Re: LF: Re: 136kHz LPF toroids?

[Gary - G4WGT <g4wgt@tiscali.co.uk>]

Mal,

I was making the point clear as Roger is a UK amateur & 1 watt ERP is currently the legal maximum on the 136kHz band.

Gary - G4WGT.

On 25 July 2010 19:52, mal hamilton <g3kevmal@talktalk.net> wrote:

No so, only in the UK generally, and 10w erp has been authorised in the past,  other countries 20 plus watts erp.

If you have a vy small antenna you would need around 5Kw to get 1w erp and would need about 10 T-200 toroids stacked times 2 for your filter.

The trend in the past on 137 has been to work long haul with the odd local QSO.

mal/g3kev

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

From: Gary - G4WGT

To: rsgb_lf_group@blacksheep.org

Sent: Sunday, July 25, 2010 7:39 PM

Subject: Re: LF: Re: 136kHz LPF toroids?

Hi Mal,

You wrote :-

The aim on this band is for at least 1W erp

The maximum allowed ERP for this band (136kHz) is 1 watt ERP.

73

Gary - G4WGT.

On 25 July 2010 19:19, mal hamilton <g3kevmal@talktalk.net> wrote:

Roger

A T- 200 is ideal but maybe too large for u. Except you have a large antenna 20w is not enough on 137 for any serious impact.

The aim on this band is for at least 1W erp

de mal/g3kev

 

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

From: Roger Lapthorn

To: rsgb_lf_group@blacksheep.org

Sent: Sunday, July 25, 2010 6:58 PM

Subject: LF: 136kHz LPF toroids?

Some advice please....

1. I'm about to construct a 136kHz transverter with an output power up to 20W. What's the best choice of toroid for the TX output low pass filter inductors for this sort of power level?  Around 54uH is required and this is rather too much for a T50 (red) toroid that I used on 500kHz. I don't want anything too physically large if I can avoid it.
2. Also, are there any readily available canned inductors (or toroids) suitable for use as the input tuned circuit on RX? Something like the KANK3333 inductors from Toko? Again, nothing too big unless this is a necessity for large signal handling.

Thanks in advance for inputs.

73s
Roger G3XBM

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