RE: RE : [Elecraft] Oscilloscope help part 2 ;-)

[Robert McGwier]

Jean Francois:

I recently purchased a 4 channel, auto scaling, 400 Mhz Tektronix
scope for under $500 US on Ebay and this included 3 probes, two
of them 400 Mhz, one 100 Mhz.  This is much more capable
than what you are talking about.  Have your looked there lately?

Bob
N4HY

-Original Message-
From: [EMAIL PROTECTED]
[mailto:[EMAIL PROTECTED] Behalf Of Jean-François
Ménard
Sent: Tuesday, June 22, 2004 3:27 PM
To: elecraft@mailman.qth.net
Subject: RE : [Elecraft] Oscilloscope help part 2 ;-)


Thanks Ron for your clear answer. I understand, I think this is will be fine
for me for now. You know higher they can take, higher will be the price
also. This scope is actually around 500$ CDN That the maximum I can
affort for a scope for now... But maybe in the futur, I could get a hand on
a better scope (maybe a used one) for a good price.

Anyway, for now, I think it will be very handy, at least for my
understanding of a scope and for basic readings I need.

Another good message I will keep in my files !!!

Thanks again.



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Re: [Elecraft] KSB2 Mod for Increased Mike Gain

[Earl W Cunningham]

Roy, W4WFB wrote:

"Does anyone remember a mod where a 5.6K resistor replaces the 1K
resistor at R14 on the KSB2 board for increased mike gain?  I cannot find
my notes on this mod.  I thought it was a KI6WX mod, but I can't find it
in John Grebenkemper's write-ups."
==
Although this is a popular mod for those using low-output dynamic mikes,
I don't believe it was ever included in the "official" mod list on the
Elecraft Web site.

I replaced R14 with a 6.8K resistor on my KSB2 to get adequate mike gain.
 Before that, I had to holler into the mike to get the VOX to trip.

73, de Earl, K6SE
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RE: [Elecraft] KSB2 Mod for Increased Mike Gain

[Ron D'Eau Claire]

Yes. The original suggestion was to swap R14 and R2 on the SSB board. That
raised the input resistance and improved the mic sensitivity a great deal. 

After some testing, it was decided that reducing R2 was a bad idea. Doing so
could allow the Speech IC, U3, to over-drive balanced modulator U5. 

So leave R2 at 5.6 k. You can use any value handy from 5 to 10k for R14 to
improve the mic audio level. 

Note that if you do that and select to attenuate the mic input level with
the MENU commands (set SSBA = 1), the amount of attenuation you get won't be
10 dB any longer. Few ops seem to use the mic input attenuator anyway or, if
they do, care if the attenuation is actually 10 dB. 

Ron AC7AC

-Original Message-
Does anyone remember a mod where a 5.6K resistor replaces the 1K resistor at

R14 on the KSB2 board for increased mike gain?  I cannot find my notes on
this 
mod.  I thought it was a KI6WX mod, but I can't find it in John 
Grebenkemper's write-ups.  Thanks.  Roy Morris  W4WFB 


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Re: [Elecraft] Fully loaded K2 for sale

[js]

Hi Group,

I have just completed a K2 with all of the options except the antenna tuner.
This K2 was built for sale.  It is new and unused except some test runs. It
includes the following options:

KSB2 - SSB adaptor
KNB2 - noise blanker
KBT2 - internal battery kit
KDSP2 - dsp module
K160RX - 160 metre module and 2nd RX antennna

The rig has been carefully aligned with spectrogram.  The current price for
all of the above including shipping is about USD1,110. My price is USD 1,299
plus shipping.

Warranty: I will repair any K2 that's fails due to my workmanship within 90
days. Shipping is not included on warranty work. New radios have a one year
parts warranty from Elecraft.  Purchase documents will be provided for
reference.

I have built 6 K2's to date including 1 KPA100's and many K2 options. Please
email me direct if you are interested in this K2
TNX & 73

Johnny Siu VR2XMC

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[Elecraft] solution to Q7/Q8 shorting to ground

[Brian Mury]

K2 #4283 has been on the air for a couple days or so.

