Craig,
As Tom and others quite rightly reminds us, unwanted outputs from TX
come in a wide variety of forms.
I remember, many years back, doing a 160 meter contest in which (to
try to gain an edge) we ran 'duplex' using a second receiver on a
separate low dipole about 1 wavelength and at right angles to the
main TRx dipole at 100 feet. The setup did work remarkably well, but
the limiting factor was the phase and other wideband noise rather
than the close in stuff. As I recall, an IC-735 as the TRx was
noticeably worse than an old FT-101 in this regard. I think UK
coastal radio stations would put all the TX on one site and all the
RX on another, several miles away. Some one knew 'too difficult'
when they saw it!
I hadn't realised the old TS-50 had a good reputation. Will check
that out as they are quite cheap radios on the used market now.
Personally, I find that the ARRL and RSGB technical reviews are still
the best guides as to ham radio equipment performance. While the
text of reviews sometimes appears 'dumbed down', the figures usually
speak for themselves.
Regards.
Mark.
---------------------------------------------
At 11:32 03/07/2006, zdtech wrote:
>Hi Mark
>
>I believe its not so much the 3rd order products but the higher
>order products that causes the problems. I believe even the MK5 has
>the problem of ALC induced splatter. However you are correct in
>stating that the Mk5 in class A has the best 3rd IMD figures
>around. However considering that the HF8010A is typically down 50 db
>and it does not use a class A final says something about its design.
>See the work by SM5BSZ, it makes for some interesting reading. The
>Little TS50 has by his measurements some of the best close in and
>wideband IMD numbers. Likewise the FT1000D. I have been wanting
>to buy a clean transmitter but have not settled on one because of
>this very reason. Can you recommend any commercial or ham
>transmitter that has very good IMD suppression?
>
>Craig
>VK3HE
>
>
>
>
>
>Mark Hill wrote:
>>Craig,
>>
>>Surely, for purity and on SSB, a Yaesu FT-1000MP Mk-V with th PA
>>set to class 'A' would not insult too much?! Is the Rockwell even better?
>>
>>Regards.
>>
>>Mark.
>>
>>---------------------------------------------
>>At 05:30 03/07/2006, zdtech wrote:
>>
>>>Whats interesting is that if you look at the Eimac published data on the
>>>4CX10000D running at 1350 volts on the screen, the 3rd order IMD
>>>figure is close or equal to the 4CX10000J's. This data comes from Care
>>>and Feeding, the old edition. Considering that you need a higher
>>>filament current transformer i would say its advantages are small
>>>compared to the readily available D version. However if you picked them
>>>up at a cheap price one would never say no! The 4CX600J or 4cx350FJ
>>>would make a super driver for this J rated bottle. However it would be
>>>a insult to drive any of these tubes with the any of the current model
>>>ham model transceivers. The Rockwell HF 8010A would be a superb low IMD
>>>driver match for these excellent tubes..
>>>
>>>Craig
>>>VK3HE
>>>
>>>Peter Voelpel wrote:
>>>
>>>>All the J-types are low distortion, gain of both is about 20db
>>>>
>>>>73
>>>>Peter, DF3KV
>>>>
>>>>-----Original Message-----
>>>>From: amps-bounces@contesting.com [mailto:amps-bounces@contesting.com] On
>>>>Behalf Of Joe Subich, W4TV
>>>>What are the differences between the 4CX1000J and 4CX10000D -
>>>>particularly to explain the 10 KW vs. 15 KW output difference
>>>>in the "normal operation" figures on the Eimac short form
>>>>catalog (www.cpii.com/eimac)? Of course, with a listed gain
>>>>of 4.5, it would seem to take 2500 W or so to drive either of
>>>>them to their full capability ...
>>>>
>>>>
>>>>
>>>>_______________________________________________
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>>>>Amps@contesting.com
>>>>http://lists.contesting.com/mailman/listinfo/amps
>>>>
>>>>
>>>>
>>>_______________________________________________
>>>Amps mailing list
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>>>http://lists.contesting.com/mailman/listinfo/amps
>>>
>>
>>*******************************************
>>Mark Hill - G4FPH
>>E-mail: g4fph@mjha.co.uk
>>Current web pages at: www.g4fph.net
>>Old web pages at: www.qsl.net/g4fph
>>----------------------------------------------------------------------
>>Dipoles resonant on 1942 / 3720 / 7085 kHz
>>Three element wire beam coming soon on 14180 kHz!
>>----------------------------------------------------------------------
>>Remember - SIDE for HV safety:
>>S witch off
>>I solate
>>D ump
>>E arth
>>*******************************************
>>
>>
>>_______________________________________________
>>Amps mailing list
>>Amps@contesting.com
>>http://lists.contesting.com/mailman/listinfo/amps
>>
>>
>
*******************************************
Mark Hill - G4FPH
E-mail: g4fph@mjha.co.uk
Current web pages at: www.g4fph.net
Old web pages at: www.qsl.net/g4fph
----------------------------------------------------------------------
Dipoles resonant on 1942 / 3720 / 7085 kHz
Three element wire beam coming soon on 14180 kHz!
----------------------------------------------------------------------
Remember - SIDE for HV safety:
S witch off
I solate
D ump
E arth
*******************************************
_______________________________________________
Amps mailing list
Amps@contesting.com
http://lists.contesting.com/mailman/listinfo/amps
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