LPAM Antenna ideas wanted

[gunterm]

Hey guys,

I have a part 15 transmitter, and also aquired an LPB ATU box just in case...

But is it possible to get decent range with a simple antenna matched with this box? I was thinking along the lines of a wire 15-30 feet long that could be matched with this box.

 

[radioboy]

Hi Matt,

I've done Part 15 (and am still doing it) and I've done carrier-current..but I never have tried
to match a Part 15 system with a c-c box.

In my situation, the Part 15 system (I have a Rangemaster) has worked better than my previous c-c system.
I'm off the beaten path, in the back of a 17 acre farm. At the time, I didn't know about neutral injection, and a transformer stopped the signal before it got out of my yard.

I still have an LPB c-c box wired in on the meter pole out back..haven't used it since 1995! I barely got
1/4 mile out of it in the daytime, and that was with a 30-watt LPB xmitter.

 

[slim101]

I was thinking along the lines of a wire 15-30 feet long that could be matched with this box.

Part 15 sez 3 meters max (118").

 

[gunterm]

So if its 3 meters maximum, then how do you match it to the transmitter?

 

[rfry]

So if its 3 meters maximum, then how do you match it to the transmitter?

An inductor is used resonate it. However the radiation resistance of this short radiator is very low (barely exceeding 0.1 ohm even at 1700 kHz). So the radiation efficiency of the antenna system including losses in the coil and r-f ground is poor -- radiating maybe less than 1% of the power applied to it, assuming that the tx can match into the total resistance of that non-reactive load.
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