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Author Topic: Linear power amplifier with 10 W output for frequencies between 100 kHz and 2000  (Read 10430 times)

Offline OZNRH

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@Pieritz: When you ask about the sensitivity of used MOSFET, do you talk about as modules or single MOSFET?
The Greek modul use an IRF640 and the German use two types RD06HHF and RD16HHF, here you must 'Google' the datasheets.

If you talk about as modules, the Greek has about 27dB. at 28V. Look here:
http://www.rfsource.gr/files/PM62FDC.pdf

The German has 30 dB Gain at 13.5V, 10mW in, 10W out (P/P):
http://www.qrpproject.de/UK/qrppa2008.html

My setup: 'Home made Exiter --> QRP-PA2008 (inside the exiter) --> PM62FDC' --> SB1000 --> 1 kW P/P (250W AM).

The Spitfire: One of my friends has a Spitfire and I will ask him about he has a diagram, but i think it has a kind of LP filter there adjust to a '3 meter wire', so the output impedance is 'unknown', but if he has a diagram, I will see what there can be done so it works as 50 Ohm.

Best 73 Ole :)..
« Last Edit: July 30, 2014, 0836 UTC by OZNRH »
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Offline jpdesroc

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Hi,
I just found your 2014 forum's topic about your search of an RF amplifier
to make more power out of your Spitfire transmitter.
I'm looking for the exact same type of amplifier for my SSTRAN transmitter.
So far I managed to get more power from it by using around 25 feet of wire
'stapled' to my basement ceiling. Doing so I went from 10% reception to around 60-70%
on my Harman Kardon AM receiver ! The wire placement is very important and picky though..
So what RF amplifier did you find since then ??
Thanks.
Jean-Pierre Desrochers
Canada

Offline OgreVorbis

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Hi,
I just found your 2014 forum's topic about your search of an RF amplifier
to make more power out of your Spitfire transmitter.
I'm looking for the exact same type of amplifier for my SSTRAN transmitter.
So far I managed to get more power from it by using around 25 feet of wire
'stapled' to my basement ceiling. Doing so I went from 10% reception to around 60-70%
on my Harman Kardon AM receiver ! The wire placement is very important and picky though..
So what RF amplifier did you find since then ??
Thanks.
Jean-Pierre Desrochers
Canada

https://www.ebay.com/itm/AM-MW-RADIO-BAND-DIGITAL-LCD-DDS-TRANSMITTER-40-WATT-PEP/323960968980

This guy normally has EXACTLY what your looking for, but it looks like he's out of stock right now. It takes about 0.1 watt and makes about 6-8W.
This is a fully build transmitter that he makes. Maybe you would find it interesting. Keep an eye on his shop, the amps will probably be back. I've seen them disappear briefly before.

The real name is Lesvos Electronics of Greece.


Check this (RF INPUT:0.1-1W)
But it is a bit overkill: https://www.ebay.com/itm/AM-LINEAR-AMPLIFIER-150W-600W-PEP-MF-HF-0-4-3MHz/233237832811
It probably won't drive to full power, but it should still produce a lot of power.
« Last Edit: October 29, 2019, 0103 UTC by OgreVorbis »
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Offline OgreVorbis

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... you will need a tuner/SWR analyzer for that kind of power though. An MFJ SWR analyzer should do.
And of course an antenna in your basement is not optimal for this.
Try putting a long wire outside and then ground to a water pipe in the basement.

Here is another option: https://www.ebay.com/itm/20W-HF-PA-20-watts-24v-HF-amplifier-for-HAM-radio-CW-SSB-FM-digital/332643829840
You need an attenuator -20db for it: https://www.ebay.com/itm/Attenuator-SMA-MF-6GHz-Male-to-Female-2W-1-60DB-RF-Coaxial-Attenuator/323827300226

Start a new thread next time. It's not good to resurrect old threads from 2014 even if they are somewhat relevant.
« Last Edit: October 29, 2019, 0132 UTC by OgreVorbis »
Radio and Programming Blog: http://dosaidsoft.com/wp/

Offline Stretchyman

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100mW with a wire taped to the ceiling?

?
'It's better to give than receive' so why RX when you can TX!

                            Buy one from me, NOW!

Great discounts on ALL my transmitters if purchased via HFUnderground


                                              ;)