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No, it's not meant to be left in line, as it sucks up all the power and is not a "sampling" wattmeter. Peter Parker had a really simple sampling as a tuning indicator using a toroid, a couple of turns of wire, and an LED with the coax passing through the center. When I saw that, I wondered if it would be possible to use a similar sampling scheme and map it to a Nano. If? calibrated with a known source, I wonder how accurate it might be.
Jack, W8TEE
From: N8DAH <Dherron@...>
To: [email protected]
Sent: Friday, December 22, 2017 1:43 PM
Subject: Re: [BITX20] Dummy
Jack,
?Any chance at the code? I have pretty much all of that ready to go and a dummy load that would love that as a add on. Could it be used inline for active monitoring of output? I need a good meter but no radio funds outside spare parts at this time.
73
?David
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The diode doesn't matter much, but we wanted it to have a breakdown voltage of over 250V since some fairly hefty RF could be coming through. The code is in the Projects book and can also be downloaded from McGraw-Hill.
Jack, W8TEE
From: Trent Trent <vk7hrs@...>
To: [email protected]
Sent: Friday, December 22, 2017 2:57 PM
Subject: Re: [BITX20] Dummy
Have u got the sketch for that Jack and also can any other diode be used
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Jack, Chapter 6, Dummy Load,? Pages 119 - 130?? Is that correct?
Marco - KG5PRT
On Fri, Dec 22, 2017 at 2:17 PM, Jack Purdum via Groups.Io <jjpurdum@...> wrote: The diode doesn't matter much, but we wanted it to have a breakdown voltage of over 250V since some fairly hefty RF could be coming through. The code is in the Projects book and can also be downloaded from McGraw-Hill.
Jack, W8TEE
Have u got the sketch for that Jack and also can any other diode be used
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Yep. I'm away from my system, but you may have to redefine a pin or two since the original DL in the book used a 16x2 LCD rather than an OLED, but it should be too hard to figure out.
Jack, W8TEE
From: M Garza <mgarza896@...>
To: [email protected]
Sent: Friday, December 22, 2017 3:24 PM
Subject: Re: [BITX20] Dummy
Jack, Chapter 6, Dummy Load,? Pages 119 - 130?? Is that correct?
Marco - KG5PRT
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Jack, Thanks.
I really need to make time to read your books.? I am sure I will, once I actually start playing with the Nano.
Thanks again.
Marco - KG5PRT
On Fri, Dec 22, 2017 at 2:26 PM, Jack Purdum via Groups.Io <jjpurdum@...> wrote: Yep. I'm away from my system, but you may have to redefine a pin or two since the original DL in the book used a 16x2 LCD rather than an OLED, but it should be too hard to figure out.
Jack, W8TEE
Jack, Chapter 6, Dummy Load,? Pages 119 - 130?? Is that correct?
Marco - KG5PRT
|
Nice.
I assume they are 1W parts.
With shorter leads, might work better at VHF if that's of interest.
From what I see on Mouser, the surface mount parts are cheaper than the old style radial leaded parts,
??
Could do a small circuit board with pads for those surface mount resistors and the diode rectifier circuit.
Holes cut in the circuit board allow oil to contact the bottom of the surface mount resistors too.
Not sure how well connectors would do in that oil, so just solder any wires and coax to the board.
Coax ties into the middle of the board, resistors radiate out for minimum trace lengths.
I need a good dummy load.
Jerry, KE7ER
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On Fri, Dec 22, 2017 at 11:48 am, Jack Purdum wrote:
We used 20 1K¦¸ metal film resistors connected in parallel. They are linked like this:
?
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Diz has a nice kit for an inline SWR/Power indicator,? $12, good up to 100W.
If we had a couple spare analog pins at the Raduino, could use that for sensing.
Jerry, KE7ER
On Fri, Dec 22, 2017 at 12:12 pm, Jack Purdum wrote:
No, it's not meant to be left in line, as it sucks up all the power and is not a "sampling" wattmeter. Peter Parker had a really simple sampling as a tuning indicator using a toroid, a couple of turns of wire, and an LED with the coax passing through the center. When I saw that, I wondered if it would be possible to use a similar sampling scheme and map it to a Nano. If? calibrated with a known source, I wonder how accurate it might be.
