LF: Re: [rsgb_lf_group] EB8ARZ/2 heard last night, W1VD amp

[N1BUG <paul@n1bug.com>]

Hello Rik,

Thanks for this information. I had only the knowledge that
50V=1000W, 30V=350W. From this I tried to "invent" some math and
thought that 13V=65W seems about right. :-) But I wasn't sure.

73,
Paul N1BUG



On 04/02/2018 09:10 AM, Rik Strobbe rik.strobbe@kuleuven.be
[rsgb_lf_group] wrote:
>  
> 
> ​Hello Paul,
> 
> 
> +90% is good for a class D amp.
> 
> I had similar values for my G3YXM clone at 137 kHz.
> 
> At 475 kHz my class D push-pull PA has a skightly less (abt. 85%)
> efficiency, but with 2xIRF450 I do not worry about 45 W heat
> dissipation at 250 W output.
> 
> 65W at 13Vdc indicates that 50Vdc should give the 1kW you are aiming
> for.
> 
> 
> 73, Rik  ON7YD - OR7T
> 
> 
> --------------------------------------------------------------------
> *Van:* rsgb_lf_group@yahoogroups.co.uk
> <rsgb_lf_group@yahoogroups.co.uk> namens N1BUG paul@n1bug.com
> [rsgb_lf_group] <rsgb_lf_group@yahoogroups.co.uk>
> *Verzonden:* maandag 2 april 2018 13:40
> *Aan:* rsgb_lf_group@blacksheep.org;
> rsgb_lf_group@yahoogroups.co.uk; Discussion of the Lowfer (US,
> European, & UK) and MedFer bands
> *Onderwerp:* [rsgb_lf_group] EB8ARZ/2 heard last night, W1VD amp
>  
>  
> 
> There is still life in the band! I returned to WSPR-2 for a bit last
> night. I was heard by DL/SWL. I am pleased to report I heard
> EB8ARZ/2 for the first time. I hope he is checking WSPRnet to be
> aware of this. Has anyone else in North America heard him?
> 
> I have finally finished building my W1VD kilowatt deck. During the
> first tests is produced about 65 watts at 13 volts with efficiency
> in the low to mid 90 per cent range. I don't know if that is what I
> should expect at this voltage but efficiency and waveforms look
> good. I found some server power supplies which I will try to modify
> to power the amp. If that works I may get to the full 1 watt EIRP soon.
> 
> http://www.n1bug.com/w1vd-first-test.jpg
> 
> 73,
> Paul N1BUG