Re: Nova Scotia Boston DX

[Dan Strassberg <dan.strassberg@worldnet.att.net>]

At 02:52 PM 6/3/97 +0000, you wrote:
>I said:
>
>> Bob says that that gives 'BZ an ERP of 100kw to the west; given 
>>the way the signal bombs across the eastern US, I can believe that.
>
>And Dan Strassberg replies:
>
>>100 kW is conservative. Given that most stations use less efficient 
>antennas
>>(the minimum efficiency for most classes of AMs is 175 
>mV/m/kW--unattenuated
>>at 1 mile) and WBZ (and nearly all other Class Is) uses half-wave towers,
>>which produce in excess of 240 mv/m/kW, the effect is more like 200 kW.
>
>I would guess that WBZ is slightly less efficient than that, because I 
>believe their Hull towers are actually half-wave at their pre-NARBA 
>frequency (990, I think).  I suppose it doesn't matter all that much in the 
>long run.

If that's true, and I don't think it is, the towers would be an even greater
fraction of a wavelength at 1030. Wavelength is inversely proportional to
frequency. What's 0.5 wavelength at 990 is 0.52 wavelength at 1030. I have
always suspected that NARBA moved nearly all stations up the dial, rather
than down, for just this reason. One exception was what is now 1490; it used
to be 1500. But I suspect that WBZ's move from Millis to Hull was
coordinated with NARBA. Donna: do you know? I think NABA took effect
sometime in March 1940, although I don't know the exact date. I'm pretty
sure BZ's TX move did take place in 1940. If it took place in March, we can
be reasonably certain that the move in location and the move in frequency
took place at the same time.

- -------------------------------
Dan Strassberg (Note: Address is CASE SENSITIVE!)
ALL _LOWER_ CASE!!!--> dan.strassberg@worldnet.att.net
(617) 558-4205; Fax (617) 928-4205

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