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My Project Details

About "The Bike"

The bike is an inexpensive 16 speed mountain bike, but with the heavy trailer being pulled behind the bike I rarely get out of 2nd gear!

The radio has now got continually variable power output from 10 mW to 50 Watts when using just the bike, or up to 250 Watts when pulling the trailer behind the bike.

The radio I now use is a handlebar mounted Alinco DX70-TH in a zipped waterproof cover powered by two pairs of selectable 7Ah 12 Volt gel batteries, which give a total of about 4 hours of use at 50W output, two of the batteries are mounted on the rear pannier and the other two batteries mounted under the cross bar.

I operate on all HF bands "Pedal Bicycle Mobile" whilst on the move, and operate very close to the sea near to where I live.

Lots of RF toroid filters are used to eliminate RF feedback problems, (especially when using the amplifier) this is because the antenna is only a short distance away from the transceiver. A band switchable quarter wave coiled up coax line is used between the radio and the input to the amplifier to achieve good RF stability.

The antenna's are home designed / home made "HI Q" mono-band top loaded verticals which are 3.5 Metres long, and have a dedicated 75mm diameter air spaced coil.

From time to time when feeling energetic I use a small trailer, which can be seen in the picture above (which is very difficult to pedal up the hills!) as it weighs 100Kg, as the on board batteries are very heavy.

The trailer contains two 12 Volt / 40Ah gel cells in parallel powering a modified solid state Italian "RM KL500 Linear Amplifier" which can run up to 250 Watts output, but I generally run it at about 150 Watts to conserve battery power, this gives about 4 to 5 hours operational use.

About "The HF Pedestrian Mobile"

I also enjoy "Pedestrian Mobile" on 15,17, 20 and 40M SSB and get really close to the sea using a small 2-wheel lightweight easy to pull along trolley or cart this can be seen with me in the pictures above.

The radio can quickly be removed from the cart when I can't pull the trolley on the beach and is then carried in a "back-pack" as seen in the picture above; the RF power output is continually adjustable between 100mW and 30 Watts maximum.The DC power comes from a single 12 Volt gel battery inside the back-pack and the antenna is a home-made top loaded vertical.

The transceiver is another modified Alinco DX70 powered by a 24Ah battery; alternatively a single 7Ah battery supplies the radio when carried in the backpack.

A recent addition is a modified KL500 linear amplifier to the pull along pedestrian mobile trolley,the amplifier is powered from an additional 38Ah battery mounted on the bottom of the trolley. The amplifier is adjustable to power levels continually adjustable down to 100 mW on low power to a maximum of 250 Watts on high power, however the battery life is limited when running maximum power output so I usually run it at 150 Watts maximum output power this provides me with around 2 hours use with the amplifier switched on.

The antenna is a very lightweight home-made top loaded vertical about 3.5 metres long, this is tuned against the frame of the backpack or trolley, (whichever is in use) using a similar, but physically smaller ground tuning system as on the bicycle, and can be seen in the picture above on the right, it is the small yellow box below the antenna.

I have also added digital voice recording to the pull along pedestrian mobile trolley, which enables me to playback the QSO's and manually enter them into my computer log when I get home.

When operating HF bicycle or pedestrian mobile, many people stop me as their curiousity gets the better of them and the large antenna on the back of the bike or cart draws a lot of attention!

I tell them its amateur or ham radio and the usual question then follows as to "what is ham radio" or what is amateur radio" so a lot of time can be spent on describing the unusual side to our hobby! The HF pedestrian mobile set-up allows me to operate well away from the main public areas and reduces the number of people who continually ask!

About "The HF Car Mobile"

Operational mobile from the car using 50 Watts output power from yet another Alinco DX70TH, I am active on 6, 10, 15, 17, 20, 40, 80 and 160 Metres using home made aerials; either centre loaded 2.5 metre long mono-band antennas (for high speed) or top loaded 3.5 metre long mono-band vertical aerials for 10,15,17 or 20 Metres mounted on a triple magnetic mount.

I also have a modified 7 metre fibreglass pole which locks onto the back of the car for use on 40 and 80 Metres when static mobile as seen in the picture above.

The car body is tuned in a similar way to the bicycle to enhance the ground-plane.

20M pedestrian mobile as received by VK3GFS

Group Recording