K3 - CQWW SSB Observations - R U kidding?

[DOUGLAS ZWIEBEL]

The K3 is as simple or complex as you want to make it.  I have a pair
of K3s (and still a K2) and I contest 99% of the time I'm on the
radio.  Honestly, I hardly ever touch anything other than the tuning
knob.  I think many folks using "other" radios NEED to play with the
knobs because of the inherently inferior design of the RX.  The K3 is
so good "as is" one really does not need to "twiddle the knobs" much
at all.  You certainly are NOT going into the menus during the contest
(if you're a serious all band contester).  I am not saying you can't
twiddle around, but for 99% of the contacts, there is no need.

Too complicated?  Well, selfishly, I hope that rumor continues to
spread so those us who already own the K3 can maintain our undeniable
advantage for contesting in crowded, multiple strong signal
environments.  Hey, I did win both modes CQWW for USA qrp last year
(yes, using the K3).

And yes, there are several BIG contest stations that have moved to all
K3s (including Multi-multi).

Just because a radio is capable of being "changed on the fly to the
nth degree" does not mean you're doing that all the time (or more than
once or twice a year).

de Doug KR2Q
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[Bob Maser]

Doug, I was very happy to read you analysis of the K3 radio.  I have mine on
order and it should arrive tomorrow barring another snow storm like we had
yesterday.  I have be reading most of the posts to the Elecraft reflector
and it is quite intimidating.  My plan is to apply power, connect an antenna
and a mic and start playing.  I just sold my Flex 5000A because I got tired
of all the tweaking and discussion. Your post has given me hope.  BTW, a
good friend of mine in the Rochester area has just received  8 K3's  for his
multi-multi station.  He doesn't think that the K3 is complicated at all.

Bob W6TR Fort Collins, CO
----- Original Message -----
From: "DOUGLAS ZWIEBEL" <[hidden email]>
To: "Elecraft Reflector" <[hidden email]>
Sent: Thursday, October 29, 2009 11:46 AM
Subject: [Elecraft] K3 - CQWW SSB Observations - R U kidding?

> The K3 is as simple or complex as you want to make it.  I have a pair
> of K3s (and still a K2) and I contest 99% of the time I'm on the
> radio.  Honestly, I hardly ever touch anything other than the tuning
> knob.  I think many folks using "other" radios NEED to play with the
> knobs because of the inherently inferior design of the RX.  The K3 is
> so good "as is" one really does not need to "twiddle the knobs" much
> at all.  You certainly are NOT going into the menus during the contest
> (if you're a serious all band contester).  I am not saying you can't
> twiddle around, but for 99% of the contacts, there is no need.
>
> Too complicated?  Well, selfishly, I hope that rumor continues to
> spread so those us who already own the K3 can maintain our undeniable
> advantage for contesting in crowded, multiple strong signal
> environments.  Hey, I did win both modes CQWW for USA qrp last year
> (yes, using the K3).
>
> And yes, there are several BIG contest stations that have moved to all
> K3s (including Multi-multi).
>
> Just because a radio is capable of being "changed on the fly to the
> nth degree" does not mean you're doing that all the time (or more than
> once or twice a year).
>
> de Doug KR2Q
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
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> Please help support this email list: http://www.qsl.net/donate.html
>

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[ab2tc]

Hello,

I also found Doug's posting refreshing. Reading the posts on the reflector, it's very easy to get the impression that the K3 is complex and intidimidating to operate. Nothing could be farther from the truth. I upgraded from the simple, "entry level" IC-718 and find that I operate the K3 pretty much same way as that radio. I adjust the AF volume to a comfortable level, tune around and talk into the microphone. When the going gets tough, like in the CQWW contest, I crank the hi cut down to 2.1kHz (lo cut stays at 0.3kHz always) and watch the 1.8kHz filter kick in. Occasionally I need the noise blanker. This is an excellent radio which does not need a lot of knob twiddling to perform its duty. The new macro feature is very interesting and I have every intention of creating a few, but so far I have just continued to operate the radio on the bands. One of these days, but with 15m starting to come back to life, at least in contests....

AB2TC - Knut

Bob Maser wrote

Doug, I was very happy to read you analysis of the K3 radio.  I have mine on
order and it should arrive tomorrow barring another snow storm like we had
<snip>

Doug,

Did you have to let the secret out?  Rats!  Lets try to keep this quiet...ok?

