Re: [Elecraft] Dummy loads for dummies

[Bill Johnson]

And you can add a slight twist to reduce wind whipping, etc.  I don't like
it, though.  PITA for me.  

73,
Bill
K9YEQ

-Original Message-
From: Elecraft [mailto:elecraft-boun...@mailman.qth.net] On Behalf Of
Richard Fjeld
Sent: Wednesday, December 28, 2016 10:07 PM
To: elecraft@mailman.qth.net
Subject: Re: [Elecraft] Dummy loads for dummies

FWIW,  comments to consider about open wire feedline from my experience:

Window line has shattered in the cold winter winds. Frost, snow, and ice
easily accumulates. It catches the wind easily.
On the plus side, window line conductors do not fold over on each other. 
Conductors stay evenly spaced.

Ladder line does require measures to keep conductors from twisting and
folding over on each other. As Ron mentions, tension is necessary.
Ladder line has less problems in inclement weather. Ladder line is much
better in the wind.

I designed my loop and ladder line so that I can melt ice off it. That would
be more difficult to do with window line.

Dick, n0ce


On 12/28/2016 12:01 PM, Ron D'Eau Claire wrote:
> Wes makes an excellent point: "window" line and open wire line are not 
> the same. Both the resistive losses in the relatively tiny wires in 
> the window line and the webs of insulation impact its performance as 
> described in his paper.
>
> My open wire line is homebrew, using #10 or #12 copper wire spaced 
> with common "dog bone" insulators sold for end insulators. They hold 
> the wires about 3 inches apart. Typically, one spacer every 3 or 4 
> feet is quite adequate to maintain the spacing with the lines under
tension.
>
> 73, Ron AC7AC
>
>
__
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Elecraft@mailman.qth.net

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html Message
delivered to k9...@live.com
__
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Elecraft@mailman.qth.net

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to arch...@mail-archive.com

Re: [Elecraft] Dummy loads for dummies

[Richard Fjeld]

FWIW,  comments to consider about open wire feedline from my experience:

Window line has shattered in the cold winter winds. Frost, snow, and ice 
easily accumulates. It catches the wind easily.
On the plus side, window line conductors do not fold over on each other. 
Conductors stay evenly spaced.

Ladder line does require measures to keep conductors from twisting and 
folding over on each other. As Ron mentions, tension is necessary.
Ladder line has less problems in inclement weather. Ladder line is much 
better in the wind.

I designed my loop and ladder line so that I can melt ice off it. That 
would be more difficult to do with window line.

Dick, n0ce


On 12/28/2016 12:01 PM, Ron D'Eau Claire wrote:
> Wes makes an excellent point: "window" line and open wire line are not the
> same. Both the resistive losses in the relatively tiny wires in the window
> line and the webs of insulation impact its performance as described in his
> paper.
>
> My open wire line is homebrew, using #10 or #12 copper wire spaced with
> common "dog bone" insulators sold for end insulators. They hold the wires
> about 3 inches apart. Typically, one spacer every 3 or 4 feet is quite
> adequate to maintain the spacing with the lines under tension.
>
> 73, Ron AC7AC
>
>
__
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Elecraft@mailman.qth.net

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to arch...@mail-archive.com

Re: [Elecraft] Dummy loads for dummies

[M. George]

I guess I'll chime in on the dummy load discussion (pictures below).  Over
the last few months, I have picked up a couple Bird Termaline Coaxial
Resistor dummy loads (these may be the models K9YC is referring to).  I got
tired of the crappy cantenna style QRO loads that are typical of the
current Ham Radio market.  The capillary motion of the oil getting all over
the top of the can... attracting dirt, bugs etc... these usually get
relegated to the garage sooner than later. (or dumpster)  I have never seen
any leaking from the following Bird oil filled dummy loads.  Nor have I had
to replace any of the gaskets.

This thread is a bit off topic at this point, but In my humble opinion, I
would consider the following Bird dummy loads to be ones to consider for
your shack. If you are patient on fleaBay, you will find some really good
deals, especially if you are willing to clean them up and have been filled
with the proper dielectric oil.  I don't think anyone would buy one new...
over $800 for the Bird 8401 listed below for example.  But at surplus /
used prices, if you can find one from $50 to $250, it will be the last QRO
dummy load you will ever buy.  They all use Bird QC connectors like you
would find on a Bird 43 watt meter.  If you make it through this email,
I'll admit I got a little obsessed with buying and cleaning up several Bird
dummy loads!  I'm guilty as accused... ;)

*Bird 8401* (the perfect ham shack dummy load IMHO, still in production
)
Over
$800 new???.  I was very lucky to find a new / old stock one of these with
the cardboard still wrapped around it for $250 shipped.  $250 for a dummy
load you ask???  Well for a commercial piece of Bird equipment that will
handle 600 watts continuous and is good from DC to 3ghz.  De-rated, this
load will handle 1.5kw for 10 minutes easily and more if you put a fan on
it.  This is more dummy load than I'll ever need in the shack and the one I
will never sell.

Here are pictures of my *Bird 8401*:
http://www.nc7j.com/downloads/ng7m/Bird8401DummyLoad/ (new old stock, no
cleanup required)

*Bird 8404* (identical to the 8401 except that it has an N connector gender
bender with mount on the front).  I picked up one of these in rough shape
shipped for $52 shipped and restored it for my good buddy W7CT Jim.  We
added new Shell dielectric transformer oil and the total cost was $82.

Here are pictures of W7CT's $82 *Bird 8404* (before and after cleanup with
new oil):
http://www.nc7j.com/downloads/W7CT/Bird%208404%20Coaxial%20Resistor%20Termaline/

*Bird 8201* Most common Bird 500 watt dummy load you will find on
fleaBay.  Still
in production
.
I picked up one of these in great shape shipped for ~$150.  This will be
the easiest model to find and probably the best value.  Rated from DC to
1ghz, it's probably the best bargain in a Bird QRO dummy load that is still
in production.  Again, de-rated, this will handle 1.5kw for many minutes...
and more with a fan.

Before and after clean up pictures of my *Bird 8201 *(like new condition):
http://www.nc7j.com/downloads/ng7m/Bird8201DummyLoad/

*Bird 8135* Little brother dummy load to the 8401 / 8201, still in
production
.
150 watts continuous. These are easily found on fleaBay in the $60 to $150
price range.  150 watts continuous. Good from DC to 4ghz with a bit higher
VSWR along the way.  The one I found was like new and looks like the
current production pictures on the Bird website.  A cool little oil filled
dummy load to pair up with your K3 line, or match with an 8201/8401.

*Bird 8166* Dry 150 watt continuous dummy load, good from DC to 2.5ghz with
a bit higher VSWR (no longer in production
).
You can find these used for around $65 to $150.

Anyway, this is more information than most wanted to see in dummy loads!!
There are many other Bird models out there.  I got over my Bird dummy load
obsession, but I'm happy with what I found and they all make a great
addition to the shack.  There are certainly models from Bird that will
handle much more power, but I'm still of the opinion that the 84/82 line
are the perfect size for use in the shack.

Off my dummy load soap box.

Max NG7M



On Wed, Dec 28, 2016 at 1:52 AM, Jim Brown 
wrote:

> On Wed,12/28/2016 12:26 AM, Edward R Cole wrote:
>
>> I have a big old Sierra Electronic 500w coaxial load with heat sink and
>> built in power meter; weighs about 40-50 lbs; makes a dandy door stop,
>> too!  It is rated to 1000-MHz.
>>
>
> I found a nice oil-cooled dummy load with a big heat sink integral to it
> at a ham

Re: [Elecraft] Dummy loads for dummies

[Ron D'Eau Claire]

Wes makes an excellent point: "window" line and open wire line are not the
same. Both the resistive losses in the relatively tiny wires in the window
line and the webs of insulation impact its performance as described in his
paper. 

My open wire line is homebrew, using #10 or #12 copper wire spaced with
common "dog bone" insulators sold for end insulators. They hold the wires
about 3 inches apart. Typically, one spacer every 3 or 4 feet is quite
adequate to maintain the spacing with the lines under tension. 

