N5ESE's T1 review -- excellent, but one correction

[wayne burdick]

Monty,

Thanks for comprehensive review of our T1 ATU
(http://www.dit-dididit-dit.com/t1_atu.htm). I'm glad it worked well
for you in field tests. We may make a few assembly and owner's manual
tweaks based on your feedback. (We could have used you as a field
tester :)

One important comment: There is definitely no need to use stacked cores
for both transformers in the SWR bridge. Balance is excellent even with
a stacked core at transformer T2 only, because the characteristics of
the bridge are set strictly by the turns ratio, which is the same on
both transformers (8:1). There is also no need for a stacked core at
transformer T1 for power dissipation reasons, since only T2 sees the
effect of the voltage step-up and corresponding core heating. We have
fully tested the unit at its maximum rated power with just the one
stacked core.

We did send out an incorrect version of the errata sheet to a few
builders that claimed 7 turns were required on T2. Hopefully you got
the word to use 8!

73,
Wayne
N6KR

---

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[Leigh L. Klotz Jr WA5ZNU]

I just finished my T1 and am trying it out on a trip now with my FT817.  
(I have my KX1 as a backup.)

I was confused by the battery clip instructions too, as the diagram for
installing them takes some time to orient.  But I figured out that when
installing the battery, the narrow tab goes to the battery's narrow
post, and the wide tab goes to the battery's wide post.  I didn't see
this in the manual, and it is kind of obvious once you figure it out,
but noting it in the manual might be soothing.

I was also confused by "face down" for the bottom of the chassis in the
final instalation of the board into the case.  Again, obvious once you
start to do it, but it wasn't clear to me whether the face of the bottom
was the closed side or the open side (whixh would be the face of the
completed box).

Despite my tightening the screw on the GND lug with needle-nose, it was
loose after I soldered it. I don't know if it will get loose again.  
Perhaps I have the washer in the wrong place.

Leigh / WA5ZNU

On Tue, 5 Apr 2005 8:11 pm, wayne burdick wrote:

> Monty,
>
> Thanks for comprehensive review of our T1 ATU
> (http://www.dit-dididit-dit.com/t1_atu.htm). I'm glad it worked well
> for you in field tests. We may make a few assembly and owner's manual
> tweaks based on your feedback. (We could have used you as a field
> tester :)
>
> One important comment: There is definitely no need to use stacked cores
> for both transformers in the SWR bridge. Balance is excellent even with
> a stacked core at transformer T2 only, because the characteristics of
> the bridge are set strictly by the turns ratio, which is the same on
> both transformers (8:1). There is also no need for a stacked core at
> transformer T1 for power dissipation reasons, since only T2 sees the
> effect of the voltage step-up and corresponding core heating. We have
> fully tested the unit at its maximum rated power with just the one
> stacked core.
>
> We did send out an incorrect version of the errata sheet to a few
> builders that claimed 7 turns were required on T2. Hopefully you got
> the word to use 8!
>
> 73,
> Wayne
> N6KR
>
> ---
>
> http://www.elecraft.com
>
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[Tom Hammond-3]

Hi Leigh:

>Despite my tightening the screw on the GND lug with needle-nose, it was
>loose after I soldered it. I don't know if it will get loose again.
>Perhaps I have the washer in the wrong place.

For what it may be worth, I used a flat washer on BOTH sides of the plastic
case (up against the case itself). Then, I used a hand-held socket to
tighten the nut. Using the flat washers allowed me to apply a higher amount
of force to tighten the nut since they spread the compressive forces out of
a slightly wider area of plastic.

I also used two flat washers between the nut and the thumbscrew, so I can
sandwich the wire between the washers and not have the thumbscrew try to
expel the wire as it's being tightened down.

I also used a slightly longer screw and then used a pair of heavy-duty wire
cutters to impart a 'bunged-up thread' right at the end of the screw. this
keeps the thumbscrew from being accidently unscrewed and lost.

73,

Tom   N0SS

[Andrew Moore-4]

I used Spectrogram to set up my K2's filters.  When lining up the
frequency peak with the marker for my preferred sidetone (650 Hz in my
case), the typical display shows the usual bandwidth shape, plus a
relatively sharp (and very narrow bandwidth) spike slightly offset from
the center of the overall filter bandwidth.  Something like this:

http://www.photogs.org/filters.jpg

Do I aim for putting the marker on the sharp peak (slightly offset from
center), or the approximate center of the wider bandwidth shape?

--Andrew, NV1B


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[Don Wilhelm-3]

Andrew,

That spike looks like an actual signal within the passband.  It may be some
kind of pickup in the noise generator you are using or on the connecting
cable (coax?), or it could be pickup in the audio path to the computer.  It
certainly does not look like any shape that exists in the actual filter, so
NO - do not set it to line up with the marker.

Change the K2 VFO to a different frequency and see if it moves - if so, it
is an RF signal, if it doesn't move, it is likely an extra audio tone coming
from somewhere (and it may not be in the K2 - and likely is not).  You could
probably just ignore that spike too.

73,
Don W3FPR

> -----Original Message-----
>
> I used Spectrogram to set up my K2's filters.  When lining up the
> frequency peak with the marker for my preferred sidetone (650 Hz in my
> case), the typical display shows the usual bandwidth shape, plus a
> relatively sharp (and very narrow bandwidth) spike slightly offset from
> the center of the overall filter bandwidth.  Something like this:
>
> http://www.photogs.org/filters.jpg
>
> Do I aim for putting the marker on the sharp peak (slightly offset from
> center), or the approximate center of the wider bandwidth shape?
>
> --Andrew, NV1B
>
>

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[Tom Hammond-3]

Hi Andrew:

>I used Spectrogram to set up my K2's filters.  When lining up the
>frequency peak with the marker for my preferred sidetone (650 Hz in my
>case), the typical display shows the usual bandwidth shape, plus a
>relatively sharp (and very narrow bandwidth) spike slightly offset from
>the center of the overall filter bandwidth.  Something like this:
>
>http://www.photogs.org/filters.jpg
>
>Do I aim for putting the marker on the sharp peak (slightly offset from
>center), or the approximate center of the wider bandwidth shape?

