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
>>>
>>
>> _______________________________________________
>> Amps mailing list
>> Amps@contesting.com
>> http://lists.contesting.com/mailman/listinfo/amps
>>
>>
>> -----
>> No virus found in this message.
>> Checked by AVG - www.avg.com
>> Version: 10.0.1424 / Virus Database: 2411/4976 - Release Date: 05/03/12
>>
>>
>> _______________________________________________
>> 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
_______________________________________________
Amps mailing list
Amps@contesting.com
http://lists.contesting.com/mailman/listinfo/amps
|