ARLA/CLUSTER: Re: ENC: RF Concepts/Alpha Amplifiers Monthly newsletter

[cu3di portugalmail.pt]

A quem interessar


> Para os proprietários de lineares da ALPHA, segue abaixo um email sobre
> uma promoção de um boné gratuito da marca para aqueles que coloquem  
> comentários no eham.net
> Como eu não tenho vou ficar sem o boné :

> 73´s CU3DI


> -----Mensagem original-----
> De: Steve Farkas [mailto:molly  alpharadioproducts.ccsend.com] Em nome de
> Steve Farkas
> Enviada em: quarta-feira, 10 de novembro de 2010 20:19
> Para: adriano.perazio  uol.com.br
> Assunto: RF Concepts/Alpha Amplifiers Monthly newsletter
>
> Having trouble viewing this email?
> www.rfconcepts.com
> http://campaign.r20.constantcontact.com/render?llr=eka89lcab&v=001T6qkBt
> jSWrMYa3og-COkdLWEoMYPDWTH9zQYIyfym5CwmjKQw2vKR9KQ6VgFdtb4Juv8P02eChpnbO
> Vi4ZIcDidWMuYVBgEHgKrwF2eHPhkod1O04OAffkSvdCf0tfwsGP6CjG9Z9cdbTg7a24J6qq
> vReXGW6hYJ
>
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> ~~~~~~~~
>
> ALPHA NEWSLETTER
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> ~~~~~~~~
>
> Our new Alpha 8406
> Full Legal Limit
> No Time Limit
> 6 Meter Amplifier Is Shipping!
> If you're looking for the most robust, six meter amplifier in the
> market, check
> it out.  We've posted some new pictures of the amps guts on the website.
> Last month we shipped the first few amps and our customers love it.
> We've got another
> 20 going through the line right now, but it won't fill the outstanding
> backlog.
>  More to follow next month.  So, if you're in the market for a great 6
> meter amp,
> get your order in so we can build one for you!
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> ~~~~~~~~
>
> November, 2010
> You can call us at 303-473-9232 or visit our website at
> www.rfconcepts.com
> [http://r20.rs6.net/tn.jsp?llr=eka89lcab&et=1103840911843&s=3704&e=001DF
> 5ErJcMsiBSJgPg4Z5Y_8yExZcpKSgAJhoHKDCo8Tn4HiI8rWv92efXeJ9gIftNdhObTTaitu
> 2xAykuvI5uXxoctlFnNNpt5CqhRuirmRNUUDhmQ3WzRg==]
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> ~~~~~~~~
>
> Write an Article for our Newsletter and get a Gift Certificate worth
> $200 [http://visitor.constantcontact.com/email.jsp?m=1102056358212]
> If you have an interesting Alpha Amplifier story, send it to us.  If we
> publish
> it, we'll send you a $200 Alpha Gift Certificate.
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> ~~~~~~~~
>
> HELP WANTED
> We're looking for an Electro Mechanical Engineer that would like to help
> us with
>  a project we're working on.
> If you'd like to help, send me an email with your resume.
> stevef  rfconcepts.com
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> ~~~~~~~~
>
> Newsletter Signup
> [http://visitor.constantcontact.com/email.jsp?m=1102056358212]
> Go to our website at www.rfconcepts.com
> [http://r20.rs6.net/tn.jsp?llr=eka89lcab&et=1103840911843&s=3704&e=001DF
> 5ErJcMsiBSJgPg4Z5Y_8yExZcpKSgAJhoHKDCo8Tn4HiI8rWv92efXeJ9gIftNdhObTTaitu
> 2xAykuvI5uXxoctlFnNNpt5CqhRuirmRNUUDhmQ3WzRg==]
> fill in your email address on the front page to sign up for our
> Newsletter.  We
> send a newsletter about once a month.
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> ~~~~~~~~
>
> Free Hat!
> Post a review of a current model Alpha product on eHam or your favorite
> online review
> system and receive a FREE hat with YOUR CALL embroidered on the back
>
> We want you to tell the world about your experience with Alpha products.
> It's the
> best advertising we can find.
