It looks like the new IC-9700 is one step closer to being available. It’s now on the Icom website. You can see more along with the Icom pre-release brochure on the Icom website here.
I have been operating using the FT8 digital mode on the 6m band using our remote operating gateway quite a bit this summer. The SDR-based remote operating gateway in our station allows us to operate our station from other rooms in our home as well as from outside our QTH via the Internet. When I’m at home, I have computers set up with outboard monitors to create an operating setup for FT8 digital contacts on the 6m and other bands. The photo above shows this setup. Having the extra screen space and multiple laptops enables control of our station, making and logging QSOs, and checking propagation via Reverse Beacon Networks as we operate.
This laptop runs the WSJT-X software (left windows above) which conducts QSOs in FT8 and other weak signal modes and the JTAlert Software (lower right windows above) which interfaces WSJT-X to the DXLab logging suite. JTAlert displays all callsigns decoded by WSJT-X and compares them to my log to determine which potential contacts are new DXCC’s, Grids, States, etc. JTAlert adds contacts to my logs in DXLab when a QSO is completed using WSJT-X.
The windows laptop also runs the DXLab logging suite. DXLab handles logging of QSOs, one-click pointing of our antennas based upon the callsign being worked, and uploading contacts to LoTW, eQSL, and ClubLog for confirming contacts.
I like to use the second computer to monitor propagation and strength of my FT8 signal while operating.
I use two tools to assess propagation conditions while I am operating. The first is PSKReporter which is a Reverse Beacon Network (RBN) tool that is enabled by WSJT-X and most other digital mode software programs. Each time WSJT-X decodes a stations transmission, it reports the decoded callsign along with location and signal strength information to the PSKReporter website. This website then uses this information to display all of the stations that hear my and other’s transmissions in real-time. The RBN information is used to determine where a given band is open and as a tool to determine how much transmit power is needed to provide acceptable signal strength at stations that I am trying to work.
The DXMaps website shows a real-time map view of contacts being made on the 10m and higher bands. This second tool provides a real-time view of band conditions and opening on bands like 6m which have somewhat unpredictable propagation characteristics.
Together, these tools help to determine where to point antennas and what stations we can work on the 6m band.
The second laptop also runs Teamviewer remote control software. This provides access to the antenna switching controls, SWR and power monitoring equipment, station electrical power, and amplifier controls in our shack. These tools are important elements in safely operating and controlling our station when we are not in the same room as the radios and other equipment we are using.
I’ve been using the remote operating setup described here on the 6m band quite a bit over the last few weeks. I hope this post provides some ideas that other can use.
We have been working on project to scale our open house activities to provide an opportunity to learn about Amatuer Radio and to showcase some of the modern, “hi-tech” aspects of the Amatuer Radio Service. This project was debuted at the NETT event at NEAR-Fest. We used our Portable Satellite Station, Remote Operating Gateway, and our Mobile HF Stations as part of this activity. There might be some ideas here that you can use to create an exciting operating activity at you local club or Ham Fest.
One of the best meteor showers of the fall, the Orionid Meteor Shower, will peak on Friday night with over a dozen meteors streaking across the night sky every hour.
Source: Orionid meteor shower: Friday night to bring excellent viewing conditions in the Eastern US.
It looks like this weekend is going to be a good time to work Meteor Scatter contacts on 6m! The Orionid’s peak tonight (Friday) and tomorrow (Saturday) night, October 20th and 21st. We’ll be operating using WSJT-X MSK144 mode on 6m. We are planning to use our Remote Operating setup to take advantage of our SDR’s receiver capabilities and the connected 500w amplifier.
As explained in a previous article, we have been working on enhancing our FlexRadio 6700 based Remote Operating Setup to include additional remote control client options, better remote networking via the Internet, and better integration with our microHAM system.
This project involved the addition of the following capabilities to our base Remote Operating Setup:
- An upgrade to FlexRadio SmartSDR V2 to add improved networking of our FlexRadio 6700 radio over the Internet
- The addition of a FlexRadio Maestro Console to make it easier to operate our station remotely and to enable sending CW via paddles.
