The new backpack consists of a “Clansman metal frame” carrying a modified Alinco DX-70TH transceiver, this is powered by a lightweight 22Ah LIPO battery which has its own dedicated charger.
The antenna is a modified MFJ-1979 17ft telescopic stainless steel antenna which is matched against a toroidal ground tuning unit (GTU).
The system does not require an ATU as the antenna is adjustable in length to provide a good match between 14MHz and 30MHz, the ground tuning provides the necessary ground coupling for the antenna to work against, there is more information about GTU principles on https://www.g4akc.co.uk/ground-tuning-units-gtus/
The set up provides up to 90 Watts RF into the antenna and the whole backpack including antenna is only 17 pounds in weight.
This set up is an update to my original backpack from a few years ago shown here: https://www.g4akc.co.uk/hf-backpack/
Went out onto the beach here in Blackpool a couple of days after completion of the backpack pedestrian mobile and the results were excellent with contacts into South Africa, USA, Canada and South America, signal reports were really good and it was easy to carry for the hours operations along the beach.
I have now added an LDG Z100 auto ATU to the manpack to give better impedance matching on the move.