[Elecraft] JT65A output power variations
hb9ari
hb9ari at bluewin.ch
Thu Nov 12 03:41:30 EST 2009
Hello,
Many thanks to Julian, Lance, Matt, Richard, Ken, Joe and Lyle
for interesting considerations derived from my "JT65 output power
variations" subject!
To conclude,
DATA A is perfectly usable with VOX: i will migrate to this mode
Compression is not recommended: i never use it
From my side i will (re)verify the following points:
-1- Use of 8poles 2.8kHz for TX
-2- TX EQ set to "flat"
-3- Soundcard output level ~ constant (i've done that as 1st searching
procedure but to reverify...)
TNX one more time and
73, Rudolf
PS (OT) Matt, for me, West Coast contacts were done on 14MHz or 18MHz
between 15:00 and 18:00 UTC (when conds were good!). For me, when i'm
ready at my shack and if conds seems good, i can e-mail to your private
address;
i'm internet ready with a wireless modem, slow but usable.
Matt Zilmer wrote:
> OK Rudolf or Rudi (for JT65),
>
> I don't know what date to suggest for a schedule. If you keep me in
> mind and let me know what band you'll be on (and when), I'll try to
> get on the air. I also have not worked HB-land on JT65.
>
> I have you in monitoring log at SNR -26, which is workable - or at
> least it was on that night.
>
> :)
>
> 73,
> matt W6NIA
> K3 #24
> K2 #2810
>
> On Wed, 11 Nov 2009 23:57:14 +0100, you wrote:
>
>
>> Hi Matt,
>>
>> I enjoy to contact you in JT65 before Winter "break"!
>> My shack is in a camping site and accessible only
>> during not too cold days (805m over sea level)
>> At home QTH, i work with my old coil loaded mobile
>> Hustler antenna fixed at balcony at 3rd floor with ~30°
>> tilt from vertical position...
>> If i remember, i've never contacted the West coast with
>> this configuration; may be for this Winter???
>>
>> 73 QRO de Rudi (instead of Rudolf for JT65...), HB9ARI
>>
>> Matt Zilmer wrote:
>>
>>> Ken & Rudi,
>>>
>>> I monitored you two working on 20m JT65A a few days ago, when I was
>>> getting this computer set up and the levels right (again - new
>>> laptop). Any idea how many other K3'ers are into JT65A?
>>>
>>> 73,
>>> matt W6NIA
>>> K3 #24
>>>
>>> On Wed, 11 Nov 2009 13:10:25 -0800 (PST), you wrote:
>>>
>>>
>>>
>>>> Rudolf,
>>>>
>>>> We have worked many times on JT65A , I also use a K3.
>>>> I operator in the Data mode , ( setup data mode for USB )
>>>> and have had no problem for about a year.
>>>> I think this is the best way to run data modes.
>>>> I set the shift at 1250 hz and the BW at 1200 HZ.
>>>> The JT65 software only looks at 1200 hz bandwidth.
>>>> This works for me.
>>>> GL 73 Ken K5DNL
>>>>
>>>> ------------------------------------------------------------------
>>>>
>>>>
>>>> --- On Wed, 11/11/09, hb9ari <hb9ari at bluewin.ch> wrote:
>>>>
>>>>
>>>>
>>>>> From: hb9ari <hb9ari at bluewin.ch>
>>>>> Subject: Re: [Elecraft] JT65A output power variations.
>>>>> To: "Elecraft-forum" <Elecraft at mailman.qth.net>
>>>>> Date: Wednesday, November 11, 2009, 9:59 AM
>>>>> Hello Matt,
>>>>>
>>>>> Yes, TX EQ is flat. I've tried to compensates
>>>>> with TX EQ, but i've all "reseted" to "flat".
>>>>>
>>>>> Thank you for this indication.
>>>>>
>>>>> 73 QRO de Rudolf
>>>>> HB9ARI
>>>>>
>>>>> Matt Zilmer wrote:
>>>>>
>>>>>
>>>>>> Since you're using USB, you might want to be sure you
>>>>>>
>>>>>>
>>>>> have the TX EQ
>>>>>
>>>>>
>>>>>> "flat". Or use DATA A, where the EQ doesn't
>>>>>>
>>>>>>
>>>>> apply.
>>>>>
>>>>>
>>>>>> 73,
>>>>>> matt W6NIA
>>>>>>
>>>>>> On Wed, 11 Nov 2009 11:28:36 +0100, you wrote:
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>> Hi Julian,
>>>>>>>
>>>>>>> Thank you for your fast answer!
>>>>>>> A 1st point, as with the FT857, i'm using
>>>>>>> USB mode for JT65A. For the filter used,
>>>>>>> i ordered a 8 poles 2.8k with my K3,
>>>>>>> but i'm not sure if the 5 poles 2.7k "original"
>>>>>>> and always installed as FIL2 is not
>>>>>>> selected during TX???; next week-end, when
>>>>>>> active at my "external" shack, i will look how
>>>>>>> to remove the 2.7k filter, as i've also problem
>>>>>>> with center filter when i adjust the HI LO
>>>>>>> filter controls; when the 2.7k filter is
>>>>>>>
>>>>>>>
>>>>> (automatically)
>>>>>
>>>>>
>>>>>>> selected, i've a big discontinuity with
>>>>>>>
>>>>>>>
>>>>> filter setting.
>>>>>
>>>>>
>>>>>>> As you say, i will look if the 2.7k is not
>>>>>>>
>>>>>>>
>>>>> selected
>>>>>
>>>>>
>>>>>>> during TX. I read also the "problems" when in
>>>>>>> DATA A mode, but as said, i'm working in USB
>>>>>>> (as recommended for JT65A for all RF bands)
>>>>>>> and VOX work at perfection too.
