[TowerTalk] triplexers and stacking

[Richard (Rick) Karlquist]

There is a problem with getting the phase shifts equal.
First of all, the triplexers need to be equal delays,
when tested in a 50 ohm system.  Then the mismatch
of the 3 tribanders must be low or at least the
same.  Depends on the individual tuning of the triplexers.
Seems like a lot of moving parts to get right.

Rick N6RK

On 3/21/2017 8:29 PM, Rudy Bakalov via TowerTalk wrote:
> Mike,
>
> Option #3 can be executed slightly differently and it is what I am pursuing.
>
> You don't need 9 HP BPFs, only 3. The sequence of devices, starting from the tribander and going to the shack is:
>
> 1) 3 x Tribanders with single feed line each
> 2) Each feed line goes into a triplexers and you get separate lines for 20,15, and 10.  In total, you get 3 x 20, 3 x 15, and 3 x 10
> 3) You take all the individual band lines and stack them using 3 stack matches
> 4) Now you have 3 feed lines again- for 20, 15, and 10
> 5) Install HP BPFs on each feed line, for a total of 3 BPFs
>
> Haven't built it yet.  It's a summer project, along with expanding the remote SO2R switch.
>
> Rudy N2WQ
>
> Sent using a tiny keyboard.  Please excuse brevity, typos, or inappropriate autocorrect.
>
>
>> On Mar 21, 2017, at 8:50 PM, Mike DeChristopher <mfdechristopher at gmail.com> wrote:
>>
>> I know some of you are using (or have used) a triplexer with your
>> tribander. Having very limited experience with triplexers and
>> tribanders, I'm hoping you can assist with a thought experiment we're
>> working through.
>>
>> For the purposes of this discussion, we'll ignore the pitfalls of
>> stacking tribanders themselves, at least where it comes to pattern,
>> elevation, separation, etc. -- let's assume we have that all worked
>> out.
>>
>> Phase 1: Take a three -high stack of identical tribanders, each single
>> feed. We want to do the reasonable thing and use a stack match of some
>> sort. This probably works OK.
>>
>> Phase 2: Now we want to host a multiop. We'll need to separate the
>> feeds with a triplexer (BPF's included) between the stack match and
>> the shack. Now we have three feeds coming in and a shared stack for
>> 10, 15, and 20. The obvious downfall is that three operators are
>> chained to the same stack configuration; for example, the 10m op wants
>> to use only the top beam while the 20m op wants to run EU
>> simultaneously on the full stack -- fisticuffs break out as operators
>> fight for the stack control box.
>>
>> Phase 3: The next logical step is to put a triplexer and the BPF's per
>> tribander. So we now have three feeds per antenna, which can then be
>> run into three stack matches (one each for 10, 15, and 20). At this
>> point, we'd truly have three independently-controlled stacks. The only
>> shared controls would be rotors.
>>
>> [Given the cost of nine HP BPF's, three triplexers, three stack
>> matches, other assorted hardware, the nearly-logical suggestion might
>> be "build another tower and use monobanders" -- but that's why this is
>> a thought experiment, after all.]
>>
>>
>> Question 1: Has anyone done this (Phase 3 above)?
>>
>> Question 2: If one used tribanders with separate feeds for each band,
>> could one forego the triplexers and simply use BPF's between each
>> feedpoint and the stack match?
>>
>> 73,
>> Mike N1TA
>> _______________________________________________
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>>
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