Showing posts from 2015

Simpleceiver ~ Part 24

A Single Schematic for the Simpleceiver! Quite honestly I bristled a bit when I received several requests for a single overall schematic for the Simpleceiver project. Many of the inputs were if I had a single schematic I could better understand the project. Friends that is why we have the block diagram. Well I guess my bent is if you don't understand the circuit blocks having the whole schematic may not lead to a "Level 5 Enlightenment". Another goal of the Simpleceiver was to encourage experimentation and the modules have been designed for the most part to enable matching to 50 Ohms. You can simply replace a Simpleceiver module with a different module and have a go at it so long as you look at the impedance match. An overall schematic may make that task more difficult. But one kind soul  DuWayne, KV4QB has taken on the chore to create such a schematic which is in a pdf format (Sorry guys no GIF's or jpg --so don't send me an email about the quality coming from…

Simpleceiver ~ Part 23

Revisions to the Simpleceiver Detector We are delighted to see that there are homebrewer's out there who are building this project and that is most gratifying. This gives me a sense that all of the time I spend developing circuits and maintaining this blog is having some impact and benefit to the greater ham community. In an exchange of emails with Bob, K6GGO, who built the product detector with the intent of having an 8.0 MHz IF, he reported that he physically built the circuit and ran some test to characterize the performance. His conclusion was that the circuit performed nicely but was seeing an output response capability that extended beyond 100 kHz and in fact had seen a peak response closer to 200 kHz. My response to Bob was that I had seen the same thing but simply ignored anything beyond 20 kHz as this was AUDIO and anything beyond that would never be heard by humans --maybe your dog would hear it? So in the interest of those who would have sleepless nights knowing that …

Simpletransreceiver ~ Part 22

Thoughts on the Control Circuitry We have all heard that a long journey must start with the first step ( I guess 22 parts qualifies this as a long journey). With the Holidays my bench time has been somewhat limited but I did want to provide some of my thoughts on a control circuit for the transreceiver in the event there are those who want to forge ahead. Perhaps one of the most critical items to make the receiver and transmitter play as a unit is how to control the transition from receive to transmit AND to accomplish that end without hiccups, burps, spurious artifacts, hot switching, "kerchunks" and on an on. Those who have followed my projects will find that I like to recycle circuits from prior projects chiefly so I am not continuously trying to reinvent the wheel and secondly since they are proven their performance is known. The solid state control circuit that you will see shortly was a result of a project I did in 2009 where everything was switched with relays. At t…

SimpleTransReceiver ~ Part 21

The J310 Companion Transmitter ~ The Journey Continues!Addendum: 12/16/2015 Simple Transmitter Board Layout
Addendum: 12/18/2015 NEWS FLASH 9A3XZ, has a working Simpleceiver! Bravo Mikele.

If it hasn't hit you right between the eyes, by now, then turn off your soldering iron. So far we have built what I consider a pretty decent receiver for not a lot of money. There is ongoing development work on that part of the project inclusive of the incorporation for the W7ZOI Hycas AGC. That addition is not quite ready for prime time; but we are close. The building of that receiver involved what I call a common template, the J310's configured as a Dual Gate MOSFET. That has worked very well and you only need to listen to the you tube videos and you can adjudge for yourself. We also introduced the use of LT Spice as a simulation tool. Most of the time is spent at the computer and when we are ready to solder up a circuit it is pretty much the final configuration so there is minimum time w…

Simpleceiver ~ Part 20

Transition to the Superhet Configuration Addendum: Schematic for the W7ZOI AGC Circuit.Addendum #2: The Transmitter Block Diagram Addendum #3: 12/15/2015 Simpleceiver Software located on Look for the Simpleceiver Software Link  In Part 19 we recapped the elements of the Direct Conversion Receiver and now in Part 20 we will move to the Superhet configuration. For the last week or so I have been listening to the Simpleceiver Superhet and there is a great deal of satisfaction to finally see all of the blocks and endless simulations come together. Cost wise there is about $60 in parts with the most expensive being the AD9850 followed by the LCD. I purchase parts in bulk and so my cost estimate may be skewed versus buying resistors one at a time. In summary --the sound and frequency stability outshines the $60 investment! Let us start by looking at the Superhet block diagram as shown below. The darkened blocks are from the Direct Conversion Receiver. So to make the con…

