Amplifying the Peaberry

General discussion and support for the Peaberry SDR V2.

Amplifying the Peaberry

Postby KB3ZTR » Tue Jul 23, 2013 3:30 am

I'm looking to put together an HF setup based on a Peaberry SDR, but my biggest limitation seems to be in getting it above a 1W output. I found this linear amplifier kit designed to take a 10mW signal and step it up to 10W. It seems like the 1 watt output of the Peaberry would be too much. Could someone advise me on the best way to modify/attenuate the peaberry or its signal to get a safe wattage for the amplifier?


Alternatively, what are some good (and affordable) amps to use with a Peaberry? I looked around and didn't find much that could get it up to 5 or 10W. For that matter, is there a way to modify the Peaberry to transmit at 5W from the start, so that it can be amplified up into the 50W range eventually?


Thanks,
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Re: Amplifying the Peaberry

Postby AE9RB » Tue Jul 23, 2013 8:40 am

Here's some amps you can look at: HardRock-50, HF Packer, Ten-Tec 418, HPSDR PennyWhistle, Elecraft KXPA100, Ramsey QAMP, and THP HL-45B. This list is far from compete and I don't recommend any one in particular.
73 David AE9RB
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Re: Amplifying the Peaberry

Postby KC5SB » Tue Jul 23, 2013 3:30 pm

I have used the HPSDR Pennywhistle with my Softrock Ensemble RXTX. It's good for 16 watts PEP out with the softrock. I'm planning on trying it with my Peaberry V2 when I get it finished.

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Re: Amplifying the Peaberry

Postby KB3ZTR » Tue Jul 23, 2013 11:18 pm

The PennyWhistle has a max drive of a 1/4 watt, doesn't it? What are you doing to reduce the power of your Softrock/make the input acceptable for the amp?
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Re: Amplifying the Peaberry

Postby KC5SB » Tue Jul 23, 2013 11:27 pm

I am using the PSDRIQ software. You can reduce the drive from the softrock in that program. I have not gotten far enough into HDSDR to know if there is a drive level control - might have to build an attenuator.

73,

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Re: Amplifying the Peaberry

Postby KC5SB » Sun Aug 11, 2013 5:17 pm

Since finishing my V2 I have started playing with HDSDR. The more I learn about HDSDR the better I like it. Anyway, back to the subject at hand - you can reduce power output by using one of the sliders when in transmit mode. This should allow driving the Pennywhistle at reduced levels without using an attenuator. I tried it with a QRP wattmeter and it works. There is also a slider for mic gain when in transmit mode.

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Re: Amplifying the Peaberry

Postby uv199 » Tue Aug 13, 2013 11:06 pm

Bill, I have been looking over the HPSDR Pennywhistle. From what I am reading it should work fine with the Peaberry. If you have a chance to use it with the Peaberry please share your experience with it.
I found 1 discussion on this amp and a comment was made that it is a Transmit Only amplifier and that you cannot receive through the amp. That would mean some kind of switch in order to bypass the amp since the Peaberry has one antenna connection. Is this true and if so what have you done to receive? Also can it handle all of the modes of operation that the Peaberry transmits on?

Thanks for any info you can provide.

Paul N3FTL
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Re: Amplifying the Peaberry

Postby KC5SB » Wed Aug 14, 2013 2:07 am

Hi Paul. I have used the Pennywhistle with my Softrock Ensemble RXTX before and plan to use it with my Peaberry V2. Yes, you have to rig up a TR switch to switch the XCVR antenna jack from the antenna on RX to the input of the amp on TX. I used a simple transistor circuit to control the 12vdc relay primary and a the DPDT relay contacts to switch the antenna. Probably not real efficient but it worked. I'm working a a control unit now for the Peaberry and the amp which will incorporate TR switching, but have not been able to spend much time on it because of other demands on my time. I used a radio shack 275-249 relay.

As far as I know the amp will work with all modes but I have only used it on SSB. My method of antenna switching would not work on CW break in because of the slow speed of the relays.

I plan to use the Peaberry AMP jack to activate the switching circuit, but I am having some issues with it. It is showing a relatively high resistance when in TX mode. I may have a bad solder joint in the optoisolator circuit, but I have not had time to check yet.

Bill KC5SB
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Re: Amplifying the Peaberry

Postby rw6hch » Wed Aug 14, 2013 5:07 pm

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Re: Amplifying the Peaberry

Postby hansvi » Thu Aug 29, 2013 7:41 pm

I recently found an interesting page describing hf amplifier design.
Here's the link: http://www.sm0vpo.com/tx/rf_pa_cct_00.htm
73,
Hans - ON8VQ
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