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Amplifier

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Dennis Watkins-3

Amplifier

I would suggest that a redesign on the K2/K3s would be a starting
point. The cheesy connectors on the back of the k3 will not stand up to
a strong field from a 1.5kw amp with the tower mounted to the house.
To much leakage for me.
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Josh Fiden

Re: Amplifier

Which connectors? What's the anticipated problem? Please explain. Tnx

73
Josh W6XU

Sent from my mobile device

> On Apr 6, 2017, at 9:28 AM, Dennis Watkins <[hidden email]> wrote:
>
> I would suggest that a redesign on the K2/K3s would be a starting point. The cheesy connectors on the back of the k3 will not stand up to a strong field from a 1.5kw amp with the tower mounted to the house. To much leakage for me.
>

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Vic Rosenthal

Re: Amplifier

In reply to this post by Dennis Watkins-3

Hmm, I am running 1.2+ kW to a dipole on the roof about 20 feet above my K3, which has no RF problems though other devices in my shack do!

Vic 4X6GP

> On 6 Apr 2017, at 19:28, Dennis Watkins <[hidden email]> wrote:
>
> I would suggest that a redesign on the K2/K3s would be a starting point. The cheesy connectors on the back of the k3 will not stand up to a strong field from a 1.5kw amp with the tower mounted to the house. To much leakage for me.
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Bill-3

Re: Amplifier

That proximity would scare me - I'd feel like I was on a skewer in a
microwave oven.

--
Many of life's problems can be solved by simply deciding what
we can do without. - John Dolan

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John Dolan

Re: Amplifier

In reply to this post by Vic Rosenthal

What Cheesy connectors are you referring to?

WB4YAL John

*Many of life's problems can be solved by simply deciding what we can do
without. -JohnDolan <https://www.qrz.com/db/WB4YAL>*

*Many of life's problems can be solved by simply deciding what we can do
without. -JohnDolan <https://www.qrz.com/db/WB4YAL>*

On Fri, Apr 7, 2017 at 3:42 AM, Vic Rosenthal <[hidden email]> wrote:

> Hmm, I am running 1.2+ kW to a dipole on the roof about 20 feet above my
> K3, which has no RF problems though other devices in my shack do!
>
> Vic 4X6GP
>
> > On 6 Apr 2017, at 19:28, Dennis Watkins <[hidden email]> wrote:
> >
> > I would suggest that a redesign on the K2/K3s would be a starting
> point. The cheesy connectors on the back of the k3 will not stand up to a
> strong field from a 1.5kw amp with the tower mounted to the house. To
> much leakage for me.
> ______________________________________________________________
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>

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Wes Stewart-2

Re: Amplifier

In reply to this post by Bill-3

I assume you're commenting on the 1KW 20' away, although failed to say so. Turn
this scenario around: pretend that you were trying to do medical treatment or
research by heating your body to a biologically significant temperature. How
much power to a transducer 20' away would it take?

On 4/7/2017 3:10 AM, Bill wrote:
> That proximity would scare me - I'd feel like I was on a skewer in a microwave
> oven.
>

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Edward R Cole

Re: Amplifier

In reply to this post by Dennis Watkins-3

In the USAmerica ham's now have the *responsibility* of determining
the safe operating zones for each antenna per FCC regulation. I
doubt many ever do the calculation. Fortunately Australian ham Doug
MacArthur (sk) VK3UM (a well known eme'r) has written a program which
you can download for free. I will simulate the emf fields base on
your input data like antenna, power, height, band and produces the
legal exclusion zones where RF exposure is considered dangerous.

http://www.vk3um.com/emr%20calculator.html

Its not hard to use and provides some interesting if not surprising
info about your station safety.

As I already stated, it is the legal requirement for all US hams to
have evaluated safe range for humans before operating.

Eg: half-wave dipole, 1400w, line loss 0.5 dB, 14.2 MHz: exclusion =
3.06m radially; safe height 2.60m for FCC. Also provides ARPNSA and
CEU radiation limits.

73, Ed - KL7uW

Date: Fri, 7 Apr 2017 10:42:32 +0300
From: Vic Rosenthal <[hidden email]>
To: Elecraft Reflector <[hidden email]>
Subject: Re: [Elecraft] Amplifier
Message-ID: <[hidden email]>
Content-Type: text/plain; charset=us-ascii

Hmm, I am running 1.2+ kW to a dipole on the roof about 20 feet above
my K3, which has no RF problems though other devices in my shack do!

