Re: LF: Re: RTTY QSO 500 KHz

["DENNIS EASTERLING" <dennis.easterling@btinternet.com>]

Hi Graham

 

Regarding my RTTY, am using MTTY software with PTT and FSK signals taken via the computer COM port to TX via two 2N2222 transistors operating as emitter followers.   The output of the FSK stage goes via 5k to a 1k pot with a forward biased silicon diode across it, to stabilise the voltage at 0.6V.  The slider selects the amount of voltage fed via a 68k resistor to a BA102 varactor in series with a 25pF trimmer, which is across the tuned circuit of the VFO.   The slider sets the amount of shift from 23Hz to 170Hz, though I would not like to rely on the 23Hz setting too much, owing to slight drift.  This arrangement normally works well, but I had problems with Chris due to a modification I made to the VFO for another purpose.  I am thinking of replacing the 2N2222s with opto-isolators, in an attempt to reduce noise on receive.   I also plan to try a loop antenna at the end of the garden for the same purpose.

 

73 Dennis M0JXM.

----- Original Message -----

From: Graham

To: rsgb_lf_group@blacksheep.org

Sent: Wednesday, October 22, 2008 10:03 PM

Subject: Re: LF: Re: RTTY QSO 500 KHz

Dennis,

 

Interesting on the rtty contact, what method are you using for 'tx' ?

 

What is your locator square ? you may be in the 'dead zone' in terns of distance , Gary and myself are roughly the same distance north , but after 70 miles or so ,there is a 'dead zone' till about 200 , I don't know, may be a band 100 miles wide after that, that's a problem with the band and as you can see at 600 miles, signals show up  quite well at Shetland, while not showing at Glasgow

 

 

 

I posted this 18/10 , :  was that you on cw ?

 

Seeing a very  low signal on 502.350 no audio .. looks like a cw cq call ?  60 second tx with 'gap'

 

35 ft top load .. no atu ... ft897-d  atten 'on'

 

G

 

G0NBD

 

IO83LK

From: DENNIS EASTERLING

Sent: Wednesday, October 22, 2008 5:54 PM

To: rsgb_lf_group@blacksheep.org

Subject: LF: Re: RTTY QSO 500 KHz

Hi Gary

 

You may have heared me using RTTY on the 18th as I had a QSO with Chris G3XIZ earlier which went wrong, and was testing my TX later during your QSO with him.   My main problem is that I appear to be getting our reasonably well, but not so good on receive so didn't hear you.

Sorry about that.   I am working on the receive problem which is probably due to high QRN at my location.

 

73 Dennis M0JXM

 

----- Original Message -----

From: Gary - G4WGT

To: LF -RSGB LF Group

Sent: Saturday, October 18, 2008 8:28 PM

Subject: LF: RTTY QSO 500 KHz

Hi LF,

 

Just had a good RTTY QSO with Chris G3XIZ.

 

Is there any other station can use RTTY, 45 Baud, 85 Hz shift ?

 

Please look for my CQ calls on 503.600 KHz

 

73,

 

Gary - G4WGT - IO83QP.

 

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