I thought I'd pass on something that might help others. After bolting on
the heatsink (the bottom rear part of the case) to Q7 and Q8, the manual
says to check that the collectors are not shorted to the case. Mine
were. I had the heatsink on and off quite a few times trying to find the
problem. Everything looked fine, but as soon as I would tighten the
screws the short would reappear.

I finally noticed that the four holes (for Q7, Q8 and the 2D fastener)
had burrs around their edges from when they were drilled. When I would
tighten the screws, the burrs would get pushed up inside the hole in the
transistors, causing the short. Removal of the burrs solved the problem.

-- 
73, Brian
VE7NGR

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[Elecraft] KSB2 Mod for Increased Mike Gain

[Unifiedtx]

Does anyone remember a mod where a 5.6K resistor replaces the 1K resistor at 
R14 on the KSB2 board for increased mike gain?  I cannot find my notes on this 
mod.  I thought it was a KI6WX mod, but I can't find it in John 
Grebenkemper's write-ups.  Thanks.  Roy Morris  W4WFB 
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Re: [Elecraft] Metal Oxide Power Resistors Inductive?

[Stuart Rohre]

Trev,
Way back in 1960's  I wondered the same about Corning tin oxide resistors
like these axials.

I measured many after work with HP Vector Impedance Meters, forerunners to
the MFJ et al.

The results I got showed they were good up to 108 MHz the high end of the
4815 Z meter.  I also had run them down below 500kHz with the 4800 Z meter.

It is likely these are OK, depending on how they are deposited.  If spirals
are done solenoid style there is likely some inductance, but if wound right,
it can be canceled.
72,
Stuart
K5KVH


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Re: [Elecraft] Dumb(?) dummy load question

[Stuart Rohre]

Eric, the RS resistors are inductive, and probably wire wound and unsuited
for 50 ohm impedance to RF.   You would need compensation capacitor networks
for them for each band.

You only measured their DC values as 50 ohms.  Impedance is an AC /RF
quantity.

RS used to carry a true QRP dummy load, black with fins and coax connector.
MJF and Ten Tech sell low cost non inductive dry resistor loads.  Ten Tec's
is a kit.
73,
Stuart
k5KVH


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[Elecraft] Fully loaded K1 for sale

[Don Brown]

Hi

I just completed a K1 with all of the options except the internal battery. This 
K1 was built for sale and is new and unused. It has the 40, 30, 20, and 15 
meter four band board and also has a extra two band board set up for 80 and 17 
meters. It includes the noise blanker and internal automatic antenna tuner. It 
also includes the tilt stand. The current price for all of the above including 
shipping is about $590. My normal charge to build all of the above is $340 for 
a total of $930

Warranty: I will repair any K2,  K1 or KX1 that's fails due to my workmanship 
within 90 days. Shipping is not included on warranty work. New radios have a 
one year parts warranty from Elecraft.

I have built 14 K2's to date and 4 K1's. 5 KPA100's, 3 KAT100's and all of the 
options many times. I built Wayne and Eric's personal radios and have been a 
field tester for Elecraft several times. I was a field tester for the XV50, 
XV144 transverters and have built 5 of them. I was also a field tester for the 
KRC2 band switching box and the KPA100. I have built one KX1 with all options 
so far. I have built one or more of everything Elecraft makes including all the 
micro kits.

Please email me if you are interested in this K1

Thanks

Don Brown
KD5NDB
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Re: [Elecraft] Metal Oxide Power Resistors Inductive?

[Don Brown]

Hi

MOS resistors are not inductive at HF frequencies and make great dummy loads. 
The Elecraft DL1 and the OHR 100 watt dummy load use several MOS resistors in 
parallel or series parallel. The oxide is deposited on a ceramic base in a 
single coating so there is not any coiling to create inductance. I use them to 
make dummy loads by soldering a 51 ohm 5 watt inside a PL259 connector. You can 
use a PL259 to BNC adaptor so it will fit the K2, K1 or KX1. These loads will 
take 15 watts for a short time. I also have one of these with a 100 ohm MOS 
resistor and another with a 25 ohm resistor (2 51 ohm in parallel) that I use 
to check or calibrate the SWR bridges in the antenna tuners or KPA100. You can 
get them from Mouser in 1 watt 3 watt and 5 watt sizes

Don Brown
KD5NDB


  - Original Message - 
  From: Trevor Jacobs 
  To: elecraft@mailman.qth.net 
  Sent: Tuesday, June 22, 2004 12:35 PM
  Subject: [Elecraft] Metal Oxide Power Resistors Inductive?


