Re: Cricket Chirps but...

Jim, N5IB

I've encountered similar problems with BCB interference. Often the type of antenna tuner used will make the difference. Many autotuners are L-network configurations, with shunt capacitive elements, making them inherently low-pass networks. I believe the T1 is this configuration, but don't have a schematic of the AT200Pro. (have the tuner, but they don't publish the sch in the manual)

In one particularly troublesome case, using the rig's internal L-network autotuner left it susceptible to BCB interference, but bypassing the internal tuner and using an external T-match tuner took care of the problem.

The T-match, with its shunt inductive element, is inherently high-pass, and can provide at least some degree of attenuation of BCB signals, often enough to prevent the overload. The MFJ-969 is of this type.

The downside, of course, is that a high-pass type tuner does not help suppress harmonics from the Tx.
But if the Tx was clean to begin with - no harm, no foul.

Your other option, of course, is to build a simple high pass filter with a cutoff a bit above 3 MHz. I'd put it in line between the Cricket and the tuner, so it can see a nice, friendly, 50 ohm environment.


---In 4sqrp@..., <davebelville@...> wrote :

Thanks for the info David. I am using a G5RV with it also but am using it with a LDG AT200ProII tuner. Maybe I will try a different tuner. I have an Elecraft T1 I can try. I can also try it with my end fed wahr and unun.
Thanks again for the information. I really want to make the little critter work. 

73 Dave, KD9VT

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