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KPA500 Clicks & Pops

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Bob McGraw - K4TAX

Re: OT - Power and my earlier post

Yes and when running PSK-31 if you don't get IMD reports of between -21dB and/or more like -29dB then most likely something at your station needs improvement. Usually overdrive either in the audio system or RF path is a contributing factor. ALC action is often one culprit. Some radios leave the SP or EQ circuits in the path. They should be OFF or bypassed.

Bob, K4TAX

Sent from my iPhone

> On Oct 17, 2018, at 9:35 PM, Walter Underwood <[hidden email]> wrote:
>
> Specifically about PSK31, that encoding needs a very linear transmit system. The 25 W recommendation keeps the signal and the peaks in the linear region of most 100 W amps. Modes that do not use phase shift keying on a single carrier might not have the same linearity requirements.
>
> A clean 25 W PSK31 transmission might be heard better than a distorted 100 W PSK31 transmission.
>
> wunder
> K6WRU
> Walter Underwood
> CM87wj
> http://observer.wunderwood.org/ (my blog)
>
>> On Oct 17, 2018, at 6:52 PM, Jim Brown <[hidden email]> wrote:
>>
>> On 10/17/2018 6:36 PM, Bob McGraw K4TAX wrote:
>>> At the same time, many of my contacts are made with 50 watts or less.
>>
>> Yup. I mostly use FT8, JT65, and MSK144 on 6M and 160M. I generally run as much power as I can on 6M, and on 160M to work EU or AF. OTOH, I'm still trying to finish 160M WAS QRP (need VT and SC), and recently worked the KH1 expedition on 160 with 5W using FT8. They were specifically using FT8 trying to put some EU stations in the log. I've since learned that AA7JV was the op.
>>
>> 73, Jim K9YC
>>
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Edward R Cole

Re: KPA500 Clicks & Pops

In reply to this post by Bob McGraw - K4TAX

Guess I got a few replies to my comments. I will try to respond to
all in this one:

James-w6jhb: Bob did reply back and was referring to using digital
on 160m, which is harder to work than upper bands like 20m. More
power helps. I have done some operating on 600m (before it became a
ham band) and FCC limits 630m operations to 5w EIRP which is a real
test of ability and equipment. Yet CW and digital modes are making
some surprising DX contacts on a band that is not known for
ionospheric prop (D-layer only).

Wes-N7WS: Uh, I never mentioned running 10mw. I did suggest 10% (of
full power) might be quite adequate on digital. So that would be
150w for a KPA1500 or 50w for a KPA500. Yes, I have heard that some
are making HF digital contacts at 10mw (or such) but that is a
personal challenge (as I see it). Again 160m is a special case with
limited prop as compared to 20-10m. I would probably use full power
if I were on 160m (currently that is 100w from my KXPA100).

Many still use CW on eme but that is on 432 and up these
days. 6m-eme is 100% digital and 2m-eme is 99%. I made some of my
early 2m contacts using CW.

Fred-K6DWG: Sorry but you are not correct on how JT65, FT8, and
other WSJT modes work. Yes, you run the receiver RF bandwidth at
nominal 2.5-KHz (SSB) width but that is just to make operating with
various Doppler offsets easier (as you can see all the signals within
the wider bw. But the detection bw of JT65 is 4.7 Hz and that is a
large part of why it is approx 10-dB more sensitive than CW. S+N/N
of 4.7 Hz over 50-Hz (apparent detection bw of the human ear/brain)
does reduce the noise power vs signal. JT-65 and other of these
digital modes are FSK with the sw detecting single tones. The shift
freq of JT-65 is over a wider range but that does not affect
detection. I believe psk-31 is much wider detection bw (often
referred to as RBW) so it is not near as good for weak signal
operation. I understand that more power may be needed to overcome HF
noise floors that are much higher than VHF+ where eme is done. Still
not convinced that one needs QRO for terrestrial path loss. QRM
maybe requires it. I have no local eme QRM. Pile ups are on the
receiving end of multiple stations calling me (KL7 is rare on eme).

Bob-K4TAX: Yeah I get it. It depends on frequency band as far as
how well signals reach. As I already stated, I never mentioned
10mw (Wes thru that into the discussion) but I do think one does not
need to run the same power as a CW or SSB contact if using a NB
digital mode. Of course that varies with band conditions and
distance worked. FT8 (in particular) is getting thru when poor band
conditions prevent CW/SSB from happening. Using the power necessary
is a given - just don't see that running (near) max power is
necessary (all the time which seems to be the HF mentality -
regardless of mode or conditions).

