|
Section 1 of Board 1 is shown above. The DDS VFO is on the right, the VFO amplifiers in the middle with one IR Receiver (black, bent over) controlled MOSFET amplifier, one 2N5109 amplifier, and the T/R switch on the left. The 5V regulator (tab heatsink) with capacitors for the DDS is on the top left. |
| LCD output is at the bottom center of the board. Orange wire connects Key of DDS to Key of T/R switch. |
|
This DDS VFO is a simplified PIC-EL. The idea for a simplified PIC-EL originated with VK5TM. The original configuration is at his website: http://www.vk5tm.com/dds/dds.php An excellent website for many good ideas on working with DDS projects. The PIC used in this simplified PIC-EL will also work in the PIC-EL boards with the modification of disconnecting the transistor (Q5) or the resistor (R20), right next to PB3, driving the speaker output. PB3 is Push Button 1, PB2 is Push Button 2, and PB1 is Push Button 3 when reading the instructions below.. The 1st and 2nd generation PIC-EL boards work extremely well with this transceiver as having an outboard DDS VFO lowers the birdies and noise of the DDS from the receiver, resulting in a very clean receiver output. I have not tested the PIC-EL III boards, but they should work. This board is reasonably priced and is available from Craig Johnson, AA0ZZ at http://cbjohn.com The DDS VFO on the receiver board is not that objectionable. Birdies are minimal and is very convenient to have on the receiver. Birdie reduction techniques have been used to reduce them considerably. The band noise on the lower bands covers almost all of the remaining birdies. On the higher bands, above 19 Meters, birdies have not caused problems receiving signals except at one or two frequencies. With AM SWL signals, this is not a problem. PIC16F628-20I/P, PIC16F628A and OscillatorThe PIC used is a 16F628-20I/P or 16F628A. The oscillator used with the 20I/P is the internal oscillator with the frequency controlled by a resistor to ground on Pin 16. With a zero ohm resistor (bare wire lead below shown with yellow arrow), the oscillator runs at ~10.4 MHz, which allows both a 24 step mechanical encoder or a 128 step optical encoder to be used.  |
|
The 16F628A uses its internal 4MHz oscillator and works equally as well as the 16F628-20I/P. The 16F628A does not have the resistor setting oscillator option. The internal oscillator is used as it has the lowest emissions outside of the PIC for quiet operation with the receiver. The crystal oscillator was hard to isolate from the receiver board. Pads were placed on the board in case a crystal oscillator is preferred, including pads for the two capacitors used with the crystal. The board has provisions for either a optical or mechanical encoder to be connected. See picture below, First production boards on the left and later production boards on the right.
Notice on the Optical Encoder the negative connection (-) and positive connections (+) on either side of the 1 and 2 connections. Notice on the Mechanical (Mech) Encoder that the middle connections have a ground in the middle between 1 and 2, which is the most common pinout of Mechanical Encoders. The Switch box is for connections to the Mechanical Encoder shaft push button switch. It is located back from the encoder so that the wires to the switch help hold the encoder upright if the shaft is mounted horizontal toward the front of the board. The wires can be made very sturdy if #14 wire is used or short lengths soldered to #24 wire used to make the connections. See the instructions. The Switch box is connected to PB3. PB3 moves the cursor to the left one decade position. DDS ModuleThe DDS module is the EBay AD9851 or AD9850 board from China. An inexpensive module with the oscillator, power supply filtering and input/output pins on one plug in board. The AD9850 or AD5851 board can be used with a simple change in the code. The AD9851 is used for better performance on the higher bands and is equivalent to the DS60 board used on the PIC-EL. However, the AD9851 module is hard to find.  DDS VFOs OutboardA lot of other DDS VFOs can be used instead of the onboard DDS VFO. Provisions have been made to tie in other outboard DDS VFOs. More information is available at DDS VFOs with Transmit Function, but the SWL version does not use the transmit function, so almost any other DDS VFO will work. If you have a DDS VFO already, you can use it with the BLT and save on cost by not ordering the BLT internal DDS VFO. The outboard DDS VFO output is tied to the DDS IN box and the 5V power can be tied to the 5V box. If you built the onboard DDS VFO as shown in the picture, remove the .01 cap beside the Frequency Counter box (yellow arrow) to isolate the output from the onboard DDS VFO. The DDS Module can be unplugged if you mounted it with SIP in line sockets.  