I think you mean manually select the antenna. The 2000A has that drawback, too
-- the user has to manually select the antenna. That's one reason I wrote my
own antenna switching software, which passes my antenna selection to the 2000A
and pre-selects the segment when the radio does a band change.
73, Dick WC1M
73, Dick WC1M
> On Dec 4, 2016, at 4:18 PM, MU 4CX250B <4cx250b@miamioh.edu> wrote:
>
> Very good point, Dick. The 9500 accepts 4 antennas per band segment,
> but the user has to manually select the segment.
> Jim w8zr
>
> Sent from my iPhone
>
>> On Dec 4, 2016, at 2:08 PM, Dick Green <wc1m73@gmail.com> wrote:
>>
>> That's a good strategy if you only have one antenna per band, but not if,
>> like me, you have multiple antennas and antenna combinations per band.
>> That's why I leave AlphaMax on all the time. It's a necessity. Like you, I
>> rarely use SSB, so maybe that's why autotune doesn't keep tuning.
>>
>> Ultimately, the 2000A architecture may make more sense because it allows
>> storing tuning parameters for up to 10 antennas per band. No dynamic
>> autotune, but it's not necessary unless you vary the power level a lot.
>>
>> 73, Dick WC1M
>>
>>> On Dec 4, 2016, at 3:59 PM, MU 4CX250B <4cx250b@miamioh.edu> wrote:
>>>
>>> I don't think the autotune in the 9500 is oversensitive to impedance
>>> variations. It's rather that the optimal tuning point depends on the
>>> drive level. If you tune the 9500 with, e.g., 20 Watts of drive, it
>>> will tune for maximum output and efficiency at that drive. If you
>>> increase the drive to, say, 40W, the optimal tune and load settings
>>> will be substantially changed. It's normally best to autotune the amp
>>> for its rated output of 1500W, then turn off the autotune and save
>>> that setting. That way you won't be causing the autotune to hunt if
>>> you lower the drive power. I seldom use SSB, so don't know if the
>>> autotune tries to follow fluctuating voice peaks. I hope not!
>>> 73,
>>> Jim w8zr
>>> Sent from my iPad
>>>
>>>> On Dec 4, 2016, at 1:43 PM, Dick Green <wc1m73@gmail.com> wrote:
>>>>
>>>> Strange that the factory recommends keeping autotune off. I've never found
>>>> that to be necessary with the 87A. Once it finds a match, the autotune
>>>> stops hunting. Could be that they're concerned about antennas that are
>>>> harder to match than mine, which are all resonant at the operating
>>>> frequency. That said, I my understanding is that the 9500 autotune is
>>>> considerably faster than the 87A, so maybe it's more sensitive to slight
>>>> impedance variations.
>>>>
>>>> 73, Dick WC1M
>>>>
>>>> 73, Dick WC1M
>>>>
>>>>> On Dec 4, 2016, at 12:48 AM, Bill Turner <dezrat@outlook.com> wrote:
>>>>>
>>>>> ------------ ORIGINAL MESSAGE ------------(may be snipped)
>>>>>
>>>>>> On Sat, 03 Dec 2016 19:08:33 -0800, Paul wrote:
>>>>>>
>>>>>> I believe the Alpha will auto tune if it wants to based
>>>>>> on poor SWR, but the ACOM only auto tunes when you ask it to.
>>>>>
>>>>> REPLY:
>>>>>
>>>>> The Alpha 9500 can be left in autotune mode, but the manual recommends
>>>>> against it because of continuous "hunting" for a match. This no doubt
>>>>> will cause excessive wear on the stepper motors too.
>>>>>
>>>>> Best to tune it once and shut off autotune. That's what I do and it
>>>>> works fine.
>>>>>
>>>>> 73, Bill W6WRT
>>>>>
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>>>> http://lists.contesting.com/mailman/listinfo/amps
>>>
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