73, Ron AC7AC

-Original Message-
From: Elecraft [mailto:elecraft-boun...@mailman.qth.net] On Behalf Of Wes
Stewart
Sent: Tuesday, December 27, 2016 8:00 PM
To: elecraft@mailman.qth.net
Subject: Re: [Elecraft] Dummy loads for dummies

You might be interested in this: http://k6mhe.com/n7ws/Ladder_Line.pdf

On 12/27/2016 1:22 PM, Paul C wrote:
> Here's another naive idea of mine:  I'm planning to use ladder line too.
Now I'm waiting for the other shoe to drop, when I realize coax will be my
only practical choice.
>
> Paul KG5KXG
>

__
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Elecraft@mailman.qth.net

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html Message
delivered to r...@elecraft.com

__
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Elecraft@mailman.qth.net

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to arch...@mail-archive.com

Re: [Elecraft] Dummy loads for dummies

[Mark Goldberg]

I also found one of the big oil filled dummy loads at a Hamfest. It handles
500W easily. I bring a phone powered USB powered VNA with me to Hamfests to
check things out. You never know what you will find!

73,
Mark
W7MLG

On Dec 28, 2016 8:25 AM, "David Olean"  wrote:

> It always pays to keep your eyes open.  The local (and only ) surplus
> store here has a pile of heat sinks that look just great for a 250 watt
> solid state PA. The good part is that they also have a pair of SMA
> connectors, PC boards, and associated flanged 50 ohm resistor good for
> several hundred watts. I think I paid $15 for one, so I got two DC to 2.4
> GHz dummy loads for $7.50 each. It is easy to modify them for what ever
> connector you want. Jim is right, but always bring a pocket ohm meter! heh
> heh.
>
>
> Dave K1WHS
>
>
> On 12/28/2016 8:52 AM, Jim Brown wrote:
>
>> On Wed,12/28/2016 12:26 AM, Edward R Cole wrote:
>>
>>> I have a big old Sierra Electronic 500w coaxial load with heat sink and
>>> built in power meter; weighs about 40-50 lbs; makes a dandy door stop,
>>> too!  It is rated to 1000-MHz.
>>>
>>
>> I found a nice oil-cooled dummy load with a big heat sink integral to it
>> at a hamfest many years ago. It's rated 500W continuous. That was a good
>> day. Doorstop -- you betcha! :) Measured it with my VNWA and found that
>> it's good well into UHF. No attached power meter though, but found a nice
>> Bird with some slugs on another day.
>>
>> I've also found industrial quality 10W and 100W dummy loads at hamfests
>> that were salvaged from cell sites. One purchase yielded nearly ten of them.
>>
>> This is the sort of stuff I look for at hamfests (some call them flea
>> markets or swap meets). Also high quality connectors and adapters.
>>
>> 73, Jim K9YC
>>
>> __
>> Elecraft mailing list
>> Home: http://mailman.qth.net/mailman/listinfo/elecraft
>> Help: http://mailman.qth.net/mmfaq.htm
>> Post: mailto:Elecraft@mailman.qth.net
>>
>> This list hosted by: http://www.qsl.net
>> Please help support this email list: http://www.qsl.net/donate.html
>> Message delivered to k1...@metrocast.net
>>
>>
> __
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:Elecraft@mailman.qth.net
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
> Message delivered to marklgoldb...@gmail.com
>
__
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Elecraft@mailman.qth.net

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to arch...@mail-archive.com

Re: [Elecraft] Dummy loads for dummies

[David Olean]

It always pays to keep your eyes open.  The local (and only ) surplus 
store here has a pile of heat sinks that look just great for a 250 watt 
solid state PA. The good part is that they also have a pair of SMA 
connectors, PC boards, and associated flanged 50 ohm resistor good for 
several hundred watts. I think I paid $15 for one, so I got two DC to 
2.4 GHz dummy loads for $7.50 each. It is easy to modify them for what 
ever connector you want. Jim is right, but always bring a pocket ohm 
meter! heh heh.



Dave K1WHS


On 12/28/2016 8:52 AM, Jim Brown wrote:

On Wed,12/28/2016 12:26 AM, Edward R Cole wrote:
I have a big old Sierra Electronic 500w coaxial load with heat sink 
and built in power meter; weighs about 40-50 lbs; makes a dandy door 
stop, too!  It is rated to 1000-MHz.


I found a nice oil-cooled dummy load with a big heat sink integral to 
it at a hamfest many years ago. It's rated 500W continuous. That was a 
good day. Doorstop -- you betcha! :) Measured it with my VNWA and 
found that it's good well into UHF. No attached power meter though, 
but found a nice Bird with some slugs on another day.


I've also found industrial quality 10W and 100W dummy loads at 
hamfests that were salvaged from cell sites. One purchase yielded 
nearly ten of them.


This is the sort of stuff I look for at hamfests (some call them flea 
markets or swap meets). Also high quality connectors and adapters.


73, Jim K9YC

__
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Elecraft@mailman.qth.net

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to k1...@metrocast.net



__
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Elecraft@mailman.qth.net

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to arch...@mail-archive.com

Re: [Elecraft] Dummy loads for dummies

[Jim Brown]

On Wed,12/28/2016 12:26 AM, Edward R Cole wrote:
I have a big old Sierra Electronic 500w coaxial load with heat sink 
and built in power meter; weighs about 40-50 lbs; makes a dandy door 
stop, too!  It is rated to 1000-MHz.


I found a nice oil-cooled dummy load with a big heat sink integral to it 
at a hamfest many years ago. It's rated 500W continuous. That was a good 
day. Doorstop -- you betcha! :) Measured it with my VNWA and found that 
it's good well into UHF. No attached power meter though, but found a 
nice Bird with some slugs on another day.


I've also found industrial quality 10W and 100W dummy loads at hamfests 
that were salvaged from cell sites. One purchase yielded nearly ten of 
them.


This is the sort of stuff I look for at hamfests (some call them flea 
markets or swap meets). Also high quality connectors and adapters.


73, Jim K9YC

__
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Elecraft@mailman.qth.net

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to arch...@mail-archive.com

Re: [Elecraft] Dummy loads for dummies

[Edward R Cole]

http://www.kl7uw.com/2M80_inside_1.jpg

In the photo the large black square at bottom of the pc board is a 
surface-mount 56-ohm 35w resistor (good at 2m) and available from 
Mouser.  I believe there were 51-ohm values also.  This used in a 
23-dB pi-attenuator to take 10w down to 50mw for driving a Toshiba 
SAV-36 RF amplifier module in the 80w 2m amp that I build.  W6PQL 
sells 150w surface mount loads that are good at 1296 MHz.  All you 
need is a small pcb and a large heat sink.


TO-220 form probably more convenient as one can mount them directly 
to a heat sink with a tapped hole for a 4-40 machine screw and using 
a little heat sink compound.  If the heat sink is large enough air 
cooling is sufficient.


I have a big old Sierra Electronic 500w coaxial load with heat sink 
and built in power meter; weighs about 40-50 lbs; makes a dandy door 
stop, too!  It is rated to 1000-MHz.  Got in trade somewhere?  I 
would not want to pay retail for one; probably in range of $2/watt.


73, Ed - KL7UW
  http://www.kl7uw.com
Dubus-NA Business mail:
  dubus...@gmail.com 


__
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Elecraft@mailman.qth.net

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to arch...@mail-archive.com

Re: [Elecraft] Dummy loads for dummies

[Nr4c]

Carefull. Are they wire-wound power resisters cased in ceramic. If so they are 
likely inductive and of marginal use as withvRF they will not be just resistive 
but somewhat inductive and this will skew your results. 

Sent from my iPhone
...nr4c. bill


> On Dec 27, 2016, at 9:43 AM, Paul C  wrote:
> 
> I made my own dummy load last night from two 100 ohm resistors wired in 
> parallel.  They are rated for 10 watts each and look like little bricks.  I 
> measured the resistance at 51 ohms.  Do you think this is close enough or 
> should I reduce it to 50?
> 
> Paul KG5KXG
> __
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:Elecraft@mailman.qth.net
> 
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
> Message delivered to n...@widomaker.com

__
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Elecraft@mailman.qth.net

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to arch...@mail-archive.com

Re: [Elecraft] Dummy loads for dummies

[Wes Stewart]

You might be interested in this: http://k6mhe.com/n7ws/Ladder_Line.pdf

On 12/27/2016 1:22 PM, Paul C wrote:

Here's another naive idea of mine:  I'm planning to use ladder line too.  Now 
I'm waiting for the other shoe to drop, when I realize coax will be my only 
practical choice.

