Return to the Peashooter Build
Updated 2/21/2022 ~ Box It Up. A Homebrew Plywood Case made from 1/8-inch Hobby Plywood.
The Lower Board Contains the Plessey IF with Diode Steered USB/LSB Filters. Two pieces of wood are used to sturdy up the sides and the Front and Back panels are screwed to these side braces. This is yet another Box Building Option for the GTBITB! The 1/8 Plywood was purchased from JoAnn Fabric's in the Hobby Department.
***********
A Ham Radio Movie. Spies, Intrigue, Heroes and Ham Radio --- a central part of this Cheesy Movie is the use of Ham Radio, Vintage Homebrew 1947!
Yesterday I received a POP Email (Pick On Pete Email) almost hinting that my projects looked terribly unfinished since they typically seem to be a smattering of boards lying on the bench top. The email also suggested that I share how to GTBITB (Get The Boards In The Box). This is akin to Getting Mary Jo into the back seat of the 57 VW Beetle. (In Passing GTBITB also = Get The Babe In The Backseat.)
But in retrospect that seemed like a reasonable suggestion. Finding ready-made enclosures can be difficult and expensive. Spending $67 for a box containing parts costing $20 is an inequity. Thus, Homebrew extends to the box itself. So, I will spend a bit of time sharing what I do.
True I do have a few tools in my shop that most hams do not have. (A CNC and a Manual Milling Machine along with a tabletop metal break and a humungous bench vise). That said a one of those tools should be in every ham shack where serious homebrewing may ensue. The Bench Vise and Harbor Freight are the watchwords. The vise is not only useful for holding materials while you beat the metal but can be used as a metal break to bend metal.
Hand tools and PPE are other adds to the list. Keep in mind if you don't have the tools, you can't GTBITB (Mary Jo Included). The listing below would be useful for ANY home project and not radio specific.
- Eye Protection, Gloves and Dust Masks
- A Vise with 6" Wide Jaws
- A Large Rubber Mallet
- Ball Peen Hammer
- Heavy Duty Tin Snips
- 1-Inch-wide Wood Chisel
- Set of Metal Files
- Miter Box
- Metal Square
- Vise Grips
- Assortment of C Clamps
- Hack Saw
- Electric Drill with assorted metal drilling bits
- Well lighted Work area
- The most important tool: Noodling with the adoption of a standard process for making enclosures.
Most of my project enclosures take the form below with a base plate, front and back panels and 1/4-inch aluminum angle stock for stiffening the assembly. [One of the new headpiece photos shows a box assembly and even sports a recessed panel for the Color TFT. This actually is a repurposed Front Panel that had a gaping hole dead center. Some noodling gave rise to a larger hole with a recessed panel to fill the void. While not implemented I thought of adding grain of wheat lamps to sort of side light the area just like the radios of old. The Black Picture frame serves no purpose other than to hide some holes and adds another color to the mix.]
All of these materials can be purchased via Amazon. Luckily Jeff stocks 1/16-inch aluminum plate that is already in convenient sizes including that used for the front and back panels. This leaves the cutting of the angle stock as the major task. That is why you bought the Mitre box!
Below is a 3Cx800A7 Linear Amplifier and this enclosure was made exactly like that above. Maybe you missed it but look at the angle stock on the sides -- a perfect place to attach the side panels -- ever so important with 2000 VDC floating around that box!
Don't overlook the use of PC Material as a building resource. I have used PC Board for bottom plates and in one transceiver the bottom plate is the heat sink for the IRF510. PC Board can be used for front panels and takes paint very well with the proper preparation.
This Front panel was made from a piece of PC Board that originally was a front panel of another project.
The side panels on this same radio were made from "galvanized flashing stock" sold in the roof section of Home Depot and a sheet about the size of a sheet of typing paper costs about $1. BTW -- you can solder to the flashing stock.