Vic 4X6GP

73, Ed - KL7UW
http://www.kl7uw.com
Dubus-NA Business mail:
[hidden email]

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Mike Harris-9

Re: Amplifier

In reply to this post by Wes Stewart-2

I had the opportunity to borrow an R&S professional field strength meter
from the local telco when there were concerns over the installation of
mobile phone towers in town. The worriers obsessed over the towers but
completely ignored the little transmitters they and their kids would be
clamping to the side of their brains.

My HF beam is 12.5 metres high on a tower. With 1kW from the amp,
standing directly at the base of the tower the field strength measured
was well below the guidlines for RF exposure.

Living at the base of a steep sloping ridge to the south it was easy to
elevate myself to the plane of the antenna beaming at me from about 35
to 40 metres. When the TX at 1kW was keyed there was no indicated
increase in field strength over the background reading. Also duty cycle
comes into play.

There are a couple of FCC bulletins, OET65 and specifically for radio
amateurs OET65B which go into a lot of detail on this subject. They are
dated late 1997 and I've not check to see if there are more recent
revisions.

Regards,

Mike VP8NO

On 07/04/2017 09:50, Wes Stewart wrote:

> I assume you're commenting on the 1KW 20' away, although failed to say
> so. Turn this scenario around: pretend that you were trying to do
> medical treatment or research by heating your body to a biologically
> significant temperature. How much power to a transducer 20' away would
> it take?
>
>
> On 4/7/2017 3:10 AM, Bill wrote:
>> That proximity would scare me - I'd feel like I was on a skewer in a
>> microwave oven.

briancom

Re: Was Amplifier

In reply to this post by Edward R Cole

"Considered dangerous" isn't quite right. The jury is out of the exact
danger levels of RF for all the various frequencies. These distances
are more of an accepted limit that protects you from inquiries regarding
RF exposure. Pointing to the distances being met helps get you off the
hook.

People will be surprised to see how small the distances these
calculations are-- especially at lower frequencies.

One note often overlooked. The distance is defined as the distance from
feedpoint (usually center) of the antenna.

Also the duty cycle can be considered in the calculation. There are
stock duty cycles for SSB and CW given in the documentation.

Antenna gain may have to be included.

It used to be that anything at 100 watts and below at HF was exempted.
I believe that has changed.

73 de Brian/K3KO

On 4/7/2017 16:06 PM, Edward R Cole wrote:

> In the USAmerica ham's now have the *responsibility* of determining the
> safe operating zones for each antenna per FCC regulation. I doubt many
> ever do the calculation. Fortunately Australian ham Doug MacArthur (sk)
> VK3UM (a well known eme'r) has written a program which you can download
> for free. I will simulate the emf fields base on your input data like
> antenna, power, height, band and produces the legal exclusion zones
> where RF exposure is considered dangerous.
>
> http://www.vk3um.com/emr%20calculator.html
>
> Its not hard to use and provides some interesting if not surprising info
> about your station safety.
>
> As I already stated, it is the legal requirement for all US hams to have
> evaluated safe range for humans before operating.
>
> Eg: half-wave dipole, 1400w, line loss 0.5 dB, 14.2 MHz: exclusion =
> 3.06m radially; safe height 2.60m for FCC. Also provides ARPNSA and CEU
> radiation limits.
>
> 73, Ed - KL7uW
>

Jim Brown-10

Re: Amplifier

In reply to this post by Vic Rosenthal

Problems like what Dennis is describing are often caused by failure to
properly bond together all equipment in the shack, to bond that
equipment to building ground, and to bond all building grounds together.

That said, the original KIO3 board fails to follow the good engineering
practice of connecting cable shields to the shielding enclosure at the
point of entry. This failure is, sadly, widespread in ham radio,
computers, and consumer gear of all sorts. It is a MAJOR cause of hum,
buzz, and RFI. It was brought to the attention of the world of pro audio
by Neil Muncy, W3WJE (SK) in a landmark AES paper in 1994.