> If you post a review of a current model Alpha amplifier on
> the eHam review system at www.eHam.net
> [http://r20.rs6.net/tn.jsp?llr=eka89lcab&et=1103840911843&s=3704&e=001DF
> 5ErJcMsiAWHnn-v95qYRt3KczWYolGxB30tXSuTXydX9x0x3LO4ApyS8cqh_9WelCNEaV522
> -FtfJL5gMHF3Z83R0b8yGN5Z3qxflrJg4=]and/or
> any other online review
> system that you feel comfortable using, and send us a note pointing it
> out, WE WILL
> SEND YOU A FREE HAT WITH YOUR CALL EMBROIDERED ON THE BACK.
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> ~~~~~~~~
>
> Just ok.  We're building more amps than ever.
> Demand for both the Alpha 8410, 8406, and Alpha 9500 amplifiers have
> driven us back
> into a slight backlog position.  We've increased the build plan and will
> be back
>  to "IN STOCK" soon.  If you're looking for an amp for this season, get
> your order
> into the system.
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> ~~~~~~~~
>
> The New Alpha Tube Warranty Extension Program
> available now
>
> We've put together an extended tube warranty program for new amplifier
> sales.  Our
> normal (industry leading) warranty is four years on the amplifier, and
> one year
> on the tube(s).  We're now offering a 4/4 warranty to cover the amp and
> extend the
> tube warranty for the coincident amp warranty.  This offer is only
> available to
> NEW orders. The prices for the extension are as follows:
> Alpha 9500 Autotune
> one 3CX1500A7 - $275
> Alpha 8410 - Manual Tune
> both 4CX1000's - $375
> Alpha 8406 - 6 Meter amp
> one 4CX1500 - $325
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> ~~~~~~~~
>
> Not well.  We have about 30 days of repairs in the shop.  One day last
> week we received
> 10 legacy  amps
> We've got brad working along with the others repairing amps, and he'll
> be on it
> until the number is down to at least two weeks.  Sorry for the delay.
> It's a busy
> season for us
> Remember - we have some NOS (new, old stock) parts that are 40 years
> old!  We still
> repair amplifiers that were purchased new in the 70's.  If you're
> looking for QRO
> parts, call us!
> We're turning amps in  about a 4 weeks.  The only amps in the shop that
> have been
> there longer than 4 weeks are ones we're waiting on parts from our
> vendors.  We're
> still trying to get it down below a couple of weeks, but if you've got
> an amp that
> needs some service, get the amp over here so we can get it fixed.
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> ~~~~~~~~
>
> Thinking about a new amplifier but just can't quite swing a new 9500 or
> 8410?
> Here's a picture of an 87A.  We get trade-ins all the time.  Our techs
> go through
> them, make sure they're up to par, and we post them in the preowned
> section.
> A PREOWNED Alpha amplifier will get you legendary ALPHA quality without
> the new
> amp price tag.
> Why buy a lesser amplifier from a different manufacture when you can get
> a preowned
> ALPHA for about the same price?
> Why not own the best.
> There's a special section on our website listing our certified preowned
> equipment
> HERE
> [http://r20.rs6.net/tn.jsp?llr=eka89lcab&et=1103840911843&s=3704&e=001DF
> 5ErJcMsiDJpI3n9clQhLYdNSSupO3oHq9H1FYkw0dvqHXZfnJ79ytFD3SFLQ8vVBSAaDFkOc
> Vy3c9FVhwp4FblPOPqjtIii2OCiutohAr9qTtp28IxHS9rCM3DuTsRYLjn9mH9zZl9fnjOEe
> pkYUOaW7qL2SgI].
> Or call Molly at 303-473-9232 and ask her about the Preowned Alpha
> Inventory.
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> ~~~~~~~~
>
> to all of our Alpha customers and enthusiasts.
> We're thrilled you're enjoying our products. Let us know if you have any
> questions
> or comments.
> All the best, and 73's from the whole gang at RF Concepts/Alpha
> Amplifiers.
> Steve, WA2NFR
> Michael, AA6DY
> Glenn, AEØQ
> Brad, KØHM
> Carey, KXØR
> Mike, K6AER
> Molly, WØMOM
> Gordon, WØRUN
> Mike
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> ~~~~~~~~
>
> Letter from the President, Steve Farkas, WA2NFR
> November 2010 -
> During the month of October, we shipped more amplifiers than any month
> in the last
> year - and ended with a backlog.  Check out the reviews on eHam if you
> get a chance.
