[Lf] Balloon flying]

[Andre' Kesteloot]

Alan Melia wrote:

> Hi All, as a result of the donation of some old mags I came across the
> following table in an article in 73 mag (April 1972 ), which may be of
> interest to those without a tower contemplating a BIG vertical. The table
> relates to lift generated by a helium filled balloon at different gas
> temperatures.
>
> Balloon        Gas vol         lift (lb)         lift (lb)
> diam. ft          cu.ft.         @0degC       @20degC
> 2                   4                0.25               0.25
> 3                  14               1                    0.75
> 4                  33               2                    2
> 5                  65               4                    4
> 6                 113              7                    7
> 7                 180             12                  11
> 8                 268             18                  17
> 9                 381             26                  24
> 10               523             36                  33
> 11               696             48                  44
> 12               904             62                  58
> Sorry to our metric friends (1ft=0.3m and 1lb=0.45kgm or there abouts) I
> think metres are unknown the other side of the pond. They even measure the
> size of the engine bay in cubic inches (It IS the engine bay isn't it?)
>
> It goes on up to 16 feet diameter but I reckon if you have got a big enough
> garden to blow up a 16 foot diameter ballon you have enough room for tower!
> He mentions flying a 160foot vertical with an 8foot weather balloon inflated
> to 3.5 feet diameter. (He ran out of gas). He also relates burning out a
> 30AWG aerial wire with about 180 watts on 80m. Though I must admit I have no
> idea how he derives an impedance of feed 50ohms for the end of a halfwave!
> That shouldn't bother us as, at least I, will be quite happy with a quarter
> wave on 136!
>
> Cheers de Alan G3NYK
> Alan.Melia at btinternet.com