Elecraft

Product Suggestion - 500W Dummy Load

Classic

List

Threaded

27 messages Options

Byron Peebles

Product Suggestion - 500W Dummy Load

I'd love to find Elecraft offering a 500W dummy load to match the K-Line.
No one even makes a sturdy paint can anymore.

73, Byron
______________________________________________________________
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
Message delivered to [hidden email]

Bob McGraw - K4TAX

Re: Product Suggestion - 500W Dummy Load

Here you can find some nice 500 watt CCS Bird loads for $250 or so.

http://www.nm3e.com/loadSampler.htm#LoadSampler

Otherwise, it is Ameritron and MFJ that have the gallon bucket loads
with oil for under $100.

73
Bob, K4TAX
K3S s/n 10,163

On 9/17/2015 7:19 PM, Byron Peebles wrote:

> I'd love to find Elecraft offering a 500W dummy load to match the K-Line.
> No one even makes a sturdy paint can anymore.
>
> 73, Byron
> ______________________________________________________________
> 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
> Message delivered to [hidden email]
>
>
>

______________________________________________________________
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
Message delivered to [hidden email]

Don Wilhelm-4

Re: Product Suggestion - 500W Dummy Load

In reply to this post by Byron Peebles

While a dummy load that has a power rating greater than your maximum
transmit power is a worthwhile addition to any hamshack - at higher
power levels, I do not see them being used as precision measurement
devices, but only as a temporary load for the purposes of "tuning up" or
operating into a dummy load for test purposes.

While the "Tune Up" situation has been largely eliminated for "No Tune"
amplifiers, there is still the question of how to do a TUNE into an
antenna when you have a tuner such as the KAT500 in line - but that
tunes into the antenna at reduced power with the Elecraft K-line, and
the tune cycle is relatively short.

The net that I see of all that is one does not need a precision dummy
load for high power levels.
At the 100 watt level, I do find a need for precision dummy loads which
can be used for lab measurement devices, bu at higher power levels in
the normal hamshack, I do not understand a need for a precise 50 ohm
non-inductive load (as long as you do not stray too far from that 50 ohm
point.

In other words, the gallon size "cantenna" dummy loads should suffice
for most purposes in the ham shack that I can conceive of - primarily
providing a suitable load for a high power transmitter for routine test
purposes.

Those who do precision measurements at high power levels will have to
invest in precision dummy loads, but for typical ham use, I don't think
that level of precision is necessary. Such precision comes at a cost.

73,
Don W3FPR

On 9/17/2015 8:19 PM, Byron Peebles wrote:

Grant Youngman

Re: Product Suggestion - 500W Dummy Load

> On 9/17/2015 8:19 PM, Byron Peebles wrote:
>> I'd love to find Elecraft offering a 500W dummy load to match the K-Line.
>> No one even makes a sturdy paint can anymore.
>>

Actually, Ameritron still makes a “Cantenna" style dummy load. I’ve had the same one sitting under my desk for 20+ years.

Grant NQ5T

______________________________________________________________
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
Message delivered to [hidden email]

Matthew Cook

Re: Product Suggestion - 500W Dummy Load

In reply to this post by Byron Peebles

http://www.ebay.com.au/itm/DUMMY-LOAD-RESISTOR-HYBRID-TERMINATION-800W-50OHM-DC-1GHZ-17-0376-DICONEX-/191284146241?hash=item2c896c7041

Heatsink, length of coax and a plug... finished !

73

Matthew
VK5ZM

On 18 September 2015 at 09:49, Byron Peebles <[hidden email]> wrote:

Bob McGraw - K4TAX

Re: Product Suggestion - 500W Dummy Load

In reply to this post by Don Wilhelm-4

Don, et al:

I do agree that we typically do not need a precision load nor do we
likely need a "full legal limit CCS" load. Most loads have a power vs.
time de-rating curve. Just following that practice will save on lots of
$$ and space.

Yes the Cantenna loads are generally suitable. I find the Z to be 50
ohms +/- 10% or so. They will handle legal limit power for 2 or3
minutes and 100 to 300 watt power for almost CCS times. As a rule, they
are good for HF and become a bit less so suitable for VHF.

I prefer dry loads as they are less "messy" where one uses an oil filled
load it seems they all want to weep a bit. Oh my gosh should on kick
one over and the lid separate. As a suggestion, solder the lid in place
at 3 or 4 locations around the edge.