  Hey Gang,

  This brings up a question I've wondered about. Are Metal Oxide power
  resistors inductive? Such as these:
  
http://www.xicon-passive.com/specs/mo.pdf
 ? I don't see a spec in the data
  sheet.

  73's Trev - K6ESE
  http://www.qsl.net/k6ese


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[Elecraft] Metal Oxide Power Resistors Inductive?

[Trevor Jacobs]

Hey Gang,

This brings up a question I've wondered about. Are Metal Oxide power
resistors inductive? Such as these:
http://www.xicon-passive.com/specs/mo.pdf ? I don't see a spec in the data
sheet.

73's Trev - K6ESE
http://www.qsl.net/k6ese


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RE : [Elecraft] Oscilloscope help part 2 ;-)

[Jean-François Ménard]

Thanks Ron for your clear answer. I understand, I think this is will be fine
for me for now. You know higher they can take, higher will be the price
also. This scope is actually around 500$ CDN That the maximum I can
affort for a scope for now... But maybe in the futur, I could get a hand on
a better scope (maybe a used one) for a good price.

Anyway, for now, I think it will be very handy, at least for my
understanding of a scope and for basic readings I need.

Another good message I will keep in my files !!!

Thanks again.

-Message d'origine-
De : [EMAIL PROTECTED]
[mailto:[EMAIL PROTECTED] De la part de Ron D'Eau Claire
Envoyé : 22 juin 2004 11:12
À : elecraft@mailman.qth.net
Objet : RE: [Elecraft] Oscilloscope help part 2 ;-)


Keep in mind, Jean-François, that if you use that 'scope to search for
distortion in a waveform, you probably shouldn't try to investigate
waveforms above 1 or 2 MHz with a "14 MHz" oscilloscope. It will work well
at 14 MHz and above for simply "peaking" a signal for maximum amplitude as
Don says, but not for looking for spikes, noise and other artifacts in a
waveform. 

That's because noise, spikes, etc., appear at frequencies much higher than
the fundamental signal. For example, if you had access to a variable
frequency square wave generator and applied it to the scope input terminal,
you'd see nice square waves on the display until you raised the frequency
above 1 or 2 MHz. Then they'd start looking less square and more rounded. As
you continue to raise the frequency by the time you raised it to 14 MHz the
waveform on your scope would look more like a sine wave than a square wave. 

That happens because the leading and trailing edges of a square wave are
really at a much higher frequency than the fundamental  frequency of the
square wave. If you look at the plot of a square wave and carefully traced
over it a sine wave whose rise and fall matched that of the leading and
trailing edges of the square wave, you'd see that many cycles of sine wave
would  fit in the space of one cycle of square wave. Unless your 'scope can
handle that higher frequency, it can't reproduce the steep shape of the
leading and trailing edges and they will look rounded. 

So you might have a really distorted signal at 10 or 15 MHz showing noise or
parasitic oscillations, etc., but on your 14 MHz scope the signal might look
like a very clean sine wave. 

In practice, the usual "rule of thumb" is that the vertical amplifier in a
oscilloscope should have about 10 times the bandwidth of the
highest-frequency signal that you want to view to see the "shape" of the
signal and to look for artifacts. That's why most 'scopes used for HF up to
30 MHz have vertical amplifier bandwidths of several hundred Megahertz. 

Let me reiterate, that is a concern only if you are looking at the shape of
the waveform. As long as you can see some vertical deflection, it is FB for
"peaking" a stage for maximum output. 

Ron AC7AC

-Original Message-

My oscilloscope have only an input amplifier bandwidth of 14 Mhz 
maximum... will it be enough to adjust all bandpass on all bands ???


