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PA3AKK > ANTENN 22.05.09 15:35l 47 Lines 2028 Bytes #999 (0) @ WW
BID : 46536_PI8CDR
Read: GUEST
Subj: Ask 70cm 21el Tonna Yagi info
Path: IZ3LSV<IQ3GO<SR1BSZ<F4BWT<PI8CDR
Sent: 090522/1430Z @:PI8CDR.#DRE.NLD.EU #:46536 [Beilen] $:46536_PI8CDR
From: PA3AKK@PI8CDR.#DRE.NLD.EU
To : ANTENN@WW
Dear reader,
A few weeks ago I became a (15 year?) old 21 element 70 cm beam made by
Tonna.
The construction is as follows:
Length Measured
Element in mm Spacing in mm
Boom part 1
Reflector 350
Folded Dipole 320 138 (dipolespacing 40 mm)
Director 1 320 51 or 64 > The user has to make a choice but
Director 2 310 67 or 73 > But what are the differences. What is
Director 3 300 182 or 163 > the aim of Mr. Tonna? I have no doc.
Director 4 300 183 I asked several other radioamateurs
Director 5 294 200 But several opinions.
Director 6 294 235 Tonna doesn't use a balun so the coax
Boom part 2 goes direct to the dipole and only a
Director 7 294 270 pipe around the coax prevents standing
Director 8 284 270 waves over the shield. The impedance can
Director 9 284 270 be ajusted with the spacing between the
Centre of boom driven element and the first director.
Director 10 284 270 The one tells the higher spacing is for
Boom part 3 use with a 4:1 balun. The other tells it
Director 11 284 270 is for frequency ajustment high or low
Director 12 284 270 in the 70 cm band for ATV or SSB DX.
Director 13 284 270 Who is right or is it a combination of
Director 14 284 270 both effects?
Boom part 4 Offcourse I can make measurements
Director 15 284 270 but what tells Mr. Tonna in his doc?
Director 16 280 270 Here is no Internetconnection so I do my
Director 17 280 270 question in the packetnetwork.
Director 16 280 270
Director 19 280 270
The boom has a total length of 4605 mm.
Quoted figures: Unkmown for me.
73, Wim
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