It would do well for folks to consider switching and tuning methods so
as not to put a signal on the air. Although this typically can't be
done with automatic type tuners, with manual tuners, using an antenna
bridge will allow one to adjust the tuner for a proper match and not put
a signal on the air. Then with older amps, tuning those into a dummy
load again will not put a signal on the air. When the amp is switched to
the tuner then all is well and no QRM has been generated.

73 Bob, K4TAX

K3S s/n 10,163

On 9/17/2015 8:37 PM, Don Wilhelm wrote:

> While a dummy load that has a power rating greater than your maximum
> transmit power is a worthwhile addition to any hamshack - at higher
> power levels, I do not see them being used as precision measurement
> devices, but only as a temporary load for the purposes of "tuning up"
> or operating into a dummy load for test purposes.
>
> While the "Tune Up" situation has been largely eliminated for "No
> Tune" amplifiers, there is still the question of how to do a TUNE into
> an antenna when you have a tuner such as the KAT500 in line - but that
> tunes into the antenna at reduced power with the Elecraft K-line, and
> the tune cycle is relatively short.
>
> The net that I see of all that is one does not need a precision dummy
> load for high power levels.
> At the 100 watt level, I do find a need for precision dummy loads
> which can be used for lab measurement devices, bu at higher power
> levels in the normal hamshack, I do not understand a need for a
> precise 50 ohm non-inductive load (as long as you do not stray too far
> from that 50 ohm point.
>
> In other words, the gallon size "cantenna" dummy loads should suffice
> for most purposes in the ham shack that I can conceive of - primarily
> providing a suitable load for a high power transmitter for routine
> test purposes.
>
> Those who do precision measurements at high power levels will have to
> invest in precision dummy loads, but for typical ham use, I don't
> think that level of precision is necessary. Such precision comes at a
> cost.
>
> 73,
> Don W3FPR
>
> On 9/17/2015 8:19 PM, Byron Peebles wrote:
>> I'd love to find Elecraft offering a 500W dummy load to match the
>> K-Line.
>> No one even makes a sturdy paint can anymore.
>>
>> 73, Byron
>> ______________________________________________________________
>> 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
>> Message delivered to [hidden email]
>>
>
> ______________________________________________________________
> 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
> Message delivered to [hidden email]
>
>
>

Bob McGraw - K4TAX

Re: Product Suggestion - 500W Dummy Load

In reply to this post by Matthew Cook

Don't forget to add a BIG heat sink to the materials list along with
some thermal compound.

73
Bob, K4TAX
K3S s/n 10,163

On 9/17/2015 9:15 PM, Matthew Cook wrote:

> http://www.ebay.com.au/itm/DUMMY-LOAD-RESISTOR-HYBRID-TERMINATION-800W-50OHM-DC-1GHZ-17-0376-DICONEX-/191284146241?hash=item2c896c7041
>
> Heatsink, length of coax and a plug... finished !
>
> 73
>
> Matthew
> VK5ZM
>
> On 18 September 2015 at 09:49, Byron Peebles <[hidden email]> wrote:
>
>> I'd love to find Elecraft offering a 500W dummy load to match the K-Line.
>> No one even makes a sturdy paint can anymore.
>>
>> 73, Byron
>> ______________________________________________________________
>> 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
>> Message delivered to [hidden email]
>>
> ______________________________________________________________
> 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
> Message delivered to [hidden email]
>
>
>

k6dgw

Re: Product Suggestion - 500W Dummy Load

In reply to this post by Grant Youngman

Strangely, these non-inductive resistors do not last forever. When I
came home from SE Asia to Houston in 67, I filled my Heath with mineral
oil [interesting story on a Sunday], and it measured 51 ohms DC. Today,
it measures 74 ohms DC.

73,

Fred K6DGW
- Northern California Contest Club
- CU in the 50th Running of the Cal QSO Party 3-4 Oct 2015
- www.cqp.org

On 9/17/2015 7:12 PM, GRANT YOUNGMAN wrote:
>
>> On 9/17/2015 8:19 PM, Byron Peebles wrote:
>>> I'd love to find Elecraft offering a 500W dummy load to match the K-Line.
>>> No one even makes a sturdy paint can anymore.
>>>
>
> Actually, Ameritron still makes a “Cantenna" style dummy load. I’ve had the same one sitting under my desk for 20+ years.
>
> Grant NQ5T

