LF: VLF - G3XIZ QRT - Buckets!

["Dave G3WCB." <ganymede444@btopenworld.com>]

Chris,

 

Marcus uses stacked buckets - see e-mail below. He did post a photo of his coil, but I can't find it at the moment.

 

73, Dave G3WCB

 

Dear Henny,

the coil consists of seven ordinary ten-liter polypropylene household

buckets, inserted upside-down into one another. The diameter of the buckets

is about 25 cm at the bottom and 21 cm near the top. Each bucket carries 460

turns of 0.4 mm enameled wire. The lead from the top end of one winding to

th bottom end of the next has to run alomg the winding, and is insulated

with several strips of tape an foam material. Total DC resistance is about

320 ohms.

The resonance is adjusted by the amount of overlap. Inserting the buckets

deeper into one another lowers the frequency by enhancing the mutual

inductive coupling, along with a slightly higher inter-layer capacitance. My

240 pF antenna requires a total length of about 60 cm for 9 kHz. For the 500

pF kite antenna I need only five buckets, and with larger spacing.

Best 73,

Markus (DF6NM)

-----Original Message-----
From: owner-rsgb_lf_group@blacksheep.org [mailto:owner-rsgb_lf_group@blacksheep.org]On Behalf Of Chris Osborn
Sent: 31 May 2011 15:39
To: rsgb_lf_group@blacksheep.org
Subject: Re: LF: VLF - G3XIZ QRT - MF QRV

Thank you Stefan,

 

I hope that you had a pleasant weekend and thank you for looking for the signal.

 

I have made some aerial improvements although not as much as I had anticipated.

I now have an inverted 'L'  48m long and with a mean height 11m

I have far better insulators too.

I shall do some more improvements later.

 

My loading coil became unserviceable yesterday at 06.10Z whilst transmitting.

I think that a flying insect hit the wires and exploded, causing a short-circuit.

I have had this problem before with insects with high voltages.

 

I shall try to rectify the coil and then see if my aerial shows an improvement in signal strength.

Eddie G3ZJO picks me up regularly and his VLF grabber is most useful.

 

Has anyone an easier way of making a 1.3 H loading coil ?

My present dual-overlaid winding coil took many hours to make and seems quite unreliable.

 

73 Chris G3XIZ