>As regards the source of this energy, I'd like to solicit the thoughts of
>others (including yourself). I'm not sure how much harmonic energy (ala
>Fourier) is present in the waveforms appearing at the anode. I've just never
>looked at the waveform, but given the conduction angle, there would be even
>and odd partials in the series expansion and their relative magnitudes
>could be estimated from the coefficients, and these would be the source of
>the higher frequency energy. Not so?
** True enough, Ed, , however, c. half of the voltage waveform at the
anode comes from the tank, so conduction angle is not the whole picture.
>
>Again, I've never looked into this, so I'm very happy to learn if I'm wrong,
>or to be pointed to a text for 'remedial reading'.
** If dangerous radiation comes from the anode of a HF amplifier, I
would seemingly have been a SK years ago.
>
>(Regarding the lead vest, 20+ years ago another engineer and I were aligning
>a CRT according to the manufacturers alignment instructions and the very
>last instruction on the last page was "be sure to wear a lead apron while
>performing this alignment." true story.)
** With an accelerator potential of over 20kV, this is probably a good
idea. I kind of like the lead apron thing to intimidate the competition.
I heard of one Ham in Japan whose amplifier reportedly uses a tube
(8349) that generates X-rays because it uses an anode supply of 22kVDC .
cheers
>
>Much obliged
>
>Ed N1TS
>
>
>
>----- Original Message -----
>From: "R. Measures" <r@somis.org>
>To: "Ed Briggs" <edbriggs@optonline.net>; <TexasRF@aol.com>;
><vk6apk@eon.net.au>; "AMPS" <Amps@contesting.com>
>Sent: Wednesday, March 03, 2004 10:14 AM
>Subject: Re: [Amps] 2 x 8877
>
>
>>
>>
>> >But what about at 100 mHz and 200 mHz?
>>
>> ** Ed-- What is the source of such energy? Using a cellphone would
>> seemingly provide more field strength at a more-dangerous-to-corneas
>> wavelength. Perhaps the amplifier builder should provide an shield-vest
>> to visitors in the shack like the kind dentists used to wear in days past?
>>
>> >I worry that a) there is no
>> >filtering of harmonic energy through the windows (no pi network), and
>that
>> >the inverse square law is significant when the antenna is 100 feet away
>and
>> >an vacuum tube admirers corneas are inches away.
>> >
>> >I have never measured this, though many years ago I did perform part 15
>EMI
>> >testing on communications equipment and discovered that small rectangular
>> >slots passed lots of RF energy.
>> >
>> >73s
>> >Ed N1TS
>> >'Festooned with fingerstock and nickel paint"
>> >----- Original Message -----
>> >From: "R.Measures" <r@somis.org>
>> >To: <TexasRF@aol.com>; <vk6apk@eon.net.au>; "AMPS" <Amps@contesting.com>
>> >Sent: Tuesday, March 02, 2004 3:24 PM
>> >Subject: Re: [Amps] 2 x 8877
>> >
>> >
>> >>
>> >>
>> >> >Whoa, wait a minute! That 150cm by 100 cm opening might be a waveguide
>> >> >beyond
>> >> >cutoff but the attenuation for this size opening is pretty low
>according
>> >to
>> >> >the Bill Orr Radio Handbook.
>> >>
>> >> ** My guess is that, at 28MHz, the radiation from the antenna is at
>> >> least 30db stronger than that from the window. .
>> >> >
>> >> >The chart for this size opening shows a constant attenuation from
>about
>> >> >1000mhz and lower frequencies on the order of 8db per inch. If the
>metal
>> >> >is .125
>> >> >inches thick then the attenuation is on the order of only one db!
>> >> >
>> >> >When the opening is reduced to .125 inches the attenuation is on the
>> >order
>> >> >of
>> >> >124 db per inch from about 2000mhz and down. With that level of
>> >> >attenuation a
>> >> >.125 inch thick screen would have about 30db of through loss.
>> >> >
>> >> >Cutoff means there is signal attenuation, not a total loss of
>> >transmission.
>> >> >
>> >> >73 de K5GW
>> >> >
>> >> _______________________________________________
>> >> Amps mailing list
>> >> Amps@contesting.com
>> >> http://lists.contesting.com/mailman/listinfo/amps
>> >
>> >
>
>
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