Re: LF: Re: Re: Re: Re: MF CW QSO /Marconi transmitters

[Stefan Schäfer <Stefan.Schaefer@iup.uni-heidelberg.de>]

Hi Bruce, Mal, MF,

Marconi transmitters? That sounds nostalgic. How old are they and what is the covered frequency range and max. output power and weight?
I would like to hear such a chirpy CW signal on the band. It is authentic :-) Reminds me on my first days on HF, where most of the russian stations had such a signal sound. I like it.
What a hobby, it never stops me from loosing the fascination.
Oh yes, hand given CW with a traditional key. I must try that soon. But my skills are very limited (not like when using CW paddles)...
Yesterday i've been on the monthly meeting of the local radio club. There are many OMs starting to build some components for 630m. Maybe it will be a very populated band next year. Looking forward to that :-)

73, Stefan/DK7FC


Am 06.09.2012 09:35, schrieb mal hamilton:

Hi Bruce

All those Marconi Transmitters were Chirpy in VFO mode, the T1154 was terrible to listen to slushing on/off in CW. How did they ever pass quality control !! in production.

The USA equipment at the time was generally very good Collins TCS 6 etc and the Amateur radio equipment was also good.

All equipmentIt is pretty good today, different technology and high quality components.

Most of my equipment for LF/MF has been home built although I now have some modified Decca Amplifiers in service.

Will look out for you again. I am active most days both on LF es MF but CW acty is poor these days compared to years ago especially on  137 Khz. MF might improve next year when everyone is on 472 -479

73 de mal/g3kev

 

 

 

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

From: Bruce Morris

To: rsgb_lf_group@blacksheep.org

Sent: Wednesday, September 05, 2012 9:17 PM

Subject: LF: Re: Re: Re: MF CW QSO

Mal, tks for the QSO.

I have a massive carrier here spot on 501 which is making any reception on adjacent freqs v difficult.

Rx is a Redifon R408 with good MF sensitivity and excellent vbl bandwith filters but even then it was difficult to separate your sigs out.

The QSO was a bit tricky because I had to swap the Ae over between Tx & Rx.

Also, I had no sidetone just the clunk of the key and subsequent relays.

RST was nearer 229.

Source is a Marconi Marine Oceanspan 7 Tx.

The Tx is xtal controlled but has a LC osc as reserve in case the 500kHz Xtal goes down.

I have tweaked it up to 501.

Unfortunately the HT supply to the osc is not sufficiently stabilised so I am surprised you gave me T=9 despite the distinct birdie tone!.

The Tx has 3 x 807s in the finals running 800V at 80mA into an impressive variometer. 

I am putting out abt 2 amps of RF into a LW Ae.

 

More work will be required to get a good stable signal out on 472 when we get it.

 

Rgds

 

Bruce  GW4XXF

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

From: mal hamilton

To: rsgb_lf_group@blacksheep.org

Sent: Wednesday, September 05, 2012 9:40 PM

Subject: LF: Re: Re: MF CW QSO

Cannot hear u

mal/g3kev

 

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

From: Bruce Morris

To: rsgb_lf_group@blacksheep.org

Sent: Wednesday, September 05, 2012 8:26 PM

Subject: LF: Re: MF CW QSO

Are you about for a quick try on 501kHz right now? I will be quite chirpy! GW4XXF

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

From: mal hamilton

To: rsgb

Sent: Wednesday, September 05, 2012 7:34 PM

Subject: LF: MF CW QSO

Anyone about for a CW qso on 472/500 Khz

Daylight suitable for me, no need to work in the dark

de g3kev