[TowerTalk] remote controlled tuners?

[jimlux]

On 8/3/20 11:13 AM, David Gilbert wrote:
> 
> 
> Hi, Jim.
> 
> Do you plan to use this for transmit, or for receive?
> 
> I'm no network expert, but if you intend to do this for transmit I don't 
> think you can variably shift the phase AND also at the same time have a 
> good match by this method.  Maybe you plan to switch the tuner in for 
> receive and out for transmit, or switch between two tuners.
> 

Multiple tuners.. two cascaded allows you to shift phase and transform 
the impedance so that when they are in parallel it's 50 ohms.  So 4 
tuners all together make a 50 ohm load.

I think that one might be able to get by with 3 - and you let the 
"joining point" assume arbitrary impedances. And the typical computer 
tuner has a single L and a single C, so there's not much point in 
switching multiple "C"s to the joining point.

Not a whole lot different than used in the broadcast business.


For what it's worth, on receive, you might as well do it in software.

Some years ago, I was going to try this with software on Tx, and 
separate 100 W PAs, but those PAs are still sitting as kits in the garage.



> And if you intend to do this only for receive, you could accomplish the 
> same thing via software at audio IF you use a rig with two synchronized 
> receivers, such as the Elecraft K3/K3s in diversity mode.
> 
> On the second point, I have a few times lobbied Elecraft to add that 
> capability to their firmware but they don't seem to recognize the 
> potential of it.
> 
> 73,
> Dave   AB7E
> 
> 
> 
> On 8/3/2020 10:56 AM, jimlux wrote:
>> On 8/3/20 10:20 AM, sawyered at earthlink.net wrote:
>>> Why is it that direct control of L and C are required?  I use the MFJ 
>>> high
>>> power tuner and have no issue with it on auto tune finding a good 
>>> match for
>>> my 80M phased dipole array.
>>>
>>
>> I want to use it to change the relative phase of the antennas to move 
>> the nulls.
>>
>> It's more a "phase shifter" than a "matching network"
>>
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