Monday, 23 March 2020

Ham radio-forty meter or 7MHZ band

Ham radio-forty meter or 7MHZ band

Ham radio-forty meter or 7MHZ band

The forty-meter band is very popular for not only local QSO's its also a very consistent DX band, but I have also found that DX contacts can be made throughout the solar cycle when we believe propagation is poor, forty-meters is an excellent band during winter months too.

Working the greyscale before dusk or dawn offers the radio ham DX contacts around the world. Because of its popularity, the forty-meter ham band can be very crowded the band was extended from 7.0 to 7.2 in 2003 during the world administrative conference in region one, however with an extra 100 kc/s the allocation can still be crowded.

I started off listening to the broadcast bands as an S.W.L.,(Short Wave Listener) where many Internation stations operated around the 7.1 through to 7.2 MHZ allocation, I understand by 2009 all of these stations had closed down and the band plan for region one was realigned to take into consideration the start of the digital transmission modes became 7040KHZ this increased the space for other modes too.

I use forty meters ham band quite a lot for QRP operation on CW where power levels of 5 watts or lower are common, the center of the QRP segment is 7030KHZ.

SSB or single side-band operation ensures that 7053KHZ is the lowest frequency selected this will ensure that the 2.7 kHz transmission will remain in the all mode section.

My experience using a forty meter vertical with ground plane has been very rewarding a vertical for 7MHZ is around 33 feet, I have received excellent reports on my transmitted signal with this array and 16 tuned radials all at 33 feet, noise is not too bad if you keep the aerial as far away from the house, I use a choke too to minimize noise being picked up on the coax.

A delta loop cut for the band worked very well for me in a vertically polarized configuration, divide 7 into 1005 feet to give you the total length of wire and form it into a delta shape, an equilateral triangle works well and can be located close to ground level,  feed the aerial a quarter-wave down from the apex

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