250 Watt 1GHz resistor

[Jan Panteltje]

250 Watt 50 Ohm 1GHz resistor:
http://panteltje.com/pub/250W_1_GHz_dummy_load_IMG_4563.JPG

Needed a dummy load, found this, cheap,
but look at the size, compared to the TO220 next to it!
I wonder....

 

[Bill Sloman]

On Saturday, 27 September 2014 22:19:14 UTC+10, Jan Panteltje wrote:

250 Watt 50 Ohm 1GHz resistor:

http://panteltje.com/pub/250W_1_GHz_dummy_load_IMG_4563.JPG

Needed a dummy load, found this, cheap,
but look at the size, compared to the TO220 next to it!

I wonder....

You can run resistors a lot hotter than you can run silicon devices. That translates into steeper thermal gradients and greater heat dissipation in the same space.

Some people wanted to make a diamond-based semi-conductor on the basis that they could be run hotter than silicon

http://www.geek.com/chips/81ghz-diamond-semiconductor-created-551147/

or at least sucked in investors on that basis

http://www.semiconductor-today.com/news_items/2013/NOV/YOLE_141113.shtml

suggests that the project hasn't got that far in the last ten years.

--
Bill Sloman, Sydney

 

[Jan Panteltje]

On a sunny day (Sat, 27 Sep 2014 06:08:29 -0700 (PDT)) it happened Bill Sloman
<bill.sloman@gmail.com> wrote in
<12b6bd40-2e92-477b-badd-dd912d41c4a4@googlegroups.com>:

On Saturday, 27 September 2014 22:19:14 UTC+10, Jan Panteltje wrote:
250 Watt 50 Ohm 1GHz resistor:

http://panteltje.com/pub/250W_1_GHz_dummy_load_IMG_4563.JPG

Needed a dummy load, found this, cheap,
but look at the size, compared to the TO220 next to it!

I wonder....

You can run resistors a lot hotter than you can run silicon devices. That translates into steeper thermal gradients and greater
heat dissipation in the same space.

Some people wanted to make a diamond-based semi-conductor on the basis that they could be run hotter than silicon

http://www.geek.com/chips/81ghz-diamond-semiconductor-created-551147/

or at least sucked in investors on that basis

http://www.semiconductor-today.com/news_items/2013/NOV/YOLE_141113.shtml

suggests that the project hasn't got that far in the last ten years.

The famous Uncle Al poster in sci.physics (he is PhD chem) claimed
some years agao he was only a pump away from making his own artificial
diamonds...
I challenged him, he left, tail between legs, not seen him since.
Of course Beers see their market challenged, its all make believe,
so much money for a piece of glass.

Not sure if we really need more processor power now,
we could use more peace though, world seems to go 0bananas increasingly lately.

That little weapons factory called US is fighting an other enemy,
created by them for sure.

But 4 sure there could be applications.
Maybe a bit like whatsitcalled carbon nanonano tubes...
Chips have been made with those, but mass production is hard.

I found that this resistor actually is good to 3 GHz,
that makes it usable for 2.4 GHz, where I am working on a PA
for the geostationary amateur satellite that is supposed to be launched in 2016
if the world has not evaporated or something by then,
mind you launched by the Quatar Radio Society.
http://amsat-uk.org/2014/09/21/eshail-2-ham-radio-transponders/

There is lots of fun stuff going on.
Keeps your mind fit and hands busy.

 

250 Watt 50 Ohm 1GHz resistor:

http://panteltje.com/pub/250W_1_GHz_dummy_load_IMG_4563.JPG

Needed a dummy load, found this, cheap,

but look at the size, compared to the TO220 next to it!
I wonder....

So, where is your infinite heat sink when you need it? Did you loan it out? It's in the closet, maybe?

It's not made of silicon. It's something like nichrome on AlN or BeO. Let it get hot.

