[Elecraft] JT65A output power variations.
hb9ari
hb9ari at bluewin.ch
Wed Nov 11 17:57:14 EST 2009
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
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>> ______________________________________________________________
>>>
>>>>> Elecraft mailing list
>>>>> Home: http://mailman.qth.net/mailman/listinfo/elecraft
>>>>> Help: http://mailman.qth.net/mmfaq.htm
>>>>> Post: mailto:Elecraft at mailman.qth.net
>>>>>
>>>>> This list hosted by: http://www.qsl.net
>>>>> Please help support this email list: http://www.qsl.net/donate.html
>>>>>
>>>>>
>>>>
>>>>
>>> ______________________________________________________________
>>> Elecraft mailing list
>>> Home: http://mailman.qth.net/mailman/listinfo/elecraft
>>> Help: http://mailman.qth.net/mmfaq.htm
>>> Post: mailto:Elecraft at mailman.qth.net
>>>
>>> This list hosted by: http://www.qsl.net
>>> Please help support this email list: http://www.qsl.net/donate.html
>>>
>>>
>>
>> ______________________________________________________________
>> Elecraft mailing list
>> Home: http://mailman.qth.net/mailman/listinfo/elecraft
>> Help: http://mailman.qth.net/mmfaq.htm
>> Post: mailto:Elecraft at mailman.qth.net
>>
>> This list hosted by: http://www.qsl.net
>> Please help support this email list: http://www.qsl.net/donate.html
>>
>
>
More information about the Elecraft
mailing list