Paul KG5KXG



__
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Elecraft@mailman.qth.net

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to arch...@mail-archive.com

Re: [Elecraft] Dummy loads for dummies

[Paul C]

Thanks for the ideas, Jim.  The tutorial I really want to see (or maybe make 
someday) is one about the KX1 operations for a complete QRP novice.  Such a 
video would take the ham step by step demonstrating all the features and 
explain why xyz is important.  I write software, and these kind of tutorials 
are tremendously helpful.  It's a great way to encourage others to adopt your 
product.

It's too bad I won't be able to take my little rig with me on my backpacking 
trip, but there should be a next time.  Thanks for all your good ideas.  This 
is a great hobby.

73,
Paul KG5KXG

-Original Message-
From: "Jim Brown" 
Sent: ‎12/‎27/‎2016 7:13 PM
To: "elecraft@mailman.qth.net" 
Subject: Re: [Elecraft] Dummy loads for dummies

On Tue,12/27/2016 12:22 PM, Paul C wrote:
> It seems tuff to get going in QRP.

Hi Paul,

The only thing "special" about antennas for QRP operation is that 
BECAUSE you're QRP, you want the most efficient antennas that you can. 
And the simple answer to that is to study the fundamentals in the ARRL 
Handbook and the ARRL Antenna Book.

And if you plan to operate portable, you want the most efficient 
antennas that are easy to carry, and to rig when you get to your 
operating QTH.

There are some tutorials on my website about antennas. They are written 
for antennas in general, not just portable antennas.

The best portable antennas are mostly nothing more than wire. The things 
you want to BUY are the wire and things that help you rig them. Look for 
lightweight, telescoping poles that you can tape a wire to, and ways to 
rig it more or less upright. Jackite poles are nice for this use.

Carry more wire to string out as radials. When you can, keep the radials 
off the ground a few feet -- for example, string them through scrub 
trees and brush. Build dipoles for situations when you can rig two ends 
in trees. Find a lightweight method to toss weights tied to fishing line 
into trees, tie light weight antenna rope to the line, pull it into the 
tree(s), rig the antenna wire to that rope. I used to see a product 
called a "wrist rocket" that is essentially a fishing reel attached to a 
short rod for launching into a tree. If you're going to use fishing 
weights, paint them a bright color so you can find them.

One of my buddies, N6RNO, is awfully good at simply tying a fishing 
weight to a fishing line and using his arm as a sort of catapault to 
launch wires into trees. He regularly gets our dipoles for CQP 
(California QSO Party) county expeditions up 40 ft into trees. When I 
first moved to CA 10 years ago, AE6RF did that using a half empty 16 oz 
water jug.

Tossing a wire into a tree is also a great way to rig a vertical.

Whatever you do, don't waste a single penny on any commercial antenna 
for portable use. Those popular (and expensive) poles antennas with 
loading coils are poor antennas -- loading coils are the reason.

73, Jim K9YC

__
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Elecraft@mailman.qth.net

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to paul...@sbcglobal.net
__
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Elecraft@mailman.qth.net

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to arch...@mail-archive.com

Re: [Elecraft] Dummy loads for dummies

[Jim Brown]

On Tue,12/27/2016 12:22 PM, Paul C wrote:

It seems tuff to get going in QRP.


Hi Paul,

The only thing "special" about antennas for QRP operation is that 
BECAUSE you're QRP, you want the most efficient antennas that you can. 
And the simple answer to that is to study the fundamentals in the ARRL 
Handbook and the ARRL Antenna Book.


And if you plan to operate portable, you want the most efficient 
antennas that are easy to carry, and to rig when you get to your 
operating QTH.


There are some tutorials on my website about antennas. They are written 
for antennas in general, not just portable antennas.


The best portable antennas are mostly nothing more than wire. The things 
you want to BUY are the wire and things that help you rig them. Look for 
lightweight, telescoping poles that you can tape a wire to, and ways to 
rig it more or less upright. Jackite poles are nice for this use.


Carry more wire to string out as radials. When you can, keep the radials 
off the ground a few feet -- for example, string them through scrub 
trees and brush. Build dipoles for situations when you can rig two ends 
in trees. Find a lightweight method to toss weights tied to fishing line 
into trees, tie light weight antenna rope to the line, pull it into the 
tree(s), rig the antenna wire to that rope. I used to see a product 
called a "wrist rocket" that is essentially a fishing reel attached to a 
short rod for launching into a tree. If you're going to use fishing 
weights, paint them a bright color so you can find them.


One of my buddies, N6RNO, is awfully good at simply tying a fishing 
weight to a fishing line and using his arm as a sort of catapault to 
launch wires into trees. He regularly gets our dipoles for CQP 
(California QSO Party) county expeditions up 40 ft into trees. When I 
first moved to CA 10 years ago, AE6RF did that using a half empty 16 oz 
water jug.


Tossing a wire into a tree is also a great way to rig a vertical.

Whatever you do, don't waste a single penny on any commercial antenna 
for portable use. Those popular (and expensive) poles antennas with 
loading coils are poor antennas -- loading coils are the reason.


73, Jim K9YC

__
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Elecraft@mailman.qth.net

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to arch...@mail-archive.com

Re: [Elecraft] Dummy loads for dummies

[Merv Schweigert via Elecraft]

They make similar resistors up to 800 watt or more,  see them on ebay
all the time,  they are even made in 25 ohm or 100 ohm so you can
series or parallel them to what you need,  easy to make a dummy load that
will handle many KW with just a couple.  Large heat sink needed.

Makes me curious about designing with these TO-220 resistors in the 1000
Ohm size of appropriate power rating...  Parallel 20 of them like folks
do on the axials that they put in the can type dummy loads with oil.

Options:

1) 20 in parallel on a finned copper or bare aluminum sink of sufficient
size and then entire assembly in a oil wetted container.
2) Same, but only the finned side of the finned/pinned heat exchanger in
a coolant bath.

I'd like to have a rugged, high power, key down load built from easily
obtainable and replaceable parts.

__
Clay Autery, KY5G
MONTAC Enterprises
(318) 518-1389

On 12/27/2016 5:52 PM, Mel Farrer via Elecraft wrote:

One thing I might also add in.  I use the Film TO-220 style non-inductive 
resistors with a heat sink in the 200 ohm 1% configuration to test 4:1 baluns 
at 100 watt level to confirm non saturation on the small QRP baluns I make.
Mel, K6KBE



__
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Elecraft@mailman.qth.net

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to k...@flex.com



__
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Elecraft@mailman.qth.net

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to arch...@mail-archive.com

Re: [Elecraft] Dummy loads for dummies

[Don Wilhelm]

Clay,

Unless things have changed since I tested the Caddock Thick Film Power 
resistors of other than 50 ohms, I would not parallel 20 1000 ohm 
resistors to produce a 50 ohm load.  Values other than 50 ohms are not 
guaranteed to be non-reactive.


I would put 4 strings of 4 50 ohm resistors in series in parallel. Each 
resistor mounted with leads as short as possible.


I don't know about the dissipation characteristics of those resistors 
mounted in oil, and I suspect it depends on the heatsinking ability of 
the resistor mountings when immersed in the oil.
20 100 watt resistors *should* produce a 2000 watt load, but as I 
indicated, it depends on the dissipation of the individual resistors and 
how fast they can transfer their heat to the oil.  It may be necessary 
to attach the resistors to a heat sink and immerse those heat sink 
assemblies into the oil.


For all those who are looking for a suitable dummy load for high power, 
you usually do not have to be concerned about measurement quality 
impedance.  Something adequate to provide a suitable load for the 
amplifier may be all that is needed.  Having a precision 50 ohm load is 
a requirement for measurement, but not for routine amplifier tuning and 
general operating procedures.


73,
Don W3FPR

73,
Don W3FPR

On 12/27/2016 7:16 PM, Clay Autery wrote:

Makes me curious about designing with these TO-220 resistors in the 1000
Ohm size of appropriate power rating...  Parallel 20 of them like folks
do on the axials that they put in the can type dummy loads with oil.

Options:

1) 20 in parallel on a finned copper or bare aluminum sink of sufficient
size and then entire assembly in a oil wetted container.
2) Same, but only the finned side of the finned/pinned heat exchanger in
a coolant bath.

I'd like to have a rugged, high power, key down load built from easily
obtainable and replaceable parts.

__
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Elecraft@mailman.qth.net

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to arch...@mail-archive.com

Re: [Elecraft] Dummy loads for dummies

[Harry Yingst via Elecraft]

I have seen on ebay (I believe Henry Radio is the vendor) some pretty high 
wattage loads
(I believe at one time they sold a set of 4 200ohm ones to mount to a big heat 
sink.)

