Message-ID: <008201c81ce8$6d0d7cd0$0d00000a@AGB>
From: "Graham" <g8fzk@g8fzk.fsnet.co.uk>
To: <rsgb_lf_group@blacksheep.org>
References: <001101c81a9a$0be1eae0$f11e7ad5@w4o8m9> <1148957206.20071030081706@gmx.de> <001f01c81aeb$c8d92590$0e00000a@AGB> <001601c81b09$2b5e11e0$eb047ad5@w4o8m9> <000701c81b36$b23598a0$c8197ad5@w4o8m9> <001d01c81b4b$dfd78600$4b1f7ad5@w4o8m9> <016a01c81ba4$8768d4c0$6f6a6a58@wgt01> <002f01c81be8$63ee8dc0$1e1a8351@w4o8m9> <004901c81cd0$3a505e60$0d00000a@AGB> <002501c81cdf$7e3ef8c0$90297ad5@w4o8m9>
Date: Fri, 2 Nov 2007 00:36:36 -0000
MIME-Version: 1.0
Subject: Re: LF: EER Transverter and Linear Modes testing
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----- Original Message ----- 
From: "James Moritz" <james.moritz@btopenworld.com>
To: <rsgb_lf_group@blacksheep.org>
Sent: Thursday, November 01, 2007 11:32 PM
Subject: Re: LF: EER Transverter and Linear Modes testing


> Dear Chris, Graham, LF Group,
>
> Thanks to G3XIZ earlier this evening for a nice RTTY QSO on 503.5kHz. I 
> used
> MMTTY with 85Hz shift, and everything worked fine - mind you, Chris is not
> far from me, and is a good 599 signal.
>
> I am currently (2310utc) sending some test calls on 503.5kHz in PSK31 
> using
> G3PLX's Windows software - any reports/QSOs welcome.
>
>
>> Hi Jim,
>>
>>
>>
>> Interesting on the system, How are you driving it ?
>>
>>
>>
>> As for 'tests' well , what's the audio bandwidth of you system ? , 
>> looks
>> like most modes are in multipsk , but for rtty at  85 hz shift , mmtty
> has
>> that option
>>
> The driver is an IC 718 transmitting on 4.50x MHz in LSB mode, connected 
> to
> the PC sound card in the usual way for data operation. So the bandwidth is
> about 2.7kHz, although I would not want to use it all! The HF output is
> mixed down to 500 kHz with a 4MHz crystal, and also fed to a simple diode
> envelope detector to recover the modulation envelope. The 500kHz output is
> filtered and amplified linearly to about +13dBm, then applied to a 
> limiting
> amplifier to give a square wave "clock" signal for the class D output 
> stage
> with the amplitude modulation stripped off, but retaining the frequency 
> and
> phase information. The envelope detector output is used as a reference
> voltage for a series regulator feeding the DC power to the class D PA, so
> the DC supply voltage is modulated with the envelope of the original 
> signal.
> The result is the output of the class D PA looking pretty close to the
> original modulated signal. On receive, the signal path is reversed, and 
> the
> incoming signal mixed up to 4.5MHz for reception by the IC718.
>
> I have been looking at the software on NL9222's extensive download site,
> there seems to be a number of feasible modes there that might be worth
> trying - I will try installing some over the next few days.
>
> Cheers, Jim Moritz
> 73 de M0BMU
>


Ok Jim,

Thanks for that , Is this a published dsesign or your own ? , Ive added a 
page to  the 'ng'

http://groups.google.com/group/uk500khz/web/eer-transmitting

Looks like a few  stations are intrested in this , may be you can add any 
links or data to  the page ? what you describe looks to  fit with the 
general descriptions of the 'mode' , Q, do you have any problem with the 
'envalope = zero' issue ?

I can see your signal  at the moment (00-30 hrs) but its too low to  print . 
looks like a good signal at Bham ,  dont know about 'rtty' think we should 
call it 'skippy' hih ,  I did see a stronger signal earlly on, which may of 
printed ..

If your about , friday night , I will rig the tx up , see if  we can do 
anything , early in the evening , after sunset is usually the  best  signals 
from london area ?

G ..