Bert Modderman Engineer

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Products for Sale
13cm 12 watt
13cm 40 watt
MRF284 project
Lot sales
Custom build

Dish calcs.
Quad ant.


Future projects
Future projects

ATV Hobby
Received ATV

all my amplifiers are suitable for datv.
i use the -40db knee height standard
almost all amplifiers can opperate at 1/5th of the p1db power on datv.
this doesnt mean you cannot make more power,
with dvb-s you can make 60 watt or more from the 150 watt 23cm amplifier and it will still demodulate perfectly.
but the output spectrum can become very dirty.
i will explain this in more details in the future.

23cm 250watt
ON0EME is using 2 of these amplifiers parallel in their moon beacon.
Due to constant use in this beacon the hybrids burned out so i improved the output staged for new amplifiers with teflon.
3.5 watt in 250 watt out p1db at 28 volt 19amps 1296 mhz only. not menth for atv or continues use.
at 29 volt output power is around 290 - 310 watt p1db. and superlinear at this voltage to 250watt
above measurements have been confirmed by several buyers.
one buyer even tested with pulsed mode, power then was 400 watt at p6db.
i have done 440 watt atv tests myself at 30watt input but fets will die within 15 minutes.
normal usage should never exceed 300 watt for longlivity at low case temp.
requires some serious attention to the cooling, because housing is small, 10cm x 16cm.
contains copper base to spread heat..
price 520 euro. improved version, with 8cm x 10cm x 1cm
comes with temperature overheat warning output and bias input.
almost all amplifiers reach 280watt p1db after some tuning at 28 volt.

Bottom view

a 2 blower setup with copper heatsinks 125 euro extra.
this is very good cooling, only an aluminium 10 times this size can match this copper cooling.
above a certain barrier, aluminium becomes a total useless cooling.

90 euro flatmilled heatsink with fan, usable for the 150 watt and others.

more choices in heatsinks to come.....

Powermodule Amplifiers  
i can make pcb's for any kind of philips, motorola or mitsubishi modules
for example mhw720 m57762 m67715 ra18h1213g
ra60h4452m1 ra60h4452 RA30H4047 RA30H1317M RA30H1317
the ra18h1213g pcb
pcb only, 10 euro, with components 12.50 euro
shipping in enveloppe own risk 15.50 euro
milled housing is 75 euro
below a kit with components and case and RF connectors but with no powermodule 87.50 euro
can also be used with ra60h4452m1 ra60h4452 RA30H4047 RA30H1317M RA30H1317

RA18H1213G ready build in case 170 euro, see foto. (contains old pcb but comes with the new pcb when ordered)

below an amplifier build with mmic chamber complete with power module tested 190 euro.
this is good for 1mw in 3 watt out datv.

little amplifiers for 70cm 7 watt out 20mw in 12 volt 100 euro including power module.

23cm 25 / 75 / 100 watt
1 watt in 25 watt out 28volt and 2 amps
housing 11cm x 6cm
price 145 euro. uses original motorola mrf284.

5watt in 75watt p1db out 28volt and 5.5 amps.
i can only make a few of these. only few fets left.
housing is 11cm x 6cm.
price is 150 euro. 24/7 atv ssb cw jt65
same ssb output as 4 x 57762 !
atv version 1250-1280 and 1296 mhz version are available

the 1 watt in 100 watt out is sold out,
replacement is 2 watt in 140 watt out for the same price

2 watt in 140watt p1db out 28volt and 10.5 amps.
housing is 12cm x 6cm.
price is 175 euro for the cw/ssb version.
price is 225 euro for the jt65/cw/ssb/datv version which has a partial copper base, see picture below
now works from 1240 to 1310mhz in all modes, including datv.

all amplifiers can have a circulator build in. this is 75 euro extra.

regular case

case with copper in the bottom


23cm 150watt
only 10 transistor left so i rather no sell this amplifier anymore.
look for the 2 watt in 140w out replacement.

150 watt and is available in 2 versions. both 250 euro.
same ssb output as 8 x m57762 !

atv version:
8 watt in 140-150 watt amp out.
frequency range 1240mhz - 1280mhz.

ssb version:
8 watt in 150 watt p1db out.
frequency range 1290mhz - 1310mhz.

28 volt 11 amps
alu hausing.
N or sma connector input and N connector output.

13cm 25 / 170 watt
i have various amplifiers for 2320-2400Mhz.
1 stage amps upto 3 stage amps.
input power can vary from 1mw to 4watt.
output power varies from mw's to 170 watt.
higher power amps are in the making
for example:
for atv, 80mw-250mw in 90 watt out 250 euro.
800mW in 25 watt out (last 10) 160 euro
15 watt in 170 watt out 400 euro
with intergrated circulator is 75 euro extra

13cm 8watt to 30 watt conversion

This amplifier was my first amplifier i desgined for amateur use.
it made 8 watt with 25mW input.
later i got fets with higher amplification and more power so this version is outdated.
i made a kit that replaced the 2 endfets of this amp. with this kit in place it will do 30 watt with 28volt 3 amps.