Technical details of CFH (137kHz)]

Andre' Kesteloot
Wed, 03 Nov 1999 09:31:10 -0500

Alan Melia wrote:

> Thanks to Jon VE1FTL I have the following interesting details on the system
> at CFH. Jon says it is a Canadian Naval site and gives the location as
> Newport Corner.
> The transmitter is aging valve unit, capable of 25KW, but more usually run
> at 8 to 9 kW.
> Modulation is FSK +/- 42.5Hz from the nominal carrier. This power
> corresponds to 30 to 40 Amps into the aerial, which is what I think would be
> called an 'umberella' . The main radiator is about 600 feet tall (Jon hadn't
> the exact dimensions to hand)  It is capacitively loaded with a system
> consisting of the top 25% of each of the six guy spans with the ends
> connected together by a circle of wire, and then 6 more wires running from
> the top to the this circular wire. Sounds a bit like the big brother of the
> systems Dick was modelling a few weeks back.
> The station is off the air for maintenance and will not return until the
> Navy requests it. The transmitter is to be replaced by a more modern
> solid-state class C unit some time early next year.
> I guess there is enough detail there for some of you guys to estimate the
> ERP. Ok we dont know what the losses are but I reckon we could make a
> reasonable guess.
> The plus point on this is that the aerial is about what I had though it
> might be, but the power is a lot less (I thought it might be a 50kW unit) so
> the margin needed to hear a amateur signal might not be so great. Of course
> the 'answer's in the soil' !!
> Once again this is all thanks to Jon, ( who is a technician on the site )
> who has promised to e-mail me when it is due to return to the air.
> 73 de Alan G3NYK