- A new, simpler VPN solution to allow remote control of the microHAM Station Master Deluxe Antenna Controller and Elecraft KPA500 Amplifier which is part of our Remote Operating Gateway
- Updated Laptop PC VPN and Remote Control Software to allow operation of our DXLab Logging Suite software with the Maestro in SSB Phone and CW modes
- The installation of the latest version of WSJT-X software to add current JT9, JT65, FT8, MSK144, and WSPR digital modes to our Remote Operating setup
These steps are now complete and we have some good results to share.
The first part of the upgrade was to update to SmartSDR V2. This upgrade enables much improved SmartSDR operation over the Internet. Our previous approach, which used a tunneled VPN connection combined with the previous versions of SmartSDR did not always perform well when used with low-bandwidth or high latency Internet connections. SmartSDR does much better in this area.
Both the SmartSDR CAT and the SmartSDR DAX application have been updated to allow software on a PC being used to operate the FlexRadio SDRs over the Internet to gain access to CAT and sound interfaces associated with the radio.
We also added a Maestro Console to enhance the usability of the SDR radio portion of our Remote Operating Gateway. The Maestro is very easy to use and extends the available controls and display space which was limited when using just a laptop PC. The Maestro supports direct microphone connections for phone operation and also works with connected CW paddles for operation in CW mode. I have been using a single level paddle along with our Maestro as speeds of 22 WPM with full QSK. Sending CW at these speeds with the Maestro works well.
The Maestro has built-in WiFi and Ethernet connections and full support for SmartSDR V2’s connections over the Internet. The Maestro can operate from AC power or from an internal battery pack. I have a couple of spare rechargeable batteries for our Maestro to support longer operating sessions on battery.
We have been using a combination of TeamViewer Remote Control software and a router-based VPN solution to enable control of our antenna controllers and station power/amplifiers. This arrangement works well but most of our readers probably do not have a router which can support VPN connections or the networking knowledge to set up a secure VPN system.
A much simpler VPN solution can be realized by utilizing TeamViewer’s built-in VPN capability. You simply install TeamViewer on a PC in you shack which can access you station accessories and on your remote operating laptop or PC. You then enable TeamViewer’s VPN option and the configuration is complete.
We now use TeamViewer to set up both a VPN connection and a remote desktop control connection to a computer in our shack which can control amplifiers, power, and other station accessories associated with our Remote Operating Gateway We use TeamViewer in this way to control our microHAM Station Master Deluxe antenna controllers, RigRunner remote power controller, a microBit Webswitch device and an Elecraft KPA500 amplifier which are all part of our station’s Remote Operating Gateway.
With the addition of the SmartSDR and the updated TeamViewer/VPN setup, we can operate our station remotely over the Internet. We have tested our setup using a Wireless Hotspot modem and Verizon’s LTE service. The combination of our PC running the DXLab Logging Suite and the Maestro work great in this configuration.
We have found the need to initialize the networking configuration in a specific order to get everything running correctly. The steps that we use are as follows:
- Connect the laptop PC to the Internet
- Bring up the TeamViewer VPN connection
- Run SmartSDR on the laptop PC and login to SmartSDR Remote
- Bring up the DXLab’s Suite including Commander (currently, DXLab’s Commander has some issues connecting when the FlexRadio protocol is used. We have found that the KENWOOD protocol works fine.)
- Bring up the remote control application for the Elecraft amplifier and access our RigRunner power controller and microBit Webswitch units to turn on accessories as needed
- Initiate a second TeamViewer Remote Control connection and use it to run the microHAM remote antenna controller in a single window
- Shutdown SmartSDR on the laptop PC and bring up the connection to the radio via the Maestro.
There is obviously still some room for simplification in this initialization procedure. I expect that some simplification will come as all of the software involved becomes more mature and is further adapted for remote operation.
Once initialized properly, its simple to use the PC and Maestro combination to work SSB Phone or CW contacts. The DXLab Logging Suite will follow the radio, track modes, handle split operation, and allow control of our antenna rotators via DXView. We can click on spots in DXLab’s SpotCollector to automatically set the FlexRadio SDR’s mode, frequency, and split configuration. The Maestro and DXLab will stay in sync during tuning, mode changes, and other radio operations.
The final part of this project was to add the latest Version of the WSJT-X software to our Remote Operating client laptop PC to enable FT8 operation on the HF bands and MSK144 for Meteor Scatter work on 6m.