To stiffen the material the top side is made 1/2-inch longer and bent over flat using the rubber mallet on the list and the Vise top as an anvil. This process is called 'hemming" like a hem on a dress or your pants. In the second photo below, you can see the hem on either side.
The rectangular cut out on the front panel can be made by first drawing the area to be cut out on the panel and then placing masking tape on any surface not in the cut area --this protects your front panel. Then drill a series of holes (tedious) around the inside periphery and then with a wood chisel and your rubber mallet cut along the holes in the PC Board to remove the piece. File the hole to square up the area. IMPERATIVE, USE THE PPE! The dust causes cancer!
I can only share what I have done but if you really want "slick" Boxes then a CNC Mill is on your list. Of Note: Same box structure as in the 1st slides. The Black Collins Like Escutcheon is a piece of PC Board cut on my CNC.
The above radio performs as well as it looks! All band (less 30M) Dual Conversion with a 455 kHz Collins Mechanical Filter in the 2nd IF.
Making great boxes has the following formula: 68% noodling and 32% cut work. Some of the work can only come from experience and making mistakes. So, for a lot of hams who do not want to invest the learning time -- get out the plastic and spend the $67 for the $20 in parts project.
WYKSYCDS!
73's
Pete N6QW
**********
But 1st some info sharing. My homebrew SDR rigs require two soundcards. I usually bypass the internal sound cards found on the Single Board Computers and use one external card for the I and Q processing (Optimal Shop about $15) and a second card to handle the audio output and microphone input. Yes, for the nitpickers that chews up two USB ports.
In looking to reduce clutter and improve wire management, I found this jewel on Amazon and it is perfect at $11 for the audio output and microphone input. The whole assembly IS a USB Sound Card! Clutter reduced!
************
Likely there has been some grumbling from both sides of the aisle. Some hated my diversion to the SDR Peashooter whilst others hated the current shift away from the software defined radio as that is the soup du jour. I know of several who hate that I am using a non-Analog VFO.
But that sort of diversity is what makes this such a fun hobby. It is interesting to see the Giants of today's hobby who actually sort of fit the three profiles of what I just described.
We see Wes is the mostly Analog VFO guy and Hans is the Digital guy, and we see Farhan stepping on either side of the divide. Yet, we all marvel at what they create.
So, where to go from here? I am working a parallel track with finishing the Peashooter as some needed parts arrived with a few more yet to arrive. About a week should finish that jewel.
I will also be starting a 2nd build of the Peashooter that will use the MAR-6+ MMIC devices BUT with a VXO @ 19.2 MHz, a 4.9152 MHz Homebrew Filter and a Crystal BFO. There is no Digital Stuff to be seen except for maybe a LED counter (Sanjan) so I can watch the VXO drift. I have in hand the LED counter, the HB 4.9152 MHz filter, The MAR-6+ MMIC's, the VXO and the BFO. But I am awaiting a couple of ADE-1's.
When that 2nd unit is finished, I will have stepped in all three arenas and so can you. But of importance, there is a dramatic difference in capability, ranking the SDR the highest and the VXO at the lowest position.
For the last couple of days, I have really been spoiled operating the SDR Peashooter. There are just so many bells and whistles (but not 3000 menus) to engage and I didn't spend $3K to do that.
There is a ham with a 5 call who spends a lot of time on 20 and 40 Meters and the good soul that he is, his focus is to help hams adjust their 3000 menu radios. At the start of the QSO he asks what radio the other station is running and then goes about suggesting changes to equalizer settings, bandwidth adjustments, microphone distance etc. There is no doubt he has helped many hams get their appliance boxes to sound "proper".
The other day I almost gave him a call and thought I would have a bit of fun with the SDR Peashooter and get his opinion on my sound quality. Regrettably I had a phone call and that ended that opportunity. But I have listened and recorded myself on the Hermes Lite 2, so I do know how it sounds. I don't think he would have much to say about the SDR Peashooter. Also of import, no 3000 menus to adjust!
73's
Pete N6QW