>  Customers are happy with the product and they're telling other hams
> about it.
> And, at last, we shipped the first few 8406 amps to the first people on
> the list.
>  There's a production run of 20 moving through the factory right now and
> they will
> ship in the next week or so.  If you're looking for one and haven't
> ordered, get
>  that order in and we'll get it built.
> As you know, it was moving month at Alpha.  Here's one for you:  we
> moved right
> next to the contract manufacturer who's building many of our boards.
> We've got
> a great relationship with them, and they have tons of surface mount
> equipment and
> skilled assemblers.  We've been working together for quite a while now
> and they're
> doing great work for us.  This should help us get ahead of this 'out of
> stock' issue
> we've been fighting for a year.  My goal is to get these products on the
> shelf in
> sufficient quantity so that we're ALWAYS shipping from stock.  Between
> our dealers
> Amateur Electronic Supply, Ham Radio Outlet, and Radioworld, plus the
> orders we
> take on our own, demand has never been higher for our amps.  Although
> more expensive
> than many in the market, the real cost of owning one of these is the
> difference
> between the purchase price and the sales price (if you ever decide to
> part with
> your alpha).  Check out the resale values of these amps in the market.
> Many of
> the amps sell for close to or over the original purchase price.  Can't
> say that
> about too many pieces of equipment these days.
> We post some of the comments we receive on our website.  Check them out.
> It's a
>  proud group of people that own an Alpha.
> Well, time to go.  We're working on some other projects to expand our
> line of fine
> products.  Got to get back to the bench.  Speaking of getting back to
> the bench,
>  we're looking for a couple of great engineers - you don't have to live
> in the Denver
> area to apply - if you're looking for a place to work, even part time,
> and have
> your license and a lab, maybe you'd like to help?
> Although we've got a couple of projects in the works, we're looking for
> people that
> can help us expand our line of wonderful radio products quicker.
> To do this we need electrical and mechanical engineers that have an
> appreciation
>  for our ham community and a passion for excellence.  If you're
> interested in helping
> us with either electronics and/or electromechanical projects - call me.
> If you have a product designed or an idea for a great project that would
> help the
> ham community and would look good with an Alpha or RF Concepts name on
> it - call
>  me.
> One of the specific projects we want to build is a Switch Mode Power
> Supply that's
> capable of delivering the 3600VA of power we need for our amps.  If you
> know of
> anyone that would be interested in designing one for us, please drop me
> an email
>  or call me at the company - 303-473-9232.
> We're also looking for a machinist who has his own equipment.  We've got
> some specific
> electro-mechanical work that needs to be done.  If you're retired and
> know your
> way around a shop, give me a call.  You could help us build one of the
> coolest new
> products around.
> We're having a great time building our company.  As always, if there are
> any comments,
> please feel free to drop me a note any time or just say Hi at
> stevef  rfconcepts.com.
>  Over the last few months, I've met some of the nicest hams.  It's a
> wonderful hobby,
> isn't it?
> 73
> Steve, WA2NFR
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> ~~~~~~~~
>
> Letter from the Vice President of Sales and Support, Molly Hardman,
> W0MOM
>
> Well this month there's good news, bad news and GOOD news.
>
> Good news:  We have finally really and truly completed our move 12 miles
> NE of our
> home for the past 10+ years.  I'm tired but really excited to be in new
> digs and
>  with new energy as we gear up for our busiest time of the year.
>
> Bad news: I know people in sales aren't ever supposed to report bad
> news, however
> most of you know me too well to hide this:-  I lost my bet with Steve
> and Michael
> that the delay in our moving would have us moving in the snow......  I'm
> not yet
>  sure what the penalty will be - I'm banking on a HUGE snowstorm between
> Christmas
> and New Year.  We have been very fortunate to have enjoyed wonderful
> weather for
>  the past two weeks with only 1cold and windy day. High has been in the
> 60's and
>  70's for the past few days.....
>
> GOOD news:  Actually this section should be GOOD news, GOOD news and
> more GOOD news.
