[TowerTalk] HyGain 204BA mod

[Yuri]

Hi,
I received tons of INFO and advises, thanks to all, especially to NP2X, 
KM5VI and K5GO.
My 204BA is already on the tower since past Sunday.
SWR is 1.08: 1 on 14090,
with 1,38:1 on 14000 and 2.0:1 on 14350.
Obvious shift to the lower part of the band, but I have no time to "fine 
tune" it now, maybe next summer. Need to address other issues before it 
gets cold.
I operate mostly CW anyways.

Thanks again,

73, Yuri VE3DZ

On 9/8/2024 11:55 PM, maflukey at gmail.com wrote:
> P.P.S    One more thought, or remembrance...   With the optimized element
> spacing, the antenna will not be weight balanced and will be "tail heavy".
> You will need to add some weight to the director end of the boom to
> rebalance it.    On my optimized 204s, I place 12.5 of 1" schedule 40
> galvanized steel pipe inside of 12.5" of 1.25" schedule 40 PVC pipe and then
> slide it inside of the end of the boom, drill all the way through the entire
> assembly, and use a #10 stainless steel machine screw and nut to hold it in
> place.    The PVC pipe dielectrically insulates the galvanized pipe to keep
> it from having a corrosive reaction with the aluminum boom.   If you want to
> take some other approach, you will need about 2 lbs or a little more at the
> end of the boom to balance it out.
>
> 73 again,
> Matt
> KM5VI
>
> -----Original Message-----
> From: maflukey at gmail.com <maflukey at gmail.com>
> Sent: Sunday, September 8, 2024 10:42 PM
> To: 'Yuri' <ve3dz at rigexpert.net>; towertalk at contesting.com
> Subject: RE: [TowerTalk] HyGain 204BA mod
>
> P.S. - Yes use the original hairpin spacing.   All the 204's I have seen
> have beta match angled rods at the feed end.   Other Hy-Gain monobanders
> have straight rods.   Be sure you are using the correct rods.      Lenth
> required is generally about 14" to 15" .
>
> Matt
> KM5VI
>
> -----Original Message-----
> From: maflukey at gmail.com <maflukey at gmail.com>
> Sent: Sunday, September 8, 2024 10:35 PM
> To: 'Yuri' <ve3dz at rigexpert.net>; towertalk at contesting.com
> Subject: RE: [TowerTalk] HyGain 204BA mod
>
> Step 1:  Adjust the driven element length to center the SWR across your
> desired bandwidth.  I.E. adjust to make the SWR the same at the bottom and
> top of your desired bandwidth.
>
> Step 2:  Adjust the harpin length to minimize the SWR at the midpoint
> frequency of your desired bandwidth.
>
> Step 3:  Recheck the SWR across the desired bandwidth but it should be good
> to go.   Tweak if required.
>
> Also be sure to note that the lengths in the BV204CA file are from the
> centerline of the boom.  The element bracket length in the BV204CA file is
> 2.95 whereas the actual bracket lengths are longer - so be sure to correct
> your measurements relative to the centerline of the boom.    Also, BV204CA
> file shows DIR 1 at 157" which conflicts with the boom joining bracket.
> Position needs to be shifted forward to clear the bracket which will change
> the element length somewhat.
>
> Hope this info helps & GL.
> 73
> Matt
> KM5VI
>
>
>
> -----Original Message-----
> From: TowerTalk <towertalk-bounces at contesting.com> On Behalf Of Yuri
> Sent: Friday, September 6, 2024 1:22 PM
> To: towertalk at contesting.com
> Subject: [TowerTalk] HyGain 204BA mod
>
> Hello,
>
> I recently modified my old 204BA using the BV204CA file (YW, Yagi for
> Windows by N6BV) from the ARRL Antenna Book.
> I moved Driven Element and Director 1, changed the element tip lengths where
> necessary and changed Hairpin match length according calculations.
> According to the computer model the calculated SWR is 1.09:1 on the resonant
> frequency of 14175, and 1.40:1 on the edges: 14000 and 14350 at the 80'
> height.
> Hairpin spacing that used is 12 inches (different from the original one,
> which was 6 inches).
> In reality, I have SWR of 1.05:1 on 14090, which appears to be my new
> resonant FREQ now, and 1.6:1 on 14000 with 2.6 on 14350.
> Why is it so narrow?
> What am I doing wrong? Should I use original hairpin rod spacing of 6"?
> Old variant of this antenna was wider (better broadband) Any advise would be
> greatly appreciated.
>
> --
> 73, Yuri VE3DZ
>
>
>