[hpsdr] PS results on 6M with LDMOS

[Helmut, DC6NY]

Fine job Mike, congrats!

73, Helmut, DC6NY

-----Ursprüngliche Nachricht-----
Von: hpsdr-bounces at lists.openhpsdr.org
[mailto:hpsdr-bounces at lists.openhpsdr.org] Im Auftrag von Mike Seguin
Gesendet: Freitag, 7. Februar 2014 18:43
An: apache-labs at yahoogroups.com; hpsdr at lists.openhpsdr.org
Betreff: [hpsdr] PS results on 6M with LDMOS

***** High Performance Software Defined Radio Discussion List *****

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/Herme
s1.PNG

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

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

http://users.burlingtontelecom.net/~n1jez@burlingtontelecom.net/images/Herme
s2.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/LDMOS
1.JPG

http://users.burlingtontelecom.net/~n1jez@burlingtontelecom.net/images/LDMOS
2.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/drive
r.JPG

Tnx to all involved in rolling out PS!

Mike

-- 

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

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