Le 04-06-20, à 18:29, Don Wilhelm a écrit :

> When adjusting the bandpass filters for transmit, I do use a 'scope.
> The 'scope is doing nothing more that acting as a sensitive analog RF 
> voltmeter, so nothing complex is required on setting the 'scope time 
> base.
>
> Just connect the 'scope probe across the dummy load (I use a 10x 
> probe), press TUNE on the K2 and you should see an RF envelope display 
> on the 'scope
> face - if not adjust the vertical amp and the trigger level until 
> something
> is displayed - then set the time base so you are seeubg the CW envelope
> rather than a few cycles of the RF.
>
> As you adjust the bandpass filter, you should see the vertical 
> deflection on the 'scope face shrink and grow in response to the 
> tuning - adjust for the
> largest display height.
>
> 73,
> Don W3FPR
>
>


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RE: [Elecraft] Oscilloscope help part 2 ;-)

[Ron D'Eau Claire]

Keep in mind, Jean-François, that if you use that 'scope to search for
distortion in a waveform, you probably shouldn't try to investigate
waveforms above 1 or 2 MHz with a "14 MHz" oscilloscope. It will work well
at 14 MHz and above for simply "peaking" a signal for maximum amplitude as
Don says, but not for looking for spikes, noise and other artifacts in a
waveform. 

That's because noise, spikes, etc., appear at frequencies much higher than
the fundamental signal. For example, if you had access to a variable
frequency square wave generator and applied it to the scope input terminal,
you'd see nice square waves on the display until you raised the frequency
above 1 or 2 MHz. Then they'd start looking less square and more rounded. As
you continue to raise the frequency by the time you raised it to 14 MHz the
waveform on your scope would look more like a sine wave than a square wave. 

That happens because the leading and trailing edges of a square wave are
really at a much higher frequency than the fundamental  frequency of the
square wave. If you look at the plot of a square wave and carefully traced
over it a sine wave whose rise and fall matched that of the leading and
trailing edges of the square wave, you'd see that many cycles of sine wave
would  fit in the space of one cycle of square wave. Unless your 'scope can
handle that higher frequency, it can't reproduce the steep shape of the
leading and trailing edges and they will look rounded. 

So you might have a really distorted signal at 10 or 15 MHz showing noise or
parasitic oscillations, etc., but on your 14 MHz scope the signal might look
like a very clean sine wave. 

In practice, the usual "rule of thumb" is that the vertical amplifier in a
oscilloscope should have about 10 times the bandwidth of the
highest-frequency signal that you want to view to see the "shape" of the
signal and to look for artifacts. That's why most 'scopes used for HF up to
30 MHz have vertical amplifier bandwidths of several hundred Megahertz. 

Let me reiterate, that is a concern only if you are looking at the shape of
the waveform. As long as you can see some vertical deflection, it is FB for
"peaking" a stage for maximum output. 

Ron AC7AC

-Original Message-

My oscilloscope have only an input amplifier bandwidth of 14 Mhz 
maximum... will it be enough to adjust all bandpass on all bands ???


Le 04-06-20, à 18:29, Don Wilhelm a écrit :

> When adjusting the bandpass filters for transmit, I do use a 'scope. 
> The 'scope is doing nothing more that acting as a sensitive analog RF 
> voltmeter, so nothing complex is required on setting the 'scope time 
> base.
>
> Just connect the 'scope probe across the dummy load (I use a 10x
> probe),
> press TUNE on the K2 and you should see an RF envelope display on the 
> 'scope
> face - if not adjust the vertical amp and the trigger level until 
> something
> is displayed - then set the time base so you are seeubg the CW envelope
> rather than a few cycles of the RF.
>
> As you adjust the bandpass filter, you should see the vertical
> deflection on
> the 'scope face shrink and grow in response to the tuning - adjust for 
> the
> largest display height.
>
> 73,
> Don W3FPR
>
>


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RE: [Elecraft] Dumb(?) dummy load question

[Eric Ward]

Many thanks to all the replies indicating correctly that the resistor I was
using is wirewound, a.k.a. a coil/inductor at RF, and therefore not a useful
dummy load.
Live and learn...
73,
Eric
N0HHS 

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Re: [Elecraft] Dumb(?) dummy load question

[Mike WA8BXN]

