[Rover] Interstation Interference in Multi-Op Rovers

[Sean Waite]

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
>