[Boatanchors] Need suggestions and question on antenna for DX-100

[Glen Zook]

If you are getting 125 watts carrier output on the
DX-100 on AM carrier you are really overloading the
final amplifier tubes!

The 6146 and 6146A/8298 are rated at 67.5 watts
maximum INPUT on AM each, this per the RCA
specifications.  That means a total MAXIMUM INPUT
power of 135 watts for the DX-100.  With the usual
about 60% efficiency this would mean about 80 watts
output on 80 meters.  This efficiency drops off with
being around 50% on 10 meters.  This means about 68
watts output on 10 meters.

The 6146B/8298A and any 6146W with a code date of 1965
or after is rated at 90 watts INPUT on AM.  However,
using the 6146B/8298A in the DX-100 often results in
all sorts of problems.  Thus, use of that series of
tubes is generally discouraged in the DX-100 /
DX-100B.

For the article on the 6146 family of tubes that
appeared in Electric Radio (and has been reprinted in
several other publications) a while back go to the
K9STH website (URL listed at the end of this message).
 Choose the K9STH link from the home page and then the
article is in another link on that page.

If you cut the INPUT power on the DX-100 back to
around 100 watts on AM the station at the other end is
not going to know the difference.  However, your final
amplifier tubes are going to last several times longer
than when running at the 135 watt INPUT level.  If you
run more power INPUT than 135 watts on AM then your
final amplifier tube life is going to be greatly
reduced, sometimes by a factor of 10 or even greater.

100 watts input is going to mean around 60 watts
output on 80 meters (a little more with new tubes) and
around 50 watts output on 10 meters.

Glen, K9STH


--- Rodger <WQ9E at dtnspeed.net> wrote:

Keep in mind that high level AM puts much more stress
on antenna tuners than SSB or CW so the lower power
MFJ and similar tuners are not advisable.  Operating
AM, the DX-100 will produce around 125 watts
continuous carrier output which increases to 500 watts
on modulation peaks.  Thus the tuner gets a continuous
heating workout from the carrier and gets "tested" for
flashover on modulation peaks.









Glen, K9STH

Website:  http://k9sth.com


 
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