Doesn't matter what material. 250W is a burner. You can switch it on with the 79A 310W FDP2532 MOSFET once. It got auto-off function. Work once.

http://emc-rflabs.com/Passive-Components/Resistors/High-Power







--



John Larkin Highland Technology, Inc



jlarkin att highlandtechnology dott com

http://www.highlandtechnology.com

 

[John S]

On 9/27/2014 7:19 AM, Jan Panteltje wrote:

250 Watt 50 Ohm 1GHz resistor:
http://panteltje.com/pub/250W_1_GHz_dummy_load_IMG_4563.JPG

Needed a dummy load, found this, cheap,
but look at the size, compared to the TO220 next to it!
I wonder....

So, where is your infinite heat sink when you need it? Did you loan it
out? It's in the closet, maybe?

 

[John Larkin]

On Sat, 27 Sep 2014 12:35:16 -0500, John S <Sophi.2@invalid.org>
wrote:

On 9/27/2014 7:19 AM, Jan Panteltje wrote:
250 Watt 50 Ohm 1GHz resistor:
http://panteltje.com/pub/250W_1_GHz_dummy_load_IMG_4563.JPG

Needed a dummy load, found this, cheap,
but look at the size, compared to the TO220 next to it!
I wonder....


So, where is your infinite heat sink when you need it? Did you loan it
out? It's in the closet, maybe?

It's not made of silicon. It's something like nichrome on AlN or BeO.
Let it get hot.

http://emc-rflabs.com/Passive-Components/Resistors/High-Power



--

John Larkin Highland Technology, Inc

jlarkin att highlandtechnology dott com
http://www.highlandtechnology.com

 

On Sat, 27 Sep 2014 12:19:14 GMT, Jan Panteltje <panteltje@yahoo.com>
wrote:

250 Watt 50 Ohm 1GHz resistor:
http://panteltje.com/pub/250W_1_GHz_dummy_load_IMG_4563.JPG

Needed a dummy load, found this, cheap,
but look at the size, compared to the TO220 next to it!
I wonder....

Are you going to cook liquid nitrogen to get the heat out ?

I have used a 100 m reel of RG-58 as a dummy load for 1 GHz+ . It does
not matter if the opposite end is open or shorted .

For higher power level, you had to unreel some few meters from the
reel to help heat transfer.

 

[RobertMacy]

On Sun, 28 Sep 2014 08:10:42 -0700, <upsidedown@downunder.com> wrote:

On Sat, 27 Sep 2014 12:19:14 GMT, Jan Panteltje <panteltje@yahoo.com
wrote:

250 Watt 50 Ohm 1GHz resistor:
http://panteltje.com/pub/250W_1_GHz_dummy_load_IMG_4563.JPG

Needed a dummy load, found this, cheap,
but look at the size, compared to the TO220 next to it!
I wonder....

Are you going to cook liquid nitrogen to get the heat out ?

I have used a 100 m reel of RG-58 as a dummy load for 1 GHz+ . It does
not matter if the opposite end is open or shorted .

For higher power level, you had to unreel some few meters from the
reel to help heat transfer.

genius!

so, let's see, most cabling is a bit leaky, down what? 85 to 100 dB, so
you put in 54 dBm and transmit a healthy signal, right?

 

[Wayne Chirnside]

On Sat, 27 Sep 2014 12:19:14 +0000, Jan Panteltje wrote:

250 Watt 50 Ohm 1GHz resistor:
http://panteltje.com/pub/250W_1_GHz_dummy_load_IMG_4563.JPG

Needed a dummy load, found this, cheap,
but look at the size, compared to the TO220 next to it!
I wonder....

Need a computer?
http://www.masswerk.at/google60/

 

On Monday, September 29, 2014 5:31:00 AM UTC-4, Jan Panteltje wrote:

upsidedown wrote:
On Sat, 27 Sep 2014 12:19:14 GMT, Jan Panteltje wrote:

250 Watt 50 Ohm 1GHz resistor:
http://panteltje.com/pub/250W_1_GHz_dummy_load_IMG_4563.JPG

Needed a dummy load, found this, cheap,
but look at the size, compared to the TO220 next to it!

I wonder....

Are you going to cook liquid nitrogen to get the heat out ?