We do not use the Maestro for digital operation. We leave SmartSDR running on our remote laptop PC instead. We also use the JTAlert application to create an automated bridge between WXJT-X and the DXLab Logging Suite.
The combination of SmartSDR V2 and WSJT-X work great remotely. We have used this combination to make quite a few FT8 contacts on the HF bands as well as several Meteor Scatter contacts on 6m using MSK144 mode.
These enhancements to our Remote Operating Gateway have helped both Anita and me to operate more. I have our Maestro either in my home office or on a table in our kitchen where we can listen to the bands and work DX when the opportunities come up. Remote Operating, even its just from another room at your QTH, is great fun!
We should be able to begin the next step in our station upgrade plans – the addition of an Elecraft KPA1500 shared amplifier, in the near future. The new amplifier will enable our Remote Operating Gateway to operate at legal limit 1500w out on the HF bands and 6m.
We have a number of station upgrades planned for this fall. Our planned upgrades include:
- Enhancing our FlexRadio 6700 based Remote Operating Setup to include additional remote control client options, better networking via the Internet, and better integration with our microHAM system – you can read about this completed project here.
- Upgrading the second radio in Anita’s (AB1QB) operating position from the current Icom IC-7600 to a new an Icom IC-7610 SDR-Based Transceiver
- Adding a new Elecraft KPA1500 Solid State Amplifier to our station. The KPA1500 will be shared between the Icom IC-7610 and our FlexRadio 6700 based Remote Operating Gateway
We always begin our station projects by updating our station design documents.
Our Remote Operating enhancements will include:
- Updating our FlexRadio SmartSDR Software to V2 which provides operation of the radio over the Internet
- Using the SmartSDR CAT Cable features to create a direct interface between the FlexRadio 6700 and the microHAM Station Master Deluxe associated with the SDR
- The addition of a Maestro Control Console to our set of PC-based remote operating clients
The figure above shows an updated architecture for our Remote Operating Gateway which includes these enhancements. The planned Elecraft KPA1500 solid state amplifier will simplify the software associated with remotely controlling and monitoring the amplifier, tuner, and wattmeter components in our previous remote operating setup.
We have been quite impressed with the performance of our Icom IC-7300’s radio’s receiver. As a result, we have decided to upgrade the second radio in Anita’s operating position to an Icom IC-7610. We expect that the IC-7610’s receiver performance will be as good as or better than the IC-7300.
The Icom IC-7610 also provides a very nice external display capability which will allow us to take the best advantage of the radio’s pan adapter. We believe that the IC-7610 will integrate easily into our microHAM system. It should be a “drop-in” replacement for our current IC-7600. We hope to see the IC-7610 shipping before the end of this year.
Our final upgrade will be to add an Elecraft KPA1500 Solid State Amplifier. This amplifier provides a full 1500 watts out on all bands 160m – 6m. The new amplifier will bring the Icom IC-7610 and our FlexRadio SDR-Based Remote Operating Gateway up to full legal limit power. This will be especially helpful on the 6m band where both the IC-7610’s and the FlexRadio 6700’s excellent receiver performance will help us to take the best advantage of the extra power for Meteor Scatter and other weak signal work on 6m.
Our microHAM Station Automation System can accommodate shared amplifiers. We will take advantage of this capability when we integrated the Elecraft KPA1500 into our station. The shared amplifier setup will also allow us to eliminate one of our bandpass filters. The KPA1500 amplifier integrates autotuner and wattmeter functions into the amplifier and provides a direct Ethernet interface for remote control and management. These enhancements should eliminate the need for several of the remote control server software applications that we are currently running on a PC in our shack. Also, we can manage all of these functions from a single client application on a remote client PC. These simplifications will make our remote operating gateway setup more reliable and easier to use.
We plan to share more on these projects in future posts here on our Blog. The FlexRadio Maestro and all of the other components that we need for Remote Operating Gateway enhancements have arrived. We will complete this part of our project in the very near future and post more here.
Also, it appears that the local control interface to the new Elecraft KPA1500 amplifier is nearly identical to that used by our current Elecraft KPA500 Amplifier. This means that we can begin our shared amplifier upgrades using the KPA500. We do not have a firm date for the IC-7610 to ship and that portion of our upgrade plans is likely to be our last step in the project.