If I were going to run a tube amp again I'd be tempted to make up a high 
wattage dummy load for it.

 

  From: Clay Autery 
 To: elecraft@mailman.qth.net 
 Sent: Tuesday, December 27, 2016 7:16 PM
 Subject: Re: [Elecraft] Dummy loads for dummies
   
Makes me curious about designing with these TO-220 resistors in the 1000
Ohm size of appropriate power rating...  Parallel 20 of them like folks
do on the axials that they put in the can type dummy loads with oil.

Options:

1) 20 in parallel on a finned copper or bare aluminum sink of sufficient
size and then entire assembly in a oil wetted container.
2) Same, but only the finned side of the finned/pinned heat exchanger in
a coolant bath.

I'd like to have a rugged, high power, key down load built from easily
obtainable and replaceable parts.

__
Clay Autery, KY5G
MONTAC Enterprises
(318) 518-1389

On 12/27/2016 5:52 PM, Mel Farrer via Elecraft wrote:
> One thing I might also add in.  I use the Film TO-220 style non-inductive 
> resistors with a heat sink in the 200 ohm 1% configuration to test 4:1 baluns 
> at 100 watt level to confirm non saturation on the small QRP baluns I make.
> Mel, K6KBE
>
>

__
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Elecraft@mailman.qth.net

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to hlyin...@yahoo.com


   
__
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Elecraft@mailman.qth.net

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to arch...@mail-archive.com

Re: [Elecraft] Dummy loads for dummies

[Clay Autery]

Makes me curious about designing with these TO-220 resistors in the 1000
Ohm size of appropriate power rating...  Parallel 20 of them like folks
do on the axials that they put in the can type dummy loads with oil.

Options:

1) 20 in parallel on a finned copper or bare aluminum sink of sufficient
size and then entire assembly in a oil wetted container.
2) Same, but only the finned side of the finned/pinned heat exchanger in
a coolant bath.

I'd like to have a rugged, high power, key down load built from easily
obtainable and replaceable parts.

__
Clay Autery, KY5G
MONTAC Enterprises
(318) 518-1389

On 12/27/2016 5:52 PM, Mel Farrer via Elecraft wrote:
> One thing I might also add in.  I use the Film TO-220 style non-inductive 
> resistors with a heat sink in the 200 ohm 1% configuration to test 4:1 baluns 
> at 100 watt level to confirm non saturation on the small QRP baluns I make.
> Mel, K6KBE
>
>

__
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Elecraft@mailman.qth.net

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to arch...@mail-archive.com

Re: [Elecraft] Dummy loads for dummies

[Mel Farrer via Elecraft]

One thing I might also add in.  I use the Film TO-220 style non-inductive 
resistors with a heat sink in the 200 ohm 1% configuration to test 4:1 baluns 
at 100 watt level to confirm non saturation on the small QRP baluns I make.
Mel, K6KBE


  From: Ron D'Eau Claire 
 To: 'Paul C' ; elecraft@mailman.qth.net 
 Sent: Tuesday, December 27, 2016 3:23 PM
 Subject: Re: [Elecraft] Dummy loads for dummies
   
For parts, digikey.com and mouser.com are good friends. No minimum order, great 
prices and huge selection. 

You've gotten several suggestions for a good dummy load. And I concur with the 
others, those wire-wound resistors might be 50 ohms but their reactance may 
almost anything and dependent upon frequency. One of the original "Elecrafter 
Field Testers" and "F.O.W." - friend of Wayne (Burdick) - was Tom Hammond, 
N0SS, no sadly an S.K. But his web site has been maintained and it contains a 
great low-cost dummy load design:

http://www.mmccs.com/mmarc/n0ss/dl_30w_hf-uhf.pdf

You might enjoy looking around the web site for more KX1 info and QRP info in 
general:

http://www.mmccs.com/mmarc/n0ss/

Coaxial cable is every much as low loss as open wire line when the SWR is not 
too high. The difference in applying them is that the inherently 
higher-impedance of ladder line makes it much easier to keep the SWR on the 
line low enough to avoid excessive loss. For example, a hunk of wire between 50 
and 100 feet long strung up in the air and fed at its center will show an 
impedance of about 4,000 ohms at the frequency at which it is 1/2 wavelength 
long and perhaps as low as 40 ohms on 80 or 160 meters. With open wire line at 
about 400 ohms impedance, you will find an SWR of up to 10:1 on the feed line, 
generally much less. With 50 ohm coax, the SWR will range as high as 80:1 or 
more.

Have fun. At my shack, simple and cheap is great fun! 

73, Ron AC7AC 



-Original Message-
From: Elecraft [mailto:elecraft-boun...@mailman.qth.net] On Behalf Of Paul C
Sent: Tuesday, December 27, 2016 12:23 PM
To: Walter Underwood; elecraft@mailman.qth.net
Subject: Re: [Elecraft] Dummy loads for dummies

Ok, I won't be using these resistors after all.  Thanks for setting me 
straight. 

It seems tuff to get going in QRP.  I thought I'd roll my own when possible.  I 
am trying to keep things simple and economical, the QRP spirit.

Here's another naive idea of mine:  I'm planning to use ladder line too.  Now 
I'm waiting for the other shoe to drop, when I realize coax will be my only 
practical choice.

Paul KG5KXG

-Original Message-
From: "Walter Underwood" 
Sent: ‎12/‎27/‎2016 1:45 PM
To: "elecraft@mailman.qth.net" 
Subject: Re: [Elecraft] Dummy loads for dummies

Ah, yes, bricks. Like these?

https://www.radioshack.com/products/radioshack-100-ohm-10w-10-wirewound-resistor-2-pack#
 
<https://www.radioshack.com/products/radioshack-100-ohm-10w-10-wirewound-resistor-2-pack#>

wunder
K6WRU
Walter Underwood
CM87wj
http://observer.wunderwood.org/ (my blog)

> On Dec 27, 2016, at 11:42 AM, Vic Rosenthal  wrote:
> 
> They are undoubtedly wire-wound resistors and will have too much inductance 
> to work well as a dummy load. The resistance is fine. If you have an SWR 
> meter, check it with that. SWR below about 1.5 would mean it is usable. It 
> might be OK on 160 or 80 meters but not on higher bands.
> 
> Vic 4X6GP
> 
>> On 27 Dec 2016, at 16:43, Paul C  wrote:
>> 
>> I made my own dummy load last night from two 100 ohm resistors wired in 
>> parallel.  They are rated for 10 watts each and look like little bricks.  I 
>> measured the resistance at 51 ohms.  Do you think this is close enough or 
>> should I reduce it to 50?
>> 
>> Paul KG5KXG
>> __
>> Elecraft mailing list
>> Home: http://mailman.qth.net/mailman/listinfo/elecraft
>> Help: http://mailman.qth.net/mmfaq.htm
>> Post: mailto:Elecraft@mailman.qth.net
>> 
>> This list hosted by: http://www.qsl.net Please help support this 
>> email list: http://www.qsl.net/donate.html Message delivered to 
>> k2vco@gmail.com
> __
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:Elecraft@mailman.qth.net
> 
> This list hosted by: http://www.qsl.net Please help support this email 
> list: http://www.qsl.net/donate.html Message delivered to 
> wun...@wunderwood.org

__
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Elecraft@mailman.qth.net

This list hosted by: http://www.qsl.

Re: [Elecraft] Dummy loads for dummies

[Ron D'Eau Claire]

For parts, digikey.com and mouser.com are good friends. No minimum order, great 
prices and huge selection. 

You've gotten several suggestions for a good dummy load. And I concur with the 
others, those wire-wound resistors might be 50 ohms but their reactance may 
almost anything and dependent upon frequency. One of the original "Elecrafter 
Field Testers" and "F.O.W." - friend of Wayne (Burdick) - was Tom Hammond, 
N0SS, no sadly an S.K. But his web site has been maintained and it contains a 
great low-cost dummy load design:

http://www.mmccs.com/mmarc/n0ss/dl_30w_hf-uhf.pdf

You might enjoy looking around the web site for more KX1 info and QRP info in 
general:

http://www.mmccs.com/mmarc/n0ss/

Coaxial cable is every much as low loss as open wire line when the SWR is not 
too high. The difference in applying them is that the inherently 
higher-impedance of ladder line makes it much easier to keep the SWR on the 
line low enough to avoid excessive loss. For example, a hunk of wire between 50 
and 100 feet long strung up in the air and fed at its center will show an 
impedance of about 4,000 ohms at the frequency at which it is 1/2 wavelength 
long and perhaps as low as 40 ohms on 80 or 160 meters. With open wire line at 
about 400 ohms impedance, you will find an SWR of up to 10:1 on the feed line, 
generally much less. With 50 ohm coax, the SWR will range as high as 80:1 or 
more.