Lee - K0WA


In our day and age it seems that Common Sense is in short supply.  If you don't have any Common Sense - get some Common Sense and use it.  If you can't find any Common Sense, ask for help from somebody who has some Common Sense.  Is Common Sense divine?

Common Sense is the image of the Creator expressing revealed truth in my mind. -  J. Wolf


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[AD4C2009]

This K3 is not only not complicated to operate but its even more simple to use than an IC-7800/FT-9000/ TT OrionII/FT-2000,at the last contest I set up first my TX audio,my RX audio,and the roofer/DSP settings before it started,that was once,then after the contest was running only knobs I used were the main VFO  to move the freq,volumen control and sometimes RF gain to be able to lower the front end gain to fight QRM,there was no need to set anything else,I made more than 50 countries and more than 20 zones in the world working it for only 20 hours,If anyone can't understand how to operate a K3 then he will not be able to operate any other modern radio,73
 
AD4C
 


"For a refined ham it is compulsory to own a k3"

--- On Thu, 10/29/09, ab2tc <[hidden email]> wrote:


From: ab2tc <[hidden email]>
Subject: Re: [Elecraft] K3 - CQWW SSB Observations - R U kidding?
To: [hidden email]
Date: Thursday, October 29, 2009, 7:46 PM



Hello,

I also found Doug's posting refreshing. Reading the posts on the reflector,
it's very easy to get the impression that the K3 is complex and
intidimidating to operate. Nothing could be farther from the truth. I
upgraded from the simple, "entry level" IC-718 and find that I operate the
K3 pretty much same way as that radio. I adjust the AF volume to a
comfortable level, tune around and talk into the microphone. When the going
gets tough, like in the CQWW contest, I crank the hi cut down to 2.1kHz (lo
cut stays at 0.3kHz always) and watch the 1.8kHz filter kick in.
Occasionally I need the noise blanker. This is an excellent radio which does
not need a lot of knob twiddling to perform its duty. The new macro feature
is very interesting and I have every intention of creating a few, but so far
I have just continued to operate the radio on the bands. One of these days,
but with 15m starting to come back to life, at least in contests....

AB2TC - Knut


Bob Maser wrote:
>
> Doug, I was very happy to read you analysis of the K3 radio.  I have mine
> on
> order and it should arrive tomorrow barring another snow storm like we had
> <snip>
>

--
View this message in context: http://n2.nabble.com/K3-CQWW-SSB-Observations-R-U-kidding-tp3914434p3915045.html
Sent from the Elecraft mailing list archive at Nabble.com.
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[Julius Fazekas n2wn]

Shhhh!

You forgot varying the filter width ;o)

Just received two certificates from CQ160, second place US SO-LP (10th World) on CW (damn you ice storms! Congrats to WA1Z!) and 5th in the US SOLP SSB (shoulda put the time in)

Both with K3s, not to mention 1st SOLP in ARRL160. K2 managed to get me to 2nd (with KB7Q running a very close 3rd also with a K2)

Watch what the topbanders are using... you'll see many K3s... same for DXpeditions.

4000 K3s now? Can't be all that bad ;o)

72,
Julius
n2wn

[Bill W4ZV]

Julius Fazekas n2wn wrote

Watch what the topbanders are using... you'll see many K3s... same for DXpeditions.

A most welcome change from all those clicking Yaesu rigs.  Also from the Flex 5000's +/-2.4 kHz spurs (~ 58 dB down on 160 which will cover even strong DX signals like DF2PY, etc.)  The quality of topband signals has taken a definite upturn as more are adopting the K3.  

Kudos to Elecraft for not making the Rise/Fall times adjustable...which prevents folks from intentionally making their signals click (some do that in contests with adjustable Rise/Fall rigs in order to keep their run frequencies clear).  :-(

73,  Bill  W4ZV

[gdaught6]

Hector wrote...

> This K3 is not only not complicated to operate ...

< snip >

The "complicated" bad rap is almost surely the result of people watching this
reflector.  Things like:  

"Firmware beta version 5.555.001 allows the setting of macros to turn on your
coffeemaker at a user-programmed time, and to increase the rate of change of audio
gain with knob twist."

First, it isn't mandatory to make these continuing updates, if it isn't important to your
application(s) of the radio.  Just buy it (and build it, if you got the kit) turn it on, and
USE it!!!  It's magnificent!

Second, it's amazing that the radio can be customized infinitely, if you want.

Third, it's amazing that the company continues to provide these changes and
upgrades.  