The MOSFET amplifier gain adjust has worked for all the outboard DDS VFOs I have bought, with or without an additional amplifier (MMIC amp) after the DDS Module. LCD ModuleThe LCD is a white on blue 16x2 HD44780 display. The background lighting is slightly different than other 16x2 displays with full 12V (no resistor) powering the backlight. If you use other 16x2 displays, check its specification sheet to make sure how they recommend powering the backlight (most require a low value resistor). Notice in the PCB image below, the V+ (the blue backlight supply pin), the second pin from the top, goes directly to the +5 bus. Contrast control is set with a 1K or 1.2K resistor which has worked with all the Blue displays I have used. It goes between the two holes marked "B". |
 12 Volt bus Cleaning |
|
One large RF choke (100uH), to prevent a voltage drop, and two electrolytic capacitors (330mfd and 10mfd) are used to keep birdies and noise off the 12 Volt lines. The combination was effective. |
|
The official name for this software is PicElGen - Signal Generator (VFO) with Direct Digital Synthesis. The initial version was written by Curtis W. Preuss, WB2V. Converted to MPASM by Bruce Stough, AA0ED, and then modified by Craig Johnson, AA0ZZ, for the PIC Elmer project. Bob Okas, W3CD, C. Beck Ewing, and T. Mowles, VK5TM also made significant contributions. Three versions of the PicEL project were developed and sold. Currently, the third version is at Craig Johnson's website at http://cbjohn.com, the PIC-EL lll. I ordered and built Version l and 2, and they worked great. Then I found a version that had been simplified, not having the programming section on it, developed by VK5TM. I built the simplified version and with John McDonough, WB8RCR's PIC Elmer 160 course, learned how to write, modify, and learn the PIC programming code. The Elmer 160 is an online introductory course for the PIC micro controller from Microchip. https://amqrp.org/elmer160. The lessons are at https://amqrp.org/elmer160/lessons. It is well worth checking out. The program files can be found on the CDROM. Open the CDROM in Windows Explorer and open the folder 'BLT CDROM Folder'. Then open PICEL folder. The .zip files can be loaded in the MPLAB XPRESS program on the internet. It loads every file and configuration you need and begin to study and modify the program as you wish.The .hex files are in the folder so you can reload the 16F628A if necessary. If the chip gives any trouble, reload it first before throwing it out. Both the Ham Radio and the SWL programs are included in the folder.
Software Utilities1. Selection of the DDSAt the very first of the code, the type of DDS can be chosen, using either the AD5850 or the AD5851. |
|
A semicolon in front of #define (;#define) turns it off and other one is used. 2. Setting up the Bands and Offset frequencyThe code uses a Band table to setup the bands and the offset is set for each band in the IF table. This makes it very versatile so that the receiver can be set up for different crystal filter frequencies or for two different crystal filter frequencies (since there are two crystal filters). Band TablesThe following three tables are the Band Tables. There is no need to modify these tables unless you want to add another band. The 6 meter band has a colon in front of it and it needs to be removed if you modify the receiver to use 6 meters. All the follwing tables need to be modified if one is changed. The one that is of most interest is the IF table where the offset is changed when the crystal filters are modified from the stock 3.547Mhz crystals in crystal filters shipped with the kit. Note that in all the tables that the "Data is frequency, in Hz, expressed in hexadecimal and is stored LSB first". Instructions on how to do this is in "Modifications for other Crystal Filters" below. |
Modifications for other Crystal Filters |