Have fun. At my shack, simple and cheap is great fun! 

73, Ron AC7AC 



-Original Message-
From: Elecraft [mailto:elecraft-boun...@mailman.qth.net] On Behalf Of Paul C
Sent: Tuesday, December 27, 2016 12:23 PM
To: Walter Underwood; elecraft@mailman.qth.net
Subject: Re: [Elecraft] Dummy loads for dummies

Ok, I won't be using these resistors after all.  Thanks for setting me 
straight. 

It seems tuff to get going in QRP.  I thought I'd roll my own when possible.  I 
am trying to keep things simple and economical, the QRP spirit.

Here's another naive idea of mine:  I'm planning to use ladder line too.  Now 
I'm waiting for the other shoe to drop, when I realize coax will be my only 
practical choice.

Paul KG5KXG

-Original Message-
From: "Walter Underwood" 
Sent: ‎12/‎27/‎2016 1:45 PM
To: "elecraft@mailman.qth.net" 
Subject: Re: [Elecraft] Dummy loads for dummies

Ah, yes, bricks. Like these?

https://www.radioshack.com/products/radioshack-100-ohm-10w-10-wirewound-resistor-2-pack#
 
<https://www.radioshack.com/products/radioshack-100-ohm-10w-10-wirewound-resistor-2-pack#>

wunder
K6WRU
Walter Underwood
CM87wj
http://observer.wunderwood.org/ (my blog)

> On Dec 27, 2016, at 11:42 AM, Vic Rosenthal  wrote:
> 
> They are undoubtedly wire-wound resistors and will have too much inductance 
> to work well as a dummy load. The resistance is fine. If you have an SWR 
> meter, check it with that. SWR below about 1.5 would mean it is usable. It 
> might be OK on 160 or 80 meters but not on higher bands.
> 
> Vic 4X6GP
> 
>> On 27 Dec 2016, at 16:43, Paul C  wrote:
>> 
>> I made my own dummy load last night from two 100 ohm resistors wired in 
>> parallel.  They are rated for 10 watts each and look like little bricks.  I 
>> measured the resistance at 51 ohms.  Do you think this is close enough or 
>> should I reduce it to 50?
>> 
>> Paul KG5KXG
>> __
>> Elecraft mailing list
>> Home: http://mailman.qth.net/mailman/listinfo/elecraft
>> Help: http://mailman.qth.net/mmfaq.htm
>> Post: mailto:Elecraft@mailman.qth.net
>> 
>> This list hosted by: http://www.qsl.net Please help support this 
>> email list: http://www.qsl.net/donate.html Message delivered to 
>> k2vco@gmail.com
> __
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:Elecraft@mailman.qth.net
> 
> This list hosted by: http://www.qsl.net Please help support this email 
> list: http://www.qsl.net/donate.html Message delivered to 
> wun...@wunderwood.org

__
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Elecraft@mailman.qth.net

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html Message 
delivered to paul...@sbcglobal.net 
__
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Elecraft@mailman.qth.net

This list hosted by: http://www.qsl.net
Please help support this email list: http://w

Re: [Elecraft] Dummy loads for dummies

[Don Wilhelm]

Wes,

What you say is true, and how much it matters in practice will vary 
depending on just how much inductance is present  in those wirewound 
resistors. how much it matters depends of frequency.  The higher the 
frequency, the more it matters - and that is independent of power.


The load in question is for initial testing of a KX1 at 40 and 20 
meters.  If only an indication of some power output capability is 
required, then that load may be sufficient, but in this case, the owner 
wants to know if his KX1 is operating up to specifications, and a 
non-inductive dummy load is required for that purpose, in addition a 
means of accurately measuring the power output at a 3 to 4 watt level is 
also an essential tool.  An RF probe applied across the dummy load may 
provide that indication at 4 watts or less (along with a little math), 
but if the power is much greater than that, it will zap the most 
commonly used diode in the RF Probe (a 1N34).


So you are correct, if simply providing a load to a transmitter, the 
wirewound resistors may be OK, but if they are being used as a 
measurement tool, the results will be incorrect if only the DC 
resistance is considered.  The real result of any measurements done with 
reactive components can only be had by also considering the complex 
impedance of the load.  Measurements with an RF Probe and a DVM will not 
reveal that complex impedance that must be entered into the equation.


73,
Don W3FPR

On 12/27/2016 5:31 PM, Wes Stewart wrote:

Paul,

You've got a lot of hand wringing comments about how those are probably
wire wound resistors.  They probably are but in practice it might not
matter.  It all depends on what exactly you are trying to accomplish.

__
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Elecraft@mailman.qth.net

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to arch...@mail-archive.com

Re: [Elecraft] Dummy loads for dummies

[Alan Bloom]

I once made a dummy load with a 50W, 50-ohm wire-wound resistor.  The 
inductance was tuned out with a variable capacitor in series.  As I 
recall it worked reasonably well on 160 and 80 meters, but the bandwidth 
was too narrow to be useful on the high bands.


Alan N1AL


On 12/27/2016 02:31 PM, Wes Stewart wrote:

Paul,

You've got a lot of hand wringing comments about how those are probably
wire wound resistors.  They probably are but in practice it might not
matter.  It all depends on what exactly you are trying to accomplish.
You don't say what your usage is or how much power your TX is putting out.

Wes  N7WS

 On 12/27/2016 7:43 AM, Paul C wrote:

I made my own dummy load last night from two 100 ohm resistors wired
in parallel.  They are rated for 10 watts each and look like little
bricks.  I measured the resistance at 51 ohms.  Do you think this is
close enough or should I reduce it to 50?

Paul KG5KXG


__
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Elecraft@mailman.qth.net

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to n...@sonic.net

__
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Elecraft@mailman.qth.net

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to arch...@mail-archive.com

Re: [Elecraft] Dummy loads for dummies

[Wes Stewart]

Paul,

You've got a lot of hand wringing comments about how those are probably wire 
wound resistors.  They probably are but in practice it might not matter.  It all 
depends on what exactly you are trying to accomplish.   You don't say what your 
usage is or how much power your TX is putting out.


Wes  N7WS

 On 12/27/2016 7:43 AM, Paul C wrote:

I made my own dummy load last night from two 100 ohm resistors wired in 
parallel.  They are rated for 10 watts each and look like little bricks.  I 
measured the resistance at 51 ohms.  Do you think this is close enough or 
should I reduce it to 50?

Paul KG5KXG


__
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Elecraft@mailman.qth.net

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to arch...@mail-archive.com

Re: [Elecraft] Dummy loads for dummies

[Don Wilhelm]

I use those Caddock Thick Film Power resistors to make my own dummy 
loads.  They make flat dummy loads up to at least 200MHz with normal 
lead dress, and with care they can be flat up to 500MHz.
I have found is that the 50 ohm resistors are non-reactive, but other 
values may be capacitive.


They MUST be used on a heatsink adequate for their power rating or else 
their power rating is quite low.  They will zap in an instant if their 
power rating (device and the heatsink) are exceeded, so put them on a 
heatsink that is sufficient for the power rating.


73,
Don W3FPR

On 12/27/2016 3:21 PM, John Parker wrote:

The good non-inductive resistors are made by Caddock Electronics. Available 
from some of the catalog dealers.
John WB4UHCK3 #2165


__
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Elecraft@mailman.qth.net

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to arch...@mail-archive.com

Re: [Elecraft] Dummy loads for dummies

[Don Wilhelm]

Paul,

For the ladderline vs. coax question, you might want to take a look at 
the article I wrote for QRP Quarterly some years back.  If so, go to my 
website www.w3fpr.com and look at the Antenna, Transmission Lines and 
Tuners article.  You can also find that article at 
http://www.dxzone.com/dx19232/antennas-and-transmission-lines-myths.html 
- I am pleased that DXzone has chosen to preserve it.


73,
Don W3FPR

On 12/27/2016 3:22 PM, Paul C wrote:

Ok, I won't be using these resistors after all.  Thanks for setting me straight.