>
> I hope many of you had the opportunity work the new Caribbean entities -
> it even
>  got me on the air and it was great to hear the 8410 signals coming out
> of the group
> at PJ7E.  The amps they used are on their way back to us and if any of
> you might
>  be interested in one of them, please give me a call.  They will carry
> the full
> Alpha 4 year warranty and the cache of owning a DXpedition proven
> amplifier.
>
> Our new space is working out really well - whilst we're not quite ready
> to receive
> visitors, this is a great move for Alpha.
>
> Moving production as smoothly as possible and with as little downtime as
> possible
> was always our goal and the good news on this front is that our
> production staff
>  are in the midst of building the next 20 8406 amplifiers!  We hardly
> missed a beat
> in this department.  We have plans to build more amplifiers in November
> than even
> I thought possible, so now please call me and order them, hi, hi!
>
> I've saved best part for last - after 6 years of working with a great
> group of customers
> and a wonderful product in a windowless cave of an office I now have a
> window AND
> a view AND I get to keep the same customers and the same wonderful
> products!
>
> 73,
> Molly, WØMOM
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> ~~~~~~~~
>
> Letter from the Vice President of Engineering,
> Gordon Hardman, W0RUN
>
> Calibrating Wattmeters at RFC
>
> Gordon Hardman
>
> Accurately measuring RF power is a tricky business, to put it mildly.
> Doing so accurately
> in a meter, such as the AP4510, that can be sold at a reasonable price
> and used
> in a typical radio shack for years is even trickier. One of the keys to
> the dependability
> of the AP4510 and others in the family is the careful calibration that
> each meter
> undergoes during production. As we were breaking down and moving the
> production
> setup for the RF Concepts wattmeters to our new location last week, I
> was reminded
> of this and thought it would be worth sharing a little of it with you.
>
> Power, defined as the rate of doing work, is not a fundamental quantity,
> such as
>  energy, that can be referred to a single fundamental standard. The best
> that can
> usually be done is to use some proxy, such as temperature, to compare
> one power
> reading against another. In many practical meters for use in radio power
> measurements,
> it is really voltage that is being measured. Since we know the impedance
> of the
> system in which the voltage measurement is being made (often 50 ohms),
> the power
>  can be inferred from the voltage measurement.
>
> At the heart of the 4510 series of meters is a rugged directional
> coupler constructed
> out of strip line in a four layer printed circuit board. This coupler is
> designed
> to maintain its high directionality (ability to discriminate between
> forward and
>  reflected power) over time. The coupled arms are terminated in high
> stability resistors,
> and the voltage across these resistors is what is measured by the
> instrument. The
> RF voltage is turned into DC using wide dynamic range logarithmic
> detectors. In
> addition, a sample of the RF voltage on the "through" arm of the coupler
> is used
>  to estimate the frequency of the power being applied to it. These are
> all digitized
> by the RF microprocessor (there is a second "display" micro as well).
> One final
> parameter that is sensed by the micro is the temperature of the strip
> line PC board
> in the vicinity of the coupler.
>
> In a more simple wattmeter, there would be generally only one adjustment
> to calibrate
> the power sensor at a particular power and frequency. This would be the
> case, for
> instance, in the venerable Bird 43 wattmeter. If you want to calibrate,
> say, the
>  "2-30 MHz 2.5kW" sensor, you would have to pick the power and frequency
> at which
> you want to do this. If done with care, the power at this calibration
> point could
> be "dead on". At other powers and frequencies, you would have to rely on
> the basic
> design of the instrument to yield a reading that is as accurate as the
> designer
> could make it. There is no ability to compensate for errors due to
> non-linearities
> in the detector, errors due to different coupling factors at different
> frequencies,
> and finally, no compensation for errors due to temperature changes. The
> 4510 compensates
> for all of these, not just by hardware design, but by applying
> mathematical adjustments
> to the measurements to yield readings of improved accuracy.
>
> The 4510 series is specified over a wide frequency range (1.8-30 MHz), a
> large range
> of power (300mW to 3,000W) and over the -25 to +65C temperature range.
> Each meter
> is calibrated to determine a set of coefficients which form the basis of
> the mathematical
> corrections that are applied to the readings taken by the micro. This
> could be a
>  formidable set of data if it was in the form of a table at every
> frequency, power,
> and temperature combination. Fortunately, this is not necessary. It was
> determined
> that a set of so-called fourth-order-polynomials is sufficient to turn a
> set of
> raw readings of voltage, temperature and frequency into a highly
> accurate measurement
> of forward power, reflected power and SWR. About twenty coefficients are
> sufficient
> to describe these polynomials. The coefficients are determined in two
> stages during
> manufacturing.
