Re: [Elecraft] A few thoughts on the AXE1 extender

This reminds me of one of the first CQP county expeditions I was involved in. Out plan was to use the Icom 706MII in the car on SSB as the main radio with the Little Tarheel screwdriver antenna mounted on the liftgate. The it proved too hard to tune the antenna with the Icom, so I switched to

[Elecraft] A few thoughts on the AXE1 extender

It's a poorly kept secret that the AXE1 40 meter extender for the AX1 whip is now available...info at: https://elecraft.com/products/axe1_40-meter-antenna-extender I've been using a prototype AXE1 all summer, so I thought I'd share my experience. The AX1 (with or without the extender) is

[Elecraft] Elecraft CW Net Report

Good Afternoon,    It got hot this week.  As the temperature rose to the mid 90s the humidity dropped from its summer normal of ~ 50% down to 20%. At the same time the wind rose from 5 mph to 25 mph.  I had never seen the fire danger sign increase by two steps in one day until this week. 

Re: [Elecraft] KPA-1500 on digital modes

If my efficiency screenshots from earlier did not get through the reflector, you can see the results in a JPG file here: https://hamprojects.info/hamprojects-download-page/#elf_l1_b3RoZXJz -larry (K8UT) -- Original Message -- From: "Roger D Johnson" To: "Elecraft List" Sent:

Re: [Elecraft] K3--Too much ALC creates energy on opposite sideband?

I assume the measurements with bare K3/K3S were using 100w internal amp. I wonder how the 10w version of these radios Tx IMD perform? On 6m, I run with the KXPA100 at 11w output (K3 at very low output) to drive a 1000w Harris surplus TV linear (which is rated to 1600w continuous duty).

Re: [Elecraft] KPA-1500 on digital modes

Dear OMs and YLs, Remember that a small reduction in power, current or voltage for most electronic components gives a manifold increase in reliability. Not only is it better for other users but I will bet the KPA1500 is a lot happier (more reliable) for a 20% drop in output power which is

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

Re: [Elecraft] KPA-1500 on digital modes

I don't believe this is a class C amp. We should discuss the relevance of different classes of operation of amps, and let's be honest... it will be most efficient at max output regardless of class I believe. 73, Bill K9YEQ https://wrj-tech.com/ -Original Message- From:

[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

Re: [Elecraft] 8 pole Inrad filters for sale

Hi, The 250 is sold. Thanks -Original Message- From: elecraft-boun...@mailman.qth.net On Behalf Of Tom Sent: August 28, 2019 9:06 PM To: elecraft@mailman.qth.net Subject: Re: [Elecraft] 8 pole Inrad filters for sale Hi, BTW they are $80 each. 73 Tom -Original Message- From:

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

Re: [Elecraft] K3--Too much ALC creates energy on opposite sideband?

Has anyone collected IMD data on the different version of KPA3A amps?   I seem to recall measuring IMD when I first got my K3S, s/n 10163.   Since that time I' have experienced 2 failures of the KPA3A in my radio.   Elecraft replaced the last one with a newer "more stable" version.   I do run

Re: [Elecraft] Transmit Equalizers and FT4/8

Pete, Digital A is the correct K3 setting for all digital modes except RTTY. The equalizer is disabled in Digital A. The computer should feed the Line Input. Both the KPA500 and KPA1500 are least efficient on 6M, which means that they produce the greatest heat on that band. My KPA1500

[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

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

Re: [Elecraft] K3--Too much ALC creates energy on opposite sideband?

There is a big difference between "energy on opposite sideband" and hearing the opposite sideband. If you switch to the opposite sideband and can clearly copy the intelligence, then the issue is sideband suppression. If you hear unintelligible audio from the offending signal, that is splatter

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] K3--Too much ALC creates energy on opposite sideband?

Conrad and I have corresponded about this in the past. He is absolutely correct in worrying about the IMD performance of the K4.  I bought my K3S after being disappointed with the K3 TX IMD and thinking that the FETs would be better.  How wrong I was.  IMD was no improvement and reliability

Re: [Elecraft] Transmit Equalizers and FT4/8

" the tones used CAN be much lower than 1500 Hz. I have worked station that were down to 200 Hz. And the the tones can go as high as the sending stations transmitter will allow, typically less than 2.7-2.8 KHz. The transmitted signal frequency is the suppressed carrier frequency plus the

Re: [Elecraft] Transmit Equalizers and FT4/8

Equalizers introduce phase shift.  Even the very best ones do that.   Thus for a phase shift audio signal, either transmitted or received, use of any EQ can and will introduce phase shift in the audio path.   It is not at all advisable to have this occur with digital signals. It is highly