Try that with your Hammarlund!

73,

George T Daughters, K6GT
CU in the California QSO Party (CQP)
October 3-4, 2009


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[w7aqk]

Hi All,

I think we are getting a pretty strong message here in this thread.  It has
been my observation that avid contesters are probably the most critical hams
when it comes to their radios.  I know a few folks who I think are pretty
serious about contesting, and it certainly seems to me that they dig pretty
deep when deciding just what they want to be using.  And I would certainly
think that someone, like the person in Rochester who just dropped $25K or
more for 8 K3's, didn't do that without a lot of very serious evaluation.

I suppose some significant part of the decision making process is that, in
order to step up further (if you can really even do that!), you need to
spend $5K, $6K, or even $10K to do it.  You won't get a better RX, but you
might pick up a feature or two that is of interest.

While we seem to have something approaching a "consensus" as to the
superiority of the K3, it isn't "unanimous".  It never will be, and for a
lot of reasons.  However, I think it's pretty amazing just how extensive the
appreciation for the K3's capabilities seems to be.  It reminds me of the
domination that Collins seemed to have in the 60's.  Not everyone had one,
but most people wanted one!  Nearly every QSO I have, using my K3, turns
into a "Q & A" session about how do I like it, etc.  Obviously not everyone
has a K3 right now, but there sure are a lot of folks out there who seem to
want one!  I'm kind of enjoying being envied!

Dave W7AQK



----- Original Message -----
From: "Bob Maser" <[hidden email]>
To: <[hidden email]>; "DOUGLAS ZWIEBEL" <[hidden email]>
Sent: Thursday, October 29, 2009 12:06 PM
Subject: Re: [Elecraft] K3 - CQWW SSB Observations - R U kidding?

> Doug, I was very happy to read you analysis of the K3 radio.  I have mine
> on
> order and it should arrive tomorrow barring another snow storm like we had
> yesterday.  I have be reading most of the posts to the Elecraft reflector
> and it is quite intimidating.  My plan is to apply power, connect an
> antenna
> and a mic and start playing.  I just sold my Flex 5000A because I got
> tired
> of all the tweaking and discussion. Your post has given me hope.  BTW, a
> good friend of mine in the Rochester area has just received  8 K3's  for
> his
> multi-multi station.  He doesn't think that the K3 is complicated at all.
>
> Bob W6TR Fort Collins, CO
> ----- Original Message -----
> From: "DOUGLAS ZWIEBEL" <[hidden email]>
> To: "Elecraft Reflector" <[hidden email]>
> Sent: Thursday, October 29, 2009 11:46 AM
> Subject: [Elecraft] K3 - CQWW SSB Observations - R U kidding?
>
>
>> The K3 is as simple or complex as you want to make it.  I have a pair
>> of K3s (and still a K2) and I contest 99% of the time I'm on the
>> radio.  Honestly, I hardly ever touch anything other than the tuning
>> knob.  I think many folks using "other" radios NEED to play with the
>> knobs because of the inherently inferior design of the RX.  The K3 is
>> so good "as is" one really does not need to "twiddle the knobs" much
>> at all.  You certainly are NOT going into the menus during the contest
>> (if you're a serious all band contester).  I am not saying you can't
>> twiddle around, but for 99% of the contacts, there is no need.
>>
>> Too complicated?  Well, selfishly, I hope that rumor continues to
>> spread so those us who already own the K3 can maintain our undeniable
>> advantage for contesting in crowded, multiple strong signal
>> environments.  Hey, I did win both modes CQWW for USA qrp last year
>> (yes, using the K3).
>>
>> And yes, there are several BIG contest stations that have moved to all
>> K3s (including Multi-multi).
>>
>> Just because a radio is capable of being "changed on the fly to the
>> nth degree" does not mean you're doing that all the time (or more than
>> once or twice a year).
>>
>> de Doug KR2Q
>> ______________________________________________________________
>> Elecraft mailing list
>> Home: http://mailman.qth.net/mailman/listinfo/elecraft
>> Help: http://mailman.qth.net/mmfaq.htm
>> Post: mailto:[hidden email]
>>
>> This list hosted by: http://www.qsl.net
>> Please help support this email list: http://www.qsl.net/donate.html
>>
>
> ______________________________________________________________
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>
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> Please help support this email list: http://www.qsl.net/donate.html 

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[DOUGLAS ZWIEBEL]

On Sat, Oct 31, 2009 at 7:11 AM, David Y. <[hidden email]> wrote:
> It reminds me of the
> domination that Collins seemed to have in the 60's.  Not everyone had one,
> but most people wanted one!
> Dave W7AQK
>

Dave:

But the big difference is that while most everybody wanted Collins,
very few could afford one.  With the K3, well, it is the least
expensive (NOT "cheapest" as cheap = poor quality) of the "big
performance" rigs....BY FAR!