BTW my 495 KHz 5w EIRP CW signal has been detected about 4,000 miles,
so its quite possible. FCC limits 630m ham operation to 5w EIRP
(which is about what I get running 100w output from my PA and due to
4% antenna efficiency).

Thanks for bearing with this multi-part reply; figured it would use
less list bandwidth with this approach. Probably not worth further
on-list commentary; reply direct to me if any of you want to continue,

73, Ed - KL7UW
http://www.kl7uw.com
Dubus-NA Business mail:
[hidden email]

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Eric Swartz - WA6HHQ

Re: KPA500 Clicks & Pops

Administrator

In reply to this post by Wes Stewart-2

Folks, this endless topic has been discussed before in depth on thenlist and is available in the archives. In the interest of keeping list volume and SNR reasonable, lets end this thread.

In general, please take discussions and arguments about appropriate power levels for any mode off list for discussion.

73,
Eric
Moderater
elecraft.com
_..._

> On Oct 17, 2018, at 3:13 PM, Wes Stewart <[hidden email]> wrote:
>
> Ed,
>
> Not picking on you personally either but I fail to understand this attitude that because some digital mode or another can make QSOs with 10 mW on some path, everyone else should run only10 mW.
>
> I consider my K3S + KPA500 to be a 500W transceiver (with push buttons for selecting bands) and that's the way I run it. Often, especially when I'm beating myself up on 160, I wish for more power. When some of my DX club buddies tease me about running QRP should I ask them to lower their power so we have parity?
>
> Wes N7WS
>
> ps: When I ran 2-meter EME 30 years ago we actually heard the signals by ear.
>
>
>> On 10/17/2018 1:34 PM, Edward R Cole wrote:
>> Bob,
>>
>> A question about your statement that you run 400w in digital modes (assuming you mean FT8, etc. and not RTTY). That seems pretty extreme.
>>
>> I pretty much ignore HF usage as I am not on HF very much (primarily an eme'er on 6m+). But back at the beginnings of psk-31 I built a HB interface* for my FT-847 and did a bit of 14.070 operating (with a dipole). I was recommended to not exceeding 25w (or 25% full power). Everyone seemed to do quite well on psk-31 with low power and some ran at QRP (<5w).
>>
>> I do not get why I hear of running high power digital when 10% would communicate easily. You may remonstrate me for running 2m-eme at 1500w on JT-65 but the path loss on 2m-eme is 254 dB+ and contacts are made over a half-million mile path. Certainly not encountered by terrestrial HF users.
>>
>> Not picking on you personally, but you made the statement so figure maybe would reply. Just curious.
>>
>> 73, Ed - KL7UW
>> * that I/F later was used for JT-65 on eme 15 years ago. Now use my K3 directly connected.
>>
>> Date: Tue, 16 Oct 2018 16:59:15 -0500
>> From: Bob McGraw K4TAX <[hidden email]>
>> To: "Dauer, Edward" <[hidden email]>
>> Cc: "[hidden email]" <[hidden email]>
>> Subject: Re: [Elecraft] KPA500 Clicks & Pops
>> Message-ID: <[hidden email]>
>> Content-Type: text/plain; charset=us-ascii
>>
>> I do run 400 watts or so on digital modes. Issues are not really noted on SSB or CW modes.
>>
>> I've set the Fan Ctr to 2 and 3 and still noted the issue
>>
>> Was recently showing my K Line to some hams friends. They commented rather negatively on the point.
>>
>> Bob, K4TAX
>>
>>
>> 73, Ed - KL7UW
>> http://www.kl7uw.com
>> Dubus-NA Business mail:
>> [hidden email]
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>>
>
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ANDY DURBIN

KPA500 Clicks & Pops

In reply to this post by ANDY DURBIN

This will only be of interest to a few KPA500 owners - those who don't think loud clicks/ticks/pops are acceptable.

In the message below I reported that I had lost interest in my investigation because the click/ticks had stopped. That message is dated October 2018. Late March the ticks came back and now, early April, they are back to the annoying level that I experienced in 2018. What's different? Room temperature and consequently the powered on but not transmitting temperature of the KPA500 is much lower in the winter months.