______________________________________________________________
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
Message delivered to [hidden email]

Cliff Frescura

Re: Product Suggestion - 500W Dummy Load

Maybe the dummy load could be an option for the speaker /s

73,

Cliff K3LL

-----Original Message-----
From: Elecraft [mailto:[hidden email]] On Behalf Of Fred Jensen
Sent: Thursday, September 17, 2015 7:36 PM
To: [hidden email]
Subject: Re: [Elecraft] Product Suggestion - 500W Dummy Load

Strangely, these non-inductive resistors do not last forever. When I came home from SE Asia to Houston in 67, I filled my Heath with mineral oil [interesting story on a Sunday], and it measured 51 ohms DC. Today, it measures 74 ohms DC.

73,

Fred K6DGW
- Northern California Contest Club
- CU in the 50th Running of the Cal QSO Party 3-4 Oct 2015
- www.cqp.org

On 9/17/2015 7:12 PM, GRANT YOUNGMAN wrote:
>
>> On 9/17/2015 8:19 PM, Byron Peebles wrote:
>>> I'd love to find Elecraft offering a 500W dummy load to match the K-Line.
>>> No one even makes a sturdy paint can anymore.
>>>
>
> Actually, Ameritron still makes a “Cantenna" style dummy load. I’ve had the same one sitting under my desk for 20+ years.
>
> Grant NQ5T

______________________________________________________________
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 Message delivered to [hidden email]

______________________________________________________________
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
Message delivered to [hidden email]

Don Wilhelm-4

Re: Product Suggestion - 500W Dummy Load

In reply to this post by k6dgw

My "gallon size" dummy load is not a Heath, but that was inspiration for
mine. I came across a bunch of 620 ohm 20 watt carbon resistors a long
time ago.
I wired 12 of them in parallel and put them into a gallon can of mineral
oil. That dummy load still measures 51 ohms over the bands from 80 thru
10 meters with a minimal amount of inductance - and it is over 40 years
after I first built it.

I figure since it will do 240 watts in open air, in the oil, it should
take the legal limit for relatively short periods, but I have not
subjected it to more than 500 watts.

Yes, I have heard stories about how the Heath resistors changed value,
but my 'substitute' has not changed over the years.

73,
Don W3FPR

On 9/17/2015 10:36 PM, Fred Jensen wrote:
> Strangely, these non-inductive resistors do not last forever. When I
> came home from SE Asia to Houston in 67, I filled my Heath with
> mineral oil [interesting story on a Sunday], and it measured 51 ohms
> DC. Today, it measures 74 ohms DC.
>

______________________________________________________________
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
Message delivered to [hidden email]

Jim Brown-10

Re: Product Suggestion - 500W Dummy Load

In reply to this post by Don Wilhelm-4

On Thu,9/17/2015 6:37 PM, Don Wilhelm wrote:
> While a dummy load that has a power rating greater than your maximum
> transmit power is a worthwhile addition to any hamshack - at higher
> power levels, I do not see them being used as precision measurement
> devices, but only as a temporary load for the purposes of "tuning up"
> or operating into a dummy load for test purposes.

Remember also that dummy load ratings include a duty cycle. The cheap
stuff has a very short duty cycle -- one might be rated 100W for 1
minute. :) It's all about heat -- do you get hot enough to damage it?

Duty cycle can be interpreted two ways. One is to use a series of dits
to tune up, which gets you to full power but half the time. That's what
I do. I just sold a nice little keyer-pulser that W2VJN used to make.
Its duty cycle could be adjusted as low as 20%.

Another way to interpret it is how LONG you transmit into it. My big
professional oil filled dummy load is rated 500W for a long time (don't
remember the spec). I transmit dits (and even RTTY) into it at legal
limit for a minute or so, and it doesn't overheat. And then I let it
cool off.

73, Jim K9YC

______________________________________________________________
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
Message delivered to [hidden email]

Edward R Cole

Re: Product Suggestion - 500W Dummy Load

In reply to this post by Byron Peebles

Don't have much to say:

Had a Cantenna from Heath in the 60's - knocked over; spilt mineral
oil on the floor, threw can away!

I have acquired "dry" loads over the years rated into UHF and
sometimes to mw at flea markets and swaps. My highest power load is
500w Sierra with power meter and switch for 150 or 500w (probably
good to 1000-MHz). Have a couple Bird terminations rated 50w. Most
can handled double their rating for short duration.

