[BC] X-Banders - Was: Can traditional AM and IBOC co-exist?

[PeterH5322@aol.com]

>> X-banders are Class Bs, and Class Bs are required as a minimum (and are 
>> permitted as a maximum) 281.63 mV/m/kW at 1 km.
>> 
>> This is about 80 degrees, give or take.
>> 
>> While the Commish seems to let X-banders operate 10/1 kW with radiators 
>> of a "reasonable" height, say, 80 to 110 degrees, with 90 degrees being 
>> customary, X-banders who install, or are diplexed with taller sticks, 
>> say, 180 or 200 or 225 degrees, all good heights for this service, are 
>> still bound by 281.63 mV/m/kW at 1 km.
>
>Check KKGM, FT. WORTH.  263.70 deg. FCC shows 10 kW which must be an
>"ERP" because they also show 282.00 mV/m at 1 kilometer theoretical.

Licensed operation of KKGM is co-located with KHVN.

KKGM's 282.00 mV/m/kW at 1 km and a 263.70 degree tower is a tip-off that 
the efficiency is faked.

I don't know the particulars, but the operation could indeed be 10/1 kW, 
using a resistor to dump much of the power, thereby producing 282.00 mV/m 
per kW of input.

The KHVN LIC is 970 kHz, 1 kW-D, 0.27 kW-N, ND, Class B, 156.9 degrees, 
308.99 mV/m/kW at 1 km, which also seems faked.


(If this was pre-"Rio", KHVN would be a Class III-D, as Class III 
full-timers had a minimum night power of 0.5 kW).


CP for KKGM is 10/1 kW, ND2, 164 degrees, 361.6 mV/m/kW at 1 km, which 
seems more real, but on the weak side. Perhaps a truncated ground system 
is being used.

App for KHVN is co-located with KKGM's CP, and is 0.6/0.24 kW, ND2, 97.6 
degrees, 285 mV/m/kW at 1 km, which seems real, but on the weak side. 
Same comments as to the ground system.


If a station on a regional or clear channel can produce an RMS of at 
least 281.63 mV/m at 1 km, it is a Class B. Less than that, and it is a 
Class D.


As an exercise, let's see what the minimum power required to be a Class B 
is, assuming a tower of optimum height.

The maximum efficiency for a non-sectional would be 225 degrees, from 
which 440mV/m/kW at 1 km would be developed.

The power for 281.63 mV/m at 1 km and 0.25 kW (the minimum power for a 
Class B), but using a 225 degree stick is 102 watts.

That is, 102 watts into a 225 degree stick would produce 281 mV/M at 1 
km, the same horizontal field as 0.25 kW into a minimum conforming 
radiator, so even a 100 watter could be a Class B.