Folks
Sorry I will try again with some formatting.
Following the Teamspeak meeting, the pertinent levels for P3E:
V Tx Phase +10dBm @ 145.895MHz into 50 ohm;
V Tx Envelope 2Vp-p into 1kOhm baseband;
U/V AGC I/O: 2V full gain, 5V full compression (output capable of ~2.5mA drive);
U band IF in -15dBm @ 10.7MHz into 50 ohm;
L band IF in -15dBm @ 10.7MHz into 50 ohm;
S band IF out -15dBm @ 10.7MHz into 50 ohm.
73, Howard G6LVB
Hi all,
The +10 dBm level for the 2 meter phase is just fine.
Talking about the 2 meter amplifier, the final stage designed around the Cree silicon carbide MESFET worked very well. I presented a paper on this amplifier at the IEEE International Microwave Symposium in Hawaii a few weeks ago. Cree obtained permission from the IEEE and made available the paper on their web site:
http://www.cree.com/products/wireless_docs.htm
For the time being, it is the first paper in the list. I invite you to take a look at the paper for more details on the amplifier.
Since this amplifier needs +27 dBm of drive for an output of +43 dBm, I requested the computer model and a couple of sample devices from Cree to design a driver amplifier. Al, K2UYH, helped to obtain the samples, which are here in my house.
The final amplifier efficiency was measured at around 86 to 88%, and this number holds quite well at almost any drain voltage or output power. This is exactly what is needed for a good envelope elimination and restoration linear amplifier. Also, the RF output voltage varies linearly with the drain voltage.
I am very busy right now with a new job, new house, new state (NC), and my wife is expecting a baby boy for the first days of December. However, I hope to spend some time working on the driver to complete the 2 meter amplifier chain.
73, Marc N2UO
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participants (2)
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Howard Long -
Marc Franco