I think those are the wire wound resistors - read that as coil, inductance.
They will be useful as a dummy load only at audio frequencies. The better
way is to get a number of non-inductive resistors and put them in parallel -
20 1K resistors would be 50 ohms, if you use 1/2 watt resistors that would
give you about 10 watts. Such a dummy load will not be prefect, but much
better than a single wire wound resistor! 
73/72 - Mike WA8BXN
 
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Re: [Elecraft] Dumb(?) dummy load question

[Bob Nielsen]

On Tue, Jun 22, 2004 at 09:32:30AM -0400, Eric Ward wrote:
> In an attempt to save pennies, I got a 10W 50 ohm resistor ($1.79 for two) at 
> the Shack and soldered it to a male BNC--I figured this would make a 
> serviceable QRP dummy load.  The resistor checked out at 50.0 ohm on my DMM.
> 
> When I hooked this to my KX1 and went through the ATU alignment procedure 
> (nulling C9, etc), I only get an apparent out put of about 0.3W (according to 
> the display on the radio).  Ditto when I tune my G5RV--I get to 1:1.1, but 
> with only 0.3W.  (This antenna/feedline system is tunable by my LDG Z100 to 
> 1:1; see below.)
> 
> I had previously gone through the ATU alignment using, instead of a dummy 
> load, the G5RV routed through the external match (the LDG Z100) tuned for 
> that frequency.  I figured that would  be pretty close to 50 ohm, since it 
> achieves an apparent 1:1 on that freq with my Icom 706 rig.
> 
> When I use the tuned G5RV as a "dummy load" and go through alignment, I get 
> what appear to me more reasonable values--i.e. when I subsequently tune the 
> same antenna with the KX1 ATU, I get 4.3W and SWR of 1:1.6.
> 
> So something funky is going on and I cannot figure it out.  Is there some 
> bloody obvious reason why the 10W resistor is not a good dummy load?  Is 
> something else wrong with my rig, which otherwise is nominal in all respects? 
>  (BTW, I have R4 maxed out clockwise.)  I do not have a wattmeter, so I 
> cannot independently check output with and without the ATU installed, but the 
> rig is transmitting on 40 and 20m.
> 
> Thanks for any ideas...

Is it a non-inductive resistor?  If not, it probably won't be anywhere
near 50 ohms at R.F.

Bob, N7XY
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Re: [Elecraft] Dumb(?) dummy load question

[Jeff Anderson]

Hi Eric,

I tried this once.  The 10W 50 ohm resistors that I purchased at RS are
wirewound, and make a terrible load at RF frequencies.  The higher the freq,
the worse they get.

For reference, I just grabbed one of my resistors, and made a few
measurements with the MFJ antenna analyzer:
3.75 MHz measures as 1.9 SWR
7.12 MHz measures as 3.2 SWR
14.1 MHz measures as 7.6 SWR

Your G5RV through a tuner probably IS closer to 50 ohms, but some
combination of carbon resistors (for a total of 50 ohms) would probably be
even better.

73,
Jeff Anderson  KD7PAW

- Original Message - 
From: "Eric Ward" <[EMAIL PROTECTED]>
To: 
Sent: Tuesday, June 22, 2004 7:32 AM
Subject: [Elecraft] Dumb(?) dummy load question


In an attempt to save pennies, I got a 10W 50 ohm resistor ($1.79 for two)
at the Shack and soldered it to a male BNC--I figured this would make a
serviceable QRP dummy load.  The resistor checked out at 50.0 ohm on my DMM.

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Re: [Elecraft] Dumb(?) dummy load question

[Donald Nesbitt]

Hi Eric - if the 10W 50 ohm resistor is NOT a "non-inductive" resistor (and
if you got it at RS it is a pretty sure bet that it is a wire-wound - and -
they are not "non-inductive - but - being wire-wound - are very
inductive!!), then you are having problems because it is NOT presenting a
pure (or reasonably pure) 50 ohm load to your KX1 even though the resistor
reads 50 ohms at DC (as read by your DMM).  At RF frequencies, it will
exhibit "reactance" in addition to the "resistance" and this will make it
look like something other than a resistive dummy load to the KX1.  It will
look more like a pretty poor antenna with very high SWR and the readings
that you get on the KX1 in the calibrate position will be incorrect - VERY
incorrect!!