It seems tuff to get going in QRP.  I thought I'd roll my own when possible.  I 
am trying to keep things simple and economical, the QRP spirit.

Here's another naive idea of mine:  I'm planning to use ladder line too.  Now 
I'm waiting for the other shoe to drop, when I realize coax will be my only 
practical choice.

Paul KG5KXG

__
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Elecraft@mailman.qth.net

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to arch...@mail-archive.com

Re: [Elecraft] Dummy loads for dummies

[Bill Johnson]

Easiest solution, buy the Elecraft DL1 20 watt dummy load kit.  The guess work 
is removed.  And it is only $25.95 for the kit.  Fun to build simple to use.  
Even has an RF detector built on.

73,
Bill
K9YEQ

-Original Message-
From: Elecraft [mailto:elecraft-boun...@mailman.qth.net] On Behalf Of Walter 
Underwood
Sent: Tuesday, December 27, 2016 12:42 PM
To: elecraft@mailman.qth.net
Subject: Re: [Elecraft] Dummy loads for dummies

If you want a dummy load kit for about as much as you would pay for the box, I 
highly recommend the Oak Hills Research RFL-100 kit for $40.

http://www.ohr.com/rfl100.htm <http://www.ohr.com/rfl100.htm>

I used their “BNC in a UHF connector hole” kit to make my dummy load more 
convenient in my all-BNC shack.

http://www.ohr.com/parts.htm <http://www.ohr.com/parts.htm>

wunder
K6WRU
Walter Underwood
CM87wj
http://observer.wunderwood.org/ (my blog)

> On Dec 27, 2016, at 9:41 AM, Mel Farrer via Elecraft 
>  wrote:
> 
> Yes, and you should test the dummy load at the highest frequency you will be 
> using it.  Even leaded non-inductive resistors will have a reactive component 
> at higher frequencies.
> Frankly, I usually test them above the max frequency I intend to use it to 
> not have any concern about error.
> 
> Mel,  K6KBE
> 
> 
>  From: Ryan Noguchi via Elecraft 
> To: Paul C ; "elecraft@mailman.qth.net" 
> 
> Sent: Tuesday, December 27, 2016 8:16 AM
> Subject: Re: [Elecraft] Dummy loads for dummies
> 
>> I made my own dummy load last night from two 100 ohm resistors wired in 
>> parallel.  They are rated for 10 watts each and look like little bricks.  I 
>> measured the resistance at 51 ohms.  Do you think this is close enough or 
>> should I reduce it to 50?
> 
> 
> 
>> Paul KG5KXG
> 
> 
> If your impedance is really 51 ohms, that's an SWR of 1.02. If your antenna 
> had an SWR of 1.02, would you trim it to get to 1.00, fire up your tuner, or 
> just start operating?
> 
> However, some of those resistors that look like bricks are really coils 
> (inductors) inside, which produce a higher impedance than the DC resistance. 
> Under RF excitation, that dummy load may be well above 51 ohms impedance. 
> 
> 73, Ryan AI6DO
> __
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:Elecraft@mailman.qth.net
> 
> This list hosted by: http://www.qsl.net Please help support this email 
> list: http://www.qsl.net/donate.html Message delivered to 
> farrerfo...@yahoo.com
> 
> 
> __
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:Elecraft@mailman.qth.net
> 
> This list hosted by: http://www.qsl.net Please help support this email 
> list: http://www.qsl.net/donate.html Message delivered to 
> wun...@wunderwood.org

__
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Elecraft@mailman.qth.net

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html Message 
delivered to k9...@live.com
__
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Elecraft@mailman.qth.net

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to arch...@mail-archive.com

Re: [Elecraft] Dummy loads for dummies

[Vic Rosenthal 4X6GP]

I'm using ladder line to feed a 20m dipole on all bands from 40-10m 
(actually, it even works on 6m). Using a dipole shorter than 1/2 
wavelength can be tricky, but it should work pretty well on the design 
frequency and higher. You will need to use a balanced antenna tuner, or 
an unbalanced tuner plus a balun.


There's an article about how I did this in this newsletter:


73,
Vic, 4X6GP
Rehovot, Israel
Formerly K2VCO
http://www.qsl.net/k2vco/

On 27 Dec 2016 22:22, Paul C wrote:

Ok, I won't be using these resistors after all.  Thanks for setting
me straight.

It seems tuff to get going in QRP.  I thought I'd roll my own when
possible.  I am trying to keep things simple and economical, the QRP
spirit.

Here's another naive idea of mine:  I'm planning to use ladder line
too.  Now I'm waiting for the other shoe to drop, when I realize coax
will be my only practical choice.

Paul KG5KXG

__
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Elecraft@mailman.qth.net

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to arch...@mail-archive.com

Re: [Elecraft] Dummy loads for dummies

[Walter Underwood]

For a 10W load, it is hard to beat the OHR kit. It is just two resistors on the 
back of a connector, but you probably couldn’t buy the three components for 
$11.50. The Craddock resistors are almost $10 each in small lots.

"The CQC RFL-10 Dummy Load Kit consists of two 5 Watt 100 Ohm metal oxide 
resistors connected in parallel, giving you a nice non-inductive 50 Ohm DC 
resistance.  We've field tested these babies and they produce a remarkably flat 
1:1 SWR from 1.8 - 30 MHz. The main body of the RFL-10 is an S0-239 coaxial 
socket which allows you to create a nice in-line package. Two sturdy adapters 
are included, one that allows you to connect directly to an SO-239 coax 
connector, and another that allows you to connect to a BNC socket.  There are 
two solder connections, and that's it. 

When completed the RFL-10 will dissipate 10W  continuously, and up to 25W for 
brief periods."

http://www.ohr.com/rfl10.htm 

wunder
K6WRU
Walter Underwood
CM87wj
http://observer.wunderwood.org/ (my blog)

> On Dec 27, 2016, at 12:21 PM, John Parker  wrote:
> 
> The good non-inductive resistors are made by Caddock Electronics. Available 
> from some of the catalog dealers.
> 
> John WB4UHC
> K3 #2165
> 
> 
> On Tuesday, December 27, 2016 2:46 PM, Walter Underwood 
>  wrote:
> 
> 
> Ah, yes, bricks. Like these?
> 
> https://www.radioshack.com/products/radioshack-100-ohm-10w-10-wirewound-resistor-2-pack#
>   
>   
> >
> 
> wunder
> K6WRU
> Walter Underwood
> CM87wj
> http://observer.wunderwood.org/  (my blog)
> 
> > On Dec 27, 2016, at 11:42 AM, Vic Rosenthal  > > wrote:
> > 
> > They are undoubtedly wire-wound resistors and will have too much inductance 
> > to work well as a dummy load. The resistance is fine. If you have an SWR 
> > meter, check it with that. SWR below about 1.5 would mean it is usable. It 
> > might be OK on 160 or 80 meters but not on higher bands.
> > 
> > Vic 4X6GP
> > 
> >> On 27 Dec 2016, at 16:43, Paul C  >> > wrote:
> >> 
> >> I made my own dummy load last night from two 100 ohm resistors wired in 
> >> parallel.  They are rated for 10 watts each and look like little bricks.  
> >> I measured the resistance at 51 ohms.  Do you think this is close enough 
> >> or should I reduce it to 50?
> >> 
> >> Paul KG5KXG
> >> __
> >> Elecraft mailing list
> >> Home: http://mailman.qth.net/mailman/listinfo/elecraft 
> >> 
> >> Help: http://mailman.qth.net/mmfaq.htm 
> >> Post: mailto:Elecraft@mailman.qth.net 
> >> 
> >> This list hosted by: http://www.qsl.net 
> >> Please help support this email list: http://www.qsl.net/donate.html 
> >> 
> >> Message delivered to k2vco@gmail.com 
> > __
> > Elecraft mailing list
> > Home: http://mailman.qth.net/mailman/listinfo/elecraft 
> > 
> > Help: http://mailman.qth.net/mmfaq.htm 
> > Post: mailto:Elecraft@mailman.qth.net 
> > 
> > This list hosted by: http://www.qsl.net 
> > Please help support this email list: http://www.qsl.net/donate.html 
> > 
> > Message delivered to wun...@wunderwood.org 
> 
> 
> __
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft 
> 
> Help: http://mailman.qth.net/mmfaq.htm 
> Post: mailto:Elecraft@mailman.qth.net 
> 
> This list hosted by: http://www.qsl.net 
> Please help support this email list: http://www.qsl.net/donate.html 
> 
> Message delivered to johnj...@verizon.net 
> 
> 

__
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Elecraft@mailman.qth.net

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to arch...@mail-archive.com

Re: [Elecraft] Dummy loads for dummies

[Kevin - K4VD]

​Well now I don't think anyone said the wirewounds wouldn't work just that
you'd need to check them out. Give it a shot and see if the SWR is as
expected. I've used cheap carbon comp resistors in the past​. Heck, a light
 bulb (incandescent) probably wouldn't do a bad job.

