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Homebrew Equipment A place to show, design and discuss the weird and wonderful electronic creations from the hands of individual members. |
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5th Jan 2015, 1:58 pm | #1 |
Pentode
Join Date: Jul 2014
Location: Bangalore, India
Posts: 132
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Handy 1 kW HF Dummy Load
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5th Jan 2015, 2:59 pm | #2 |
Guest
Posts: n/a
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Re: Handy 1 kW HF Dummy Load
Keep talking loudly and you have an SSB cup of tea. It shows what an inventive bunch we are.
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5th Jan 2015, 4:43 pm | #3 |
Dekatron
Join Date: Apr 2012
Location: Worksop, Nottinghamshire, UK.
Posts: 5,549
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Re: Handy 1 kW HF Dummy Load
The spiral element in the sheath will make the impedance vary quite a bit with frequency and it will also behave like a delay line making the power factor vary too.
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6th Jan 2015, 12:01 am | #4 |
Rest in Peace
Join Date: Jun 2006
Location: Chard, South Somerset, UK.
Posts: 7,457
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Re: Handy 1 kW HF Dummy Load
Quite true Refugee, but he does say "The amplifier was successfully tested, with its Pi tank circuit providing a proper match to the dummy load".
Provided the output capacitive reactance of his Pi tank is adjusted so as to make a conjugate match with the inductance of that spiral element and provided that the resultant resistance is then 50 Ω, he should be O.K. For that condition, the P.F. will be unity. The Pi tank will need re-adjustment for changes of freq. though. Al. |