[Rover] Interstation Interference in Multi-Op Rovers

[Robin Midgett]

I have scads of CATV hard line. I'm happy to cut a section & send it to
you. 1/2", 3/4" & 1" diameters.

On Fri, Sep 22, 2017 at 1:38 PM, Sean Waite <waisean at gmail.com> wrote:

> Hi Jonesy,
>
> I don't know why my brain stuck on blocking the 6m signal at the 2m radio.
> It makes much more sense to do block the ~150MHz harmonic at the 6m radio.
> Any idea how much difference a lower Q piece of coax - either thinner
> heliax or something like LMR400 - would change the results? I gather it
> makes them a little more broadband, but I don't know for sure. CATV cable
> is great but can be a little hard to get a hold of.
>
> We were getting some minor interference on  432 as well. I might have to
> look into a stub there as well.
>
> Thanks,
> Sean WA1TE
>
> On Thu, Sep 21, 2017 at 9:21 PM Jonesy W3DHJ <mailserver at jonz.net> wrote:
>
> > On Thu, 21 Sep 2017, Sean Waite wrote:
> >
> > >Thanks, I suspected it might be something like that. We get some lighter
> > >interference on 70cn as well, which is a few more harmonics up.
> > >
> > >My worry with the coax notch filters is bandwidth - 150MHz is pretty
> close
> > >to 2m. I suppose using higher quality coax/heliax and tuning to 51MHz
> > would
> > >help with that.
> > >
> > >The rigidity of heliax might make it rough in the rover, a 5' long chunk
> > is
> > >going to be interesting g to manage and will likely go somewhere outside
> > >the car on the ground.
> >
> > Use 3/4" cable TV "hardline" -- use it as a 144.2 mcs suck-out trap on
> > the 6M rig -- an open 1/4 wave at ~~15" or a shorted 1/2 wave at ~~32".
> >
> >                 https://w3dhj.net/catvhardline.html
> >
> > If you try to trap the 6M rig (50.130 mcs) at the 2M rig, you run into
> > the problem of the 6M trap working just as nicely at 150.39 mcs -- which
> > may be too close, Q-wise, for the 2M rig.
> >
> > Another issue - besides just "interference" - is the possibility of
> > blowing out the front end of the 2M receiver with simply the
> > overpowering by the 6M rig.  I blew out a 2M GasFET preamp because
> > my 6M halo is mounted between my stacked pair of 2M halos.
> > Sigh...  I just do without that GasFET preamp now.
> > I can certainly hear anyone that can hear me!  HI!HI!
> >
> > Jonesy
> > --
> >   Marvin L Jones     | W3DHJ      | W3DHJ  | https://W3DHJ.net/
> >    Pueblo, Colorado  |  @         | Jonesy |     __
> >     38.238N 104.547W |   jonz.net | DM78rf | 73  SK
> >
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