>>>>>>>
>>>>>>> My best 73, Rudolf
>>>>>>> HB9ARI
>>>>>>>
>>>>>>> PS As i expect to get 50W output when i set
>>>>>>> the control to 50W, i've adjusted the audio input
>>>>>>> level for max bars on ALC. For PSK31, i work
>>>>>>> with ~ 10 to15W max for 100W selectes with
>>>>>>> the control and "local" receiving give me an
>>>>>>>
>>>>>>>
>>>>> "acceptable"
>>>>>
>>>>>
>>>>>>> -24 to -28dB IMD.
>>>>>>>
>>>>>>>
>>>>>>> Julian, G4ILO wrote:
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>> hb9ari wrote:
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>>> Hello,
>>>>>>>>>
>>>>>>>>> As i use principally JT65A (snice ~
>>>>>>>>>
>>>>>>>>>
>>>>> 2years),
>>>>>
>>>>>
>>>>>>>>> i've remarked transmit output power
>>>>>>>>>
>>>>>>>>>
>>>>> variations
>>>>>
>>>>>
>>>>>>>>> depending where the audio is located in
>>>>>>>>>
>>>>>>>>>
>>>>> the waterfall,
>>>>>
>>>>>
>>>>>>>>> as i'm not speaking English, it's
>>>>>>>>>
>>>>>>>>>
>>>>> difficult to explain correctly;
>>>>>
>>>>>
>>>>>>>>> if i'm ~ in the middle of the waterfall (~
>>>>>>>>>
>>>>>>>>>
>>>>> 1200Hz)
>>>>>
>>>>>
>>>>>>>>> i get over 3dB in output power variations;
>>>>>>>>>
>>>>>>>>>
>>>>> for an expected
>>>>>
>>>>>
>>>>>>>>> 50W output power, between some tones of
>>>>>>>>>
>>>>>>>>>
>>>>> the JT65A
>>>>>
>>>>>
>>>>>>>>> modulation, the output level can vary from
>>>>>>>>>
>>>>>>>>>
>>>>> 20W
>>>>>
>>>>>
>>>>>>>>> to 60W; if i'm working away from the
>>>>>>>>>
>>>>>>>>>
>>>>> "middle",
>>>>>
>>>>>
>>>>>>>>> variations are lower and acceptable but
>>>>>>>>>
>>>>>>>>>
>>>>> most
>>>>>
>>>>>
>>>>>>>>> of time, "central" frequencies are
>>>>>>>>>
>>>>>>>>>
>>>>> used...
>>>>>
>>>>>
>>>>>>>>> I've always worked with this "problem" as
>>>>>>>>>
>>>>>>>>>
>>>>> i
>>>>>
>>>>>
>>>>>>>>> expect some AGC effect by the receiving
>>>>>>>>>
>>>>>>>>>
>>>>> side...
>>>>>
>>>>>
>>>>>>>>> I would appreciate to have an explanation
>>>>>>>>> of this effect.
>>>>>>>>>
>>>>>>>>>
>>>>>>>>>
>>>>>>>>>
>>>>>>>>>
>>>>>>>>>
>>>>>>>> This topic has been brought up before in the
>>>>>>>>
>>>>>>>>
>>>>> context of RTTY. The reason is
>>>>>
>>>>>
>>>>>>>> that there is no automatic level control in
>>>>>>>>
>>>>>>>>
>>>>> DATA A mode (or rather, there
>>>>>
>>>>>
>>>>>>>> is, but it is very slow acting to avoid
>>>>>>>>
>>>>>>>>
>>>>> causing IMD on PSK31 signals) so
>>>>>
>>>>>
>>>>>>>> there is no compensation for ripples in the
>>>>>>>>
>>>>>>>>
>>>>> roofing filter passband. It has
>>>>>
>>>>>
>>>>>>>> been suggested that the problem is less when
>>>>>>>>
>>>>>>>>
>>>>> using the 8-pole SSB roofing
>>>>>
>>>>>
>>>>>>>> filter as it has less ripple than the standard
>>>>>>>>
>>>>>>>>
>>>>> 5-pole filter.
>>>>>
>>>>>
>>>>>>>> The output should not vary as much as you
>>>>>>>>
>>>>>>>>
>>>>> suggest while working within the
>>>>>
>>>>>
>>>>>>>> normal passband for JT65A operation so I'm
>>>>>>>>
>>>>>>>>
>>>>> wondering if you have correctly
>>>>>
>>>>>
>>>>>>>> adjusted the audio input level in DATA A to
>>>>>>>>
>>>>>>>>
>>>>> get 5 bars on the ALC scale.
>>>>>
>>>>>
>>>>>>>> This will not prevent the power varying for
>>>>>>>>
>>>>>>>>
>>>>> different tones during a
>>>>>
>>>>>
>>>>>>>> transmission but it should help maintain a
>>>>>>>>
>>>>>>>>
>>>>> constant average level when
>>>>>
>>>>>
>>>>>>>> working at different places within the
>>>>>>>>
>>>>>>>>
>>>>> passband.
>>>>>
>>>>>
>>>>>>>> -----
>>>>>>>> Julian, G4ILO. K2 #392 K3 #222.
>>>>>>>> * G4ILO's Shack - http://www.g4ilo.com
>>>>>>>> * KComm - http://www.g4ilo.com/kcomm.html
>>>>>>>> * KTune - http://www.g4ilo.com/ktune.html
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>> ______________________________________________________________
>>>>>
>>>>>
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>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>> ______________________________________________________________
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>>>>>
>>>>>
>>>>
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>>>
>>>
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>
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