Now that I've built the DSP and CODEC sections- it is time to check it. If you're just starting out, Glenn VK3PE has an excellent page with a suggested Picastar build sequence. I have found the page very useful, though I have definitely not followed the suggested sequence. My build follows more the order in which the parts arrive. I am indebted to Bill Verstelle N7OQ, who kindly agreed to program a couple of EPROMs and sent them out to me pronto. Thanks Bill!

I already have the DSP code and parameters file on my hard drive via the Picaproject group, and G3VPx's Hobcat program is installed. Connecting a serial cable from my PC comm port to the DB9 on the Combo board with the toggle switch next to the DB9 swung closest to the DB9 allows loading of the DSP code and parameters directly via Hobcat. In Hobcat go to: Setup->Select DSP Parameter File-> USER2B2.XJP

At powering up the Combo board with a programmed 27C256 or 27C512 EPROM, the LED should blink at about 2 times per second.
Back in Hobcat go to: Tools-> DSP direct loader(comport)-> Procede. The counter then advances and the DSP LED should no longer blink but appear to flicker a good bit. If everything is OK after the count completes at 19900, you should hear "Hi" in Morse if you have speakers connected to the audio amplifier and the LED should now be extinguished. Part 6 of the original Radcom articles which you can find in the Picaproject files section has details of all this though you can skip worrying about loading via QUICKBASIC thanks to Hobcat and Ian's g reat work. It feels like real progress.

Here is a photo of the completed G4TZR Low Pass Filter built on the boards designed by Glenn, VK3PE and for use in the Combo star. No shields yet. The relays are from Mouser, Mica Caps are from Surplus Sales of Nebraska, toroids are from W8DIZ at KitsandParts.com.

From Completed LPF with Mouser Relays

While looking for cores for the G6ALU 20W and 150W PA units for the Picastar (not officially a part of the Star) I found Amidon had a few of the parts I need and decided to order them. Browsing the site, I found the 6 hole ferrite chokes I need for  the 150W PA (FB43-5111-2.5 or a VK200-3A) plus a slightly larger replacement for the T68-61 listed for T2. I first wound a FT50-61 but it is so small I'm worried it may saturate in use so I will tyr the FT82-61 from Amidon.

I wanted to order parts via the Amidon website but the BN-43-1502 for T3 of the 20W PA and the FB-43-402 were not listed on the site. I called and it was suggested I place a note in the order field to add the two extra parts. Amidon have a $15 minimum for a web order, which is very reasonable. I returned to the site and tried to place the order- then found with only four parts total, I needed to buy at least $15 of the two remaining parts- plus what I really wanted. As their e-commerce system was preventing me from placing an order I was forced to call in the order via phone. Amidon staff are very nice and personable, reading back each item carefully and with detail. Somehow I still ended up with FB-43-1502 rather than BN-43-1502 and BN-43-402 instead of FB-43-402! So if you need BN-43-402 or FB43-1502 I will make you a deal. It's easy to miss those niggling details- what you think you hear is often not what was said. I believe  it may have been my mistake- but I'm not entirely sure.

When I called them to explain my dilemma; I found they do have a BN-43-1502 but they do not have a FB-43-402 stock number; but they do carry the Fair-Rite 2643540402 which is listed as a suitable part- unfortunately they have a minimum order of $40 when you place an order containg ANY Fair-Rite products- oh boy. We had several rounds of discussion regarding how to resolve my situation and they finally agreed to take my order for a $15 minimum (normal phone orders are minimum $25) and confirm the order via email first (they did take my email address the first time, but I never got a confirmation from them). This time I did get an email confirmation from them and I confirmed the order. Lesson learned- get it in writing. Next time I will insist any verbals orders to be verified via email first.

Would I buy from Amidon again? Of course. They are nice people and fairly easy to deal with. In fact, I'm surprised they even would accept a call from an Amateur Radio builder- we're so much trouble to deal with for one or two small items.Some Amateur distributors such as Universal Radio do carry a few Amidon parts. It might be easier to have them add an item to their next order, providing the request is not too esoteric.

Toko have discontinued the formers used in the Band Pass Filters of the original Picastar as designed and built by Peter Rhodes, G3XJP. There are many options available to builders, including the winding of toroids for the filters- with toroids used in the 30M filter actually implemented by at least one builder.