Most likely this is what you are experiencing and there is nothing wrong
with the rig as evidenced by the fact that when you run it into an SWR close
to 1:1 it seems to read correctly!

Bottom line - see if you can get your $ back at RS and get an actual dummy
load that is close to purely resistive at RF.  Have fun es 73  --don n4hh
K2/100/KAT100/etc/etc/#2028 and KX1/etc #243

- Original Message - 
From: "Eric Ward" <[EMAIL PROTECTED]>
To: 
Sent: Tuesday, June 22, 2004 9:32 AM
Subject: [Elecraft] Dumb(?) dummy load question


In an attempt to save pennies, I got a 10W 50 ohm resistor ($1.79 for two)
at the Shack and soldered it to a male BNC--I figured this would make a
serviceable QRP dummy load.  The resistor checked out at 50.0 ohm on my DMM.

When I hooked this to my KX1 and went through the ATU alignment procedure
(nulling C9, etc), I only get an apparent out put of about 0.3W (according
to the display on the radio).  Ditto when I tune my G5RV--I get to 1:1.1,
but with only 0.3W.  (This antenna/feedline system is tunable by my LDG Z100
to 1:1; see below.)

I had previously gone through the ATU alignment using, instead of a dummy
load, the G5RV routed through the external match (the LDG Z100) tuned for
that frequency.  I figured that would  be pretty close to 50 ohm, since it
achieves an apparent 1:1 on that freq with my Icom 706 rig.

When I use the tuned G5RV as a "dummy load" and go through alignment, I get
what appear to me more reasonable values--i.e. when I subsequently tune the
same antenna with the KX1 ATU, I get 4.3W and SWR of 1:1.6.

So something funky is going on and I cannot figure it out.  Is there some
bloody obvious reason why the 10W resistor is not a good dummy load?  Is
something else wrong with my rig, which otherwise is nominal in all
respects?  (BTW, I have R4 maxed out clockwise.)  I do not have a wattmeter,
so I cannot independently check output with and without the ATU installed,
but the rig is transmitting on 40 and 20m.

Thanks for any ideas...
73,
Eric
N0HHS
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Re: [Elecraft] Dumb(?) dummy load question

[Don Wilhelm]

Eric and all,

That 50 ohm power resistor you are using will be highly inductive - it is a
wirewound type, meaning it is a coil of resistive wire.  Yes, it measures 50
ohms at DC, but for AC, the resistive (and reactive) value depend on the
frequency of operation.

For those wishing to save a buck on a dummy load, check out the power film
resistors by Caddock (MP series), they are non-inductive up to 500 mHz -
Mouser carries them priced from about $3 to $9 depending on the rating.
They are available in power ratings from 15 to 100 watts, but must be used
with an adequate heatsink - the 15 watt is derated to 1.5 watts without a
heat sink and the 60 watt version is derated to 3.5 watts.  An easy to find
source of heat sink material is computer CPU coolers.  See Tom Hammond's
website www.qsl.net/n0ss for one implementation.  You can see the reisitors
themselves at www.mouser.com/caddock.

Another alternative is the Elecraft DL1 mini-kit - a good 50 ohm load with a
built in tap for connecting the DMM to measure voltage and calculate the
power.

73,
Don W3FPR

Life is what happens when you are making other plans

- Original Message - 

In an attempt to save pennies, I got a 10W 50 ohm resistor ($1.79 for two)
at the Shack and soldered it to a male BNC--I figured this would make a
serviceable QRP dummy load.  The resistor checked out at 50.0 ohm on my DMM.

When I hooked this to my KX1 and went through the ATU alignment procedure
(nulling C9, etc), I only get an apparent out put of about 0.3W (according
to the display on the radio).  Ditto when I tune my G5RV--I get to 1:1.1,
but with only 0.3W.  (This antenna/feedline system is tunable by my LDG Z100
to 1:1; see below.)



