[Amps] Hard bus bar copper and inductor Q

[Conrad PA5Y]

Wrong use of the word annealed, the copper is hardened somehow and is 
darker than normal copper. I don't like it so I will buy some thin pure 
cooper sheet and cut in in a guillotine. That way I get exactly what I 
want.

Regards

Conrad PA5Y

On 2017-08-31 21:48, Conrad PA5Y wrote:
> Hello again, I have gathered almost everything that I need for my
> 3CX800A7 conversion from 2m to 6m.
> 
> I have choice of materials for L1.
> 
> I have some 6mm soft copper pipe, some 4mm soft copper pipe and some
> 3mm silver plated copper wire. All the tubing is C102 copper and forms
> very nicely. VE7RF suggested that I use some flat strap and make L1 a
> flat wound coil to reduce capacitance between turns, it is also very
> easy to drill for blocking caps.  This makes sense to me.
> 
> The strap that I have is 17mm wide and 1.5mm thick but I have some
> concerns. It was used as bus bar material and is much harder than the
> C102 copper tube that I have. It is also considerably darker in
> colour. It forms into coils quite easily and is not particularly
> springy so I am fairly sure that it is not Beryllium copper. I suspect
> that it has been annealed. I am worried that the resistivity will be
> high but surely as it was used for busbars it won't be lossy, will it?
> 
> Soon I will have a DER EE DE-5000 LCR meter which I am told are very
> good value for money and I can measure component Q so I should see the
> difference between the flat bar and the copper tube, if there is a
> problem. I know for sure that the copper tube is C102 soft copper. I
> would be interested in hearing from anyone who has this instrument and
> what they think of it.
> 
> Any advice? In the past I have made a number of QRO VHF amps for 6m
> and without exception the efficiency has been good. This is the first
> one that I have actually designed myself and I expect the loaded Q to
> be 10-12, previous amplifiers had big tubes, lots of stray C and had a
> higher Q and were mainly copies or adaptations of published designs.
> This time I want to design and truly understand what I am doing.
> 
> I am still somewhat mystified by Anode RFCs for VHF amplifiers, I can
> plug numbers into the GM3SEK spread sheet but I do not know exactly
> how to design a good choke. Most of the stuff that I found on google
> was concerned with multi-band HF amplifiers and the perils of series
> resonance. What are the rules of thumb. I can do the calculations but
> what are my goals?
> 
> Hopefully this will give the reflector a kick and start some
> interesting discussion.
> 
> Regards
> 
> Conrad PA5Y
> 
> 
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