Having browsed the Yahoo Group homebrew-radios and piastar-users groups (searching groups is nearly futile as the yahoo search results are not reliable); I have decided to use the Lodestone formers as suggested by Glenn. More than a few builders have wound the Lodestone formers and found good results.

Glenn, VK3PE writes:

Paul, M1PVC, has very kindly provided winding details for the Lodestones. I have uploaded them to my Web pages:

http://www.carnut.info/singleboard/Ver_B/BUILDERS/M1PVC/Paul_M1PVC.htm#lodestone

Paul has created a very nice spreadsheet to assist in the Band Pass Filter coil winding details for the Lodestone coils.

I plugged in the L45-10 to Paul\'s spreadsheet tentatively for a 6 meter BPF and based on Paul\'s build, here is what I have decided to use in total:

L45-2-CT-B-4 (9) 160 M, 80 M, 60 M
L45-6-CT-B-4 (10) 40 M, 30 M, 20 M, IF
L45-10-CT-B-4 (9) 17/15 M, 12/10 M, 6 M

This gives a total of 28 formers for the build- at about USD 2.30 each though it is hard to place an order for one unit as Lodestone (like many other commoditiy suppliers) require $50 minimum per line item- bringing the minimum cost to $150 per builder plus shipping and requiring the purchase of at least three times the number of formers as needed for the build. We certainly will have spares.

For parts kitting of the VK3PE Picastar Combo BB I have created the following Project lists on Mouser's site:

G6ALU 20W PA (17 Parts) kit fa4b2da8f4
G6ALU 150W PA (25 Parts) kit 23e952ec8a
G4TZR LPF (8 Parts) kit 89c5f85562
W4ZCB Buzzer (14 Parts) kit 48864d9961
Ponyprog Atmel Programmer (8 Parts) kit 88316e381c
Ian's Basic I2C Interface (6 Parts) fbd3ad9d32
VK3PE Combo Board B (143 Parts) kit 9895e7ac61

Access via "EZBuy" https://www.mouser.com/Tools/Tools.aspx and go to "Project and Cart Sharing" enter one of the project IDs listed above. Most of the RF parts are missing E.G. Toroids, RF transistors, and magnet wire. This may save some time for you but is not guaranteed error free and certainly not complete so review the lists yourself before doing an EZ Buy.

Select the project(s), put one or more in your cart, and add or remove what you need. Pricing is very competitive and Mouser are a proven reliable source. I also found some of the backordered semiconductors such as the Atmega 2560, LM4950TS, ULN2803A, and LM7805CT at avnetexpress.avnet.com - very easy to deal with and the Amtegas were about $5 each less than at Mouser.

73

Bill N4BKT

Busy Saturday- I picked up a few items at the Orlando, FL Hamfest last week. It is one of my favorite hamfests to attend. I got a deal on board standoffs, RG-174 (20' for one buck) SO-239s, nice knobs- new and used (see photos), a nice heatsink (2 dollars), one pound of Kester silver bearing solder for 2 bucks, and my best buy was a Sencore CM2125 Computer Monitor Analyzer for a song. I stripped this fine instrument done to the chassis as a donor housing for the Combo Boards provided by Glenn, VK3PE. This chassis is the perfect size for the boards- it looks like it was custom sized for the main board. I used some of the long stand offs which means I don't even need to remove the units which are swaged into the chassis. The black heatsink is from Surplus Sales ($15) and the larger natural aluminum unit is the 2 dollar unit from the hamfest.

Picastar Combo Chassis N4BKT

There does not appear to be enough room for the large display and the encoders. I can choose the encoders with the 128 x 64 display, OR the larger 320 x 240  touch display and no encoders. Not having built or operated a Trxavr Picastar- I'm not sure which I would prefer yet. One certain thing you'll find here is choices. Ian and Glenn have them listed at their sites. It feels like progress on the project. I did also build most of the transformers for the G6ALU 20W PA today, plus I also created Mouser projects for both the 20W and 150W G6ALU Power Amplifiers.