And lets not forget that with rigs like the IC7800 or FT9000, you
really cannot pick and choose what you want to anywhere near the
degree that you can with the K3.  For example, I have resonant
antennas, so no Antenna tuner here.  I am not serious about low band
DXing, so no 2nd receiver here, I already had an external DVK, so
didn't get that either, I don't care about FM, etc etc etc.  My K3's
(pair) were a down-right BARGAIN on par with the "bottom end" of the
other guy's cost wise, but on par with their TOP END (and then some)
performance-wise.  Who says you can't have your cake and eat it too?
:-)

de Doug KR2Q
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[John-483]

At 05:45 AM 31/10/09, you wrote:
>.  For example, I have resonant
>antennas, so no Antenna tuner here.
>
>de Doug KR2Q

Hi Doug,

I did opt for the tuner here, even though my antennas are resonant. I
did so to have the ant1/2 option. I made a (wish list) suggestion to
Elecraft for a module, to replace the ATU module, that only had a
ANT1/2 switch on it and two antenna ports. Wonder if any others would
like that feature? It would be nice if the stock K3 came with the 2
antenna port module, or optional ATU. The hole is there...

John k7up
K3 #501 2-K2's  K1....

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[AD4C2009]

Thst's a great suggestion because I order mine as well with the tuner that I didn't need just to have the two antenna ports(SO-239)in the back,if they could make just a small board with a relay it will be better and save others some money from the tuner.In a year I have the radio I have enever used the tuner.
 
AD4C

 

"For a refined ham it is compulsory to own a k3"

--- On Sat, 10/31/09, John <[hidden email]> wrote:


From: John <[hidden email]>
Subject: Re: [Elecraft] K3 - CQWW SSB Observations - R U kidding?
To: [hidden email]
Date: Saturday, October 31, 2009, 3:22 PM


At 05:45 AM 31/10/09, you wrote:
>.  For example, I have resonant
>antennas, so no Antenna tuner here.
>
>de Doug KR2Q

Hi Doug,

I did opt for the tuner here, even though my antennas are resonant. I
did so to have the ant1/2 option. I made a (wish list) suggestion to
Elecraft for a module, to replace the ATU module, that only had a
ANT1/2 switch on it and two antenna ports. Wonder if any others would
like that feature? It would be nice if the stock K3 came with the 2
antenna port module, or optional ATU. The hole is there...

John k7up
K3 #501 2-K2's  K1....

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[juergen piezo]

Hi

Another good option to have on this board would be a directional coupler
for oscilloscope and spectrum analyzer monitoring. The Elecraft CP1 on this board would be a great option.

A 2nd option could also be a dummy load using one of those very cheap RF film resistors. This would have to be mounted onto the case for a heatsink.

John

--- On Sat, 10/31/09, Hector Padron <[hidden email]> wrote:

> From: Hector Padron <[hidden email]>
> Subject: Re: [Elecraft] K3 - CQWW SSB Observations - R U kidding?
> To: [hidden email]
> Date: Saturday, October 31, 2009, 2:34 PM
> Thst's a great suggestion because I
> order mine as well with the tuner that I didn't need just to
> have the two antenna ports(SO-239)in the back,if they could
> make just a small board with a relay it will be better and
> save others some money from the tuner.In a year I have the
> radio I have enever used the tuner.
>  
> AD4C
>
>  
>
> "For a refined ham it is compulsory to own a k3"
>
> --- On Sat, 10/31/09, John <[hidden email]>
> wrote:
>
>
> From: John <[hidden email]>
> Subject: Re: [Elecraft] K3 - CQWW SSB Observations - R U
> kidding?
> To: [hidden email]
> Date: Saturday, October 31, 2009, 3:22 PM
>
>
> At 05:45 AM 31/10/09, you wrote:
> >.  For example, I have resonant
> >antennas, so no Antenna tuner here.
> >
> >de Doug KR2Q
>
> Hi Doug,
>
> I did opt for the tuner here, even though my antennas are
> resonant. I
> did so to have the ant1/2 option. I made a (wish list)
> suggestion to
> Elecraft for a module, to replace the ATU module, that only
> had a
> ANT1/2 switch on it and two antenna ports. Wonder if any
> others would
> like that feature? It would be nice if the stock K3 came
> with the 2
> antenna port module, or optional ATU. The hole is there...
>
> John k7up
> K3 #501 2-K2's  K1....
>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
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> Please help support this email list: http://www.qsl.net/donate.html
>
>
>
>      
> ______________________________________________________________
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[David Gilbert]