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Re: [Elecraft] Dumb(?) dummy load question

[David A. Belsley]

Eric:
  I don't know what sort of resistor you got, but many larger wattage 
resistors may be fine for 50 ohms at DC, but they can have significant 
inductance and capacitance that causes them to have a very different 
impedance at RF.  If you have an antenna analyzer like the MFJ 259, 
give it a scan.  You are really much better off getting yourself an 
honest dummy load designed to be 50 ohms up to 30MHz or better.


best wishes,

dave belsley, w1euy


On Jun 22, 2004, at 9:32 AM, Eric Ward wrote:

In an attempt to save pennies, I got a 10W 50 ohm resistor ($1.79 for 
two) at the Shack and soldered it to a male BNC--I figured this would 
make a serviceable QRP dummy load.  The resistor checked out at 50.0 
ohm on my DMM.


When I hooked this to my KX1 and went through the ATU alignment 
procedure (nulling C9, etc), I only get an apparent out put of about 
0.3W (according to the display on the radio).  Ditto when I tune my 
G5RV--I get to 1:1.1, but with only 0.3W.  (This antenna/feedline 
system is tunable by my LDG Z100 to 1:1; see below.)


I had previously gone through the ATU alignment using, instead of a 
dummy load, the G5RV routed through the external match (the LDG Z100) 
tuned for that frequency.  I figured that would  be pretty close to 50 
ohm, since it achieves an apparent 1:1 on that freq with my Icom 706 
rig.


When I use the tuned G5RV as a "dummy load" and go through alignment, 
I get what appear to me more reasonable values--i.e. when I 
subsequently tune the same antenna with the KX1 ATU, I get 4.3W and 
SWR of 1:1.6.


So something funky is going on and I cannot figure it out.  Is there 
some bloody obvious reason why the 10W resistor is not a good dummy 
load?  Is something else wrong with my rig, which otherwise is nominal 
in all respects?  (BTW, I have R4 maxed out clockwise.)  I do not have 
a wattmeter, so I cannot independently check output with and without 
the ATU installed, but the rig is transmitting on 40 and 20m.


Thanks for any ideas...
73,
Eric
N0HHS
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[Elecraft] Multicore Solder

[Joe Roof]

I'm trying to identify the flux in some rolls of Multicore solder, and
the Multicore/Loctite site doesn't list these types.  I would appreciate
any
description of the following flux types.  X38B; WRAP3.
Thanks for the help.
72
Joe, W4JHR



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Re: [Elecraft] K2 #4293 KAT2, KNB2 etc.

[Don Wilhelm]

The peak reverse voltage rating of the diode is the limiting factor for the
RF probe.  A 1N34 diode should be fine for power measurements of up to 25
watts across a 50 ohm resistive load - it will make little difference
whether connected to the antenna jack or the dummy load.

For higher power levels, a higer rated diode could be used or 1N34 diodes
could be used in series - the low voltage readings will be more inaccurate
if that is done.

A coax TEE adapter is one easy way to connect the RF probe to the coax
center conductor.

73,
Don W3FPR

Life is what happens when you are making other plans

- Original Message - 
I did R1 adjustment during lunchbreak using RF-probe and got it about right.
I will check cantenna resistance afterwards and re-adjust if necessary.
I was worried about breaking RF-probe, but now I believe I can connect it
with dummy load and can't connect it directly to antenna jack.



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[Elecraft] Dumb(?) dummy load question

[Eric Ward]

In an attempt to save pennies, I got a 10W 50 ohm resistor ($1.79 for two) at 
the Shack and soldered it to a male BNC--I figured this would make a 
serviceable QRP dummy load.  The resistor checked out at 50.0 ohm on my DMM.

When I hooked this to my KX1 and went through the ATU alignment procedure 
(nulling C9, etc), I only get an apparent out put of about 0.3W (according to 
the display on the radio).  Ditto when I tune my G5RV--I get to 1:1.1, but with 
only 0.3W.  (This antenna/feedline system is tunable by my LDG Z100 to 1:1; see 
below.)

I had previously gone through the ATU alignment using, instead of a dummy load, 
the G5RV routed through the external match (the LDG Z100) tuned for that 
frequency.  I figured that would  be pretty close to 50 ohm, since it achieves 
an apparent 1:1 on that freq with my Icom 706 rig.