Problems caused by this design failure are greatly reduced by the proper
bonding outlined above, and by the use of ferrite common mode chokes on
wiring connected to the defective equipment. Proper bonding is described
in the slides for a talk I've given to several ham conventions. The
concepts have been incorporated into a new ARRL book on power and
grounding by N0AX.

http://k9yc.com/GroundingAndAudio.pdf

73, Jim K9YC

On Fri,4/7/2017 12:42 AM, Vic Rosenthal wrote:
> Hmm, I am running 1.2+ kW to a dipole on the roof about 20 feet above my K3, which has no RF problems though other devices in my shack do!
>
> Vic 4X6GP
>
>> On 6 Apr 2017, at 19:28, Dennis Watkins <[hidden email]> wrote:
>>
>> I would suggest that a redesign on the K2/K3s would be a starting point. The cheesy connectors on the back of the k3 will not stand up to a strong field from a 1.5kw amp with the tower mounted to the house. To much leakage for me.

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George Danner-2

Re: Was Amplifier - Now RF exposure limits

In reply to this post by briancom

Ed & Brian,
My father had severe health consequences from working in a classroom with
operating military radars!

Since the adoption of OET 65 in the late 90s, all licensees (including Hams)
have had the responsibility to insure their station is in complete
compliance with RF exposure limit guidelines.

Most likely during your last license renewal or application for a new
license, you checked a box stating you would insure compliance with
non-ionization radiation limits.
Those guidelines are contained in bulletin OET 65.
For Hams OET 65 Supplement B
(https://transition.fcc.gov/bureaus/oet/info/documents/bulletins/oet65/oet65b.pdf)
gives us some shortcuts to insure compliance without the tedious
calculations. Many of the tables were provided by ARRL & the W5YI Group.

There are also calculators available on the internet to make it quite easy.
Googleing "amateur radio oet 65 calculator" returned many to choose from.

The only caveat I will give is that most of the shortcuts and calculators
are for a single transmitting antenna at a specific location. Multiple
radiating antenna WILL change the protection distances - Field Day & group
contesting come to mind!

Use to be we had to submit OET 65 compliance statements when licensing all
transmitters for Broadcast Stations ranging from 150 MHz to 23 GHz. I
believe we finally could use just a blanket cover statement ; but it has
been a while since I licensed a non-Ham transmitter.

You do need to insure you are in compliance - to protect your family,
friends, neighbors and yourself.

73
George
AI4VZ

From: brian

"Considered dangerous" isn't quite right. The jury is out of the exact
danger levels of RF for all the various frequencies. These distances
are more of an accepted limit that protects you from inquiries regarding
RF exposure. Pointing to the distances being met helps get you off the
hook.

People will be surprised to see how small the distances these
calculations are-- especially at lower frequencies.

One note often overlooked. The distance is defined as the distance from
feedpoint (usually center) of the antenna.

Also the duty cycle can be considered in the calculation. There are
stock duty cycles for SSB and CW given in the documentation.

Antenna gain may have to be included.

It used to be that anything at 100 watts and below at HF was exempted.
I believe that has changed.

73 de Brian/K3KO

On 4/7/2017 16:06 PM, Edward R Cole wrote:

Jim Brown-10

Re: Was Amplifier

In reply to this post by briancom

On Fri,4/7/2017 9:27 AM, brian wrote:
> "Considered dangerous" isn't quite right. The jury is out of the
> exact danger levels of RF for all the various frequencies. These
> distances are more of an accepted limit that protects you from
> inquiries regarding RF exposure. Pointing to the distances being met
> helps get you off the hook.

In informal conversation with Ed Hare, W1RFI, several years ago, he
observed that based on consensus research, FCC limits on radiation were
quite conservative (that is, erring a lot in favor of safety).

73, Jim K9YC

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k6dgw

Re: Was Amplifier - Now RF exposure limits

In reply to this post by George Danner-2

On 4/7/2017 4:05 PM, Ron D'Eau Claire wrote:
> Remember, the microwave oven was "invented" by an engineer working around
> magnetron RF sources and discovered the "Hershey" chocolate bar in his shirt
> pocket had melted. When he figured out why, the "Radar Range" (first brand
> of microwave oven) was born.
So the story goes. However, I believe I invented the microwave oven
when I discovered I could cram a hot dog into the feedhorn and it would
heat up in a few tens of seconds. Sadly, Amana came along with the name
"Radar Range," and "cram it into the feedhorn" as a name was consumer
toast. I've also noted that chocolate bars get really soft in my shirt
pocket, magnetrons or not.

