[time-nuts] Re: Composite sky GPS - with an added digression

[Bob Camp]

Hi

If you are just trying an experiment, there are cable TV splitters from
places like Lowes or Home Depot that go up to 2 GHz. You do need to 
look at the label on the part to be sure, they don’t all go past 1 GHz.

Bob

> On Jul 2, 2023, at 11:50 AM, Lux, Jim via time-nuts <time-nuts at lists.febo.com> wrote:
> 
> On 7/1/23 4:03 PM, Hal Murray via time-nuts wrote:
>> Jim Lux said:
>>> Non ideal antennas make the grating lobes wiggle or be wavy along their long
>>> axis. Of course what YOU care about are the nulls (and to a lesser  extent
>>> the phase smoothness as you traverse the pattern).  I've looked a lot of
>>> these kind of models and your saving grace is that the nulls are deep only
>>> when the signals from the antennas are equal strength, which doesn't really
>>> happen much.
>> In the case of interest, the signal strength will be strongly unbalanced.
>> 
>> It would be interesting to plot the signal strength as a satellite goes from
>> one receiver to the other.  You could make several plots with the antennas
>> pointed up at different angles so the field of view would overlap more or less.
>> 
>> What do I need to combine a pair of antennas?
>> 
>> 
>> 
> Did some sample plots in a subsequent post.
> 
> You'd need a power combiner - which is just a splitter used in reverse. Depending on signal levels and whether there are LNAs on the antennas, it could be as simple as just hooking the antennas up in parallel.
> 
> If you're an all passive system, then something like a Minicircuits ZX10-2-25 (or any of a dozen or more) would do. With a dB hit from the loss through the combiner.
> 
> https://www.minicircuits.com/WebStore/dashboard.html?model=ZX10-2-25-S%2B
> 
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