I have used a 100 m reel of RG-58 as a dummy load for 1 GHz+ . It does
not matter if the opposite end is open or shorted .

Thats is about 59 dB attenuation ...

It will still reflect.. 2 x 59 dB?

Then terminate it ... with an 0603 resistor. Problem solved.

Cheers,
James Arthur

 

[Jan Panteltje]

On a sunny day (Sat, 27 Sep 2014 12:35:16 -0500) it happened John S
<Sophi.2@invalid.org> wrote in <m06sgs$uvv$2@dont-email.me>:

On 9/27/2014 7:19 AM, Jan Panteltje wrote:
250 Watt 50 Ohm 1GHz resistor:
http://panteltje.com/pub/250W_1_GHz_dummy_load_IMG_4563.JPG

Needed a dummy load, found this, cheap,
but look at the size, compared to the TO220 next to it!
I wonder....


So, where is your infinite heat sink when you need it? Did you loan it
out? It's in the closet, maybe?

http://panteltje.com/pub/big_3kg_heatsink_IMG_3745.GIF
For reasonable values of infinite.

 

[Jan Panteltje]

On a sunny day (Sun, 28 Sep 2014 18:10:42 +0300) it happened
upsidedown@downunder.com wrote in
<1s8g2a1ripe06p0sb0uea1av24de5i8jq9@4ax.com>:

On Sat, 27 Sep 2014 12:19:14 GMT, Jan Panteltje <panteltje@yahoo.com
wrote:

250 Watt 50 Ohm 1GHz resistor:
http://panteltje.com/pub/250W_1_GHz_dummy_load_IMG_4563.JPG

Needed a dummy load, found this, cheap,
but look at the size, compared to the TO220 next to it!
I wonder....

Are you going to cook liquid nitrogen to get the heat out ?

I have used a 100 m reel of RG-58 as a dummy load for 1 GHz+ . It does
not matter if the opposite end is open or shorted .

Thats is about 59 dB attenuation ...
It will still reflect.. 2 x 59 dB?

For higher power level, you had to unreel some few meters from the
reel to help heat transfer.

The idea is interesting though.

 

[Tom Gardner]

On 27/09/14 18:35, John S wrote:

On 9/27/2014 7:19 AM, Jan Panteltje wrote:
250 Watt 50 Ohm 1GHz resistor:
http://panteltje.com/pub/250W_1_GHz_dummy_load_IMG_4563.JPG

Needed a dummy load, found this, cheap,
but look at the size, compared to the TO220 next to it!
I wonder....


So, where is your infinite heat sink when you need it? Did you loan it out? It's in the closet, maybe?

In a local stream/river perhaps?

 

[John S]

On 9/29/2014 4:31 AM, Jan Panteltje wrote:

On a sunny day (Sun, 28 Sep 2014 18:10:42 +0300) it happened
upsidedown@downunder.com wrote in
1s8g2a1ripe06p0sb0uea1av24de5i8jq9@4ax.com>:

On Sat, 27 Sep 2014 12:19:14 GMT, Jan Panteltje <panteltje@yahoo.com
wrote:

250 Watt 50 Ohm 1GHz resistor:
http://panteltje.com/pub/250W_1_GHz_dummy_load_IMG_4563.JPG

Needed a dummy load, found this, cheap,
but look at the size, compared to the TO220 next to it!
I wonder....

Are you going to cook liquid nitrogen to get the heat out ?

I have used a 100 m reel of RG-58 as a dummy load for 1 GHz+ . It does
not matter if the opposite end is open or shorted .

Thats is about 59 dB attenuation ...
It will still reflect.. 2 x 59 dB?

Like, below the noise floor of your receiver.

For higher power level, you had to unreel some few meters from the
reel to help heat transfer.

The idea is interesting though.

