Ts are not necessarily High pass nor are Ls for that matter.
On 5/4/12 4:59 PM, Rob Atkinson wrote:
> I wouldn't touch a T network. High pass = no pass here
>
> 73
>
> Rob
> K5UJ
>
> On Fri, May 4, 2012 at 8:37 AM, Tom Thompson<tlthompson@qwest.net> wrote:
>> Kevin Schmidt, W9CF, has a nice Java app where you can study the losses
>> in a T-network tuner at http://fermi.la.asu.edu/w9cf/tuner/tuner.html
>>
>> Tom W0VJ
>>
>> On 5/4/2012 7:22 AM, Carl wrote:
>>> The first series of tests even had the MFJ coils catching on fire in the
>>> ARRL lab at well under power ratings on 160.
>>>
>>> Tuners with 250pf max on 160 will always be inefficient, a High C tuner with
>>> 500pf will be very efficient and require proportionally less L. The higher Q
>>> results in less bandwidth so there is no free lunch.
>>>
>>> Its so much easier to modify an amp to be able to do the matching and toss
>>> the tuner in the dumpster.
>>>
>>> Those with autotune amps are left swinging in the wind and need autotune
>>> tuners (-;
>>>
>>> Carl
>>> KM1H
>>>
>>>
>>>
>>> Carl
>>> KM1H
>>> ----- Original Message -----
>>> From: "Roger (K8RI)"<k8ri@rogerhalstead.com>
>>> To:<amps@contesting.com>
>>> Sent: Friday, May 04, 2012 3:32 AM
>>> Subject: Re: [Amps] Antenna tuner loss
>>>
>>>
>>> On 5/3/2012 12:32 PM, Dan Hearn wrote:
>>>> ARRL tested some popular commercial antenna tuners and reported the
>>>> results in QST as follows. They covered 160-10 and various loads. All were
>>>> quite lossy on the low bands with low Z loads.
>>> And there are people out there that didn't expect this? They are
>>> running into low impedance loads which means high currents and high
>>> losses. I believe the Palstar manual even mentions this. Also the
>>> power handling capability drops off substantially with low Z loads
>>>
>>> 73
>>>
>>> Roger (K8RI)
>>>> February, 2003
>>>> Product Reviews
>>>> High Power Antenna Tuners:
>>>> • AMERITRON ATR-30
>>>> • MFJ-986
>>>> • PALSTAR AT1500CV
>>>> • TEN-TEC 238A
>>>> • VECTRONICS HFT-1500
>>>>
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