The hardest duty on my loads is when optimizing the output of a new
unit where I'm keyed up longer than I should.

But I do have a question on how adjusting a tuner into a 50-ohm load
saves one from transmitting a signal once the tuner is connected to
an antenna that may not be 50-ohms. On 600m my inverted-L is Z = 0.8
+j680. Tuning into a 50-ohm load does nothing to help match the
antenna. The amplifier is solid state with input and output
transformers (no adjustment).

I think, unless you use a high power tetrode or triode, that no one
tunes amplifiers anymore. Solid state amps are broadband and need LP
filters to keep from amplifying harmonics. BTW my 2m-8877 is capable
of 2000w* RF output so pretty hard to find a dummy load to take
that. Fortunately the amp does not change much so very little tuning
is ever needed (of course I am on a small segment of one band about
200-KHz wide). Of course the answer is to tune antenna at lower
power and hope the High Power amp will always be looking at 50-ohms.

I do not have a QRO 2m antenna tuner but the antenna SWR < 1.25 so
only the anode tuning needs a light adjustment occasionally (loading
has not be adjusted for 8 years). My "dummy load" has 19.2 dBd gain
and radiates well.

*I operate at 1365w CW which allows for about 9% variance in meter
accuracy to stay legal.

73, Ed - KL7UW
http://www.kl7uw.com
"Kits made by KL7UW"
Dubus Mag business:
[hidden email]

______________________________________________________________
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
Message delivered to [hidden email]

Tim Heasman

Re: Product Suggestion - 500W Dummy Load

Hi All,
My Cantenna has sat in a bucket since I built it many many years ago.
No seen it as yet from our house move last month, but have not seem any
oil stains as yet. I am sure the boss would have told me!
73
Tim
gm4lm
On 18/09/2015 19:00, Edward R Cole wrote:

> Don't have much to say:
>
> Had a Cantenna from Heath in the 60's - knocked over; spilt mineral
> oil on the floor, threw can away!
>
> I have acquired "dry" loads over the years rated into UHF and
> sometimes to mw at flea markets and swaps. My highest power load is
> 500w Sierra with power meter and switch for 150 or 500w (probably good
> to 1000-MHz). Have a couple Bird terminations rated 50w. Most can
> handled double their rating for short duration.
>
> The hardest duty on my loads is when optimizing the output of a new
> unit where I'm keyed up longer than I should.
>
> But I do have a question on how adjusting a tuner into a 50-ohm load
> saves one from transmitting a signal once the tuner is connected to an
> antenna that may not be 50-ohms. On 600m my inverted-L is Z = 0.8
> +j680. Tuning into a 50-ohm load does nothing to help match the
> antenna. The amplifier is solid state with input and output
> transformers (no adjustment).
>
> I think, unless you use a high power tetrode or triode, that no one
> tunes amplifiers anymore. Solid state amps are broadband and need LP
> filters to keep from amplifying harmonics. BTW my 2m-8877 is capable
> of 2000w* RF output so pretty hard to find a dummy load to take that.
> Fortunately the amp does not change much so very little tuning is ever
> needed (of course I am on a small segment of one band about 200-KHz
> wide). Of course the answer is to tune antenna at lower power and
> hope the High Power amp will always be looking at 50-ohms.
>
> I do not have a QRO 2m antenna tuner but the antenna SWR < 1.25 so
> only the anode tuning needs a light adjustment occasionally (loading
> has not be adjusted for 8 years). My "dummy load" has 19.2 dBd gain
> and radiates well.
>
> *I operate at 1365w CW which allows for about 9% variance in meter
> accuracy to stay legal.
>
> 73, Ed - KL7UW
> http://www.kl7uw.com
> "Kits made by KL7UW"
> Dubus Mag business:
> [hidden email]
>
> ______________________________________________________________
> 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
> Message delivered to [hidden email]
>

ae4pb

Re: Product Suggestion - 500W Dummy Load

In reply to this post by Edward R Cole

Forgive me in advance if this is a stupid question.

Is there any reason you have to tune at full power? It seems to me that
tuning can be accomplished easily with much lower power. The same thing goes
for the ATU to the antenna. I don't see why we need more than a few MW at
most for the ATU to Antenna link.