Metal film resistors are notoriously fragile.  They will typically meet
their published dissipation specs just fine, but they go from being OK
to being an open in a flash (literally) when overstressed.  I personally
would never use one in any application where the power they were
expected to handle wasn't rigid controlled.  Check with any industrial
control manufacturer and you will hear the same story.

73,
Dave   AB7E


juergen piezo wrote:
> A 2nd option could also be a dummy load using one of those very cheap RF film resistors. This would have to be mounted onto the case for a heatsink.
>
> John
>
>  
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[Don Wilhelm-4]

Dave,

I can vouch for that statement.  I do use the Caddock Thick Film 50 ohm
resistors as precision dummy loads.  They are flat up to 500 MHz with
good mounting using no leads.  They MUST be mounted on a heat sink, and
yes, they will go open in a flash if the rated power is exceeded (don't
bother to ask me how I know that).

So, recommending them for a K3 application may not be the best, but if
you want an inexpensive dummy load, got a heat sink from a defunct
computer CPU cooling device and one of those resistors and connect it to
a BNC or UHF jack using zero length leads - but don't exceed its power
rating (they are available up to 100 watts).

73,
Don W3FPR

David Gilbert wrote:

> Metal film resistors are notoriously fragile.  They will typically meet
> their published dissipation specs just fine, but they go from being OK
> to being an open in a flash (literally) when overstressed.  I personally
> would never use one in any application where the power they were
> expected to handle wasn't rigid controlled.  Check with any industrial
> control manufacturer and you will hear the same story.
>
> 73,
> Dave   AB7E
>  
>

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[David Cutter]

Putting several in parallel on a suitable outboard heatsink is not expensive
and, properly rated, will cater for any load.  As with semiconductors, the
trick is to not exceed the "junction" temperature.  As always, follow the
manufacturer's recommendations then add your own fiddle factor.  MIL 217
taught me a lot.

David
G3UNA
We've drifted off this thread subject somewhat, my apologies.

> Dave,
>
> I can vouch for that statement.  I do use the Caddock Thick Film 50 ohm
> resistors as precision dummy loads.  They are flat up to 500 MHz with
> good mounting using no leads.  They MUST be mounted on a heat sink, and
> yes, they will go open in a flash if the rated power is exceeded (don't
> bother to ask me how I know that).
>
> So, recommending them for a K3 application may not be the best, but if
> you want an inexpensive dummy load, got a heat sink from a defunct
> computer CPU cooling device and one of those resistors and connect it to
> a BNC or UHF jack using zero length leads - but don't exceed its power
> rating (they are available up to 100 watts).
>
> 73,
> Don W3FPR
>
> David Gilbert wrote:
>> Metal film resistors are notoriously fragile.  They will typically meet
>> their published dissipation specs just fine, but they go from being OK
>> to being an open in a flash (literally) when overstressed.  I personally
>> would never use one in any application where the power they were
>> expected to handle wasn't rigid controlled.  Check with any industrial
>> control manufacturer and you will hear the same story.
>>
>> 73,
>> Dave   AB7E
>>
>>

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[gm3sek]

David Gilbert wrote:

>juergen piezo wrote:
>> A 2nd option could also be a dummy load using one of those very cheap
>>RF film resistors. This would have to be mounted onto the case for a
>>heatsink.
>>
>> John
>
>Metal film resistors are notoriously fragile.  They will typically meet
>their published dissipation specs just fine, but they go from being OK
>to being an open in a flash (literally) when overstressed.  I personally
>would never use one in any application where the power they were
>expected to handle wasn't rigid controlled.  Check with any industrial
>control manufacturer and you will hear the same story.
>
>73,
>Dave   AB7E

This isn't an industrial control application where huge surges may be
encountered.

TO220 film resistors make excellent RF dummy loads, up to at least
50MHz. Many of these resistors are also used in RF power attenuators and
as  "passive grid" loads in tetrode amplifiers. Power handling depends
on the resistor rating, but is limited mostly by the performance of the
heatsink (which is mandatory, because the power dissipation of the bare
T220 package is only a few watts).

