Message-ID: <E0C48E9888094FD7923352AE2CBBE37C@mal>
From: <g3kevmal@talktalk.net>
To: <rsgb_lf_group@blacksheep.org>
References: <6DB8451D7F3D3947A5918808A59621EA07C88048@servigilant.vigilant.local> <1391943913.20180607115759@gmail.com> <DB5PR10MB0119680ADBCC0ECEB3F8A6A4EC640@DB5PR10MB0119.EURPRD10.PROD.OUTLOOK.COM>
In-Reply-To: <DB5PR10MB0119680ADBCC0ECEB3F8A6A4EC640@DB5PR10MB0119.EURPRD10.PROD.OUTLOOK.COM>
Date: Fri, 8 Jun 2018 16:17:30 +0100
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Subject: LF: Re: First MF transmission from Oscar LU1DOW
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Hi Jim
The mod you suggest would be easy enough technically but mechanically it 
would be difficult to fit the larger inductor required for 472 Khz into the 
cabinet
I would suggest building and external inductor/capacitor and then disable 
the internal L/C COMPONENTS and feed the RF from the tubes via a suitable 
capacitor to the external MF cct and you should be in business.
With this sort of power output you would need to ensure that the RF 
connectors, coax, and Antenna loading inductor can handle the power. 
Different ball game when using high levels of RF especially at LF/MF
Why not modify one of your DECCA amplifiers as i have done and it works a 
treat. It has been in service now for several years and is as steady as a 
rock working into my 1/4 wave inv L antenna.
73 and gl with your project
de MAL/G3KEV/SCARBOROUGH/IO94SH


-----Original Message----- 
From: James Cowburn
Sent: Thursday, June 7, 2018 12:19 PM
To: rsgb_lf_group@blacksheep.org
Subject: RE: LF: First MF transmission from Oscar LU1DOW

Great work and as has been said, nice to see a tube amp doing the heavy 
lifting !

I wonder if I could press my TL922 into service on MF?   It's lying idle 
since I got my SPE 1K.  Any comments on how I might need to mod it much 
appreciated

At the moment, I feed the signal from my Elad SDR Tx from the    0dBm output 
into a broadband 1w ebay special and then the 1w goes into a Hafler 9505 and 
gives me about 500W up the wire

Cheers


Jim G7NKS

-----Original Message-----
From: owner-rsgb_lf_group@blacksheep.org 
[mailto:owner-rsgb_lf_group@blacksheep.org] On Behalf Of Chris Wilson
Sent: 07 June 2018 11:58
To: VIGILANT Luis Fernández <rsgb_lf_group@blacksheep.org>
Subject: Re: LF: First MF transmission from Oscar LU1DOW


Hello Luis,

Please  pass  congratulations  to  Oscar  and  good  luck  on his next 
endeavour. Nice to see a valve (tube) amp in use, I am still hankering after 
building one myself for LF. Good to see Argentina on the MF map, I always 
thought they were all beef farmers or wealthy polo players ;)

Thursday, June 7, 2018, 9:17:14 AM, you wrote:

>
>
>
> Hi MF
>
>
>
> While there is only residual activity in north hemisphere, we are
> aproaching winter solstice in south hemisphere
>
>
>
> Oscar, LU1DOW, confirms his first QRSS transmissions were successfully
> received by LU8YD at 1000km. See picture attached
>
> This is the first MF ham transmission in Argentina. A great
> achievement
>
>
>
> Oscar is using a tube amplifier with a 4CX1500A running about 1400w if
> I recall correctly. The antena is a Marcony T
>
> 20m long and 20m high. He was using this setup in LF and recently
> modified it to MF but the bad weather delayed
>
> the transmissions untill now
>
>
>
> Next goal is to modify the exciter to be able to work with WSPR.
> Martin YV7MAE and Ruben EB8ARZ looks like ideal
>
> candidates to receive his transmission
>
>
>
> Good luck Oscar !
>
>
>
> 73 de Luis
>
> EA5DOM
>


-- 
Best regards,
Chris                            mailto:dead.fets@gmail.com