Rightly or wrongly when I was in the hobby the first time I ran a TS-850
into an SB-220 to an MFJ roller tuner connected to an antenna switch
feeding: 80m inverted V, 30m/40m rotatable dipoles, and a triband beam.
Whenever I tuned on the inverted V or outer band limits of where my antennas
where tuned I ended up putting labels on the ATU on cap position and a
number/clock combo that represented a roller inductor position for each band
area I cared about. It ended up I rarely had to tune up anything one the air
because I knew where the antenna tuning was using just the Rig and ATU;
tuned the APM into a paintcan MFJ load then switch it inline. I was all set
and never had issues when I needed to kick in the horses.

Now my debate is 500w vs 800w... there's a larger difference between 500w
and 800w than between 800w and 2.5kw signal wise if I understand
correctly...

Jerry Moore
AE4PB, K3S - S.N. 010324

-----Original Message-----
From: Elecraft [mailto:[hidden email]] On Behalf Of Edward
R Cole
Sent: Friday, September 18, 2015 2:00 PM
To: [hidden email]
Subject: Re: [Elecraft] Product Suggestion - 500W Dummy Load

Don't have much to say:

Had a Cantenna from Heath in the 60's - knocked over; spilt mineral oil on
the floor, threw can away!

I have acquired "dry" loads over the years rated into UHF and sometimes to
mw at flea markets and swaps. My highest power load is 500w Sierra with
power meter and switch for 150 or 500w (probably good to 1000-MHz). Have a
couple Bird terminations rated 50w. Most can handled double their rating
for short duration.

The hardest duty on my loads is when optimizing the output of a new unit
where I'm keyed up longer than I should.

But I do have a question on how adjusting a tuner into a 50-ohm load saves
one from transmitting a signal once the tuner is connected to an antenna
that may not be 50-ohms. On 600m my inverted-L is Z = 0.8
+j680. Tuning into a 50-ohm load does nothing to help match the
antenna. The amplifier is solid state with input and output transformers
(no adjustment).

I think, unless you use a high power tetrode or triode, that no one tunes
amplifiers anymore. Solid state amps are broadband and need LP filters to
keep from amplifying harmonics. BTW my 2m-8877 is capable of 2000w* RF
output so pretty hard to find a dummy load to take that. Fortunately the
amp does not change much so very little tuning is ever needed (of course I
am on a small segment of one band about 200-KHz wide). Of course the answer
is to tune antenna at lower power and hope the High Power amp will always be
looking at 50-ohms.

I do not have a QRO 2m antenna tuner but the antenna SWR < 1.25 so only the
anode tuning needs a light adjustment occasionally (loading has not be
adjusted for 8 years). My "dummy load" has 19.2 dBd gain and radiates well.

*I operate at 1365w CW which allows for about 9% variance in meter accuracy
to stay legal.

73, Ed - KL7UW
http://www.kl7uw.com
"Kits made by KL7UW"
Dubus Mag business:
[hidden email]

______________________________________________________________
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 Message
delivered to [hidden email]

______________________________________________________________
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
Message delivered to [hidden email]

Fred Smith-2

Re: Product Suggestion - 500W Dummy Load

In reply to this post by Byron Peebles

I can tell you this there is a world of difference between 800w and 2.5k or even 1.5k for that matter. I am in 0 land and very hard to break the coasts on a good day at times so a little extra helps break those pile ups.
Fred N0AZZ

Sent via the Samsung Galaxy S6 edge+, an AT&T 4G LTE smartphone-------- Original message --------From: [hidden email] Date: 09/18/2015 1:16 PM (GMT-06:00) To: 'Edward R Cole' <[hidden email]>, [hidden email] Subject: Re: [Elecraft] Product Suggestion - 500W Dummy Load
Forgive me in advance if this is a stupid question.

Is there any reason you have to tune at full power? It seems to me that
tuning can be accomplished easily with much lower power. The same thing goes
for the ATU to the antenna. I don't see why we need more than a few MW at
most for the ATU to Antenna link.

Rightly or wrongly when I was in the hobby the first time I ran a TS-850
into an SB-220 to an MFJ roller tuner connected to an antenna switch
feeding: 80m inverted V, 30m/40m rotatable dipoles, and a triband beam.
Whenever I tuned on the inverted V or outer band limits of where my antennas
where tuned I ended up putting labels on the ATU on cap position and a
number/clock combo that represented a roller inductor position for each band
area I cared about. It ended up I rarely had to tune up anything one the air
because I knew where the antenna tuning was using just the Rig and ATU;
tuned the APM into a paintcan MFJ load then switch it inline. I was all set
and never had issues when I needed to kick in the horses.