 

On Monday, September 29, 2014 10:23:17 AM UTC-4, Jan Panteltje wrote:

On a sunny day (Mon, 29 Sep 2014 05:18:10 -0700 (PDT)) it happened
dagmargoo...@yahoo.com wrote:
On Monday, September 29, 2014 5:31:00 AM UTC-4, Jan Panteltje wrote:
upsidedown wrote:
On Sat, 27 Sep 2014 12:19:14 GMT, Jan Panteltje wrote:

250 Watt 50 Ohm 1GHz resistor:
http://panteltje.com/pub/250W_1_GHz_dummy_load_IMG_4563.JPG

Needed a dummy load, found this, cheap,
but look at the size, compared to the TO220 next to it!

I wonder....

Are you going to cook liquid nitrogen to get the heat out ?

I have used a 100 m reel of RG-58 as a dummy load for 1 GHz+ . It does
not matter if the opposite end is open or shorted .

Thats is about 59 dB attenuation ...

It will still reflect.. 2 x 59 dB?

Then terminate it ... with an 0603 resistor. Problem solved.

Genius!

Only prob I have is that 100 meter cable is bigger than my resistor + heatsink.

Easy--use a bigger heat sink.

All kidding aside, that is a pretty nice broadband resistor you bought.

Cheers,
James Arthur

 

[Jeroen Belleman]

On 2014-09-29 11:31, Jan Panteltje wrote:

On a sunny day (Sun, 28 Sep 2014 18:10:42 +0300) it happened
upsidedown@downunder.com wrote in
1s8g2a1ripe06p0sb0uea1av24de5i8jq9@4ax.com>:

On Sat, 27 Sep 2014 12:19:14 GMT, Jan Panteltje <panteltje@yahoo.com
wrote:

250 Watt 50 Ohm 1GHz resistor:
http://panteltje.com/pub/250W_1_GHz_dummy_load_IMG_4563.JPG

Needed a dummy load, found this, cheap,
but look at the size, compared to the TO220 next to it!
I wonder....

Are you going to cook liquid nitrogen to get the heat out ?

I have used a 100 m reel of RG-58 as a dummy load for 1 GHz+ . It does
not matter if the opposite end is open or shorted .

Thats is about 59 dB attenuation ...
It will still reflect.. 2 x 59 dB?

Impedance tolerances on cheap cables and connectors make that
the reflection is rarely better than -35dB or so. You need
precision components to get a fair chance of doing better.

Jeroen Belleman

 

[Jan Panteltje]

On a sunny day (Mon, 29 Sep 2014 05:18:10 -0700 (PDT)) it happened
dagmargoodboat@yahoo.com wrote in
<369435cd-4d0e-4718-a0b2-2ca745f598c5@googlegroups.com>:

On Monday, September 29, 2014 5:31:00 AM UTC-4, Jan Panteltje wrote:
upsidedown wrote:
On Sat, 27 Sep 2014 12:19:14 GMT, Jan Panteltje wrote:

250 Watt 50 Ohm 1GHz resistor:
http://panteltje.com/pub/250W_1_GHz_dummy_load_IMG_4563.JPG

Needed a dummy load, found this, cheap,
but look at the size, compared to the TO220 next to it!

I wonder....

Are you going to cook liquid nitrogen to get the heat out ?

I have used a 100 m reel of RG-58 as a dummy load for 1 GHz+ . It does
not matter if the opposite end is open or shorted .

Thats is about 59 dB attenuation ...

It will still reflect.. 2 x 59 dB?

Then terminate it ... with an 0603 resistor. Problem solved.

Genius!

Only prob I have is that 100 meter cable is bigger than my resistor + heatsink.
To measure output power would it still be correct to measure the voltage over that cable at the lead end?
And especially at lower powers...

I ordered one of these for sat uplink, this with a 24 dB dish I am eying makes about 7500 W
http://www.ebay.com/itm/221556214361
Testing will have to be somewhere in the boonies far away from me.
Sidelobes..

Wonder if I can cook in the beam.
Wonder if it can fry the sat receiver...

path attenuation = 32.45 + 20.log(2400000000) + 20.log(40000) = 312.095 dB

mm probably not...


Whatdoyouthink?

