[hpsdr] PS results on 6M with LDMOS

[Warren C. Pratt]

Nice results Mike!  I look forward to seeing results with the driver.

By the way,  especially with the driver, you MAY be able to null the IMD 
a little more by cranking up the Amplifier Delay parameter.

73,
Warren  NR0V

On 2/7/2014 9:42 AM, Mike Seguin wrote:
> ***** 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/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
>


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