft] KPA-1500 on digital modes

It would be interesting to know the efficiency of the Expert amp at various voltage/power levels. John KK9A Roger D Johnson n1rj wrote: I just did a quick check: At 1500 watts eff is 56% and pwr diss is 1179 watts 1000 44 1273 500 30

Re: [Elecraft] KPA-1500 on digital modes

Yes. It has been mentioned on this list that the KPA500 is designed to be most efficient at 500 Watts and running at lower power does not mean saving the amp. Sent from my iPhone ...nr4c. bill > On Aug 29, 2019, at 3:11 PM, Bob McGraw K4TAX wrote: > > My KPA500 runs from a low of 35% to a hi

Re: [Elecraft] KPA-1500 on digital modes

st" Sent: 2019-08-29 17:44:05 Subject: Re: [Elecraft] KPA-1500 on digital modes I just did a quick check: At 1500 watts eff is 56% and pwr diss is 1179 watts 1000 44 1273 500 30 1120 My Expert 1.3K-FA had 3 voltage levels

Re: [Elecraft] KPA-1500 on digital modes

: Re: [Elecraft] KPA-1500 on digital modes They bias the LDMOS devices at 1 amp each. That is minimal in overall heat when you are pulling over 40 amps at high power. Dave wo2x Sent from my waxed string and tin cans. > On Aug 29, 2019, at 1:29 PM, David Gilbert wrote: > > &

Re: [Elecraft] KPA-1500 on digital modes

I just did a quick check: At 1500 watts eff is 56% and pwr diss is 1179 watts 1000 44 1273 500 30 1120 My Expert 1.3K-FA had 3 voltage levels: 48 volts for full power (1300 watts) 38 800 watts 32 450 I no lo

Re: [Elecraft] KPA-1500 on digital modes

craft-boun...@mailman.qth.net On Behalf Of Andy Durbin Sent: Thursday, August 29, 2019 2:57 PM To: elecraft@mailman.qth.net Subject: [Elecraft] KPA-1500 on digital modes "No one has mentioned amplifier efficiency at differing power levels." I have for the KPA500 and I have provide

[Elecraft] KPA-1500 on digital modes

"No one has mentioned amplifier efficiency at differing power levels." I have for the KPA500 and I have provided links to test data. I would expect the KPA1500 to have similar characteristics but I'd like to see equivalent test data for it. 73, Andy, k3wyc

Re: [Elecraft] KPA-1500 on digital modes

My KPA500 runs from a low of 35% to a high of 55% depending on power.   Lower power is least efficient.   Thus I always run close or at maximum rated power.    Also the load impedance will affect efficiency. 73 Bob, K4TAX On 8/29/2019 2:04 PM, John Simmons wrote: No one has mentioned amplifi

Re: [Elecraft] KPA-1500 on digital modes

No one has mentioned amplifier efficiency at differing power levels. -John NI0K Andy Durbin wrote: "They bias the LDMOS devices at 1 amp each. That is minimal in overall heat when you are pulling over 40 amps at high power." You beat me to it. My KPA500, keyed but with no RF input, showed 0

[Elecraft] KPA-1500 on digital modes

"They bias the LDMOS devices at 1 amp each. That is minimal in overall heat when you are pulling over 40 amps at high power. " You beat me to it. My KPA500, keyed but with no RF input, showed 0.5 A at 76.7 V. That's only 38 W which is a small part of the 400 W plus PA dissipation seen in som

Re: [Elecraft] KPA-1500 on digital modes

They bias the LDMOS devices at 1 amp each. That is minimal in overall heat when you are pulling over 40 amps at high power. Dave wo2x Sent from my waxed string and tin cans. > On Aug 29, 2019, at 1:29 PM, David Gilbert wrote: > > > This was discussed here not long ago, and it is normal for

Re: [Elecraft] KPA-1500 on digital modes

This was discussed here not long ago, and it is normal for any linear amplifier.  It needs to be biased up to be linear, and that bias energy ends up as heat even if you don't use it. I worked as a component engineer at Collins Radio in Cedar Rapids when I first got out of college.  One of

Re: [Elecraft] KPA-1500 on digital modes

arry (K8UT) -- Original Message -- From: "N4ZR" To: "Elecraft List" Sent: 2019-08-29 07:59:23 Subject: [Elecraft] KPA-1500 on digital modes Elecraft's published specs rate the KPA-1500 for 1500 watts output on all modes.  In prepping for this weekend's contest