When I use the tuned G5RV as a "dummy load" and go through alignment, I get 
what appear to me more reasonable values--i.e. when I subsequently tune the 
same antenna with the KX1 ATU, I get 4.3W and SWR of 1:1.6.

So something funky is going on and I cannot figure it out.  Is there some 
bloody obvious reason why the 10W resistor is not a good dummy load?  Is 
something else wrong with my rig, which otherwise is nominal in all respects?  
(BTW, I have R4 maxed out clockwise.)  I do not have a wattmeter, so I cannot 
independently check output with and without the ATU installed, but the rig is 
transmitting on 40 and 20m.

Thanks for any ideas...
73,
Eric
N0HHS
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[Elecraft] Elecraft KX1 mini-log attaches to back cover

[Ted Ellmore]

While I haven't tried this yet, I've considered mounting my KX1 to 
a clipboard. You could cut a thin plate of material, say plexiglass, 
Formica, sheet aluminum or whatever, using Wayne's mini-log sheet as a 
template, (flipping it over before installing under the thumbscrews), and 
allowing enough sticking out at the top for the clipboard clip to grab. You 
would also need to either notch or drill a hole large enough to allow the 
upper foot to pass through, and also install a filler strip(wood or other 
material) under the upper edge to fill the remaining space between the 
plate and the upper foot. In use, the lower feet could act as handy "hold 
downs" for a paper log sheet that would be aligned to take advantage of the 
nifty work light. Just thinking aloud.


Ted Ellmore (KF4VCP)
[EMAIL PROTECTED] 



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[Elecraft] summercamp in Denmark (OZ)

[Henning V. Mikkelsen]

Hello All
>From the 3. of july and the following week, the 75. annual national OZ
summercamp
is held near Korsoer, on the island of Sealand.

There will be a QRP night, on the 4. of july, with some informal lectures
given and stations
on show, including a brandnew KX1 and K2 as well as a lot of other homebrew
radios. we
expect to be active on 20 to 80 meters throughout the evening / night.

A big thanks to Elecraft for helping out on prices for the event.

We hope to be able to show pictures afterwards on the summercamp homepage
where you also can find more info.  www.radiohobby.dk/lejr2004/

Everybody is of course more than welcome to show up. Just please remember
to checkin
at the campingcounceler at arrival.

73-
Henning  OZ4XF

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Re: [Elecraft] K2 #4293 KAT2, KNB2 etc.

[Jukka Tarvainen (OH4MFA)]

Thank You Don!

I did R1 adjustment during lunchbreak using RF-probe and got it about right.
I will check cantenna resistance afterwards and re-adjust if necessary.
I was worried about breaking RF-probe, but now I believe I can connect it
with dummy load and can't connect it directly to antenna jack.

73 Jukka, OH4MFA
K2 #4293

>--Alkuperäinen viesti--
>Reply-To: "Don Wilhelm" <[EMAIL PROTECTED]>
>From: "Don Wilhelm" <[EMAIL PROTECTED]>
>To: "Jukka Tarvainen (OH4MFA)" <[EMAIL PROTECTED]>,
>   
>Subject: Re: [Elecraft] K2 #4293 KAT2, KNB2 etc.
>Date: Mon, 21 Jun 2004 09:16:36 -0400
>
>
>Jukka,
>
>Why not just use the RF probe built from the parts supplied with the K2
kit
>and you will have an instrument that you can trust?  The RF probe built
into
>the Heath cantenna MAY be the same thing, but I just can't recall how it
>is
>configured.
>
>Then you can use the RF probe (and your DMM) connected across the dummy
load
>to measure the rms RF voltage and determine the power output = V*V/R. 
(The
>DMM should read the rms value of the RF voltage directly for voltages above
>about 1 volt)
>
>Of course, you must know the resistance of the dummy load accurately too
>if
>you are expecting to do an accurate calibration.  For a dummy load to be
>a
>true dummy load, it must be entirely resistive (no reactance) at the
>frequency it is being driven.  The old Heath cantenna is only OK in this
>respect, and I have heard reports that the resistance does change a bit
with
>age.  (You can check a dummy load by measuring it with an antenna analyzer.)
>
>73,
>Don W3FPR
>



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