As for your other idea, using ladder line, it's about the best choice for
QRP I think as it generally is lower loss. I use 600 ohm ladder line but I
don't know if that's any better or worse electrically than 450 ohm window
line or even 300 ohm tv line.

Kev
__
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Elecraft@mailman.qth.net

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to arch...@mail-archive.com

Re: [Elecraft] Dummy loads for dummies

[Mel Farrer via Elecraft]

Or these, they are good to VHF range.  
non inductive resistor Passive Components | Mouser
But if you want something that is good to microwave, then use 4 each 200 ohms 
1206 chip resistors around a panel mount female BNC connector.  Works slick.
Mel, K6KBE

  
|  
|  
|  
|   ||

  |

  |
|  
|   |  
non inductive resistor Passive Components | Mouser
 non inductive resistor Passive Components are available at Mouser Electronics. 
Mouser offers inventory, pricing,...  |   |

  |

  |

 



  From: Walter Underwood 
 To: "elecraft@mailman.qth.net"  
 Sent: Tuesday, December 27, 2016 11:44 AM
 Subject: Re: [Elecraft] Dummy loads for dummies
  
Ah, yes, bricks. Like these?

https://www.radioshack.com/products/radioshack-100-ohm-10w-10-wirewound-resistor-2-pack#
 
<https://www.radioshack.com/products/radioshack-100-ohm-10w-10-wirewound-resistor-2-pack#>

wunder
K6WRU
Walter Underwood
CM87wj
http://observer.wunderwood.org/ (my blog)

> On Dec 27, 2016, at 11:42 AM, Vic Rosenthal  wrote:
> 
> They are undoubtedly wire-wound resistors and will have too much inductance 
> to work well as a dummy load. The resistance is fine. If you have an SWR 
> meter, check it with that. SWR below about 1.5 would mean it is usable. It 
> might be OK on 160 or 80 meters but not on higher bands.
> 
> Vic 4X6GP
> 
>> On 27 Dec 2016, at 16:43, Paul C  wrote:
>> 
>> I made my own dummy load last night from two 100 ohm resistors wired in 
>> parallel.  They are rated for 10 watts each and look like little bricks.  I 
>> measured the resistance at 51 ohms.  Do you think this is close enough or 
>> should I reduce it to 50?
>> 
>> Paul KG5KXG
>> __
>> Elecraft mailing list
>> Home: http://mailman.qth.net/mailman/listinfo/elecraft
>> Help: http://mailman.qth.net/mmfaq.htm
>> Post: mailto:Elecraft@mailman.qth.net
>> 
>> This list hosted by: http://www.qsl.net
>> Please help support this email list: http://www.qsl.net/donate.html
>> Message delivered to k2vco@gmail.com
> __
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:Elecraft@mailman.qth.net
> 
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
> Message delivered to wun...@wunderwood.org

__
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Elecraft@mailman.qth.net

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to farrerfo...@yahoo.com


   
__
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Elecraft@mailman.qth.net

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to arch...@mail-archive.com

Re: [Elecraft] Dummy loads for dummies

[Paul C]

Ok, I won't be using these resistors after all.  Thanks for setting me 
straight. 

It seems tuff to get going in QRP.  I thought I'd roll my own when possible.  I 
am trying to keep things simple and economical, the QRP spirit.

Here's another naive idea of mine:  I'm planning to use ladder line too.  Now 
I'm waiting for the other shoe to drop, when I realize coax will be my only 
practical choice.

Paul KG5KXG

-Original Message-
From: "Walter Underwood" 
Sent: ‎12/‎27/‎2016 1:45 PM
To: "elecraft@mailman.qth.net" 
Subject: Re: [Elecraft] Dummy loads for dummies

Ah, yes, bricks. Like these?

https://www.radioshack.com/products/radioshack-100-ohm-10w-10-wirewound-resistor-2-pack#
 
<https://www.radioshack.com/products/radioshack-100-ohm-10w-10-wirewound-resistor-2-pack#>

wunder
K6WRU
Walter Underwood
CM87wj
http://observer.wunderwood.org/ (my blog)

> On Dec 27, 2016, at 11:42 AM, Vic Rosenthal  wrote:
> 
> They are undoubtedly wire-wound resistors and will have too much inductance 
> to work well as a dummy load. The resistance is fine. If you have an SWR 
> meter, check it with that. SWR below about 1.5 would mean it is usable. It 
> might be OK on 160 or 80 meters but not on higher bands.
> 
> Vic 4X6GP
> 
>> On 27 Dec 2016, at 16:43, Paul C  wrote:
>> 
>> I made my own dummy load last night from two 100 ohm resistors wired in 
>> parallel.  They are rated for 10 watts each and look like little bricks.  I 
>> measured the resistance at 51 ohms.  Do you think this is close enough or 
>> should I reduce it to 50?
>> 
>> Paul KG5KXG
>> __
>> Elecraft mailing list
>> Home: http://mailman.qth.net/mailman/listinfo/elecraft
>> Help: http://mailman.qth.net/mmfaq.htm
>> Post: mailto:Elecraft@mailman.qth.net
>> 
>> This list hosted by: http://www.qsl.net
>> Please help support this email list: http://www.qsl.net/donate.html
>> Message delivered to k2vco@gmail.com
> __
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:Elecraft@mailman.qth.net
> 
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
> Message delivered to wun...@wunderwood.org

__
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Elecraft@mailman.qth.net

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to paul...@sbcglobal.net
__
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Elecraft@mailman.qth.net

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to arch...@mail-archive.com

Re: [Elecraft] Dummy loads for dummies

[John Parker]

The good non-inductive resistors are made by Caddock Electronics. Available 
from some of the catalog dealers.
John WB4UHCK3 #2165 

On Tuesday, December 27, 2016 2:46 PM, Walter Underwood 
 wrote:
 

 Ah, yes, bricks. Like these?

https://www.radioshack.com/products/radioshack-100-ohm-10w-10-wirewound-resistor-2-pack#
 


wunder
K6WRU
Walter Underwood
CM87wj
http://observer.wunderwood.org/ (my blog)

> On Dec 27, 2016, at 11:42 AM, Vic Rosenthal  wrote:
> 
> They are undoubtedly wire-wound resistors and will have too much inductance 
> to work well as a dummy load. The resistance is fine. If you have an SWR 
> meter, check it with that. SWR below about 1.5 would mean it is usable. It 
> might be OK on 160 or 80 meters but not on higher bands.
> 
> Vic 4X6GP
> 
>> On 27 Dec 2016, at 16:43, Paul C  wrote:
>> 
>> I made my own dummy load last night from two 100 ohm resistors wired in 
>> parallel.  They are rated for 10 watts each and look like little bricks.  I 
>> measured the resistance at 51 ohms.  Do you think this is close enough or 
>> should I reduce it to 50?
>> 
>> Paul KG5KXG
>> __
>> Elecraft mailing list
>> Home: http://mailman.qth.net/mailman/listinfo/elecraft
>> Help: http://mailman.qth.net/mmfaq.htm
>> Post: mailto:Elecraft@mailman.qth.net
>> 
>> This list hosted by: http://www.qsl.net
>> Please help support this email list: http://www.qsl.net/donate.html
>> Message delivered to k2vco@gmail.com
> __
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:Elecraft@mailman.qth.net
> 
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
> Message delivered to wun...@wunderwood.org

__
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Elecraft@mailman.qth.net

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to johnj...@verizon.net


   
__
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Elecraft@mailman.qth.net

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to arch...@mail-archive.com

Re: [Elecraft] Dummy loads for dummies

[Walter Underwood]

Ah, yes, bricks. Like these?

https://www.radioshack.com/products/radioshack-100-ohm-10w-10-wirewound-resistor-2-pack#
 


wunder
K6WRU
Walter Underwood
CM87wj
http://observer.wunderwood.org/ (my blog)