>
> The first step is frequency calibration. After being assembled and
> undergoing a
> basic functional test, each RF board is connected to a computer
> automated test (CAT)
> setup. A computer controlled signal generator applies power to one port
> of the board,
> and an accurate power meter with a computer interface is connected to
> the other.
>  The computer communicates with the micro on the RF board over its
> serial interface.
> The CAT computer steps through from 1800 kHz to 29700 kHz in 100 kHz
> steps, and
> records the forward and reflected power readings. These data are stored
> in a file.
>
> The second step is the temperature compensation. In this test, a group
> of six boards
> is placed in a temperature chamber, and again the CAT computer controls
> everything.
> The temperature of the boards is first taken down to -25C. Once their
> temperature
> (as reported via their own individual on-board sensors) has stabilized,
> then the
>  readings from all the boards are recorded in files. Two different power
> levels
> are recorded here, since one of the major effects we are measuring is
> the drift
> of the log detectors intercept point with temperature, and a minimum of
> two measurements
> is needed to determine this. The temperature is then increased in steps
> up to a
> high of +65C, and measurements are recorded along the way.
>
> The third step is to "crunch" all this data and distill it down to the
> twenty coefficients
> needed by each board when it is part of a meter. This calibration data
> is stored
>  in yet another file on one of the CAT computers. In order to keep all
> these files
> from getting mixed up, we use a unique electronic serial number (ESN)
> which we get
> by using a specific temperature sensor which has a unique code embedded
> in it. All
> files for a particular board have this ESN as part of their filename.
>
> The fourth and final step is to upload the coefficients into the board.
> Again, the
> CAT computer makes sure that the ESN of the target board matches the
> filename of
>  the coefficient file, and passes the data over the serial port to the
> RF board.
>  There it is stored in non-volatile EEPROM, and the calibration is
> complete.
>
> We have been using this process for many years, and found it to be quite
> reliable.
> The equipment is being cleaned, re-calibrated and installed at our new
> location,
>  and so wattmeter production will continue there to the same high
> standards as at
> the old location.
>
> Gordon, WØRUN
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> ~~~~~~~~
>
> 
>
> The second installment of a three part article on Lightning Protection
> by Mike Higgins
> - K6AER
>
> Grounding and Hardware- Part Two
>
> In the second series we will discuss the AC panel surge protectors,
> ground rods,
>  sphere of influence of ground systems, grounding in poor soil and
> grounding material.
>
> As mentioned in the first part of the series the AC panel in your home
> needs a surge
> protector attached to the main panel. Surge protectors on plug strips
> are too far
> from the panel to do any good. Also the AC panel needs to have its
> ground bonded
>  with all other grounds so that all of the grounds are at the same
> potential. This
> is an NEC (National Electrical Code) requirement for electrical shock.
> First let
>  us talk about Panel grounds in a home application. The NEC code
> requires a resistance
> to be below 37 ohms. If the ground rod resistance is above that point a
> second ground
> must be added. The problem with this is the actual ground resistance is
> not stated.
> Two ground rods may still be an inadequate ground when it comes to
> lightning. Again
> think of a voltage divider. If your ground resistance is 34 ohms and
> your ground
>  potential is 3000 volts during a lightning surge that is a very high
> voltage on
>  the safety ground. If you can add a much deeper ground rod you could
> lower the
> ground rod resistance to 3.4 ohm, in which case your ground potential
> during the
>  same strike would be 300 volts. A much easier voltage potential to
> mitigate for
>  your sensitive electronic equipment.
>
> Surge protectors are generally flash over tubes and MOV's, Metal Oxide
> Varistors.
> These semiconductors devices start conducting at a set voltage. All
> surge protectors
> must be connected through a circuit breaker because they will develop a
> permanent
> short during a very high level strike. MOV's take a few microseconds to
> conduct
> during a strike and some energy may get by before they go into full
> conduction.