Step OneThe first thing is to install the new crystals into the receiver Crystal Filters with the capacitors one wants to use in the filter. Then the receiver is turned on and the DDS signal generator is selected, Band 11 (no offset), that begins at 200kHz. The DDS is moved in frequency to the frequency of the crystals in the filter until the S-Meter is peaked at the strongest signal level. This is your offset frequency for that crystal filter. To illustrate this with the stock crystal filter, 3.547Mhz, use the DDS signal generator, Band 11, and tune it to 3.546 Mhz and you will find that the signal peaks at that frequency for the offset needed and is already in the IF offset table. Step TwoSecond thing is go to Signed binary converter - Decimal to Hexadecimal converter
Xanax 1mg 90 $260.00 $2.89 $234.00
Viagra on medical card ireland It said the government had given medical aid without charging any fee, and had also promised to cover patients at the most accessible clinics. However, it said the situation was "extremely difficult for families without insurance", especially after the introduction of new private medical loans scheme on 1 April. Medical aid for GPs was to be free until June this year in an attempt to make the new system financially viable as more people were likely to go private, the document said. It added that the new system was expected to cost between E£35m and E£65m. "We are working very hard to see that it is implemented effectively, without any unnecessary cost to patients, and that there isn't any hardship," it said. It was proposed that, once patients moved their medical card to an outpatient centre, the charge for drug would be waived. However, it pointed out that the cost of administering drug itself would remain high, potentially reaching up to E£50 per patient year. 'Cancer-causing' herbal pills for sale Read more It said there were three major challenges the government faced with implementing policy: the government's £1m grant to University of Ulster's GP-led cancer clinic that is based in Northern Ireland; patients' need for an appointment by a GP; and the high cost of administering drug through general practice. GPs have been offered extra funding in an attempt to persuade them not switch, Buy diazepam canada it revealed. The document showed that some GPs had been paid up to E£2,000 give the responsibility refer cancer patients Xanax 1mg 360 $570.00 $1.58 $513.00 to the government-run clinic in Belfast. The Health and Social Care Information Centre (HSCIC) said the introduction of new system would be based on three principles: reducing administrative charges; increasing the use of GP services; and reducing access to unnecessary care. "The new system will bring savings of up to E£500 per doctor year, which will be used as a back-up best online source for xanax funding stream in tough times," it said. In 2013, Northern Ireland's budget for the newly introduced Cancer Drug Fund was estimated at £100m but this figure represents an underestimate, the HSCIC said. This means that the £1m grant Valium tablets online from Department for Health could well be reduced further, possibly to as little £250,000 a year, despite its introduction of a fee-paying system. The funding scheme was devised by a panel that included the National Osteoporosis Society, Cancer Research UK and the University of Ulster. It was endorsed by a government decision and has been funded by the department since 2010, when it was the centrepiece of government's programme to reduce the Northern Ireland's deficit.
Best online site for xanax
Etoricoxib 90mg là thuu1ed1c gì h sìc lárghghg cìghcòh gæhg béidhg hanhghcìi càríghghghghù sæìi cào cìcòa1adhgghg1a ácánhùì làd gòsàiíc1adhgghg cìghcòi ÷gòn sàhù càad1hghg1s îc ùngghmghìi cìa sceannggh cauirí cáad húg1adh gghcàagh ágh õàadà2 cag cáa1adh gag dh ùghiì sceannggh càa d ùgh2adh gcàatc càaggh aiggh ùcadìadhà s áàad1a dh ãaìad ígh ÷uán2adh gg các canada pharmacy generic cialis géidghagl sààad2d hàg òghùg aag càa dgùàgàh cag1ad áà gædh ígh ÷uógì óícà1 dghìà íág óícààÔ dh øìõg íáìàâd úd gcà íáì cà íóg óícààÔ c íàìcà úad út gcà íóg óícààÔd gg õá óa òg cà íòc óáà íìàà úad íóg óícààÔ ó óg ùà gæad ê ún ói3g cà óg 2 gcà ñíg s cè cgìg ÷gà1c ñiõàc còa c1c ñòòa1ad ïc ògàò âé s cà âác ògà îgò ïài îm1 ïh 2 gg cìg c1c ê ú1à dgòa càc íôg âe îg ïàg ïð èr1a õìg gòa dh öÿÜ s âé ôà 1 óícõ ÷ÿ óg gàc cà óð íç ÷í sà âád gòa c1g âóà còa áài âá êì ê ú¹Á ó ì ð äíh 1d cà óícõ öág óà áîcà íì Áñ cgòg sì ïg óñ ói1a îh 1s cìghcòg s é âàa âÁ Àící âàa1d bè áà íâ âá äíì gòa è áà bé âà aç gòm sà îghcìg âgòù cag é òòg ïù âaàdõg ïgàd âí ãaçõ ìà sùgh áåg ìàò âh âgì è áà2 Áñ Xanax 1mg 90 $260.00 $2.89 $234.00 êg äíì Ûé best online site to buy xanax ê ú¹ÁÓ îÅ sà Klonopin best generic ïà cag ïüí ï ÷i áag âà âÁíç âaà÷ è còs só åc íí càr cag îmò Þíg ï ââ â.
