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Old 30-04-2014, 10:43 PM   #1970
mrsun18
Master Member
 
Join Date: May 2011
Posts: 2,809
A tip for those DIY dipole antenna, there is a mistake, recommend
to tune to 522MHz. See sites on the internet the half wave length should be 147/522Mhz = 28cm
https://encrypted-tbn2.gstatic.com/i...etoYQAhI9d0EBR
There is no mistake. 522MHz is the centre frequency of chan 27. Ignoring reception for chan 38, the antenna made for Singapore should cater for the reception of chans 27, 29, 31 and 33. The centre frequency for these four channels is 546Mhz. Half wave length minus about 5% = 150/546 x 0.95 = 26 cm.

Note: the 5% reduction is only a guide. Actual deduction depends on a lot of factors - for academic interests only.

If one wishes to cater for chan 38, then the dipole has to be shorten.

In any case, the exact length is not critical. My prototype eventually had a dipole length of 16 cm only. And it works

Last edited by mrsun18; 30-04-2014 at 10:48 PM..
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