>
> Ground rods have what is known as a Sphere of Influence. The cubic
> volume of the
>  "sphere" is the area of a circle around the ground rod times twice the
> length of
> the ground rod. This is the volume where the ground rod will have an
> effect on ground
> conduction. An 8 foot ground rod will have a circle with radius of the
> length of
>  the ground rod times twice its depth. For an 8 foot ground rod this is
> 16 feet
> diameter circle and 16 feet deep or 3215 Cubic feet of earth.
>
> If you were to use a 20 foot ground rod the Sphere of Influence would be
> a 40 diameter
> and 40 feet deep or 50,240 cubic feet of earth. This is 15.6 times as
> much earth
>  conductivity as a 8 foot ground rod. It is much easier in most cases to
> put in
> a single deep ground rod rather than 15, 8 foot ground rods.
>
> In addition your ground Sphere of Influence for each ground rod must not
> overlap.
> If it does you are not getting the maximum earth connection due to
> overlapping Spheres.
>
> Ground resistance is measured with a Megar impedance meter. This is not
> a DVM meter
> but a meter that looks at the earth impedance with an AC signal from
> several ground
> points as laid out at specific distances from the ground rod. Meters
> such as AEMC,
> Fluke, Extech and others. The meters can use a ground probes or they can
> be the
> clamp on types.
>
> Homes must be below 37 ohms. Commercial applications such as high rise
> buildings
>  must be below 10 ohms. In tower technologies we like to have the tower
> locations
> below 4 ohms in resistance. Never trust the impedance of ground rods
> that have been
> in the soil for some time. The soil can be very acidic and the ground
> rod might
> be gone just below the surface.
>
> In the case of very poor soil condition you may have to use soil
> enhancers or use
> conductive backfill such as Bentonite or other chemical backfills. This
> is poured
> in and around the coring hole dug for the ground rod. You can read about
> conductive
> back fill HERE.
> [http://r20.rs6.net/tn.jsp?llr=eka89lcab&et=1103840911843&s=3704&e=001DF
> 5ErJcMsiDi-ROMDAbWZVhfjAl3zTkiRtLvqeQ1-Q_MlVHW3ByjWt-WvhSh2j45_iACg-5OYi
> bAUvB2svlgkIpeeQT9DFgcebg2T9Gja_n3_7fk8E-O5aCa4NRFpaOJGBjf1bR8RA0VFIdGxC
> 8m_BK8rjSXrqGyxauTOGXbDvDHbvLKCj0EQQ==]
>
> Grounding material is generally copper. Copper does not have to be the
> only material
> but for most purposes it is preferred due to its low resistance. With
> many millions
> of volts and amps during a lighting strike any resistance translates
> into higher
>  voltage potential. Lightning strikes are very short in duration and
> tales of cars
> being vaporized are myth. A typical lightning strike is about 8
> microseconds in
> 80% strength trailing off to about 20 microseconds in total duration.
> The cloud
> will act as a relaxation oscillator providing many of these short
> duration strikes
> until the cloud has discharged to below its potential and the ionized
> path dissipates.
> When cloud friction builds up another potential to earth and lightning
> strike will
> occur again.
>
> For those of you who disconnect the coax during a storm remember that a
> lightning
> strike can travel several miles and ten feet inside your ham shack in
> nothing. It
> is much better to have your coaxes grounded than to let the lightning
> travel around
> the home looking for a good ground path.
>
> Most grounding cable is round solid copper. Remember that much of the
> lightning
> energy is RF in nature and long ground runs will behave as an antenna at
> resonant
> frequencies. For instance 33 feet is a quarter wave at 7 MHz and very
> little grounding
> of RF energy would take place from 3-14 MHz. For this reason your ground
> cable should
> be as short as possible.
>
> Flat copper strap is best for grounding for the surface area has better
> skin effect
> for RF grounding. Outdoor only use solid copper grounding strap. Weather
> will corrode
> a braided strap in no time. Braided strap is OK to use indoors.
>
> Route all coaxes and control lines from surge protectors close to the
> ground and
>  place all surge protectors as close as possible to the grounding
> demarcation point.
> The further the surge protectors are from the lowest impedance of ground
> the higher
> the voltage during a lightning strike.
