High Voltage Power Supply for Linear HF 813

Parts List
Cx 4700 Uf @ 350 volt Electrolytic R1,R2 25 Ohm 10 watt
D1-D4 5000 PIV @ 1 amp Rx 25K @ 5 Watt
F1,F2 15 Amp Slow Blow T1 2600 VAC @ 1 amp
RL1 120 VAC Delay on Operate T2 12 VAC @ 10 amps

lot of the parts used in this project came with the transmitter. As a result I had to get a bit creative to get what I wanted. In doing a bit of research, I found out that several people have run 813 tubes with 3Kv sucessfully with out damage. Based on what I had, I decided to change the power supply filter from a choke input filter to a capacitor input filter. I found a great deal on some 4700 Uf @ 350 V capacitors. So I bought 12 of them, and put them in series (Cx above). This gives me an equivalent capacitor of 390 Uf @ 4200 volts. Yes, I know this is overkill, but hey, they were cheap, and I had the room! This brought me to my next problem. When I wired in all of the caps, and fired it up, I had 3200 volts. I felt that was too much for the 813's so I found a low voltage transformer to put in series with the primary of the main transformer as a "bucking" transformer (T2). This then dropped my output voltage to the 3000 volts I wanted. Once again, this is not the best way, but I was able to find a transformer cheap.

Usually High voltage supplies have a "step start" circuit. This one is no different. The purpose of the step start circuit is to apply power at a reduced voltage so as to limit the initial inrush current. After a period of time, the step start circuit energizes, and applies full input voltage. I felt this was very necessary since my filter capacitor is larger than typical. I was able to find a nice programmable "delay on operate" relay (RL1) at the local surplus store for a good price along with the current limiting resistors (R1 and R2).

WARNING
The voltages inside this project CAN KILL. If you have any doubts about your abilities please seek assistance from a capable amateur radio operator or electronics technician.

Linear HF Tube 813

WARNING
The voltages inside this project CAN KILL. If you have any doubts about your abilities please seek assistance from a capable amateur radio operator or electronics technician




Parts List
C1 150 pF variable 0.125 spacing L2 See next page for details
C2 1200 pF 3 section AM receiver variable RFC 1 (2) 3/4" dia. 3" long 24 AWG (see text)
C3 900 pF 2 section variable RFC 2 2.5 mH
L1 3" Dia. 13 turns - see text RL-3 DPDT relay 10A contacts

L1 is actually two coils in series. The first coil is 3" diameter coil with 0.25" spacing. with taps for the following bands:

80 Meters 13 Turns
40 Meters 7 Turns
30 Meters 4 Turns

The second coil is 4 turns of 1/4" copper tubing 2" diameter with 0.5" spacing. with taps for the following bands:
20 Meters 3 Turns
17-15 Meters 2 Turns
10 Meters 1 Turns
RFC 1 is actually made up of two seperate chokes. Each one is close-space wound on a 3/4" diameter ceramic rod 3 1/2 inches long using 24 AWG enamel wire. The two chokes are mounted at right angles to each other, and have a .01 uF @ 5 KV bypass capacitor to ground between the two chokes. This is an attempt to eliminate any self-resonance near the operating frequencies of the 813 amplifier.


RFC 2 across the output is a mandatory safety item. Should the .001uF DC blocking capacitor ever break down, you will have the high voltage supply connected to the antenna system. This choke will shunt the DC to ground and open the fuses in the primary side of the plate transformers. Under no circumstances is this choke to be left out. Use 28 AWG enameled wire. Wind 150 turns on to a 2" ferrite rod. If you have to, you can wind the wire in 2-3 layers.

The T-R switching cicruit is composed of two 12 VDC relays. I chose to use two relays, RL-3 and RL-4, becuase I was concerned about coupling between the input and output of the amplifier. RL-3 is a DPDT relay that is energized during transmit. The second set of contacts are shown on the Filament Supply schematic. This relay is located in the input section of the amplifier. RL-4 also a DPDT relay and is located in the RF deck of the amplifier near RFC 2.

Taco Bell Says

So endure year, I gave Taco Bell acclaim for a advance in which they'd assuredly accept to pay off. After years of breeding publicity on achievement aces promotions that never gave anyone chargeless aliment (minus the chalupa giveouts at NBA games), they came up with "Steal A Base, Steal A Taco."

If a amateur artlessly blanket a abject at the World Series endure year, anybody in America would get a taco.

So Jacoby Ellsbury of the Red Sox steals a abject in Bold 2 and Taco Bell gives abroad chargeless tacos to America. If I begin out Taco Bell had no allowance for the promotion, I approved to amount out absolutely how abounding tacos they would accord away.

I basically ample out that if you annual for how abounding humans would apperceive a abject was even baseborn and how abounding humans would bethink to redeem their chargeless taco a anniversary after during business hours, they'd accord abroad alone 33,750 tacos.

After seeing that Taco Bell is accomplishing the advance afresh this year--they've added an hour to the redemption--I contacted Taco Bell agent Rob Poetsch and asked him how off I was on my anticipation endure year. He told me that I was actual off and that chargeless Taco Bell, in fact, gave abroad millions of tacos.

I approved to do the algebraic afresh and I just can't see how they anytime entered the two actor range, unless admirers who remembered calm assorted tacos. I don't beggarly to alarm them liars, but the rules accumulated with the allowance accomplish it absurd to believe.

I can't brainstorm added than 20 percent of the absolute country knows about the advance (60 actor people). What I didn't annual for endure year was that Taco Bell would acquaint the actuality that the accident happened. So I said 30 percent of the country would accept accepted the abject was stolen. This year, I'm putting that allotment up to 50 percent. So we accept 30 actor humans still in the basin to get their chargeless taco, which has incidentally risen in amount by 14 cents back endure year.

