LF: Re: PA3BCA

[Minto Witteveen <minto.witteveen@gmail.com>]

0.5 mH, nice!
According to my measurements I will need a 3.5 mH loading coil, your 0.5 is just a bit more than I need at 500 KHz…

73’s, Minto pa3bca

 

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Ceterum censeo Carthaginem delendam esse

 

From: mal hamilton

Sent: Friday, August 12, 2011 20:21

To: rsgb_lf_group@blacksheep.org

Subject: Re: LF: PA3BCA

 

My loading coil is 0.5 mH approx wound with 3mm litz wire, it has no cover just a glass lid on top. Air and rain circulates around it to keep it cool and weather changes has little effect ie sunshine or showers, even during stormy windy wx there is very little loading variations.

If you have a large loading coil and short antenna wires circumstances could be different.

g3kev

 

 

----- Original Message -----

From: Stefan Schäfer

To: rsgb_lf_group@blacksheep.org

Sent: Friday, August 12, 2011 7:02 PM

Subject: Re: LF: PA3BCA

 

Hi Minto,

Am 12.08.2011 19:42, schrieb Minto Witteveen:

How much power were you generating?

73’s, Minto pa3bca

 

 

It changes all the time. Not even sure since i just have an E field probe to decouple some power from my TX antenna and feed it to a 50 uA amperemeter, shunted by a potentiometer. This poti was adjusted to show 100% full scale when using 120 W RF before some weeks. Now reduced the parallel R on the poti so it shows just 25 uA then. Got 50 uA anyway by QRO and more (not sure). So it should be arround 500W. This is -6 dBfs :-)

But the antenna, i.e. the coil and its cover is very lossy it seems. When there was rain, i have up to twice the losses :-( Need to search for an alternative cover (mustn't burn, so a water barrel is no alternative...).


73, Stefan/DK7FC