?
?
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I have an SWR bridge from kitsandparts but wouldn't know where to start to get a nano to read from it and output on oled. I have everything but the code experience I keep trying but just no good with code.
?
?I will be watching for the write in qst always look forward to your projects.
?
73
? David
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If I'm reading this correctly, it looks like only A7 on the Nano is currently free. I like the idea!
Jack, W8TEE
From: Jerry Gaffke via Groups.Io <jgaffke@...>
To: [email protected]
Sent: Friday, December 22, 2017 4:07 PM
Subject: Re: [BITX20] Dummy
Diz has a nice kit for an inline SWR/Power indicator,? $12, good up to 100W.
If we had a couple spare analog pins at the Raduino, could use that for sensing.
Jerry, KE7ER
On Fri, Dec 22, 2017 at 12:12 pm, Jack Purdum wrote:
No, it's not meant to be left in line, as it sucks up all the power and is not a "sampling" wattmeter. Peter Parker had a really simple sampling as a tuning indicator using a toroid, a couple of turns of wire, and an LED with the coax passing through the center. When I saw that, I wondered if it would be possible to use a similar sampling scheme and map it to a Nano. If? calibrated with a known source, I wonder how accurate it might be.
?
?
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I built this QRP one from eBay ordered parts. Randy does a nice job explaining the build. You can also take power measurements using the Elecraft owners manual chart. See ? Sent from Mike's iPad WA1MAD
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Moving to an i2c LCD would help.
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Show quoted text
On Fri, Dec 22, 2017 at 02:03 pm, Jack Purdum wrote:
If I'm reading this correctly, it looks like only A7 on the Nano is currently free. I like the idea!?
From: Jerry Gaffke via Groups.Io <jgaffke@...>
Diz has a nice kit for an inline SWR/Power indicator,? $12, good up to 100W.
If we had a couple spare analog pins at the Raduino, could use that for sensing.
|
Jack
The toroidal "current transformer"? idea works quite well.? Use that to sample current, and
diode and restive divider to sample voltage.? From that your Arduino can calculate impedance,
power, etc.?
An FT37-43 core works well for HF applications.? I got the original idea from Wim SP5DJJ and
Peter VK3YE made it into a video on you tube from my web site.
Of course for accurate measurements you need the load or burden resistor
in place of the simple LED indicator.
We do this all the time with Bourne or Stockton type SWR bridges but just
don't call them "current transformers".? No, I don't know why.
Arv? K7HKL
_._
On Fri, Dec 22, 2017 at 2:07 PM, Jerry Gaffke via Groups.Io <jgaffke@...> wrote: Diz has a nice kit for an inline SWR/Power indicator,? $12, good up to 100W.
If we had a couple spare analog pins at the Raduino, could use that for sensing.
Jerry, KE7ER
On Fri, Dec 22, 2017 at 12:12 pm, Jack Purdum wrote:
No, it's not meant to be left in line, as it sucks up all the power and is not a "sampling" wattmeter. Peter Parker had a really simple sampling as a tuning indicator using a toroid, a couple of turns of wire, and an LED with the coax passing through the center. When I saw that, I wondered if it would be possible to use a similar sampling scheme and map it to a Nano. If? calibrated with a known source, I wonder how accurate it might be.
?
?
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Arv,
Cool idea for antenna current indicator.? Will think about trying that soon.
As for dummy loads....After realizing that all of my 50 ohm resistors were wire?wound and reading z=162 on my antenna analyzer, I found the RFP 100-50TW Flange terminations 50?ohm? 100W?from 0-6?Ghz.? Available from ebay
for about $1 each.? Mounted to heatsink in photo.? Analyzer shows flat z=50 ohm in 40M band (did not try other bands yet).? Obviously this heatsink will not work with 100W but should be fine at 5-10W.? I have a few of these 50 ohm terminations from ebay so?
am mounting another one on a larger heatsink with a fan.