[Elecraft] KPA-1500 on digital modes

"Elecraft's published specs rate the KPA-1500 for 1500 watts output on all modes. In prepping for this weekend's contest, I've been running it at closer to 700 watts, because I've found that even just running on CW, with its much lower duty cycle, my amp reaches 70C quickly. " You seem to be a

Re: [Elecraft] KPA-1500 on digital modes

eases to 50% and at 1500 watts to 60%. (see screenshots) -larry (K8UT) -- Original Message -- From: "N4ZR" To: "Elecraft List" Sent: 2019-08-29 07:59:23 Subject: [Elecraft] KPA-1500 on digital modes Elecraft's published specs rate the KPA-1500 for 1500 w

[Elecraft] KPA-1500 on digital modes

Elecraft's published specs rate the KPA-1500 for 1500 watts output on all modes.  In prepping for this weekend's contest, I've been running it at closer to 700 watts, because I've found that even just running on CW, with its much lower duty cycle, my amp reaches 70C quickly.  I don't do that mu

Re: [Elecraft] KPA-1500 Power Output Variation

Concerning the output variation, I’ve noticed that when I change bands while the amplifier is hot, the output on the new band starts out high, then gradually drops. This would seem to indicate that the LPF is heating, and that the loss in the filter is several hundred Watts. That’s no big deal i

Re: [Elecraft] Elecraft KPA 1500 thoughts

Actually, it does.  I reported on this in a message to the reflector titled "TX Test Mode Garbage"  dated 7-25-2017 As a follow up Wayne wrote: Hi Wes, TX TEST mode activates the entire TX strip because it turns on PTT to test the keying of downstream devices. This was requested by our origin

Re: [Elecraft] Elecraft KPA 1500 thoughts

Thanks Bob and yes that worked. Randy WB8ART From: Bob Wilson, N6TV [mailto:n...@arrl.net] Sent: Monday, August 26, 2019 7:45 PM To: Randy (Art) Cc: Elecraft Reflector Subject: Re: [Elecraft] Elecraft KPA 1500 thoughts On Sun, Aug 25, 2019 at 12:59 PM Randy (Art) wrote: 1. I

Re: [Elecraft] KPA-1500 Power Output Variation

One thought, have you run the Elecraft TX GAIN Calibration procedure recently? It's built in to the K3 Utility. Unfortunately, the Utility sets the TX gain at a midpoint frequency on every band, frequencies I rarely use, and I was observing first dit "power spikes" in the output of the KPA1500 wh

Re: [Elecraft] kpa 1500

On Mon, Aug 26, 2019 at 12:17 PM Randy (Art) wrote: > Another issue I wonder if someone has found an elegant solution to connect > or devices to the ACC connector as with the enhanced cable to the KPA 1500 > I > need access to other ports. We need a splitter/breakout device. > Hi Randy, Yes, t

Re: [Elecraft] Elecraft KPA 1500 thoughts

On Sun, Aug 25, 2019 at 12:59 PM Randy (Art) wrote: > 1. I use my K3 and amp on all bands 160 thru 6 and have the internal 2 > meter xfter using with a HB PQL LDMOS amp I built. It uses RCA phone for > its PTT and the KPA 1500 is using the enhanced cable. When I go from 6 to > 2 > meters t

Re: [Elecraft] kpa 1500

Probably HTML 73, Fred ["Skip"] K6DGW Sparks NV DM09dn Washoe County On 8/26/2019 12:54 PM, Jim Brown wrote: Blank post 73, Jim K9YC On 8/26/2019 12:46 PM, Richard Thorne wrote: __

Re: [Elecraft] kpa 1500

Blank post 73, Jim K9YC On 8/26/2019 12:46 PM, Richard Thorne wrote: __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This li

Re: [Elecraft] kpa 1500

__ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: ht

Re: [Elecraft] kpa 1500

“We need a splitter/breakout device.” N6TV’s Y Box. From: elecraft-boun...@mailman.qth.net on behalf of Randy (Art) Sent: Monday, August 26, 2019 12:12:05 PM To: elecraft@mailman.qth.net Subject: [Elecraft] kpa 1500 Pete that would be in k3 test mode

[Elecraft] kpa 1500

Pete that would be in k3 test mode. Another issue I wonder if someone has found an elegant solution to connect or devices to the ACC connector as with the enhanced cable to the KPA 1500 I need access to other ports. We need a splitter/breakout device. Randy WB8ART ___

Re: [Elecraft] Elecraft KPA 1500 thoughts

TX Test mode?  On the K3 or the KPA-1500? 73, Pete N4ZR Check out the Reverse Beacon Network at , now spotting RTTY activity worldwide. For spots, please use your favorite "retail" DX cluster. On 8/25/2019 3:58 PM, Randy (Art) wrote: I recently got the KPA 1500 amp an

