Re: keying circuit


Jim Sheldon
 

Wayne & all,
The only reason not to have all the grounds tied together is in case there is an older rig that uses high voltage, negative voltage, in the keying circuit like some of the older Kenwoods that had tube finals and the Heathkit tube rigs.  Some people still do have them ya know, hi hi.
 
If that were the case, one could get into a bit of trouble due to voltage feedback on the ground circuit keying rigs that weren't supposed to be keyed.  
 
I really don't see a problem with it as 99 percent of the rigs today have + voltage on the tip circuit in the Jack and most everything is solid state anyway, but like I said, there are still that 1 percent of the older rigs in use.
 
I'd bet that most people who have the older rigs would be using opto-isolators or reed relays of some sort when using a solid state keyer for CW.  Mechanicals such as hand keys/bugs wouldn't be a problem except for the possibility of the negative voltage on the old grid-block keying rigs affecting the newer positive voltage keying circuits.  The other problem would be that a grid block keyed rig usually had a negative 80 volts or so on the key jack and that might prove detrimental to any solid state devices unless they were designed to handle high voltage.
 
Jim - W0EB

> Hi David and the group.
> Just curious, why not tie all the grounds together? am I missing
> something here? With my "multi switching" box all the grounds are
> tied together and I've had no problems...
>
> God Bless all de Wayne - KC0PMH
>
>
> On Tue, Oct 15, 2013 at 4:15 AM, David Martin
> wrote:
>
>
>> I agree, you should not tie all the
>> grounds together, it can cause problems... been there done that.
>>
> You can get a 3 pole rotary switch from Jameco and that will allow
>
>> you to switch 3 circuits.  You'd want to do this if you are using
>> an iambic key.
>>
>
> You will need to mount any jacks used on a non-metalic surface to
>
>> keep the ground circuits isolated from each other.
>>
> On 10/14/2013 10:57 PM, Todd F. Carney / K7TFC wrote:
>>>
>>>
>>> I'm with WB9DLC. A rotary switch is the way to go. Use one pole
>>> for the signal and one for each ground. That is, don't use a
>>> common ground. Run a separate ground from each radio.
>>>
>>>
>>> Also, I'd be inclined to use a "break-before- make" rotary
>>> rather than a "make- before-break" variety.
>>>
>>>
>>> Best
>>>
>>>
>>> Todd
>>>
>>> On Oct 14, 2013 8:46 PM, "WB9DLC - Mike Barrell"
>>> wrote:
>>>>
>>>>
>>>> Radio Shack has a 2 pole 6 pos.
>>>> Switch Model: 275-1386.
>>>>
>>>>
>>>> Can't imagine making it any more
>>>> complicated.
>>>>
>>>>
>>>> 73
> Mike - WB9DLC
>
>>>>
>>>>  
>>>> On Oct 14, 2013 11:40 PM, "n0jrn" wrote:
>>>>>
>>>>>
>>>>> Thanks Nate:
>>>>>
> BUT, I have all the isolation I
>
>>>>> need inside the electronic
>>>>>
> keyer. I just want to switch it's
>
>>>>> output to multiple rigs
>>>>>
> and not sure if I need anything to
>
>>>>> protect from RF etc.
>>>>>
> I'm looking into this for a friend
>
>>>>> and he wants to use his
>>>>>
> keyer on 4 seperate rigs without
>
>>>>> plugging and unplugging.
>>>>>
> I don't see much of a problem with
>
>>>>> just switching the output
>>>>>
> of the keyer.
>
> Just curious if I need to protect
>
>>>>> the circuit in some fashion.
>>>>>
> 73 Jerry
>
> ----- "Nate Bargmann"
>
>>>>> wrote:
>>>>>
>> * On 2013 14 Oct 21:26 -0500,
>>
>>>>> n0jrn wrote:
>>>>>
>>> Gang:
>>>
>>> IF you have an
>>>
>>>>> electronic keyer and you want to use
>>>>>
>>> it with multiple rigs
>>>
>>>>> without plugging and unplugging
>>>>>
>>> all the time, what
>>>
>>>>> circuit would you use to switch
>>>>>
>>> between rigs.
>>>
>>> Electronic keyer would
>>>
>>>>> go to the switch and switch
>>>>>
>>> to multiple outputs.
>>>
>>> Doesn't seem like it
>>>
>>>>> would take much more than the
>>>>>
>>> switch but would you use
>>>
>>>>> diodes on the outputs,
>>>>>
>>> capacitors on the
>>>
>>>>> grounds ??
>>>>>
>> Seems like the ideal
>>
>>>>> application for optocouplers. Bias one for
>>>>>
>> positive keying and the other
>>
>>>>> for negative keying (TS-520, TS-830,
>>>>>
>> etc.). Use as many as needed
>>
>>>>> for multiple rig outputs. Isolation
>>>>>
>> between rigs and between the
>>
>>>>> tigs and keyer.
>>>>>
>> 72, de Nate >>
>>
>> --
>>
>> "The optimist proclaims that
>>
>>>>> we live in the best of all
>>>>>
>> possible worlds. The
>>
>>>>> pessimist fears this is true."
>>>>>
>> Ham radio, Linux, bikes, and
>>
>>>>> more: http://www.n0nb.us
>>
>>
>>>>> ------------------------------------
>>>>>
>> 4SQRP Website: http://4sqrp.com OzarkCon is coming April 4-5,
>>
>>>>> 2014 in Branson, MO
>>>>>
>>>>> Groups Links
>>
>
> --
> David Martin - K5DCM ---o0o---
> Mountain Home, Arkansas
> Guns don't kill people, any more than spoons & forks cause
>
>> obesity.
> I guess most people don't think because it's too tedious for them!
> What I like about naps is, I can get them done while I'm sleeping.
> If they can, they do; without thinking if they should.

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