> On Dec 27, 2016, at 11:42 AM, Vic Rosenthal  wrote:
> 
> They are undoubtedly wire-wound resistors and will have too much inductance 
> to work well as a dummy load. The resistance is fine. If you have an SWR 
> meter, check it with that. SWR below about 1.5 would mean it is usable. It 
> might be OK on 160 or 80 meters but not on higher bands.
> 
> Vic 4X6GP
> 
>> On 27 Dec 2016, at 16:43, Paul C  wrote:
>> 
>> I made my own dummy load last night from two 100 ohm resistors wired in 
>> parallel.  They are rated for 10 watts each and look like little bricks.  I 
>> measured the resistance at 51 ohms.  Do you think this is close enough or 
>> should I reduce it to 50?
>> 
>> Paul KG5KXG
>> __
>> Elecraft mailing list
>> Home: http://mailman.qth.net/mailman/listinfo/elecraft
>> Help: http://mailman.qth.net/mmfaq.htm
>> Post: mailto:Elecraft@mailman.qth.net
>> 
>> This list hosted by: http://www.qsl.net
>> Please help support this email list: http://www.qsl.net/donate.html
>> Message delivered to k2vco@gmail.com
> __
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:Elecraft@mailman.qth.net
> 
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
> Message delivered to wun...@wunderwood.org

__
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Elecraft@mailman.qth.net

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to arch...@mail-archive.com

Re: [Elecraft] Dummy loads for dummies

[Vic Rosenthal]

They are undoubtedly wire-wound resistors and will have too much inductance to 
work well as a dummy load. The resistance is fine. If you have an SWR meter, 
check it with that. SWR below about 1.5 would mean it is usable. It might be OK 
on 160 or 80 meters but not on higher bands.

Vic 4X6GP

> On 27 Dec 2016, at 16:43, Paul C  wrote:
> 
> I made my own dummy load last night from two 100 ohm resistors wired in 
> parallel.  They are rated for 10 watts each and look like little bricks.  I 
> measured the resistance at 51 ohms.  Do you think this is close enough or 
> should I reduce it to 50?
> 
> Paul KG5KXG
> __
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:Elecraft@mailman.qth.net
> 
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
> Message delivered to k2vco@gmail.com
__
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Elecraft@mailman.qth.net

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to arch...@mail-archive.com

Re: [Elecraft] Dummy loads for dummies

[Walter Underwood]

If you want a dummy load kit for about as much as you would pay for the box, I 
highly recommend the Oak Hills Research RFL-100 kit for $40.

http://www.ohr.com/rfl100.htm <http://www.ohr.com/rfl100.htm>

I used their “BNC in a UHF connector hole” kit to make my dummy load more 
convenient in my all-BNC shack.

http://www.ohr.com/parts.htm <http://www.ohr.com/parts.htm>

wunder
K6WRU
Walter Underwood
CM87wj
http://observer.wunderwood.org/ (my blog)

> On Dec 27, 2016, at 9:41 AM, Mel Farrer via Elecraft 
>  wrote:
> 
> Yes, and you should test the dummy load at the highest frequency you will be 
> using it.  Even leaded non-inductive resistors will have a reactive component 
> at higher frequencies.
> Frankly, I usually test them above the max frequency I intend to use it to 
> not have any concern about error.
> 
> Mel,  K6KBE
> 
> 
>  From: Ryan Noguchi via Elecraft 
> To: Paul C ; "elecraft@mailman.qth.net" 
>  
> Sent: Tuesday, December 27, 2016 8:16 AM
> Subject: Re: [Elecraft] Dummy loads for dummies
> 
>> I made my own dummy load last night from two 100 ohm resistors wired in 
>> parallel.  They are rated for 10 watts each and look like little bricks.  I 
>> measured the resistance at 51 ohms.  Do you think this is close enough or 
>> should I reduce it to 50?
> 
> 
> 
>> Paul KG5KXG
> 
> 
> If your impedance is really 51 ohms, that's an SWR of 1.02. If your antenna 
> had an SWR of 1.02, would you trim it to get to 1.00, fire up your tuner, or 
> just start operating?
> 
> However, some of those resistors that look like bricks are really coils 
> (inductors) inside, which produce a higher impedance than the DC resistance. 
> Under RF excitation, that dummy load may be well above 51 ohms impedance. 
> 
> 73, Ryan AI6DO  
> __
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:Elecraft@mailman.qth.net
> 
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
> Message delivered to farrerfo...@yahoo.com
> 
> 
> __
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:Elecraft@mailman.qth.net
> 
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
> Message delivered to wun...@wunderwood.org

__
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Elecraft@mailman.qth.net

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to arch...@mail-archive.com

Re: [Elecraft] Dummy loads for dummies

[Mel Farrer via Elecraft]

Yes, and you should test the dummy load at the highest frequency you will be 
using it.  Even leaded non-inductive resistors will have a reactive component 
at higher frequencies.
Frankly, I usually test them above the max frequency I intend to use it to not 
have any concern about error.

Mel,  K6KBE


  From: Ryan Noguchi via Elecraft 
 To: Paul C ; "elecraft@mailman.qth.net" 
 
 Sent: Tuesday, December 27, 2016 8:16 AM
 Subject: Re: [Elecraft] Dummy loads for dummies
   
>I made my own dummy load last night from two 100 ohm resistors wired in 
>parallel.  They are rated for 10 watts each and look like little bricks.  I 
>measured the resistance at 51 ohms.  Do you think this is close enough or 
>should I reduce it to 50?



>Paul KG5KXG


If your impedance is really 51 ohms, that's an SWR of 1.02. If your antenna had 
an SWR of 1.02, would you trim it to get to 1.00, fire up your tuner, or just 
start operating?

However, some of those resistors that look like bricks are really coils 
(inductors) inside, which produce a higher impedance than the DC resistance. 
Under RF excitation, that dummy load may be well above 51 ohms impedance. 

73, Ryan AI6DO  
__
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Elecraft@mailman.qth.net

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to farrerfo...@yahoo.com

   
__
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Elecraft@mailman.qth.net

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to arch...@mail-archive.com

Re: [Elecraft] Dummy loads for dummies

[Ryan Noguchi via Elecraft]

>I made my own dummy load last night from two 100 ohm resistors wired in 
>parallel.  They are rated for 10 watts each and look like little bricks.  I 
>measured the resistance at 51 ohms.  Do you think this is close enough or 
>should I reduce it to 50?



>Paul KG5KXG


If your impedance is really 51 ohms, that's an SWR of 1.02. If your antenna had 
an SWR of 1.02, would you trim it to get to 1.00, fire up your tuner, or just 
start operating?

However, some of those resistors that look like bricks are really coils 
(inductors) inside, which produce a higher impedance than the DC resistance. 
Under RF excitation, that dummy load may be well above 51 ohms impedance. 

73, Ryan AI6DO   
__
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Elecraft@mailman.qth.net

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to arch...@mail-archive.com

Re: [Elecraft] Dummy loads for dummies

[Ken G Kopp]

Paul,

Kevin is likely correct.  If those two resistors have a sand-like finish
they're almost certain to be wire wound and therefore will have some
inductance,
which will cause your load to give "uncertain" results.

Your 51 ohm would be OK.  Your ohmmeter isn't -that- accurate, after all.

Elecraft sells a nice load kit that has an additional feature of a
calibrated wattmeter output.

73

Ken Kopp - K0PP



On Dec 27, 2016 7:44 AM, "Paul C"  wrote:

I made my own dummy load last night from two 100 ohm resistors wired in
parallel.  They are rated for 10 watts each and look like little bricks.  I
measured the resistance at 51 ohms.  Do you think this is close enough or
should I reduce it to 50?

Paul KG5KXG
__
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Elecraft@mailman.qth.net

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to kengk...@gmail.com
__
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Elecraft@mailman.qth.net

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to arch...@mail-archive.com

Re: [Elecraft] Dummy loads for dummies

[Kevin - K4VD]

​Plenty close enough. Only issue I can think of (besides the normal safety
stuff) is to make sure the resistors are not of the wirewound variety.

Kev K4VD
__
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Elecraft@mailman.qth.net

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to arch...@mail-archive.com

[Elecraft] Dummy loads for dummies

[Paul C]

I made my own dummy load last night from two 100 ohm resistors wired in 
parallel.  They are rated for 10 watts each and look like little bricks.  I 
measured the resistance at 51 ohms.  Do you think this is close enough or 
should I reduce it to 50?

Paul KG5KXG
__
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Elecraft@mailman.qth.net

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to arch...@mail-archive.com