Special thanks to Dave, K1DLM who has helped us with ideas for several aspects of this project.
Today proved out some simple, tried and true advice for me – it pays to take some time and tune through the bands. I just got a Maestro Remote Control Device for our FlexRadio SDR and I took a break around lunchtime to tune through the higher HF bands to see what I could hear. We use a Flex SDR as a Remote Operating Gateway into our station and the Maestro allows me to run our station over our home network with going down to the shack.
I am not sure why but I decided to give the 12m band a look today. When I did, I was stunned! It is about noon time and the 12m band is wide open between Africa and the US!
I worked two DX stations on 12m SSB. The first was XT2AW, Harald in Burkina Faso. Harald was working split and was not real loud but I had no trouble completing the contact with him. Excited, I tuned across 12m some more and found an old friend – Theo, ZS6TVB in South Africa. I had a very nice QSO with him. We both marveled over the propagation on the 12m band that we were experiencing. He was 57-58 here in New Hampshire!
The sunspot conditions are pretty weak (SFI 85, SN 26) to create such a good opening on 12m. I believe that we may be experiencing Transequatorial Propagation (TEP) which can provide a significant propagation enhancement on paths with traverse the equator. Anita and I experienced similar TEP propagation on 10m when we were on Bora Bora Island early in 2012 with similar solar conditions.
It just goes to show that it pays to tune the upper HF bands. Especially on days when “they are not open”. Also, 10m also appears to be open to Africa right now – I am hearing a station in Mauritania…
Dave Merchant K1DLM, our Field Day chairman, is bringing some 21st Century radio and computer technology to our Field Day setup this year. There are several aspects to this new component of our Field Day plans including –
- Two Flex-6700 Software Define Radios running over a network for our new Digital and enhanced GOTA Stations
- An on-site WiFi Network to enable using the N1MM+ Logger in network mode for sharing of log information, station activity, real-time scores, and messages
- A central Score Board and Field Day Information Computer in our public information tent
We will again be holding our 2017 Field Day operation at the Hollis-Brookline High School in Hollis, NH. We are planning on using the upper baseball field area as our main operating location. We have decided to add a third tower this year and locate it on a soccer practice field which is situated several hundred feet away from our main operating area. All of our antennas and equipment will lie within the required 1000′ circle but the third tower would situate those operating at that location away from the rest of our group. Dave’s solution to this problem was to set up a network and operate two Software Defined Radios (SDRs) at the lower site remotely from our location on the upper field.
Dave has enlisted Piece Fortin, K1FOP to be our IT Chairman for Field Day this year. Pierce has been instrumental, along with Dave, in the planning and testing of all of this new technology. Pierce and Dave have a great deal of networking and IT experience and knowledge and we could not have put together what is described here without them.
Dave K1DLM, Piece, Hamilton K1HMS, Mike Ryan K1WVO, Anita AB1QB, and I have gotten together multiple times to set up and test all of this new technology. I wanted to share some more about the equipment and the associated testing (which has been staged in the kitchen at our QTH – thank you, Anita!).
We began the testing process by setting up our 20m CW station.
This station uses an Elecraft K3S Transceiver, a K1EL WinKeyer and the N1MM+ Logger running on a Windows 10 Laptop PC. We used this station to get our basic N1MM+ setup including our Field Day CW keying macros right.
Next came our 40m SSB station. This setup uses an Icom IC-7300 Transceiver and allowed us to set up and test N1MM+ on the fly audio macro recording and playback. All three of our SSB stations will have on the fly recording and playback capability which will allow each of our SSB operators to record and use a custom set of audio macros.
Next came our Digital Station. This station uses one of the two remote Flex-6700 SDRs.
Dave, K1DLM put together a really nice package for the two Flex-6700 SDRs and associated equipment which will be located on the lower field. He used a rack system to mount the two SDRs, power supplies, a three-band Tri-plexor, a set of bandpass filters for 80m, 40m, 20m, 15m, and 10m and a 403A 8×2 networked antenna switch. This setup allows either of the two SDRs to share the tri-band yagi or the 40m and 80m Inverted-V antennas on the tower on the lower field and operate on any of the 5 available HF bands. Antenna and filter switching automatically track the frequencies of the two SDRs making the setup simple to use.
