Update on the Alpha 4040 Tuner.  We're still late, but now, it's mostly in the hands of the Software guys.

The Alpha 4040 Tuner is coming along, but of course we're about 90 days late in delivery.  We were hoping to get the pre-production units to the beta testers this month, but we're working on two problems that are taking a bit longer than we expected to solve.  Most of the tuner is doing great.  All the manufactured parts are complete and check out.  In fact, they're really looking great.  Here's a brief update of the project and our newest estimate of delivery. 

 

First the hardware update.  The tweeks we needed to make in the chassis are complete, and all the mechanical element design is done and works fine.  We've done some accelerated life tests on the stepper motor to capacitor and stepper motor to inductor devices and all is fine.  One of the boards has a bit of noise on it, so we're tracking that down and should have it solved very soon.

Now software.  The operating system is doing great.  Nice and stable.  The hardware drivers are finished, as is most of the UI.  It's pretty easy to change menus and items so no issues here. 

Our time is really being spent on the routine we call TunerD - which is the core of the application that operates the tuner.  Things are looking good, but this is the main program and the one that's taking longer than we expected it to take.   

 
All and all, we're very happy about the status, although it would be great if we were better at estimating how much time it takes to do some of these routines.  But, we're being very careful about not rushing the tuner out the door.   

 

We've received HUNDREDS of  pre-orders and are really excited to build and ship these as soon as possible.  It's good for our customers, and it's good for us.  But, we just won't ship anything before we have the meanest, most aggressive testers bang at the completed tuner and we fix the bugs they find.  They have nothing to bang at yet, but they will soon. 

 

I've instructed the group to build ten of our tuners as soon as possible.  Many of the parts are in and more are arriving every day.   These are the tuners we'll send to the Beta testers waiting. 

 

Thanks for hanging in there.  Lots to do, but we're making progress every day. 

 

Over the last couple years, I've met some of the nicest hams.  It's a wonderful hobby, isn't it?   

Steve, WA2NFR     

Letter from the Vice President of Sales, Molly Hardman, W�MOM

The Trade-in, Trade-up program has worked so well, we've decided to keep it around for a while longer.  Hundreds of hams have swapped their old, tired amplifiers for shiny new Alpha Amplifiers!  We'd like you to be the proud owner of a new Alpha 9500 or Alpha 8410 amplifier and we can help you do it by offering huge credits for your used amp towards the purchase of a new Alpha!   

It's good for everyone.  We offer huge credits when you trade your old amplifier (Alpha and other manufacturers) in on a new Alpha.  You join the ever growing Alpha family and experience what we mean by "Brick on Key", and we get a new customer!

Check out the deals Alpha Amplifier Website 

Letter from Gordon Hardman, W�RUN  

Thoughts on "Transmit Dynamic Range"  

In the limited amount of time I had at Dayton to wander around and see everything, I noticed that some of the new radios are promising quite good transmit intermod numbers. For years people have been working ever harder to get more impressive receiver dynamic range measurements, and this has now become accepted as an important measure of how good a "competition grade" transceiver is. There is considerably less effort going into ensuring the transmitted signals are just as clean. After all, having receiver noise that is inaudible is of little good if the "side frequencies" from an adjacent transmitter are strong.

Actually, a clean transmit signal is quite hard to produce. Back in the days of tube radios, the Collins 32S1 transmitter had 3^rd and 5^th order intermodulation (IM) products that were routinely measured at better than 40dB below one tone of a two-tone test. (They only promised 30dB in the specifications section of their manual for the unit- but that is typical Collins- promise good specs, and then deliver even better). Indeed, the most interesting thing about this is that Collins actually put that specification in their manual. A casual scan of a current high-end radio's manual shows that there is no spec for IM in it! This goes along with what we have observed in the lab - it is not possible to do a two-tone test by the time-honored approach of putting two audio sine waves into the mic jack. The resulting products are so poor that they are actually higher than an Alpha amplifier would produce, so you would be unable to discern the amplifier's contribution to the overall transmit spectrum. It is necessary to use two radios in cw mode, and combine their outputs in order to get a suitably clean test signal for the Alpha. This is the approach suggested by Eimac in their "Care and feeding of Power Grid Tubes" booklet. Some of the reviews in QST of radios and solid state amplifiers show similar results.

The tubes we use (4CX1000A and 4CX1500B and 3CX1500A7) were developed back in the days of the 32S1, and (not surprisingly) their performance matches the transmitters in use back then. Actually, the IM products are predictable mathematically for any tube that follows the so-called "three-halves power law".  Here's two excerpts from "Care and Feeding of Power Grid Tubes" (required reading for all engineers at Alpha Amplifiers), written by the engineers at Eimac. 

This is shown in Figure 44 from "Care and Feeding". It is clear that the bias conditions for the tube and how hard it is driven have a dramatic influence on IM performance. However, it is clear that 3^rd and 5^th order products in 30, 40 or even 50 dB down are possible.  

Figure 45 in "Care and Feeding" shows the typical data for the 4CX1500B (the tube used in the 8406). While a little hard to make out, the bias conditions in the 8406 are between these, and so the IM products are in the 40-50 dB down range. The 4CX1000A tube (used by Collins in the 30S1) was developed for exceptional IM performance in SSB service.

Back to Dayton - one of the newly announced radios there was rumored to be capable of 40dB two-tone performance. If so, an Alpha tube amp would make a nice companion to it - no need to compromise the IM performace in the amplifier!

73, Gordon, W�RUN