logo

Home



Cluster Activity

Spots per uW band today:
UK spotter or spotted only.

Solar data:
SFI
4
A-Index
4
K-Index
29
Exp.K
qui
Sunspots
act
Activity
no
GMF
Aurora?
M0DTS

My Weather

ArrayDate:28/11/21 Time:12:51
Temp:2C
Wind Speed:7.5mph
Wind Dir:315deg
Pressure:1005.34mB
Humidity:86%
Dew Point:-0.8C
UKHASnet

Most VLF antennas are up in the air but the length of wire you can get up is limited vs the wavelength of the frequency in use, hence VERY large loading coils are required to bring the antenna to resonance. Often many kilovolts are on the wire in use.

As i'm only doing tests through earth mode (for now) i've been using an earth loop antenna.


For transmit tests I've got an earth loop antenna consisting of Earth Electrodes spaced at 40m E/W and 40m N/S, also allowing 60m NE/SW.

The 8.27KHz signal at over 100V is applied between the electrodes.



Hopefully I'll be able to extend the current earth loop length of 60m to try for some Dx....!

There's the possibility of a 240m Earth Loop but the cable would need to be buried as there are sheep in the field...they love to get tangled up or chew on on wire!


For any more information email me rob at m0dts.co.uk


Tx Amplifier is currently a Behringer NX3000 with a 120-240/50-50 mains toroid as the step-up transformer on the output.

Have plans to build a H-Bridge PA like DK7FC has done, should improve efficiency and allow more power.




















Last page added:25/03/00 18:32
M0DTS.co.uk