Simpleceiver ~ Part 19

Time for a bit of a Review ~ Simpleceiver
It is always good to take a step back to review where you have been to see where you need to go. The Simpleceiver project so far has taken us from a Direct Conversion Receiver to a fully functional Superhetrodyne Receiver with a crystal filter. Our next step will take us to building an accompanying transmitter so that the project will morph into a fully functional 40 Meter SSB transceiver. The project was broken into modules so that each module could be built and tested before moving on to the next stage.

A backbone to this project has been the extensive use of LT Spice and my attempt to provide a detailed documentation of virtually all aspects which hopefully has been useful. I must confess to receiving a bit of criticism to such an approach. An email read in part "stop the blabbing and just provide me a schematic and parts list. I know how to solder two wires together." So to that end I must duly apologize to others who have felt …

Simpleceiver ~ Part 18

More Detail on the Design and Alternatives in the Simpleceiver Receiver Project.
Addendum: 12/05/2015 40 Meter CW Band Pass Filter
Addendum #2: 12/06/2015 "Mea Culpa" for the improper use of "die in the wool" (Crystal Filters)

Based on some inputs I have received, I wanted to explore several "details' of the design and also to explore the use of IF frequencies other than 12.096 MHz. So let us begin by looking at the "gain adjustment" features of the Simpleceiver design. Currently there are three stages which can manually have their gain adjusted which includes the RF Amplifier Stage and the two IF Amplifier stages. The next step of course would be to replace the manual gain controls with an AGC circuit. The use of the Dual Gate MOSFET was not accidental; but by design since it is such a versatile circuit element in that this device can be used as a oscillator, amplifier, mixer or as a  detector. We have used the J310's configured as a DGM for e…

Simpleceiver ~ Part 17

Thoughts, Concerns and Considerations-Stop for a Minute to Consider Frequency Schemes.Addendum 12/02/2015 See the video at the end of this post on Signal Handling Tests.

Part 16 was jam packed with information BUT when  homebrewing amateur rigs it is always best to take two steps back and think about what ALL can happen when you make changes. I added information to Part 16 in response to inquiries about circuit information that would enable the Simpleceiver to be placed on 20 Meters. Initially the request was for an RF amplifier stage and then I provided the Band Pass Filter constants thinking that I would receive requests for that information as well. In passing in Part 16 I mentioned you would have to change the LO frequency so that you would receive USB instead of LSB. This was done so that the same BFO frequency would be used for either band. Sometimes that is not a good solution and let us examine the WHY. Problems show up both on receive and transmit with the transmit being mor…

Simpleceiver ~ Part 16

Hey? Nobody has asked about the Crystal Filters that are being used with the Simpleceiver Project!Addendum: 11/29/2015 Another on the air video of the Simpleceiver
Addendum #2: A view of the completed Simpleceiver "al fresco"
Addendum #3: 12/01/2015 Data for a 20M RF Amp
Addendum #4: Signal Output Data for the AD9850
Addendum #5: Band Pass Filter Data for 20 Meters

The following is the schematic for the RF Amplifier stage. Please note about the Resistor "R" and how that is made. Addendum #3: To use this RF Amp on 20 Meters (Query from WA7RHG) simply make L1 = 8 Turns on the FT-37-43 core and make C2 = 10NF. Addendum #4:Based on anearlier input regarding why I used the AD9850 straight into the SBL-1 without a "booster amp". I guess the simple answer is I hooked it up and it worked --so keeping thing simple. But to get full advantage of the SBL-1 it probably would be a good idea for a booster amp. Now when you measure the output of the AD9850 + Booster Amp make…