Now my debate is 500w vs 800w... there's a larger difference between 500w
and 800w than between 800w and 2.5kw signal wise if I understand
correctly...

Jerry Moore
AE4PB, K3S - S.N. 010324

-----Original Message-----
From: Elecraft [mailto:[hidden email]] On Behalf Of Edward
R Cole
Sent: Friday, September 18, 2015 2:00 PM
To: [hidden email]
Subject: Re: [Elecraft] Product Suggestion - 500W Dummy Load

Don't have much to say:

Had a Cantenna from Heath in the 60's - knocked over; spilt mineral oil on
the floor, threw can away!

I have acquired "dry" loads over the years rated into UHF and sometimes to
mw at flea markets and swaps. My highest power load is 500w Sierra with
power meter and switch for 150 or 500w (probably good to 1000-MHz). Have a
couple Bird terminations rated 50w. Most can handled double their rating
for short duration.

The hardest duty on my loads is when optimizing the output of a new unit
where I'm keyed up longer than I should.

But I do have a question on how adjusting a tuner into a 50-ohm load saves
one from transmitting a signal once the tuner is connected to an antenna
that may not be 50-ohms. On 600m my inverted-L is Z = 0.8
+j680. Tuning into a 50-ohm load does nothing to help match the
antenna. The amplifier is solid state with input and output transformers
(no adjustment).

I think, unless you use a high power tetrode or triode, that no one tunes
amplifiers anymore. Solid state amps are broadband and need LP filters to
keep from amplifying harmonics. BTW my 2m-8877 is capable of 2000w* RF
output so pretty hard to find a dummy load to take that. Fortunately the
amp does not change much so very little tuning is ever needed (of course I
am on a small segment of one band about 200-KHz wide). Of course the answer
is to tune antenna at lower power and hope the High Power amp will always be
looking at 50-ohms.

I do not have a QRO 2m antenna tuner but the antenna SWR < 1.25 so only the
anode tuning needs a light adjustment occasionally (loading has not be
adjusted for 8 years). My "dummy load" has 19.2 dBd gain and radiates well.

*I operate at 1365w CW which allows for about 9% variance in meter accuracy
to stay legal.

73, Ed - KL7UW
http://www.kl7uw.com
"Kits made by KL7UW"
Dubus Mag business:
[hidden email]

______________________________________________________________
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 Message
delivered to [hidden email]

______________________________________________________________
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
Message delivered to [hidden email]

______________________________________________________________
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
Message delivered to [hidden email]

Grant Youngman

Re: Product Suggestion - 500W Dummy Load

The difference better 800W and 500W is about 2 dB. Barely noticeable.

The difference between 2500W and 800W is about 5dB. About an S-unit.

Grant NQ5T

Sent from my iPhone

>
> Now my debate is 500w vs 800w... there's a larger difference between 500w
> and 800w than between 800w and 2.5kw signal wise if I understand
>
______________________________________________________________
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
Message delivered to [hidden email]

Wes (N7WS)

Re: Product Suggestion - 500W Dummy Load

In reply to this post by Edward R Cole

I tested my amp (http://sadxa.org/n7ws.html#amp) with 150' of RG8 into a
Cantenna (almost) submerged in a bucket of water. Wasn't CCS but okay for my
purposes. Using the loss in coax for an attenuator isn't unheard of.

When I was still in the work force I once had to test some cables with 100 Watts
applied at elevated temperature (+85C) and VSWR = 3:1 @10GHz. For a load I used
about four feet of 0.085" semi-rigid coax (3 dB loss) shorted at the end (6 dB
return loss) coiled up in a can of water for a load. An amazing tribute to the
Hughes TWTA (and its circulator) that ran for over a hundred hours during this test.

Wes N7WS

On 9/18/2015 11:00 AM, Edward R Cole wrote:
> BTW my 2m-8877 is capable of 2000w* RF output so pretty hard to find a dummy
> load to take that.

______________________________________________________________
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
Message delivered to [hidden email]

Bob McGraw - K4TAX

Re: Product Suggestion - 500W Dummy Load

In reply to this post by ae4pb

There is no need, in fact it is considered objectionable, to adjust a
tuner at full power. It is also very hard on the components. As to an
amp, the only way I know to adjust one is working it up to full power
and than reducing drive to the power value you desire to operate.

