Message-ID: <4A02C555.3020704@ukonline.co.uk>
Date: Thu, 07 May 2009 12:26:13 +0100
From: Peter Dodd <g3ldo@ukonline.co.uk>
User-Agent: Thunderbird 2.0.0.21 (Windows/20090302)
MIME-Version: 1.0
To: rsgb_lf_group@blacksheep.org
References: <008501c9ce63$c07ecf30$0301a8c0@mal769a60aa920> <57a24ca70905061229w6c853f60w291cca01c39eec09@mail.gmail.com>
In-Reply-To: <57a24ca70905061229w6c853f60w291cca01c39eec09@mail.gmail.com>
Subject: Re: LF: Decca 5501Jeep
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
Content-Transfer-Encoding: 7bit
Sender: owner-rsgb_lf_group@blacksheep.org
Precedence: bulk
Reply-To: rsgb_lf_group@blacksheep.org


Hi Warren
I fully agree with you. The Decca 5501's were used in unattended 
stations and transmitting 24/7 under a very heavy duty cycle. There were 
several transmitters all in the same rack transmitting at the same time 
on different frequencies feeding into the same antenna through an 
ingenious automatic multi-tuning system - a remarkable bit of radio 
engineering.
I blew the FETs in one of the amplifier units because my 5501 had been 
modified  to be dual band 73 and 136kHz and one day when I QSYed I 
forgot to change all the necessary coil taps.
Check out G4FTCs web site for some interesting pictures of the Decca 
stations.

Regards

Peter, G3LDO

> Mal,
>
>     You couldn't be more wrong!!!
> I have been running a Decca in QRSS 60 for several years now at full
> power + often overnight and occasionally for days at time with ZERO
> transmitter failures. The Decca runs cool at 1.4 - 1.5 kW DC input.
> Perhaps you are not allowing for sufficient air circulation through
> the heat sinks. My Decca is in a rack with plenty of clearance above
> and below for the air to circulate. I don't think that it's a good
> idea to run the Decca sitting on a table as I've seen done in some
> shack pictures.
>
>