> One cold night in the late 1950's, working outside on a flight line of F-86D
> fighters lined up wingtip to wingtip for preflight repairs and testing, I
> concluded I must be catching the flu. I felt weak hot and sweaty after
> several minutes talking with someone. We were standing in front of the
> planes, most of which had the nose radomes removed for testing the
> fire-control radar systems. Looking up, I noticed the radar antenna of one
> plane across the way with someone sitting in the cockpit was pointing
> directly at me. On a hunch, I took a few steps to one side and the antenna
> twitched to follow me. I immediately moved completely out of the way and
> within a short time I felt quite normal.

Working my way thru college at the local TV station, the CE offered me
$50 each time to climb the tower and replace the clearance lamps twice a
year. FAA requirement. They sent me to climbing school at the local
utility, provided an approved harness, I "climbed" on a ladder inside
the tower with a fall arrestor hooked to a cable down the center. $50
was big money then. We were on a ridge, I could see the Pacific after
100 ft or so, wind was constant, and it was cold even in summer. I
climbed in the warmest part of the day, and we were on the air of
course. The last clearance lamps were at the base of the mast holding
the turnstile antenna, bottom of which was about 40 ft above me. I
warmed nicely doing those three lamps, and it made the downhill leg a
lot more comfortable. OSHA today would have had a cow.

I use an HOA-Stealth antenna with my K3 at home, an end-fed wire along
the wooden fence. I did the calcs, and at 100W, we're definitely safe.
I do flash the two touch lamps in the bedroom on 80 and 160 but those
things will turn on if I sneeze. [:-)

The calcs are really easy on the on-line devices, I used the ARRL one.
Paste the results in your station notebook and you're home free.

73,

Fred ("Skip") K6DGW
Sparks NV USA
Washoe County DM09dn

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Bill Frantz

Re: Was Amplifier

In reply to this post by briancom

<http://www.arrl.org/fcc-rf-exposure-regulations-the-station-evaluation>
indicates 100W and below is exempted for 160M thru 15M. The
figure for 12M is 75W, 10M thru 1.24M is 50W, 70cm is 70W and
it's over 100W the rest of the way up.

73 Bill AE6JV

On 4/7/17 at 9:27 AM, [hidden email] (brian) wrote:

>It used to be that anything at 100 watts and below at HF was exempted.
>I believe that has changed.

---------------------------------------------------------------------------
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There you're
408-356-8506 | fed, clothed, given medical care and so on.
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www.pwpconsult.com | thing lacking is freedom. - Dwight D. Eisenhower

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Edward R Cole

Re: Was Amplifier

In reply to this post by briancom

Brian,

First off,its apparent you did not look at the program I gave the
link to. Had you done that you would see factors for modulation,
duty-cycle, antenna gain, etc.

Next,I could not recall the FCC paper: OET 65B, but VK3UM based his
spreadsheet on this paper a similar papers done by European
authorities; note the "safe"levels differ between which gov't
authority is used. The FCC did thorough study and came up with the
guideline since they realized not all parties had the equipment or
expertise to measure near-field RF power density. Thus the
simplifying guide which will generally suffice.

More likely one can enter a few known parameters about their station
vs a total field density measurements.

I was responsible for 62 FCC commercial licenses and seven
transmitting sites, so I did the FCC calcs by hand with calculator
way before Doug wrote his EMR program.
Also did mw safety measurements in the 1970's at NASA Goldstone
Facility. The 25mw/cm^2 measured at two miles would not pass today's
limits. 85-foot dish pointed at you running 20KW CW at 2115 MHz.

I too have experience effects of mw radar testing with open waveguide
(3kW peak). Took about ten minutes to start getting a
headache. Then I threatened the stupid tech doing that with certain
bodily injury if he did not use the dummy loads - duh!

I merely wanted all you on the list to know of this handy resource
for calculating your RF exposure per gov't standards. Its a minimum
to try for.

