An AM station can easily produce "buckshot" to 40-50 kcs's out. The
reason you don't hear it very often in the US, is that on the standard
AM band, the AM stations are very bandwidth limited. The NRSC curve is
rather tight, and every AM station has to certify it is within that mask
every 14 months or so.
I'm not sure of this, but I think US shortwave stations are not
required to have any NRSC type filtering. Hence, the buckshot can go a
long ways.
Disconnect the LP-PAN, and measure/estimate the signal strength of
the buckshot at, say, 7005. Now, turn on the attenuator. If the level of
the buckshot drops by the level of the attenuator, then the radio
station is producing the buckshot. If the attenuated level drops 2 to 5
times more than the added attenuation, that then shows that the K3 is
overloading.
My Sunday night guess? The station is producing the buckshot. Just
an increase of .3 Db drive after the audio limiter can make just about
any transmitter produce garbage.
Tom Bosscher K8TB broadcast engineer for 3.5 decades...
Steve Ellington wrote:
> Lyle: Yes I do believe the LP-PAN is being overloaded but still, I do hear
> that buckshot modulation from WYFR up to about 7010kHz on the K3 so it too is
> being affected although not as much.
>
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