For manual tuners and amps, a written "tuning chart" really comes in handy.

73
Bob, K4TAX
K3S s/n 10,163

On 9/18/2015 1:16 PM, [hidden email] wrote:

> Forgive me in advance if this is a stupid question.
>
> Is there any reason you have to tune at full power? It seems to me that
> tuning can be accomplished easily with much lower power. The same thing goes
> for the ATU to the antenna. I don't see why we need more than a few MW at
> most for the ATU to Antenna link.
>
>
>
> Rightly or wrongly when I was in the hobby the first time I ran a TS-850
> into an SB-220 to an MFJ roller tuner connected to an antenna switch
> feeding: 80m inverted V, 30m/40m rotatable dipoles, and a triband beam.
> Whenever I tuned on the inverted V or outer band limits of where my antennas
> where tuned I ended up putting labels on the ATU on cap position and a
> number/clock combo that represented a roller inductor position for each band
> area I cared about. It ended up I rarely had to tune up anything one the air
> because I knew where the antenna tuning was using just the Rig and ATU;
> tuned the APM into a paintcan MFJ load then switch it inline. I was all set
> and never had issues when I needed to kick in the horses.
>
> Now my debate is 500w vs 800w... there's a larger difference between 500w
> and 800w than between 800w and 2.5kw signal wise if I understand
> correctly...
>
>
> Jerry Moore
> AE4PB, K3S - S.N. 010324
>
>
>
> -----Original Message-----
> From: Elecraft [mailto:[hidden email]] On Behalf Of Edward
> R Cole
> Sent: Friday, September 18, 2015 2:00 PM
> To: [hidden email]
> Subject: Re: [Elecraft] Product Suggestion - 500W Dummy Load
>
> Don't have much to say:
>
> Had a Cantenna from Heath in the 60's - knocked over; spilt mineral oil on
> the floor, threw can away!
>
> I have acquired "dry" loads over the years rated into UHF and sometimes to
> mw at flea markets and swaps. My highest power load is 500w Sierra with
> power meter and switch for 150 or 500w (probably good to 1000-MHz). Have a
> couple Bird terminations rated 50w. Most can handled double their rating
> for short duration.
>
> The hardest duty on my loads is when optimizing the output of a new unit
> where I'm keyed up longer than I should.
>
> But I do have a question on how adjusting a tuner into a 50-ohm load saves
> one from transmitting a signal once the tuner is connected to an antenna
> that may not be 50-ohms. On 600m my inverted-L is Z = 0.8
> +j680. Tuning into a 50-ohm load does nothing to help match the
> antenna. The amplifier is solid state with input and output transformers
> (no adjustment).
>
> I think, unless you use a high power tetrode or triode, that no one tunes
> amplifiers anymore. Solid state amps are broadband and need LP filters to
> keep from amplifying harmonics. BTW my 2m-8877 is capable of 2000w* RF
> output so pretty hard to find a dummy load to take that. Fortunately the
> amp does not change much so very little tuning is ever needed (of course I
> am on a small segment of one band about 200-KHz wide). Of course the answer
> is to tune antenna at lower power and hope the High Power amp will always be
> looking at 50-ohms.
>
> I do not have a QRO 2m antenna tuner but the antenna SWR < 1.25 so only the
> anode tuning needs a light adjustment occasionally (loading has not be
> adjusted for 8 years). My "dummy load" has 19.2 dBd gain and radiates well.
>
> *I operate at 1365w CW which allows for about 9% variance in meter accuracy
> to stay legal.
>
> 73, Ed - KL7UW
> http://www.kl7uw.com
> "Kits made by KL7UW"
> Dubus Mag business:
> [hidden email]
>
> ______________________________________________________________
> 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 Message
> delivered to [hidden email]
>
> ______________________________________________________________
> 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
> Message delivered to [hidden email]
>
>
>

mcduffie

Re: Product Suggestion - 500W Dummy Load

In reply to this post by Grant Youngman

On Fri, 18 Sep 2015 14:16:43 -0500, Grant Youngman wrote:

> The difference better 800W and 500W is about 2 dB. Barely noticeable.

Two db is quite noticeable when you are in the noise.

Gary
______________________________________________________________
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
Message delivered to [hidden email]

Bob McGraw - K4TAX

Re: Product Suggestion - 500W Dummy Load

In reply to this post by Fred Smith-2

Who runs 2.5K ? Uh, isn't that just a wee bit over the legal limit?