Although I lost interest in the investigation I continued to record PA temperature, heat sink temperature, and Z bracket temperature for every transmission I made. That's a lot of data but differences between summer and winter operating conditions may be interesting. I plan to pick a few mid winter samples to compare with a few peak summer samples.

Has anyone else who is annoyed by KPA500 click/ticks noticed any correlation with room temperature?

73,
Andy, k3wyc

________________________________
From: ANDY DURBIN
Sent: Tuesday, October 16, 2018 6:52 AM
To: [hidden email]
Subject: KPA500 Clicks & Pops

I found this quite annoying too. My approach was to try to understand how the Z bracket temperature varied relative to the heat sink temperature. I placed a thermistor on the front end of the Z bracket and another on the heat sink fin closest to the Z bracket. I logged the standard PA temperature and these additional thermistor temperatures for every transmission I made (still do). I established baseline temperature characteristics and planned to use this data to see if any mods I made changed the characteristics.

Surprise! - When I though I had enough data to move on to the next step in the investigation it stopped clicking.

Adding the thermistors only required removal of the front panel and the Z bracket screws were no touched. It continued to click after the thermistors were added and then stopped a few weeks later.

The data show the rapid change in temperature is at the PA sensor only. The heat sink and Z bracket change much more slowly and never have a large temperature difference. Their temperatures do cross over though.

One problem with temperature logging is that I had no data, except for my test notes , on the clicks themselves. I had planned to added some inexpensive sound detection modules and add this data to the logger. That's on hold until the clicks come back.

It's really nice not to have the amp click continuously on every FT8 transmission. I wish I knew what fixed it.

73,

Andy k3wyc
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Bob McGraw - K4TAX

Re: KPA500 Clicks & Pops

Come to think about it, I haven't heard mine click and pop in quite some
time. I doubt that it's seasonal, but that is an interesting twist. I
doubt that my room or the dormant equipment varies over +/- 2°F over any
given 24 hr period.

73

Bob, K4TAX

On 4/7/2019 1:11 PM, Andy Durbin wrote:

> This will only be of interest to a few KPA500 owners - those who don't think loud clicks/ticks/pops are acceptable.
>
> In the message below I reported that I had lost interest in my investigation because the click/ticks had stopped. That message is dated October 2018. Late March the ticks came back and now, early April, they are back to the annoying level that I experienced in 2018. What's different? Room temperature and consequently the powered on but not transmitting temperature of the KPA500 is much lower in the winter months.
>
> Although I lost interest in the investigation I continued to record PA temperature, heat sink temperature, and Z bracket temperature for every transmission I made. That's a lot of data but differences between summer and winter operating conditions may be interesting. I plan to pick a few mid winter samples to compare with a few peak summer samples.
>
> Has anyone else who is annoyed by KPA500 click/ticks noticed any correlation with room temperature?
>
> 73,
> Andy, k3wyc
>
>
> ________________________________
> From: ANDY DURBIN
> Sent: Tuesday, October 16, 2018 6:52 AM
> To: [hidden email]
> Subject: KPA500 Clicks & Pops
>
>
> I found this quite annoying too. My approach was to try to understand how the Z bracket temperature varied relative to the heat sink temperature. I placed a thermistor on the front end of the Z bracket and another on the heat sink fin closest to the Z bracket. I logged the standard PA temperature and these additional thermistor temperatures for every transmission I made (still do). I established baseline temperature characteristics and planned to use this data to see if any mods I made changed the characteristics.
>
>
> Surprise! - When I though I had enough data to move on to the next step in the investigation it stopped clicking.
>
>
> Adding the thermistors only required removal of the front panel and the Z bracket screws were no touched. It continued to click after the thermistors were added and then stopped a few weeks later.
>
>
> The data show the rapid change in temperature is at the PA sensor only. The heat sink and Z bracket change much more slowly and never have a large temperature difference. Their temperatures do cross over though.
>
>
> One problem with temperature logging is that I had no data, except for my test notes , on the clicks themselves. I had planned to added some inexpensive sound detection modules and add this data to the logger. That's on hold until the clicks come back.
>
>
> It's really nice not to have the amp click continuously on every FT8 transmission. I wish I knew what fixed it.
>
>
> 73,
>
> Andy k3wyc
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
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> Post: mailto:[hidden email]
>
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>