Exactamundo.
This is why the darn Low Q beast is undesireable.
The only problems that a low Q supressor solves that aren't solved
by the Hi-Q suppressor are:
1)It eliminates the requirement for selecting an L that provides
the correct phase shift to eliminate the problematic positive
feedback in a particular amplifier design thereby reducing the
mental exercise required of the designer who may lack the ability
to perform the exercise in the first place.
2)It eliminates FUD over the possible failure of the parallel R in
the High Q suppressor resulting in a new positive feedback situation
at a different frequency, caused by the introduction of that L in
the first place.
For these reasons, it's a good product.
However, with careful design derived from an understanding of the
physics involved in an amplifier, it's an unnecessary tradeoff
with regard to overall efficiency.
So, all you guys can quit arguing about the damn thing.
Yes, it works.
Yes, it solves a problem.
Yes, the problem can be solved in better ways.
Yes, some people are incapable of solving the problem otherwise
or are willing to make the efficiency tradeoff in the interest
of expediency.
Bottom line. It has a useful place in the real world but it's
not requisite to a properly functioning amplifier...
Apparently, TT chose design care and efficiency over expediency.
That would be a check on the 'pro' side in comparing amplifiers
with a mind toward purchase.
73,
-Bob
ah7i
2 wrote:
>
>>I took your statement:
>>
>>
>>>>>..... Nacherally, this meant the suppressors were doing their job.
>>>>
>>to mean, 'they were suppressing parasitics....'.
>
>
> ** They present a low Rp to the anode at vhf.
>
>>Why does a High Q suppressor, in that context, not behave in the same
>>way as a low Q suppressor if that High Q suppressor has inductance
>>and resistance that are the same as the inductance and resistance of
>>the low Q suppressor that is "doing it's job".
>
>
> ** A high Q suppressor shifts the dissipative burden onto R-sup that a
> L-sup made with resistance-wire would have have otherwise dissipated. In
> other words, what is not dissipated in L-sup must be dissipated in R-sup
> in order to obtain the same reduction in vhf gain.
>
>>behave in the same way = "get quite hot at 29MHz".
>>
>>The Low Q suppressors are moonlighting?
>>
>
> ** in order to be lossy at vhf, a suppressor must be somewhat lossy at
> 29MHz.
>
> have phun, Bob
>
>
> ----------------------
>
>>-------------------
>>
>>2 wrote:
>>
>>>>Naturally, the higher reactance results in a more intense
>>>>reactive field leading to greater I and greater I^2R.
>>>>
>>>
>>>** correct
>>>
>>>
>>>
>>>>Why doesn't the same thing happen with the same L as Hi-Q
>>>>having the same R in parallel.
>>>>
>>>
>>>** I do not understand the question. Can you phrase it a bit more
>>>determinately?
>>>
>>>
>>>
>>>>3 marks for the correct answer...
>>>>
>>>>-bob
>>>>ah7i
>>>>
>>>>
>>>>2 wrote:
>>>>
>>>>
>>>>>>Hi AMPS
>>>>>>
>>>>>>Ten Tec has released their new 2 X 4cx800 amp, the Titan 3.
>>>>>>You can see a good picture on their web page. You can clearly see a
>>>>>>Nichrome style suppressor as per Rich's web page instructions. It looks
>>>>>>similar to the one in the Emtron amplifier. Besides this, the layout may
>>>>>>be of interest.
>>>>>
>>>>>
>>>>>** After the October 1988 article on improved parasitic-suppression
>>>>>appeared in *QST*, Ten-Tec tried low VHF-Q suppressors but they abandoned
>>>>>the idea after they found such suppressors get quite hot at 29MHz on RTTY
>>>>>mode. Nacherally, this meant the suppressors were doing their job.
>>>>>
>>>>>cheers, Greg
>>>>>
>>>>>- R. L. Measures, a.k.a. Rich..., 805.386.3734, AG6K,
>>>>>www.vcnet.com/measures.
>>>>>end
>>>>>
>>>>>_______________________________________________
>>>>>Amps mailing list
>>>>>Amps@contesting.com
>>>>>http://lists.contesting.com/mailman/listinfo/amps
>>>>>
>>>>
>>>>
>>>>
>>>>_______________________________________________
>>>>Amps mailing list
>>>>Amps@contesting.com
>>>>http://lists.contesting.com/mailman/listinfo/amps
>>>>
>>>
>>>
>>>
>>>- R. L. Measures, a.k.a. Rich..., 805.386.3734, AG6K,
>>>www.vcnet.com/measures.
>>>end
>>>
>>>
>>
>>
>>
>>_______________________________________________
>>Amps mailing list
>>Amps@contesting.com
>>http://lists.contesting.com/mailman/listinfo/amps
>>
>
>
>
> - R. L. Measures, a.k.a. Rich..., 805.386.3734, AG6K,
> www.vcnet.com/measures.
> end
>
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> Amps@contesting.com
> http://lists.contesting.com/mailman/listinfo/amps
>
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