>
> The best ground rods are copper plated steel rods. The can be obtained
> in several
> lengths and may be screwed together end to end for driving into the
> ground. Unless
> you are just busting for exercise, ground rods are easiest driven into
> the ground
> with a jack hammer/ground rod attachment. For deep grounds it is best to
> have a
> drilling rig drill the hole and have the back fill placed into the hole
> after completion.
> For drilled holes copper pipe can be used providing there is good
> mechanical connection
> between sections and they are electrically well connected.
>
> 73, Mike - K6AER
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> ~~~~~~~~
>
> Notes from Mike Adell, Director of Channel Sales.
>
> Thanks to all of you and other ardent Alpha supporters, October has been
> one of
> our best months ever. We exhibited in HRO's Pacificom booth which
> produced much
> interest; we introduced our 502525 Deferred Payment plan that created
> interest,
>  we shipped more Alpha Amplifiers and Accessory products than in any
> previous month
> and we started shipping our new 8406 Alpha Amplifier. All of this was
> done while
>  we moved to a new location just down the road in Longmont, CO.
>
> And there is other news. Effective 11/1 Jack Ciaccia has accepted our
> offer to be
> Director of Government Sales and Marketing and will help us drive
> additional opportunities
> in to the Federal Government.  If any of you work for one of our
> government agencies
> and/or know of opportunities within please mention Alpha  to the
> purchasing agent
> and give Jack a call with the details. A lead means a new Alpha logoed
> baseball
> style hat for you or a family member.
>
> Many of you know Jack as WMØG, President of the Boulder Amateur Radio
> Club, a member
> of the Mile High DX Association and an ARRL Assistant Section Manager
> for the State
> of Colorado. You can reach Jack at wm0g  comcast.net
> [mailto:wm0g  comcast.net] and
> 303- 587-0993. Keep those Government leads coming!
>
> Our business with HRO, AES and Radioworld continues to flourish. Stop by
> one of
> their locations if you are in the neighborhood. In fact, I was just
> notified that
> HRO's Atlanta location has been completely remodeled and there is a
> Grand Opening
> scheduled for 12/4.
>
> All of our resellers now have a 9500 Front Panel Display which is a most
> impressive
> way to see some of the 9500 functionality.
>
> Last - I have a thought. Many of you belong to your local Ham Radio
> Club. Are there
> things other manufacturers do to support your membership?  I wonder if
> we should
>  be considering similar or unique activities as well. Any suggestions
> send them
> to me at mikea  rfconcepts.com [mailto:mikea  rfconcepts.com].  You, too,
> may receive
> one of our prized Alpha logoed hats. If you want to have your call
> letters embroidered
> on the back send me that information along with your address and, of
> course, your
> suggestion(s).
>
> Thanks and have fun out there.
>
> Mike
>
> 
>
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> ~~~~~~~~
> Forward email
> http://ui.constantcontact.com/sa/fwtf.jsp?llr=eka89lcab&m=1102056358212&
> ea=adriano.perazio  uol.com.br&a=1103840911843
>
>
> This email was sent to adriano.perazio  uol.com.br by
> sales  rfconcepts.com.
>
> Update Profile/Email Address
> http://visitor.r20.constantcontact.com/d.jsp?llr=eka89lcab&v=001Cz2gV83V
> s3qjq6pEFozWlSxbZqmc9Z08eQLgnbkD1t81MEgbDN0lTQ%3D%3D&p=oo
>
>
> Instant removal with SafeUnsubscribe(TM)
> http://visitor.r20.constantcontact.com/d.jsp?llr=eka89lcab&v=001Cz2gV83V
> s3qjq6pEFozWlSxbZqmc9Z08eQLgnbkD1t81MEgbDN0lTQ%3D%3D&p=un
>
>
> Privacy Policy:
> http://ui.constantcontact.com/roving/CCPrivacyPolicy.jsp
>
>
> Email Marketing by
> Constant Contact(R)
> www.constantcontact.com
>
>
> RF Concepts LLC | 6185 Arapahoe Road | Boulder | CO | 80303
>
>
>
> _______________________________________________
> Araucaria mailing list
> Araucaria  araucariadx.com
> http://list.araucariadx.com/mailman/listinfo/araucaria
>


----- Fim da mensagem de adriano.perazio  uol.com.br -----



________________________________________________________________________________
O email é um dos seus instrumentos de trabalho?
http://www.portugalmail.net/profissional