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TennaDipper II not

Greg DL3GJ
 

Steve and the group,

I tought I post it here - maybe someone faces similar problem?

Recently I bought the TennaDipper II from Pacific Antenna. Delivered, soldered togehter - and the LED shines. But... No matter what I connect: 50Ohm, 100Ohm, 0Ohm - LED dims at 28MHz and nowhere else. I tried with properly tuned 20m antenna (SWR 1.15:1 check with analyzer) - LED shines bright everywhere except 28MHz. I inspected all the solder joitns, placement of all parts, and have no idea what have I done wrong? Two photos attached... Any idea what should I check/adjust/replace?

Greg DL3GJ

ajparent1/kb1gmx
 

I have two of these and both work.  Both the original from years
back and the II.  I use them as a quick check for the mobile and
the other for portable.

Simple answer is some part is in the wrong place (wrong value)
or your soldering is not as good as you may believe especially
on the the leads of the toroid transformer. The critical parts are
R1,R2, R11,R12 and the transformer T1.  assembled wrong or 
bad soldering will cause problems.

In normal use the LED will be dimmer at 28mhz but with a 50 ohm
load it should not eve be on at any frequency as 50ohms is a
good match.  As the resistor value departs from 50 ohms the
led should light and get brighter depending on the value
difference from 50 ohms.

Allison

Greg DL3GJ
 

Hi Allison, thank you for your ideas - I found the problem: the both upper connections of the transformer were swapped. I resoldered it and now the device behaves as expected - and the 28MHz is not that dramatic anymore. ...now drilling the case :-) Greg

laodah@...
 

As it happens I've been fencing with problems in a ZM-2 I built. Not the same kit, but this thread has offered several possible leads. (Antenna tuners being essentially similar.) 

Thanks! 

Rob
KB7PWJ