The return of Index Laboratories

I’ve made no secret of my enthusiasm for Index Labs’ little QRP+ transceiver. As a fairly new ham back when they were released I couldn’t afford one. I wasn’t much more than a kid then, with mostly empty pockets.

But today, my new-to-me QRP+ shares shack space right along with my K3, while most other rigs – the FT840 and many QRP rigs – are relegated to the closet, packed away in boxes. I truly believe the QRP+ is destined for “classic status” of ham radio transceivers.

I was quite surprised when I recently learned that Index Labs is once again producing a piece of equipment for us hams. In fact, they have been for the past 5 years, but being CW-centric, it was news to me, and perhaps to you too.

Today, Index Labs’ produces a Class D AM transmitter for 80 and 160 meters. AM remains a fairly common mode on 80/160 and the “Super Senior” operates there with a potent output, no tuning required and is designed to be rack mounted. The transmitter is described here at the new Index Labs website.

Inside the Index Labs' "Super Senior"

With a few exchanges of emails, Bruce K7DYY (the designer of the QRP+) has me up to date on the current doin’s at Index Labs. Rather than paraphrase his summary, here with his permission, is Bruce’s description of Index Labs today and a bit of the road along the way:

The class D A M transmitters have been available for about five years now. I originally became interested in the high efficiency switchmode R F amplifier technology because it seemed elegant but relatively unused outside the commercial broadcast industry.

I was first licensed in the 1950’s when AM was still the dominant voice mode and never much cared for the sound of SSB. Until about 1990 I was CW only. Then I heard some local A M on 3870KHz and got back on “fone” with some vintage gear. I think most of the AMer’s have a similar story.

Lately I’ve been mostly on ten meters both CW and AM. Its a treat to work old friends unheard for almost a decade.

I am using a home brew SDR receiver here, built into a Super Senior transmitter. The SDR field is moving very fast and there are much sharper folks than me working on new designs. I am, however, interested in the design of EER versions of the Class D amplifier which would make possible an all mode software defined transmitter with the high efficiency.

I’m basically retired and don’t want to set up the organization that would be required for a larger scale operation. The AM transmitters seem to be a good fit at the moment. We also sell a small AM transmitter intended for use in remote villages by missionaries. This transmitter has also been purchased by the US Army for NVIS shortwave broadcast in rugged areas of Afghanistan. Finally, I make RF generators for use in Medical high power ultrasound research.

When we ended production of the QRP+, I transferred the inventory to Stan Yarema who had worked for Index Labs as a technician. He did the final test on almost all of the QRP+ transceivers. He provided service for a number of years and even built and sold a few units on a one off basis. Unfortunately, Stan has passed and the old inventory is lost. I am happy to work on the QRP+ but am limited because I don’t have spares or programming tools for the product.

After the QRP+, I contracted with SGC to develop the SG-2020 transceiver. The high efficiency transmitters followed that.

Thanks for all the info, Bruce – very interesting indeed.



  7 comments for “The return of Index Laboratories

  1. Keith Hamilton
    December 29, 2011 at 1:51 pm

    I sold my QRP+ years ago. Very sorry I did. My Dad still has his though! I told him not to sell it! N8CEP

    • December 29, 2011 at 2:46 pm

      You can still find them on eBay from time to time and I believe there’s also a Yahoo Group. I’m on my 2nd one, lightning having taken out the first years ago.

      In its time, the QRP+ offered what no other radio even came close to then: 10-160 coverage, CW & SSB in a small package. Definitely a keeper.

  2. Jim
    December 29, 2011 at 9:56 pm

    I remember those old Johnson AM rigs in the 50’s & 60’s ,
    an order of magnitude heavier.

    Class D, 1500W PEP, 10 lbs.


  3. Jerry N4EO
    January 1, 2012 at 4:54 am

    Thanks for bringing this to my attention. I have sent Bruce a deposit so I will be getting one as a homecoming treat after my wife and I return from our 10 months teaching in N Iraq come this June (2012). Can’t wait of fire it up next to my old Johnson Viking I (with single 4D32 final, 2 807’s modulating). A friend, W4XS, has been in community AM broadcasting his entire adult life and I can’t wait to drive by his station WAKM-AM 950 in Franklin, TN for a show and tell with this new

  4. January 18, 2013 at 7:21 pm

    I thought I was looking at a photo of my shack as I too have my Index Labs QRP++ sitting right next to my K3/P3!

    I tried to like its successor (sg-2020) , but it lacks the quiet QSK, quirkiness and nice audio of the Index rig.


    Dale W4OP

    • January 18, 2013 at 8:01 pm

      I’ve never used (or even seen) and SG-2020 but continue to like my QRP+. In its day, there was nothing else like it – it was the only small 10-160 CW/SSB QRP rig available for a long time.

      • Dale
        January 18, 2013 at 9:17 pm

        Hi John,
        The biggest thing going for the 2020 is its packaging- very robust. The DSP versions have very pinched RX audio- apparently an artifact of the DSP. Even in bypass mode, the audio passes through the chip and gets colored.

        The fact that the QRP+ covered 160M is a real bonus- this in a day when even some of the big rigs did not have 160M.

        Dale W4OP

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