I've been playing around with home brew mag loops over the last few months, and I've achieved excellent results on 160m with a 6ft dia four turn loop. When setting up this loop with a 250pF vacuum capacitor I found that it would tune down to 1MHz which got me thinking that it might work on 630m with a bit more capacitance thrown in. Plotting capacitance versus resonant frequency suggests another 1000pF should do it which would be easy to add if I decide to try this out.
However, before going any further into the 630m world I would be interested if anyone has any views or personal experience of mag loops on 630m, particularly as I've not come across any online discussions concerning mag loops on this band. Is it worth me persevering?
Also, when googling transmitters for 630m the other day I came across a thread (sorry, forgot to record the link) that discussed HF rigs on 630m, and it was said that the only HF rig that will transmit on 630m unmodified is the IC706, although it only claimed this with the power turned down to 2W. I'm not sure if the power restriction was mentioned for driving an amplifier or because the IC706 would not be happy running more power on this frequency. Any input here would be appreciated. I've got two of these wonderful cheap and cheerful rigs, and I wouldn't want to blow either of them up trying to use them on this band if they are unsuitable.