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Reviews Categories | Antennas: VHF/UHF+ Directional (Yagi, quad, etc.) | Diamond A-504HB 6m Beam Help

Reviews Summary for Diamond A-504HB 6m Beam
Diamond A-504HB 6m Beam Reviews: 1 Average rating: 4.0/5 MSRP: $140
Description: 4 element, 6 meter yagi beam
Product is in production.
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F5DQK Rating: 4/5 Jan 23, 2006 10:49 Send this review to a friend
Diamond/Comet comparaison  Time owned: 0 to 3 months
Thoughts about HB9CV capacitorless four elements:

Last autumn 2005 I bought both models Comet CA-52HB4 and Diamond A-504HB in order to compare them.
Because of lack of winter propagation, I'll wait next summer for trying them on air.
So I did mount them and try in my loft
Both have about same boom length (respectively 3,13 and 3,25 m).
1st impression is that Diamond is stronger build:
The A-504HB diam 12.7 mm unique elements are stronger than the CA-52HB4 ones with their 11 and 9.5 mm diameter.
Also Diamond's 32 mm boom diam instead of Comet's 25 mm confirms me this impression.
Diamond gamma tapering is immediately visible. So you have to spend a little time for the Comet one
(no mark for it), especially if you don't have any idea of the gamma prepositionning.

Serial capacitance is substitued in these models by 2 parallel wires : one between both gammas, and the other for dipole to reflector "earth"continuity
Gain of 7.8 dBd seems a little exagerate ! Mmana simulation gives 7.14 dB maxi with a 52 pF serial capacitance, but 5.8 dB without !!
Perhaps a little problem with Mmana, because I was obliged to carefully adjust gamma wire diameters and distance from the boom.
Front to back ratio of 17 dB is easy achieved..

I hope having more on air news next summer !!

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