73, Ed - KL7UW

Date: Fri, 07 Apr 2017 16:27:18 +0000
From: brian <[hidden email]>
To: [hidden email]
Subject: Re: [Elecraft] Was Amplifier
Message-ID: <[hidden email]>
Content-Type: text/plain; charset=windows-1252; format=flowed

"Considered dangerous" isn't quite right. The jury is out of the exact
danger levels of RF for all the various frequencies. These distances
are more of an accepted limit that protects you from inquiries regarding
RF exposure. Pointing to the distances being met helps get you off the
hook.

People will be surprised to see how small the distances these
calculations are-- especially at lower frequencies.

One note often overlooked. The distance is defined as the distance from
feedpoint (usually center) of the antenna.

Also the duty cycle can be considered in the calculation. There are
stock duty cycles for SSB and CW given in the documentation.

Antenna gain may have to be included.

It used to be that anything at 100 watts and below at HF was exempted.
I believe that has changed.

73 de Brian/K3KO

73, Ed - KL7UW
http://www.kl7uw.com
Dubus-NA Business mail:
[hidden email]

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Wes Stewart-2

Re: Was Amplifier - Now RF exposure limits

In reply to this post by k6dgw

I spent a good part of my career at Hughes Aircraft working on the Phoenix
Missile transmitter/receiver unit. Being an RF guy I was asked once to design
and build a 225 MHz PA that would deliver a couple of hundred watts output when
driven by an HP608 signal generator. The object was to drive a 10 dB gain Yagi
that would illuminate a Phoenix in a lab to simulate what the missile was seeing
under the wing of an F-14 on the deck of the carrier Enterprise.

Phoenix had a feature called MOAT (missile-on-aircraft-test) that preformed some
limited tests just before the aircraft was launched. A lot of failures were
happening that could not be repeated after the aircraft was removed from the
flight deck and the missile unloaded. Of course this was an operational PITA
that needed fixing. It was finally hypothesized that the failures were due to
RFI from the AN/SPS-32 OTH radar that was a feature on Enterprise. Some
analytical type determined that 100W into the Yagi 10 feet from the missile
would be the equivalent of what the missile and the deckhands were seeing on the
carrier deck.

Since our lab didn't (yet) have an anechoic chamber large enough to do the test
these guys planned to do it in a regular lab environment. I told them that I
would (and did) build the PA, but I didn't want to be anywhere near it during
the testing. I'm glad I wasn't on the carrier deck either.

Wes N7WS

On 4/7/2017 5:05 PM, Fred Jensen wrote:

> On 4/7/2017 4:05 PM, Ron D'Eau Claire wrote:
>> Remember, the microwave oven was "invented" by an engineer working around
>> magnetron RF sources and discovered the "Hershey" chocolate bar in his shirt
>> pocket had melted. When he figured out why, the "Radar Range" (first brand
>> of microwave oven) was born.
> So the story goes. However, I believe I invented the microwave oven when I
> discovered I could cram a hot dog into the feedhorn and it would heat up in a
> few tens of seconds. Sadly, Amana came along with the name "Radar Range," and
> "cram it into the feedhorn" as a name was consumer toast. I've also noted
> that chocolate bars get really soft in my shirt pocket, magnetrons or not.
>> One cold night in the late 1950's, working outside on a flight line of F-86D
>> fighters lined up wingtip to wingtip for preflight repairs and testing, I
>> concluded I must be catching the flu. I felt weak hot and sweaty after
>> several minutes talking with someone. We were standing in front of the
>> planes, most of which had the nose radomes removed for testing the
>> fire-control radar systems. Looking up, I noticed the radar antenna of one
>> plane across the way with someone sitting in the cockpit was pointing
>> directly at me. On a hunch, I took a few steps to one side and the antenna
>> twitched to follow me. I immediately moved completely out of the way and
>> within a short time I felt quite normal.
> Working my way thru college at the local TV station, the CE offered me $50
> each time to climb the tower and replace the clearance lamps twice a year.
> FAA requirement. They sent me to climbing school at the local utility,
> provided an approved harness, I "climbed" on a ladder inside the tower with a
> fall arrestor hooked to a cable down the center. $50 was big money then. We
> were on a ridge, I could see the Pacific after 100 ft or so, wind was
> constant, and it was cold even in summer. I climbed in the warmest part of
> the day, and we were on the air of course. The last clearance lamps were at
> the base of the mast holding the turnstile antenna, bottom of which was about
> 40 ft above me. I warmed nicely doing those three lamps, and it made the
> downhill leg a lot more comfortable. OSHA today would have had a cow.
>
> I use an HOA-Stealth antenna with my K3 at home, an end-fed wire along the
> wooden fence. I did the calcs, and at 100W, we're definitely safe. I do
> flash the two touch lamps in the bedroom on 80 and 160 but those things will
> turn on if I sneeze. [:-)
>
> The calcs are really easy on the on-line devices, I used the ARRL one. Paste
> the results in your station notebook and you're home free.
>
> 73,
>
> Fred ("Skip") K6DGW
> Sparks NV USA
> Washoe County DM09dn

