LF: Decca 5501-9f tuning

[Terry GW0EZY <gw0ezy@sky.com>]

Mal

 

Would appreciate a confirmation from you or anyone who has converted a 5501-9f:

 

For each of the 3 tank assemblies, I added 2 x 100 nF parallel connected Wima Cs in series with the C5-C12 bank.  This then matches the C13-C22 bank giving 10 series/parallel 100nF in each bank. I also removed C23 4.7 nF connected in parallel with  C5-C12 and C24 4.7 nF connected in parallel with C13-C22. Removal of C23 and C24 wasn’t mentioned in the G0MRF conversion notes.

 

I am driving with one of the 5 MHz DDS from eBay. This allows an easy sweep across the frequency range to check everything peaked on 137 kHz, with no guard current showing. The signal looked clean on my SDR-IQ.

 

73 Terry

 

From: owner-rsgb_lf_group@blacksheep.org [mailto:owner-rsgb_lf_group@blacksheep.org] On Behalf Of Terry GW0EZY
Sent: 07 May 2012 16:06
To: rsgb_lf_group@blacksheep.org
Subject: LF: RE: Re: RE: LF QSO - UK / EU?

 

Mal

 

A coincidence you should ask!

 

I finally got round to building a big variable PSU (20 Amp Variac feeding a 3kVa site transformer + bridge rectifier and capcaitor) did the mods to the 5501 and it fired up perfectly. At least 5A antenna current showing on the meter and my 1200 Watt dummy load warming nicely. Input 67 Volts at 22 Amps.

 

Thanks very much for the Tx. Just Have to sort out the antenna now.

 

73 Terry

 

From: owner-rsgb_lf_group@blacksheep.org [mailto:owner-rsgb_lf_group@blacksheep.org] On Behalf Of mal hamilton
Sent: 07 May 2012 15:56
To: rsgb_lf_group@blacksheep.org
Subject: LF: Re: RE: LF QSO - UK / EU?

 

Terry

Have you fired the big rocket yet ?

mal/g3kev

 

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

From: Terry GW0EZY

To: rsgb_lf_group@blacksheep.org

Sent: Monday, May 07, 2012 2:41 PM

Subject: LF: RE: LF QSO - UK / EU?

 

Hi Chris

 

Just to let you know I am copying you in GW!!

 

Sorry no Tx.

 

73 Terry GW0EZY - IO82HO 12k West Welshpool

 

From: owner-rsgb_lf_group@blacksheep.org [mailto:owner-rsgb_lf_group@blacksheep.org] On Behalf Of Chris Osborn
Sent: 07 May 2012 15:01
To: LF Group
Subject: LF: LF QSO - UK / EU?

 

LF,

 

Does anyone want a QRSS / DFCW (or even a CW !) QSO on LF ?

I've been calling and sending test signals for ages on 137.7 kHz and will be in the shack for another hour or so.

 

73

Chris G3XIZ