Anyone else tried these?
Gene?
N2IJF
toggle quoted message
Show quoted text
Jack
The toroidal "current transformer"? idea works quite well.? Use that to sample current, and
diode and restive divider to sample voltage.? From that your Arduino can calculate impedance,
power, etc.?
An FT37-43 core works well for HF applications.? I got the original idea from Wim SP5DJJ and
Peter VK3YE made it into a video on you tube from my web site.
|
sites.google.com
The original thermocouple RF ammeters are becoming almost impossible to find. However, you can build your own for relatively little cost. This simple circuit could be ...
|
Of course for accurate measurements you need the load or burden resistor
in place of the simple LED indicator.
|
|
en.wikipedia.org
A current transformer (CT) is a type of transformer that is used to measure alternating current (AC). It produces a current in its secondary which is proportional to ...
|
We do this all the time with Bourne or Stockton type SWR bridges but just
don't call them "current transformers".? No, I don't know why.
Arv? K7HKL
_._
|
I have one of the kits.? I am not implementing the CW function on the Raduino so that gives me two analog pins for SWR measurement.
|
I am using a 800 watt termination resistor in a heatsink case.? SWR is flat.? I picked it up for about $45?on ebay.
Marco - KG5PRT?
On Dec 22, 2017 6:35 PM, "Gene Nitschke" < genenitschke@...> wrote:
Arv,
Cool idea for antenna current indicator.? Will think about trying that soon.
As for dummy loads....After realizing that all of my 50 ohm resistors were wire?wound and reading z=162 on my antenna analyzer, I found the RFP 100-50TW Flange terminations 50?ohm? 100W?from 0-6?Ghz.? Available from ebay
for about $1 each.? Mounted to heatsink in photo.? Analyzer shows flat z=50 ohm in 40M band (did not try other bands yet).? Obviously this heatsink will not work with 100W but should be fine at 5-10W.? I have a few of these 50 ohm terminations from ebay so?
am mounting another one on a larger heatsink with a fan.
Anyone else tried these?
Gene?
N2IJF
Jack
The toroidal "current transformer"? idea works quite well.? Use that to sample current, and
diode and restive divider to sample voltage.? From that your Arduino can calculate impedance,
power, etc.?
An FT37-43 core works well for HF applications.? I got the original idea from Wim SP5DJJ and
Peter VK3YE made it into a video on you tube from my web site.
|
The original thermocouple RF ammeters are becoming almost impossible to find. However, you can build your own for relatively little cost. This simple circuit could be ...
|
Of course for accurate measurements you need the load or burden resistor
in place of the simple LED indicator.
|
|
A current transformer (CT) is a type of transformer that is used to measure alternating current (AC). It produces a current in its secondary which is proportional to ...
|
We do this all the time with Bourne or Stockton type SWR bridges but just
don't call them "current transformers".? No, I don't know why.
Arv? K7HKL
_._
|
You can get high power chip resistors on Ebay for a Few ?'s ... I've got four here to make a couple of 150 watt dummy loads .. Screw them to a old PC processor heatsink and away you go .
On Fri, 22 Dec 2017 at 16:18, Michael Hagen <motdog@...> wrote:
It was designed with
Bit in Mind.
I saw someone post the
QRP Labs one???? So I thought I would show a better one.? ha..
This looked real good
on the SA for return loss.
Its perfect for bit,?
you never tune long enough to hurt it?? And you can stick it
right out the back with the BNC Adaptor.
The biggest cost is
the BNC connectors.
Stick in your coffee
cup too, to reheat the Java!
I still have the
Heathkit Can -Tenna somewhere?? I remember the can rotted out,
I had to go to the paint store
and buy a new gallon
paint can.? I used to tune the SB220 into it.? I think I put
Automatic Transmission Fluid in it.
Mike, WA6ISP
On 12/22/2017 8:04 AM, Jack Purdum via
Groups.Io wrote:
Mike:
Or, how about
150W DL with builtin wattmeter for under $20? This was a build
our group did a couple of months ago. The lid is shown here.