Vic Rosenthal

Re: Was Amplifier - Now RF exposure limits

In reply to this post by George Danner-2

I strongly disagree. The heating effect - which is the only scientifically verifiable effect from RF exposure - is far smaller at HF than radar frequencies. Yes, you don't look into a horn antenna of an operating radar transmitter, but a 20 meter dipole is a different story entirely. The exposure limits mandated by the FCC (and by the authorities in this country too) serve only to cover various butts against opportunistic lawsuits.

Vic 4X6GP

> On 7 Apr 2017, at 22:55, Gmail - George <[hidden email]> wrote:
>
> Ed & Brian,
> My father had severe health consequences from working in a classroom with
> operating military radars!
>
> Since the adoption of OET 65 in the late 90s, all licensees (including Hams)
> have had the responsibility to insure their station is in complete
> compliance with RF exposure limit guidelines.
>
> Most likely during your last license renewal or application for a new
> license, you checked a box stating you would insure compliance with
> non-ionization radiation limits.
> Those guidelines are contained in bulletin OET 65.
> For Hams OET 65 Supplement B
> (https://transition.fcc.gov/bureaus/oet/info/documents/bulletins/oet65/oet65b.pdf)
> gives us some shortcuts to insure compliance without the tedious
> calculations. Many of the tables were provided by ARRL & the W5YI Group.
>
> There are also calculators available on the internet to make it quite easy.
> Googleing "amateur radio oet 65 calculator" returned many to choose from.
>
> The only caveat I will give is that most of the shortcuts and calculators
> are for a single transmitting antenna at a specific location. Multiple
> radiating antenna WILL change the protection distances - Field Day & group
> contesting come to mind!
>
> Use to be we had to submit OET 65 compliance statements when licensing all
> transmitters for Broadcast Stations ranging from 150 MHz to 23 GHz. I
> believe we finally could use just a blanket cover statement ; but it has
> been a while since I licensed a non-Ham transmitter.
>
> You do need to insure you are in compliance - to protect your family,
> friends, neighbors and yourself.
>
> 73
> George
> AI4VZ
>
>
> From: brian
>
> "Considered dangerous" isn't quite right. The jury is out of the exact
> danger levels of RF for all the various frequencies. These distances
> are more of an accepted limit that protects you from inquiries regarding
> RF exposure. Pointing to the distances being met helps get you off the
> hook.
>
> People will be surprised to see how small the distances these
> calculations are-- especially at lower frequencies.
>
> One note often overlooked. The distance is defined as the distance from
> feedpoint (usually center) of the antenna.
>
> Also the duty cycle can be considered in the calculation. There are
> stock duty cycles for SSB and CW given in the documentation.
>
> Antenna gain may have to be included.
>
> It used to be that anything at 100 watts and below at HF was exempted.
> I believe that has changed.
>
> 73 de Brian/K3KO
>
>
>
>> On 4/7/2017 16:06 PM, Edward R Cole wrote:
>> In the USAmerica ham's now have the *responsibility* of determining the
>> safe operating zones for each antenna per FCC regulation. I doubt many
>> ever do the calculation. Fortunately Australian ham Doug MacArthur (sk)
>> VK3UM (a well known eme'r) has written a program which you can download
>> for free. I will simulate the emf fields base on your input data like
>> antenna, power, height, band and produces the legal exclusion zones
>> where RF exposure is considered dangerous.
>>
>> http://www.vk3um.com/emr%20calculator.html
>>
>> Its not hard to use and provides some interesting if not surprising info
>> about your station safety.
>>
>> As I already stated, it is the legal requirement for all US hams to have
>> evaluated safe range for humans before operating.
>>
>> Eg: half-wave dipole, 1400w, line loss 0.5 dB, 14.2 MHz: exclusion =
>> 3.06m radially; safe height 2.60m for FCC. Also provides ARPNSA and CEU
>> radiation limits.
>>
>> 73, Ed - KL7uW
>
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Vic Rosenthal

Re: Was Amplifier - Now RF exposure limits

In reply to this post by k6dgw

I did this too. They cut the carrier just long enough for me to get up above the base insulator. We used to joke about being complicit in radiating trashy music.