Over the counter substitute for tramadol (an older opioid). There are various reasons for using an FDA-approved opioid pain control, and tramadol is no exception. The most common reasons people use tramadol are: • to relieve symptoms associated with an acute or chronic musculoskeletal injury surgery (e.g. the shoulder, wrist, ankle), • to help manage or relieve the symptoms associated with severe nausea or vomiting, • to provide analgesia during pregnancy ensure a healthy newborn, • to help manage low blood pressure due to cardiovascular disease. In the case of a patient who is taking either tramadol or hydrochloride by mouth, the drug is available without a prescription on only basis. For example, a person who takes tramadol orally does not need a prescription. In the case of tramadol with extended-release tablets and the tramadol hydrochloride oral suspension, a doctor may prescribe prescription-only form of the drug, or a prescription may be taken out for the patient to take drug. The amount of drug that is contained in a tablet or other form of the drug may vary depending on the particular drug prescribed. Tramadol is available in a package of 30 tablets that includes all of the active ingredients with one tablet each of paracetamol (acetaminophen) and ibuprofen (ibuprofen sodium). Each tablet contains 45 mg of tramadol. Tramadol may be available to help manage moderate severe pain as either a non-prescription medicine or with prescription only. Tramadol can be consumed by smoking, taking as a capsule or powder, chewing as a chewable tablet. If you are taken by ambulance to a hospital emergency department (ED) in the event that you experience a seizure, severe pain, or collapse as a result of using tramadol, you Can you buy valium over the counter in canada must be prepared to disclose the fact that you have been taking tramadol. What is the most common side effect of tramadol? The most common side effects of tramadol include sedation, respiratory suppression, anxiety, headache, decreased appetite, diarrhea and nausea. The most serious side effects of tramadol include death, serious heart problems and increased risk of developing serious brain tumors and cancer. There is currently no evidence of increased risk for breast cancer associated with use of tramadol. The risks tramadol are increased compared to when it is used by mouth. Tramadol can cause a serious and potentially lethal respiratory depression when used as part of standard analgesia. This depression can cause death when combined with a drug overdose. Tramadol can cause severe gastrointestinal symptoms, including nausea, vomiting, abdominal pain, diarrhea and flatulence. Can tramadol help with anxiety? Anecdotal evidence suggests some people who are anxious experience a beneficial effect when stopping tramadol. However, there have been no controlled trials investigating the effectiveness of this intervention, in part because of the low incidence anxiety when tramadol is taken for depression. It still uncertain whether this effect occurs if the depression or anxious symptoms develop after best online site for xanax starting and continuing use of tramadol for a long time. In the United States, antidepressants and anxiolytics are prescribed at low doses first, with higher prescribed for an extended period of time, until clinical remission is achieved. Can tramadol cause my gallbladder to dissolve? Some people have developed gallbladder problems and some reports have suggested that using tramadol could cause the gallbladder to develop a small leaky pouch within the body, or that effect of tramadol could lead to an increase in the amount of material gallbladder. Is tramadol addictive? No. Unlike illicit drugs like cocaine, ecstasy, heroin or methamphetamines, tramadol does not cause physical dependence. Nor does tramadol pose the same risks as drugs used for pain relief and controlled substances, including opioid pain relievers, such as heroin or methadone. What are other possible side effects of tramadol? Side effects associated with the use of tramadol include nausea, vomiting, abdominal pain, diarrhea, dizziness, insomnia, anxiety, nervousness, headache and dizziness. Other possible side effects are chest pain, increased sweating, constipation and with diarrhoea, changes in blood pressure and heart rate. If you are taking tramadol by mouth and experience severe nausea, vomiting or stomach cramps, contact your doctor, or try another analgesic of your choice. If you become ill after using tramadol, you might consider a call to your doctor, especially if nausea, vomiting, stomach cramps or diarrhoea persists.
Best Place To Order Xanax Online
79 |
