[TowerTalk] TowerTalk Digest, Vol 159, Issue 64- 30/40M dipole

[N1BUG]

Hank, thanks for the input.

I didn't like my relay idea but when I wrote that post I hadn't yet 
seen a workable alternative aside from full size parallel tubing 
dipoles for each band. I could do that, but the amount and size of 
aluminum would be getting to a point of concern for the rotator and 
mast.

I have looked at the OB1-4030 several times. If budget would allow, 
I would just buy one and be done with it. I'm not too confident 
about building one since I really don't understand the operating 
principle with that stub tapped on a coil.

I am unable to find the referenced M2 antenna on their web site.

73,
Paul N1BUG


On 03/17/2016 02:47 PM, HankP wrote:
> Paul-- I think it can be done a LOT easier than relays -
>
> I saw a suggestion for a trap - that can definitely be done - look at
> OPTIBEAM 30-40 M dipole -
>
> I have a M squared 40M1L linear loaded 40 M dipole - I played with nothing but
> a parelled 30 M dipole hanging under the 40M1L and connected right at the
> balun . It appeared it would work - but I was also trying to get a 12 meter
> resonance at the same time . That 40M1L linear loading is really screwy
> it has a resonance very close to 12 meters and "sucked" the resonance of any
> paralleled 12 meter dipole so it was virtually impossible to make oine I trusted
> for a $350 crane run . (BTW I emailed with K6MYC a couple or three times about
> this and he confirmed he had seen that sort of thing ._ I was up against
> a scheduled crane run and just dropped the whole idea - the 40M1L has a "stinger"
> at the linear loading that gives a 17 meter resonance and that works great.
>
> Your concern about the voltages across a trap is well founded - if you read
> carefully , most of the commercial 30/40 or triband dipoles will NOT handle
> 1500 watts . M2 has a 30-40 meter dipole they are advertising - might be
> worth looking at how they do that . It appears to use the coil approach
> that they offer as a non linear loaded 40 M1 dipole.  I would have to look
> back at my notes or do a quick 30/40 meter paralleled dipole EZNEC and see
> how that works . I have to run now but - if I had it to do over again.
> I would have bought the OPTIBEAM 30/40 m dipole or make a copy .
>
> I have an old KLM 40 M linear loaded 3 40 m dipole that git hit by lightning
> and  blew up the center insulator - I have a project to see if that could be
> modified to make a 30/40 m dipole by basically just playing between the
> linear loading and tip lengths and a capacitor across the linear loading
> but seems like that has not made it to top of project piles.
>
> Mi dos Centavos - as many say down here
>
> 73 Hank K7HP