Re: [Elecraft] Transmit Equalizers and FT4/8

Andy, First, I suggest that you use data A mode. This will automatically set the equalizer and audio compressor correctly making it so that you don't need to play with adjustments, except level. Second, the tones used CAN be much lower than 1500 Hz. I have worked station that were

[Elecraft] Transmit Equalizers and FT4/8

"Am I right to assume that I should set it back to flat when doing FT4/8?" If you do FT4 and FT8 right, as in using WSJT-X "split mode", the signal modulation frequency cannot be outside the range 1,500 to 2,000 Hz. Why would it be desirable to have a flat TX equalizer response? Flat is

Re: [Elecraft] Transmit Equalizers and FT4/8

No, that was indeed a typo.  The way it is normally set for SSB emphasizes the highs. Trouble is, I don't operate phone enough to catch things like that hi. 73, Pete N4ZR Check out the Reverse Beacon Network at , now spotting RTTY activity worldwide. For spots, please

Re: [Elecraft] Transmit Equalizers and FT4/8

Hi Pete, Are you sure that your minimizing SSB voice frequencies above 2000 Hz? I hope that's a typo, because its fundamentally incorrect. Its perfectly okay to use SSB mode with FT8 and other digital modes, but you MUST set TX equalization to flat and CMP to fully counterclockwise. The

Re: [Elecraft] Transmit Equalizers and FT4/8

Pete, If you are using DATA A mode, that is done for you automatically. OTOH, if you are "doing it the hard way" and using USB, then the answer is yes, and also set compression to zero. 73, Don W3FPR On 8/29/2019 9:33 AM, N4ZR wrote: I normally run my K3's TX equalizer to minimize low

Re: [Elecraft] Transmit Equalizers and FT4/8

If you run in data mode, the TX and RX equalizers are taken out of the loop. No need to reset them. Joe, KO8V > On Aug 29, 2019, at 09:33, N4ZR wrote: > > I normally run my K3's TX equalizer to minimize low frequencies and > frequencies above 2000 Hz. Am I right to assume that I should set

Re: [Elecraft] Transmit Equalizers and FT4/8

Pete, For FT4/FT8 or any other digital mode TX Equalization is set flat automatically when you select DATA mode. 73, Mark, WB9CIF -Original Message- From: elecraft-boun...@mailman.qth.net On Behalf Of N4ZR Sent: Thursday, August 29, 2019 13:34 To: Elecraft List Subject: [Elecraft]

[Elecraft] Transmit Equalizers and FT4/8

I normally run my K3's TX equalizer to minimize low frequencies and frequencies above 2000 Hz.  Am I right to assume that I should set it back to flat when doing FT4/8? -- 73, Pete N4ZR Check out the Reverse Beacon Network at , now spotting RTTY activity worldwide.

Re: [Elecraft] KPA-1500 on digital modes

It's interesting that the heat that has to be dissipated is pretty close to 1000 watts in all these scenarios! Running the amp at less than full power buys you nothing. 73, Roger On 8/29/2019 8:38 AM, Larry (K8UT) wrote: Pete, I don't run my amp at full legal limit on digital modes, but

[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

Re: [Elecraft] KPA-1500 on digital modes

Pete, I don't run my amp at full legal limit on digital modes, but typically set the input power for about 1000 watts output. One of the interesting characteristics of the amp is increased efficiency as power increases. At 600 watts efficiency is only 38%, whereas at 1000 efficiency increases

Re: [Elecraft] K3--Too much ALC creates energy on opposite sideband?

This thread instigated some experiments here.  In analyzing TX IMD in both my K3 and K3S, I've made probably hundreds of two-tone measurements using the built-in two-tone generator.  But in all of these measurements I never questioned what the audio level was, since it's not adjustable, except

Re: [Elecraft] K3--Too much ALC creates energy on opposite sideband?

I have measured the TX IMD performance of my and 2 other K3S transceivers. In my opinion it is not possible to have anything other than mediocre TX IMD performance from a K3S or a K3 at ANY power level. I am so disappointed with this aspect of the K3S. The mass market and cheap IC-7300 is

[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

Re: [Elecraft] Elecraft 20th Anniversary

Hi, I am coming back after some time to ask if you already found the time to make pics of your collection. Specially I am looking for Safari-4 and Koala pics as I am compiling the all Elecraft line-up from the first product until the K4HD...hi. Thanks, - 73 - Petr, OK1RP "Apple &