The resistor network sits in a mineral oil bath. The downside
is that this is considerably larger than yours and a little
more expensive.
Jack, W8TEE
Hey,
speaking of Dummies.? Here is one I came up with.
Its 4 -? 3W resistors.? Has RF tap (0602 Component)
either for a resistor or Cap.
Shky diode and cap.? Place for LED (0805).? 3 Pin
Molex for output monitoring.
You will have to fiddle with the values.?? Layout
has lots of ground plane, both side of the PCB.
And you need the Male BNC Adaptor to go to the back
of the Bit.
I got lots of PCB, $4 or Kit $12 (Includes BNC
Adaptor, shipping, Paypal) US.
PCB can be shipped in and envelope, but the Kit gets
a small box.
email me for more info
73's
Mike, WA6ISP
--
Mike Hagen, WA6ISP
10917 Bryant Street
Yucaipa, Ca. 92399
(909) 918-0058
PayPal ID "MotDog@..."
Mike@...
--
Mike Hagen, WA6ISP
10917 Bryant Street
Yucaipa, Ca. 92399
(909) 918-0058
PayPal ID "MotDog@..."
Mike@...
|
Use the MOX Resistors.?
I used 4 - 200 Ohm and double sided ground plane on my Dummy.
They are mounted on
each side of the PCB, Leads are about 1/16".
They are 3W.? Works
great and looked real good on the SA and my antenna analyser.
They are at Mouser for
about 10 Cents.?? That's all you need if the layout is good.?
There is no need to overkill.
Mike, WA6ISP
On 12/22/2017 11:08 AM, Jerry Gaffke
via Groups.Io wrote:
Critical
thing is, exactly what resistors did you use to build the 50 ohm
resistor assembly?
Or do we have to wait for that QST article?
For those with a spare analog pin into the Raduino and an
inclination for Arduino hacking,
you can strip out the Nano, OLED, switch and battery from Jack's
schematic.
On Fri, Dec 22, 2017 at 10:26 am, Jack Purdum wrote:
It won't be a
kit, but it has been accepted for publication by QST for
sometime in 2018. The circuit is about as simple as it gets:
?
--
Mike Hagen, WA6ISP
10917 Bryant Street
Yucaipa, Ca. 92399
(909) 918-0058
PayPal ID "MotDog@..."
Mike@...
|
So Mike, exactly what resistors did you use to build the 50 ohm resistor assembly? Jerry ##################### On Fri, Dec 22, 2017 at 06:08 pm, Michael Hagen wrote:
Use the MOX Resistors.? I used 4 - 200 Ohm and double sided ground plane on my Dummy.
#########
On 12/22/2017 11:08 AM, Jerry Gaffke via Groups.Io wrote:
Critical thing is, exactly what resistors did you use to build the 50 ohm resistor assembly?
|
Had been thinking "3W 200 ohm metal oxide on Mouser" would still be quite a selection.
But saw only a few that were normally stocked, and only one that was anywhere near $0.10 in small quantities:
? ?
Going for the 3W parts was a good steer.
If I blow $2 on 20 at 1k of the 3W Xicon resistors,
could dissipate 60W continuously without the complication of an oil bath.
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Show quoted text
On Fri, Dec 22, 2017 at 06:37 pm, Jerry Gaffke wrote:
So Mike, exactly what resistors did you use to build the 50 ohm resistor assembly?
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I got a pack of 10 of the 100 watt 50 ohm dummy loads on ebay for about $1 each.? You can get just one for a bit over a dollar.? I mounted mine on a heat sink from a destktop computer that was on the processor, complete with fan.? Works great and is flat to 30 Mhz.
Paul K0ZYV
From: M Garza <mgarza896@...>
To: [email protected]
Sent: Friday, December 22, 2017 8:20 PM
Subject: Re: [BITX20] Dummy
I am using a 800 watt termination resistor in a heatsink case.? SWR is flat.? I picked it up for about $45?on ebay.
Marco - KG5PRT?
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N8DAH
Marc Jones