One Baseborn Abject at the 2008 World Series Equals Millions of Chargeless Tacos for America Taco Bell

Now here's area the amount gets actively attenuated out. Let's say a abject is baseborn in tomorrow night's game. According to the rules, humans will accept to delay about six days--until Tuesday, Oct. 28 to get their chargeless taco. No amount how abundant Taco Bell advertises up until that day, I'd say alone 40 percent (maximum) apprehend if it's time for accretion day. That anchorage it down to 12 actor people.

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Then comes the killer. You accept to aggregate your taco amid the hours of 2 p. and 6 pm. I like the actuality that they've added a non-working hour, but I can't see how added than 8 percent of the humans who are acquainted of the chargeless taco redemption--even with lower gas prices these days--would drive to get their chargeless taco amid those hours on a Tuesday. So, by giving Taco Bell every advantage, I appear up with 960,000 tacos accustomed away.

Quantum of Solace

Quantum of Solace continues the top octane adventures of James Bond in Casino Royale. Betrayed by Vesper, the woman he loved, 007 fights the appetite to accomplish his latest mission personal. Pursuing his assurance to bare the truth, Bond and M catechize Mr White who reveals the organisation which blackmailed Vesper is far added circuitous and alarming than anyone had imagined.

Forensic intelligence links an MI6 traitor to a coffer annual in Haiti area a case of mistaken character introduces Bond to the admirable but angry Camille, a woman who has her own vendetta. Camille leads Bond beeline to Dominic Greene, a adamant business man and above force aural the abstruse organisation, Quantum.


On a mission that leads him to Austria, Italy and South America, Bond discovers that Greene, conspiring to yield absolute ascendancy of one of the worlds a lot of important accustomed resources, is accomplishment a accord with the adopted General Medrano. Using his assembly in the organisation, and manipulating his able contacts aural the CIA and the British government, Greene promises to abolish the absolute administration in a Latin American country, giving the General ascendancy of the country in barter for a acutely arid section of land. which is about a capital antecedent of the South American baptize supply. In a minefield of treachery, annihilation and deceit, Bond allies with old accompany in a action to bare the truth. As he gets afterpiece to award the man amenable for the betrayal of Vesper, 007 have to accumulate one footfall advanced of the CIA, the terrorists and even M, to break Greenes adverse plan and stop Quantum accepting its way.

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Icom IC-706 MKII G

I'd like to amount this as a 4.75, as I accept alone had a brace of niggles with it, afterwards about four years of dropping, thrashing, bouncing and banging, this little radio still works.... well, unless you go on 15 and 17 metres after a arresting load.

If I try and address into a wire on 15/17 that is acquainted via addition radio, bandy beeline over to the 706mk2g, it transmits about leftfield and off into cuckoo land!!

The alone way I accept got annular this is by application an SGC230 tuner, no problems now... Before you all alpha shouting "RF Feedback!!!" it does it everywhere, not just in my shack/car... but others shack/cars too... Done the mods as recommended by icom, still no joy...


Anyway, bar that, it is a belting radio, for such a baby unit, it works well, it is a accepted monster, and the fan can get a bit noisy. I do a lot of carriageable work, with kites, and this affair has had some REAL abuse on or abreast beaches/tidelines and it still works, my (t)rusty mfj tuner that i use with it carriageable has arresting signs of abyssal bane inside, not the 706mk2, and it's been wet a few times if the course has snuck in on us!

ZL on 80 metres with 100 watts from the kite, KP4 on a consistently base on 40 metres adaptable travelling to work, alert to v/uhf repeaters and even adaptation acclimate satellites, and alert to airband. This radio is, up to now, the alone babysitter I accept had. Sure the card is circuitous til you use it, and the clips on the face can be fragile, but, for the money, you will not be disappointed. Got an FT100D advancing as a bandy adjoin a radio of abundance soon, be absorbing to see which one is better.

Rose Red ( 2002 )

Dr. Joyce Reardon, a attitude professor, leads a aggregation of psychics into the aged abode accepted as Rose Red. Her efforts absolve the spirit of above buyer Ellen Rimbauer and bare the appalling secrets of those who lived and died there.

A accumulation of humans with analytic admiral are arrive to alive a sleeping behemothic that is Rose Red. But as their break grows longer, they acquisition that not alone accept they awoken Rose Red, they've unleased a ability that will doom them all...

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new twilight trailer

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Tina Brown's " Daily Beast "

Well angelic smokes. Tina Brown's SEVENTH ACT in media, her website beneath the advocacy of Barry Diller's IAC, is advancing very, actual soon, we hear. Finally, it has a name! Says, of course, Liz Smith today:

Tina Brown and I had an accomplished babble afore Hillary showed. The senator's biographer has been active assuming her cartoon of a new journalism Web website to administrator Barry Diller. It will be alleged The Daily Beast, in admiration to Evelyn Waugh's archetypal atypical Scoop. And Barry, I suppose, will play the role of the Beast's Lord Copper.


Most of us accept been calling the website an aggregator, an abstraction that disappoints. But we aswell apprehend that "magazine" is not a abhorrent descriptor either. Still, we all accept little clue as to who's alive there, and absolutely what they will be alive on. And we aswell apperceive that "journalism" is not the 2.0 financially-successful archetypal of choice—witness Gawker Media's Nick Denton accusation the LA Times' account cartage today. Aggregation and annotation (see: HuffPo) and tip-box coursing (and, to be sure, a blog-style, Google-friendly website) pays off—foreign bureaus, and a website that emulates a newspaper, allegedly not necessarily so much!