[Elecraft] Elecraft KPA 1500 thoughts

I recently got the KPA 1500 amp and guess I have some observations an possible upgrades that maybe considered. 1. I use my K3 and amp on all bands 160 thru 6 and have the internal 2 meter xfter using with a HB PQL LDMOS amp I built. It uses RCA phone for its PTT and the KPA 1500 is using t

Re: [Elecraft] KPA-1500 Power Output Variation

Not necessary to guess - Page 17 of the KPA-1500 manual discusses ALC.  "ALC is a useful safety mechanism, but do not use ALC as the principle [sic] power control. ...Elecraft recommends using the K3 or K3s PWR-SET-PER-BAND function to set proper drive levels, not ALC. 73, Pete N4ZR Check out

[Elecraft] KPA-1500 Power Output Variation

Has anyone actually used, observed, and measured the effect of the ALC feature of the amp in combination with the K3/K3S with regard to output power variation. I do use the method and setup as suggested in the manual for both the KPA500 and K3S with no known ill effects.   The amp drives to ra

Re: [Elecraft] KPA-1500 Power Output Variation

Here’s a way to get a worst case estimate of the effect of SWR on power output. Assume the amplifier has constant VOLTAGE gain and an output impedance much smaller than 50 Ohms. A 1.3:1 SWR means the load impedance could be as low as 39 Ohms or as high as 65 Ohms. Let’s say the SWR is 1:1 at the

Re: [Elecraft] KPA-1500 Power Output Variation

That's not the point at all.  It's about having to ride the drive level control on the K-3 constantly, especially in a contest, to avoid sudden output of 1700w. Why worry about it? No one on the other end would be able to tell one bit of difference. I see power drop -- maybe 5 - 10 percent

Re: [Elecraft] KPA-1500 Power Output Variation

Dummy load is no problem and never has been. __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl

Re: [Elecraft] KPA-1500 Power Output Variation

What about a dummy load? Sent from my iPhone ...nr4c. bill > On Aug 24, 2019, at 7:56 PM, Jim McCook wrote: > > Eric, > > If the attenuator had more attenuation that caused the drive to be closer to > the K-3 output I would think this would reduce the sensitivity of the drive > level with

Re: [Elecraft] KPA-1500 Power Output Variation

Why worry about it? No one on the other end would be able to tell one bit of difference. I see power drop -- maybe 5 - 10 percent -- as the KPA1500 heats up...likely normal. The small bit of reflected power may also have some minor effect on the wattmeter readings you see as well. 73, Greg-N4C

Re: [Elecraft] KPA-1500 Power Output Variation

On 8/24/2019 2:40 PM, Wes wrote: Jim I don't have a KPA1500, but do have a KPA500. I'm not particularly surprised at your observations based on mine with the '500. After a recent thread about amplifier efficiency I ran some tests on mine, using a well characterized dummy load and an LP-100A wa

Re: [Elecraft] KPA-1500 Power Output Variation

Eric, If the attenuator had more attenuation that caused the drive to be closer to the K-3 output I would think this would reduce the sensitivity of the drive level with respect to change in power output.  6w change in drive (from a larger input attenuator) from 80w would result in less outpu

Re: [Elecraft] KPA-1500 Power Output Variation

The internal attenuator is only rated for short term usage in cases of over drive or high reflected power. Any hw modification forcing it on will risk damage to the input attenuator components. 73, Eric elecraft.com _..._ > On Aug 24, 2019, at 3:21 PM, Andy Durbin wrote: > > "I believe tha

Re: [Elecraft] KPA-1500 Power Output Variation

Jack, Thanks for the idea.  I've not checked power in the drive line from the K-3.  However, when running the K-3 barefoot with the amp on or off at any power level I see none of these power changes in the K-3 output. Other than my previous comment about drive levels, I have to wonder if it

Re: [Elecraft] KPA-1500 Power Output Variation

Jim; It would be interesting to see the source of the variance. You might insert the Bird between the transceiver and the KPA to see if there is any variance there. The amplifier has fixed gain - it has no ability to vary its gain during transmission other than a protective pad that is inserted

Re: [Elecraft] KPA-1500 Power Output Variation

Don, I'm seeing the power changes on the front panel of the amp, on the Utility, and on the Bird external to the amplifier.  The Bird 2500w slug is about 40 years old, so it probably needs recalibrating.  Still, I can see the relative differences at all 3 spots.  There is no fault in the amp

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