Vic 4X6GP

> On 8 Apr 2017, at 03:05, Fred Jensen <[hidden email]> wrote:
>
>> On 4/7/2017 4:05 PM, Ron D'Eau Claire wrote:
>> Remember, the microwave oven was "invented" by an engineer working around
>> magnetron RF sources and discovered the "Hershey" chocolate bar in his shirt
>> pocket had melted. When he figured out why, the "Radar Range" (first brand
>> of microwave oven) was born.
> So the story goes. However, I believe I invented the microwave oven when I discovered I could cram a hot dog into the feedhorn and it would heat up in a few tens of seconds. Sadly, Amana came along with the name "Radar Range," and "cram it into the feedhorn" as a name was consumer toast. I've also noted that chocolate bars get really soft in my shirt pocket, magnetrons or not.
>> One cold night in the late 1950's, working outside on a flight line of F-86D
>> fighters lined up wingtip to wingtip for preflight repairs and testing, I
>> concluded I must be catching the flu. I felt weak hot and sweaty after
>> several minutes talking with someone. We were standing in front of the
>> planes, most of which had the nose radomes removed for testing the
>> fire-control radar systems. Looking up, I noticed the radar antenna of one
>> plane across the way with someone sitting in the cockpit was pointing
>> directly at me. On a hunch, I took a few steps to one side and the antenna
>> twitched to follow me. I immediately moved completely out of the way and
>> within a short time I felt quite normal.
> Working my way thru college at the local TV station, the CE offered me $50 each time to climb the tower and replace the clearance lamps twice a year. FAA requirement. They sent me to climbing school at the local utility, provided an approved harness, I "climbed" on a ladder inside the tower with a fall arrestor hooked to a cable down the center. $50 was big money then. We were on a ridge, I could see the Pacific after 100 ft or so, wind was constant, and it was cold even in summer. I climbed in the warmest part of the day, and we were on the air of course. The last clearance lamps were at the base of the mast holding the turnstile antenna, bottom of which was about 40 ft above me. I warmed nicely doing those three lamps, and it made the downhill leg a lot more comfortable. OSHA today would have had a cow.
>
> I use an HOA-Stealth antenna with my K3 at home, an end-fed wire along the wooden fence. I did the calcs, and at 100W, we're definitely safe. I do flash the two touch lamps in the bedroom on 80 and 160 but those things will turn on if I sneeze. [:-)
>
> The calcs are really easy on the on-line devices, I used the ARRL one. Paste the results in your station notebook and you're home free.
>
> 73,
>
> Fred ("Skip") K6DGW
> Sparks NV USA
> Washoe County DM09dn

donovanf

Re: Was Amplifier

In reply to this post by Bill Frantz

What will you do if KC3VO comes up to say hello to you at
Dayton (err... Xenia) this year?

https://www.facebook.com/ARVN.TV/videos/169836159713771/

Bob used to be a white guy before he built his 2000 watt manpack
station! :)

73
Frank
W3LPL

----- Original Message -----

From: "Bill Frantz" <[hidden email]>
To: [hidden email]
Sent: Saturday, April 8, 2017 1:16:16 AM
Subject: Re: [Elecraft] Was Amplifier

<http://www.arrl.org/fcc-rf-exposure-regulations-the-station-evaluation>
indicates 100W and below is exempted for 160M thru 15M. The
figure for 12M is 75W, 10M thru 1.24M is 50W, 70cm is 70W and
it's over 100W the rest of the way up.

73 Bill AE6JV

On 4/7/17 at 9:27 AM, [hidden email] (brian) wrote:

>It used to be that anything at 100 watts and below at HF was exempted.
>I believe that has changed.

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