73
Bob, K4TAX
K3S s/n 10,163

On 9/18/2015 1:54 PM, mfsj wrote:

> I can tell you this there is a world of difference between 800w and 2.5k or even 1.5k for that matter. I am in 0 land and very hard to break the coasts on a good day at times so a little extra helps break those pile ups.
> Fred N0AZZ
>
>
> Sent via the Samsung Galaxy S6 edge+, an AT&T 4G LTE smartphone-------- Original message --------From: [hidden email] Date: 09/18/2015 1:16 PM (GMT-06:00) To: 'Edward R Cole' <[hidden email]>, [hidden email] Subject: Re: [Elecraft] Product Suggestion - 500W Dummy Load
> Forgive me in advance if this is a stupid question.
>
> Is there any reason you have to tune at full power? It seems to me that
> tuning can be accomplished easily with much lower power. The same thing goes
> for the ATU to the antenna. I don't see why we need more than a few MW at
> most for the ATU to Antenna link.
>
>
>
> Rightly or wrongly when I was in the hobby the first time I ran a TS-850
> into an SB-220 to an MFJ roller tuner connected to an antenna switch
> feeding: 80m inverted V, 30m/40m rotatable dipoles, and a triband beam.
> Whenever I tuned on the inverted V or outer band limits of where my antennas
> where tuned I ended up putting labels on the ATU on cap position and a
> number/clock combo that represented a roller inductor position for each band
> area I cared about. It ended up I rarely had to tune up anything one the air
> because I knew where the antenna tuning was using just the Rig and ATU;
> tuned the APM into a paintcan MFJ load then switch it inline. I was all set
> and never had issues when I needed to kick in the horses.
>
> Now my debate is 500w vs 800w... there's a larger difference between 500w
> and 800w than between 800w and 2.5kw signal wise if I understand
> correctly...
>
>
> Jerry Moore
> AE4PB, K3S - S.N. 010324
>
>
>
> -----Original Message-----
> From: Elecraft [mailto:[hidden email]] On Behalf Of Edward
> R Cole
> Sent: Friday, September 18, 2015 2:00 PM
> To: [hidden email]
> Subject: Re: [Elecraft] Product Suggestion - 500W Dummy Load
>
> Don't have much to say:
>
> Had a Cantenna from Heath in the 60's - knocked over; spilt mineral oil on
> the floor, threw can away!
>
> I have acquired "dry" loads over the years rated into UHF and sometimes to
> mw at flea markets and swaps. My highest power load is 500w Sierra with
> power meter and switch for 150 or 500w (probably good to 1000-MHz). Have a
> couple Bird terminations rated 50w. Most can handled double their rating
> for short duration.
>
> The hardest duty on my loads is when optimizing the output of a new unit
> where I'm keyed up longer than I should.
>
> But I do have a question on how adjusting a tuner into a 50-ohm load saves
> one from transmitting a signal once the tuner is connected to an antenna
> that may not be 50-ohms. On 600m my inverted-L is Z = 0.8
> +j680. Tuning into a 50-ohm load does nothing to help match the
> antenna. The amplifier is solid state with input and output transformers
> (no adjustment).
>
> I think, unless you use a high power tetrode or triode, that no one tunes
> amplifiers anymore. Solid state amps are broadband and need LP filters to
> keep from amplifying harmonics. BTW my 2m-8877 is capable of 2000w* RF
> output so pretty hard to find a dummy load to take that. Fortunately the
> amp does not change much so very little tuning is ever needed (of course I
> am on a small segment of one band about 200-KHz wide). Of course the answer
> is to tune antenna at lower power and hope the High Power amp will always be
> looking at 50-ohms.
>
> I do not have a QRO 2m antenna tuner but the antenna SWR < 1.25 so only the
> anode tuning needs a light adjustment occasionally (loading has not be
> adjusted for 8 years). My "dummy load" has 19.2 dBd gain and radiates well.
>
> *I operate at 1365w CW which allows for about 9% variance in meter accuracy
> to stay legal.
>
> 73, Ed - KL7UW
> http://www.kl7uw.com
> "Kits made by KL7UW"
> Dubus Mag business:
> [hidden email]
>
> ______________________________________________________________
> 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 Message
> delivered to [hidden email]
>
> ______________________________________________________________
> 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
> Message delivered to [hidden email]
>
> ______________________________________________________________
> 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
> Message delivered to [hidden email]