 

[Jan Panteltje]

On a sunny day (Mon, 29 Sep 2014 14:23:17 GMT) it happened Jan Panteltje
<panteltje@yahoo.com> wrote in <m0bq1h$hcl$1@news.datemas.de>:

I ordered one of these for sat uplink, this with a 24 dB dish I am eying makes about 7500 W
http://www.ebay.com/itm/221556214361
Testing will have to be somewhere in the boonies far away from me.
Sidelobes..

Wonder if I can cook in the beam.
Wonder if it can fry the sat receiver...

path attenuation = 32.45 + 20.log(2400000000) + 20.log(40000) = 312.095 dB

Correction:
its 32.45 + 20.log(MHz) + 20.log(km)

32.45 + 20.log(2400) + 20.log(40000) = 192.095 dB

So...

 

[Jan Panteltje]

On a sunny day (Mon, 29 Sep 2014 08:28:27 -0700 (PDT)) it happened
dagmargoodboat@yahoo.com wrote in
<00f7e2fa-6d09-441a-987b-f0e14df2dac1@googlegroups.com>:

On Monday, September 29, 2014 10:23:17 AM UTC-4, Jan Panteltje wrote:
On a sunny day (Mon, 29 Sep 2014 05:18:10 -0700 (PDT)) it happened
dagmargoo...@yahoo.com wrote:
On Monday, September 29, 2014 5:31:00 AM UTC-4, Jan Panteltje wrote:
upsidedown wrote:
On Sat, 27 Sep 2014 12:19:14 GMT, Jan Panteltje wrote:

250 Watt 50 Ohm 1GHz resistor:
http://panteltje.com/pub/250W_1_GHz_dummy_load_IMG_4563.JPG

Needed a dummy load, found this, cheap,
but look at the size, compared to the TO220 next to it!

I wonder....

Are you going to cook liquid nitrogen to get the heat out ?

I have used a 100 m reel of RG-58 as a dummy load for 1 GHz+ . It does
not matter if the opposite end is open or shorted .

Thats is about 59 dB attenuation ...

It will still reflect.. 2 x 59 dB?

Then terminate it ... with an 0603 resistor. Problem solved.

Genius!

Only prob I have is that 100 meter cable is bigger than my resistor + heatsink.

Easy--use a bigger heat sink.

All kidding aside, that is a pretty nice broadband resistor you bought.

Yes, and it is 100% insulated from the mounting.
Its this:
http://dutchrfshop.nl/componenten/rf-dummyload-weerstanden/250-watt-rf-weerstand-50-ohm.html
if you want one.
If you wait long enough the Euro will be the same as the US dollar.

Cheers,
James Arthur

 

[Jan Panteltje]

On a sunny day (Mon, 29 Sep 2014 14:38:32 GMT) it happened Jan Panteltje
<panteltje@yahoo.com> wrote in <m0bqu4$ipu$1@news.datemas.de>:

On a sunny day (Mon, 29 Sep 2014 14:23:17 GMT) it happened Jan Panteltje
panteltje@yahoo.com> wrote in <m0bq1h$hcl$1@news.datemas.de>:

I ordered one of these for sat uplink, this with a 24 dB dish I am eying makes about 7500 W
http://www.ebay.com/itm/221556214361
Testing will have to be somewhere in the boonies far away from me.
Sidelobes..

Wonder if I can cook in the beam.
Wonder if it can fry the sat receiver...

path attenuation = 32.45 + 20.log(2400000000) + 20.log(40000) = 312.095 dB

Correction:
its 32.45 + 20.log(MHz) + 20.log(km)

32.45 + 20.log(2400) + 20.log(40000) = 192.095 dB

So...

Working this out using the online satellite uplink budget calculator from
http://www.satsig.net/linkbugt.htm
shows we have about 14 dB C/N:
http://panteltje.com/pub/2.4GHz_geostat_sat_uplink_budget.gif
That is for a 3 MHz wide DVB-S signal,
I will be transmitting testcard or test videos.

So it seems the setup is doable!

The downlink wil be at 10 +GHz and reception with a normal 80 cm dish.
So 2 separate dishes.

Interesting!

:&lt