LF: Re: 'JNT Dual purpose beacons

["James Moritz" <james.moritz@btopenworld.com>]

Dear Andy,

I would suggest a frequency between 503.825 and 503.900, to avoid the QRM 
around 504kHz some people experience, and give a bit of tolerance for 
receiver frequency errors, which are sometimes suprisingly large. For some 
reason, the frequencies below 503.9 seem to be less widely used. But since 
there are only about half a dozen stations transmitting in this mode, there 
is plenty of space.
A 25% or 33% duty cycle seems to be frequent enough to catch most 
"openings" - probably less would be OK. As for power, I would suggest 
running as much as possible - monitoring signal level of a strong beacon  is 
easier than a weak one, and a relatively high power will give the greatest 
chance of being received by the maximum number of stations under the maximum 
range of conditions. You could argue that the presence of a "strong" beacon 
would sometimes prevent reception of very weak signals nearby in frequency, 
but since this only can happen 25% or 33% of the time, and the signal is not 
so strong at a few 100 mW ERP,  it is probably not a serious objection in 
practice.
Cheers, Jim Moritz
73 de M0BMU