Topband: How Increase 160m power on FL2100z

Damien F4AZF f4azf at
Sun Apr 20 05:09:27 EDT 2014

Hi Tom,

I have ever also have a look few times on your website and infos about the
fl2100, some mods have been also done before I get the PA.

"Load" button on 160m is always at "0" "ccw" even on 1810khz or 1900khz,
just the "plate" get some influence "1" in CW part and "3" at 1850 for

Current IP at 500mA give 400w out on 160m	, 700w on 80 and 40m ...
still until 550w on 10m but the PA only used on 160m , sometimes on 80 but

For 90w IN :	1810Khz 440w          1900Khz 490w          load 0    plate0
at 1810/ 3 at 1900		but 550mA current for this for + 100 good
watts in.
So more power on higher frequency on the band.

PA0FRI on his website , on his article about the fl2100z you can read :"The
lower output on the 160 m band is due to the very low Q of the anode
circuit, because the manufacturer has cut the components. The lower power on
the higher bands is due to the decreasing efficiency of the tubes and the
higher circuit losses on the higher frequencies."

But I notice an article also from PA0FRI about an SB200, who has no 160m
band , but he create an extension for 160m band on...

Even if I m technician, I m not comfortable with tubes PA, cause I miss a
bit of practice on... so that's why I ask a bit of help. I ve buy the 2100z
nearly only for the use on the top band SO WOULD LIKE TO PERFORM IT ON 160M

Best 73s and thanks also to 3 other Hams sending me direct emails.

Damien f4azf

-----Message d'origine-----
De : Tom W8JI [mailto:w8ji at] 
Envoyé : dimanche 20 avril 2014 01:48
À : Damien F4AZF; topband at
Objet : Re: Topband: How Increase 160m power on FL2100z

> I think we must do something on the anode coil for better Q or add 
> some length, change diameter?.. or other things ..?!

The only real tank circuit  issue is range of the tank components used to
adjust the matching. Some amplifiers run outside optimum capacitor
adjustment ranges.

Are any of the capacitors bottomed out? Is the load all the way at full
mesh? What is the grid and plate current compared to other bands?


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