I finally got started on the actual assembly of my Picastar project using the Combo boards supplied by Glenn, VK3PE. The TrxAVR-B board replaces the PicNMix of the original project and adds quite a few new features. It contains two Atmega 2560 processors a MAX232, a FT-245R USB serial device and more. One 2560 drives the display, the other is dedicated to the 8 encoders that TrxAVR supports. The FT-245R was set up using ther FTDI Mprog utility, then the modified PonyProg 2000 was used to flash the hex code into IC1, then the second 2560 (IC7) was programmed on its programming port. There is a jumper between K2A and K2 to be installed (not in BOM) and some resistors in the BOM as 1K should be 100R per the notes on Glenn's site. This is the most intense of the boards in the group as far as density goes- over 178 parts and many are 0603 (3 x 6 mil)- not to mention the two 100 pin TQFP chips which were hand soldered. I followed Ian's minimum stuffing and initial checkout procedure which worked a treat.

From TrxAVR-B Picastar Project

So Debug in Hobcat shows data- I'll know more once I get the combo BB board more assembled- now on to the PIC Timer on the combo board and ancillary boards. I just started the LPF board- got shorted a couple caps but moving along. I'm now awaiting parts from China. So far the only Chinese origin parts will be keypad, encoders, and LPF relays- isn't that odd? The link above should have a photo of the LPF as far as I've assmbled it. 73 Bill

I am excited as Glen Percy VK3PE's ComboStar version BB boards arrived today. I StarTED to build a Picastar in 2007 but I only got as far as ordering the DSP and AC-97 chips, and starting to kit together the other parts. Last month I found Glenn's web site describing the "homebrew-radios" groups build of Picastars with a LCD display instead of seven segment LEDs- and found his single board version on offer.

Picastar Combo Board BB

For those not familiar- the Picastar transceiver is based on a 20 part series of articles by Peter Rhodes G3XJP which originally appeared in RadCom magazine. The name Picastar derives from the use of Microchip PIC controllers combined with the STAR acronym of "Software Transmitter And Receiver". The controller for the Picastar comes from the Peter Rhode's PicN'Mix controller, as earlier published in RadCom. The earliest articles for the project were published ten years ago now; with some components recently termed obsolete (e.g. the SoundMax AD1885). As such, the original group formed to support building a Picastar is closed, but the articles are available in a new group called Picaproject which Peter formed to be a repository of information on all his projects. If you wish to further explore how to build a star you MUST join this group to gain access to Peter's Picastar articles and code. Once you are accepted to the group, you may grab the files and code. DO read the author's terms. After you join the Picaproject group, you may ask to join the Picastar-Users group for questions pertaining to the build of a Picastar. If you plan to build a Star based on Glenn's boards; join the homebrew-radios group and check with Glenn to see if he has any Picastar combo PCB sets to spare. The version BB Combo boards contain a PicN'Mix replacement called the TrxavrB which is used to control the LCD and transceiver.

Glenn has built several stars and just recently got his first version BB based unit on the air. The boards were shipped promptly and look very good- MUCH better than DIY boards (thanks to all who worked on this, especially Glenn). Peter G3XJP's preference of DIY boards better meets the "Amateur" requirements of the hobby. I must admit I prefer to avoid the mechanical issues of DIY boards when dealing with lead spacing as small as required on some of the parts. I probably will need to build some companion boards before the project is done. I do like designing boards- not building them.

Here is what Glenn's Combo Board Version BB package consists of:
• Main PCB - contains most of the xvcr.
• LPF Board by G4TZR
• G6ALU 20W PA Board
• G6ALU 150W PA Board
• TrxavrB board by G3VPX and Error corrections
• Atmel Programmer (labeled Atmega Programmer) AKA Pony Programmer.
• W4ZCB Buzzer board (for testing the PCBs)
• Picastar Opto Encoder Board as built by VK3KBO (should you decide to build one)
• Remote USB Board (USB connector miswired)
• Ian's Basic I2C Interface Board

So I now get to work on Bill of Materials (BOMs) for each board, starting with the smaller ones first. As I sort out the build for myself, I intend to post links to my shared projects on Mouser as well as my own BOM spreadsheets and build notes. Always refer to the author's sites as I only post these items for my own guidance and reference. Use whatever stuff I post at your own risk. Photos to follow soon.

73 all- Bill N4BKT