[hpsdr] PS results on 6M with LDMOS

[Mike Seguin]

Howdy all,

I'd like to report on a few tests here on 6M using Pure Signal and a HB 
LDMOS amp.

My test setup is a bare Hermes board in an ANAN-10 case. On 6M, the 
Hermes output is 250 mW. My first test was closed loop with just the 
Hermes to verify everything was operating as expected. Firmware is 2.5 
and Software is mRX 3.28 PS.

The LDMOS Amp uses an NXP BLF-177. It is good for a kW+ on 6M. It has 
serious gain. In my tests, 1/2 watt in gives 300 watts out. That is the 
level where I ran the tests.

This screen shot is the bare Hermes setup looped back to itself with the 
sample set at 1 dB below ADC overload. All subsequent measurements were 
also set at the same 1 dB below ADC overload. (watch any wrap of the 
following URL's)

http://users.burlingtontelecom.net/~n1jez@burlingtontelecom.net/images/Hermes1.PNG

http://users.burlingtontelecom.net/~n1jez@burlingtontelecom.net/images/Hermes.JPG

Screen shot of the bare Hermes with PS active is here:

http://users.burlingtontelecom.net/~n1jez@burlingtontelecom.net/images/Hermes2.PNG

Next is a shot of the LDMOS amp @ 300 watts without PS

http://users.burlingtontelecom.net/~n1jez@burlingtontelecom.net/images/LDMOS_300W.PNG

Next is the amp with PS active

http://users.burlingtontelecom.net/~n1jez@burlingtontelecom.net/images/LDMOS_300W_PS.PNG

Here are a couple of shots of the AMP setup on the bench. I used a Bird 
sniffer on the output of my wattmeter to feed back to the Hermes.

http://users.burlingtontelecom.net/~n1jez@burlingtontelecom.net/images/LDMOS1.JPG

http://users.burlingtontelecom.net/~n1jez@burlingtontelecom.net/images/LDMOS2.JPG

The next step is to insert a 10 dB Class A driver I have to boost the 
Hermes to fully drive the LDMOS amp. Hope to have some screen captures 
of that soon. I first need to characterize it with the Hermes. This is 
the driver:

http://users.burlingtontelecom.net/~n1jez@burlingtontelecom.net/images/driver.JPG

Tnx to all involved in rolling out PS!

Mike

-- 

73,
Mike, N1JEZ
"A closed mouth gathers no feet"