It appears you already have it set correctly. You want the center of the
passband (not an errant peak) to be over the frequency marker.

Now, this having been said, that sharp peak you illustrated, is it there
ALL THE TIME? If so, that's very unusual... and it might indicate that
there was a continuous carrier (though weak) within the passband of the
filter when you were performing the alignment.

Did you use a noise generator or just band noise? I suspect band noise, and
if so, that might account for the singular peak.

73,

Tom   N0SS

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[Andrew Moore-4]

> It appears you already have it set correctly. You want the center of the
> passband (not an errant peak) to be over the frequency marker.
>
> Now, this having been said, that sharp peak you illustrated, is it there
> ALL THE TIME? If so, that's very unusual... and it might indicate that

The sharp peak was there all the time; I used band noise as the source.
It must have been a signal (ham or locally generated).  Filters are now
aligned and as an added bonus all but the narrowest filter have the same
pitch.

Thanks to all who replied.

Now if only my paddle would arrive I could get on the air.  Everything
else on #4778 is finished.

--Andrew


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[Mark J. Schreiner]

About one year ago when I built a RockMite-40 and was about to try it I heard somebody calling CQ on 7040 kHz.  I quickly plugged in my Bencher paddles to find that only one side was working and the other side didn't (new stereo 1/8" plug from R.S. was bad).  Couldn't find my straight key right off (sorry, I had moved a couple of years before and still haven't finished unpacking yet).  So, I quickly found another 1/8" plug which I clipped some wires to and tapped out my reply for my first QRPp QSO with the RockMite-40, from Allentown, PA to Wilmington, DE!  This relates to the thread about a bad fist as well, as you can imagine.  But I guess it wasn't so bad, or at least when I explained and appologized in advance to the guy in DE he must have given me great room for error, but was still able to copy me okay.  I was horrified as it was the worst code I think I had ever sent!  It was classic, though, to have a Morse code QSO by literally tapping two wires together.

Mark, NK8Q
K2 #4786
>From: Andrew Moore <[hidden email]>
>Date: Wed Apr 06 14:02:59 CDT 2005
>To: [hidden email]
>Subject: Re: [Elecraft] spectrogram question

>> It appears you already have it set correctly. You want the center of the
>> passband (not an errant peak) to be over the frequency marker.
>>
>> Now, this having been said, that sharp peak you illustrated, is it there
>> ALL THE TIME? If so, that's very unusual... and it might indicate that
>
>The sharp peak was there all the time; I used band noise as the source.
>It must have been a signal (ham or locally generated).  Filters are now
>aligned and as an added bonus all but the narrowest filter have the same
>pitch.
>
>Thanks to all who replied.
>
>Now if only my paddle would arrive I could get on the air.  Everything
>else on #4778 is finished.
>
>--Andrew
>
>
>_______________________________________________
>Elecraft mailing list
>Post to: [hidden email]
>You must be a subscriber to post to the list.
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>
>Help: http://mailman.qth.net/subscribers.htm
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[roncasa]

I'm gonna' call you "Sparky" from now on!
By the way, nice story (smile)

Ron wb1hga
"CW, an esoteric experience"

 
Mark writes:
  (snip)  horrified as it was the worst code I think I had ever sent!  It
was classic, though, to have a Morse code QSO by literally tapping two wires
together.

 

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[Kevin Rock]

One op, about a year ago, was so excited to hear the Elecraft Net he
stopped his car and worked me mobile.  He did not have a key in the car
but wound up using a piece of zip cord from a pile of junk in the back
seat of his car.  He somehow got it stripped and hooked up to his rig.  
Then I got his call at about 8 wpm.  So I slowed down and worked him.  
Welcome to ECN says I.  Got his info where he told me he had an Elecraft
rig but it was at home and he was working me mobile.  I did not get the
rest of the story until he got home and emailed me.  I have worked him
later.  He has a very fine fist once given the proper tools.  Did a
creditable job with a few wires tapping his metal dash board though!!!
    Kevin.   KD5ONS


On Wed, 06 Apr 2005 14:17:31 -0500 (CDT), <[hidden email]> wrote:

> About one year ago when I built a RockMite-40 and was about to try it I
> heard somebody calling CQ on 7040 kHz.  I quickly plugged in my Bencher
> paddles to find that only one side was working and the other side didn't
> (new stereo 1/8" plug from R.S. was bad).  Couldn't find my straight key
> right off (sorry, I had moved a couple of years before and still haven't
> finished unpacking yet).  So, I quickly found another 1/8" plug which I
> clipped some wires to and tapped out my reply for my first QRPp QSO with
> the RockMite-40, from Allentown, PA to Wilmington, DE!  This relates to
> the thread about a bad fist as well, as you can imagine.  But I guess it
> wasn't so bad, or at least when I explained and appologized in advance
> to the guy in DE he must have given me great room for error, but was
> still able to copy me okay.  I was horrified as it was the worst code I
> think I had ever sent!  It was classic, though, to have a Morse code QSO
> by literally tapping two wires together.
>
> Mark, NK8Q
> K2 #4786

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