A 50-ohm dummy load will normally use two 100-ohm resistors in parallel.
VSWR at higher frequencies is limited mostly by layout and construction
technique. For example, see
http://tinyurl.com/inpractice/#0908

Turning to conventional wire-ended metal film resistors, again my
experience is entirely the opposite. I have deliberately overloaded
samples until they were glowing bright red and the paint has completely
burned off... and still they did NOT fail. Furthermore, when they cooled
down their resistance was still within a few percent of the correct
value.

Also, it's largely a myth that tubular wire-ended metal film resistors
are "too inductive for RF". If you calculate or measure the inductance,
you'll find it's generally no more than a few tens of nanohenries, and
the effective inductance can be reduced even more by paralleling several
higher-value resistors. With care, they are even usable at 144MHz.



--

73 from Ian GM3SEK         'In Practice' columnist for RadCom (RSGB)
http://www.ifwtech.co.uk/g3sek
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[David Gilbert]

Actually, no ... it isn't the same thing.

In the vicinity of their rated dissipation, semiconductors (at least
their bulk characteristics) and non-film resistors (solid carbon or
wirewound) have a gradual exponential probability of failure with
increasing power dissipation.  Metal film resistors have a very sharp
(high order) exponential probability of failure with increasing power
dissipation.  As I said before, if you stay below the rated power
dissipation of a metal film resistor it will hold up well, but if you
exceed that by any significant amount, even briefly, you'll turn it into
a blown fuse that will make your rig very unhappy.  A semiconductor
(again, talking bulk here) and a solid carbon resistor will typically
merely degrade under the same level of abuse without catastrophic failure.

Commercially manufacturing such devices taught me a lot.

73,
Dave   AB7E



David Cutter wrote:
> Putting several in parallel on a suitable outboard heatsink is not
> expensive and, properly rated, will cater for any load.  As with
> semiconductors, the trick is to not exceed the "junction"
> temperature.  As always, follow the manufacturer's recommendations
> then add your own fiddle factor.  MIL 217 taught me a lot.
>
> David
> G3UNA
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[David Gilbert]

As I said, stay below the rated power and they should work fine.  When
they go, they don't go gradually, though.  They really are simply fuses
on a heat sink.

As far as their RF characteristics is concerned, no argument from me.

73,
Dave   AB7E

 


Ian White GM3SEK wrote:

> David Gilbert wrote:
>  
>> juergen piezo wrote:
>>    
>>> A 2nd option could also be a dummy load using one of those very cheap
>>> RF film resistors. This would have to be mounted onto the case for a
>>> heatsink.
>>>
>>> John
>>>      
>> Metal film resistors are notoriously fragile.  They will typically meet
>> their published dissipation specs just fine, but they go from being OK
>> to being an open in a flash (literally) when overstressed.  I personally
>> would never use one in any application where the power they were
>> expected to handle wasn't rigid controlled.  Check with any industrial
>> control manufacturer and you will hear the same story.
>>
>> 73,
>> Dave   AB7E
>>    
>
> This isn't an industrial control application where huge surges may be
> encountered.
>
> TO220 film resistors make excellent RF dummy loads, up to at least
> 50MHz. Many of these resistors are also used in RF power attenuators and
> as  "passive grid" loads in tetrode amplifiers. Power handling depends
> on the resistor rating, but is limited mostly by the performance of the
> heatsink (which is mandatory, because the power dissipation of the bare
> T220 package is only a few watts).
>
> A 50-ohm dummy load will normally use two 100-ohm resistors in parallel.
> VSWR at higher frequencies is limited mostly by layout and construction
> technique. For example, see
> http://tinyurl.com/inpractice/#0908
>
> Turning to conventional wire-ended metal film resistors, again my
> experience is entirely the opposite. I have deliberately overloaded
> samples until they were glowing bright red and the paint has completely
> burned off... and still they did NOT fail. Furthermore, when they cooled
> down their resistance was still within a few percent of the correct
> value.
>
> Also, it's largely a myth that tubular wire-ended metal film resistors
> are "too inductive for RF". If you calculate or measure the inductance,
> you'll find it's generally no more than a few tens of nanohenries, and
> the effective inductance can be reduced even more by paralleling several
> higher-value resistors. With care, they are even usable at 144MHz.
>
>
>
>  

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