The Digital Station’s remote SDR will be operated using a SmartSDR client running on the Digital Station laptop PC. This station will have a second monitor to better accommodate all of the windows associated with it.
The main display associated with the Digital Station will run decoders for all PSK and RTTY modes. The ability to decode multiple PSK signals simultaneously and multiple RTTY decodes are available. The Digital station also acts as the N1MM+ master station in our Field Day setup for all of the other stations which use N1MM+.
Our Satellite Station 2.0 was also added to the test setup. It uses a MacBook Air laptop running MacDoppler to control the antenna rotators and the Icom IC-9100 Transceiver which are part of our Satellite Station. A Windows 10 Surface Pro computer is included which runs N1MM+ and provides logging and other network functionality for our Satellite Station.
We also tested our GOTA station which uses the second Flex-6700 SDR and a FlexRadio Maestro to provide a more conventional “buttons and knobs” interface for our GOTA operators to use. This station will also have a laptop PC running N1MM+ for logging.
We also build and tested a Scoreboard PC. This computer will be located in the Public Information tent at Field Day and will be connected to a large display. It will show our real-time score, QSOs being logged as they are made and other useful information about our Field Day operations. This computer will also continuously play videos from our Video Collection and will provide access to IP video cameras which monitor the tower and equipment on the lower field.
Our networked N1MM+ testbed contained at least one station of each type (CW, SSB, Digital, Satellite, and GOTA) that will be part of our Field Day setup this year. The Station Masters for the additional CW and SSB stations came by to test their setups using the test bed.
The networking system which Dave and Pierce built is central to all of the technology described here. All of the gear is mounted in a single rack which will be located on the upper field during Field Day. The setup includes a Firewall/DHCP server, a commercial grade outdoor WiFi access point, a 4G LTE modem for Internet access, an Ethernet Switch, and a UPS power supply.
The upper and lower fields at our Field Day site are separated by several hundred feet. A thick line of trees between the two locations raised concerns about connecting the upper and lower sites using WiFi. Pierce came up with a great solution to this problem – we will be using MoCA Data Modems and RG6 Quad Shield 75 ohm Coax Cable to provide a 10 Mbps data link between the two sites. We tested the MoCA link using a much longer run of coax cable then we will need to use at Field Day and confirmed full 10 Mbps throughput.
Our networked N1MM+ setup will allow any station in our setup to send messages to everyone who is operating at Field Day. We can use this capability for important communications like “lunch is ready!” or “I need help from Pierce (our IT chairman) on the 40m SSB station”, or “The 6m band is wide open!”.
Our GOTA and Digital stations will be located together in the same tent and will provide our Field Day 2017 visitors to see and use 21st-century Amateur Radio technology to make contacts. We are expecting young people who participated in our High-Altitude Balloon project and from other local schools where we have done Amateur Radio activities to attend. In additional to being a learning opportunity for all of us in the Nashua Area Radio Society, we hope that the state of the art technology that we are using will generate interest among our visitors. If you are local to the Nashua, NH USA area, come pay us a visit during 2017 Field Day. We’d enjoy providing a tour for you and your family along with a chance to Get On The Air. Hope to see you at Field Day!
Every so often, I drive Fred’s truck into work and people ask me what that big antenna on the back of the truck is for. I explain to them that it is for Ham Radio. But the reply is usually, why ham radio – isn’t that outdated technology? We have cell phones and IM, etc…what do we need Ham Radio for? So I thought I would put down my thoughts as a relatively new Ham about why I enjoy spending so much of my time with Ham Radio.
The number one reason we still need Ham Radio along with all the other technology we now have is for public service. When there is a disaster and cell phones, television, etc are all not working, Ham Radio operators provide the critical communication.
Ham Radio operators help locally to keep hospitals and first responders in contact with each other to help those affected by the disaster.
Hams also use our ability to communicate around the world on HF bands to help family members around the world to get in touch with loved ones affected by a disaster.
Ham Radio operators have been on the scene helping in every disaster from the earthquakes in Nepal to the recent flooding in California.
Technology and the Maker Movement
I only became a Ham 5 years ago but many of my fellow Ham Radio operators got their license when they were in their early teens and used what they learned to launch their careers. Many have had very successful careers in STEM fields, all launched by their interest in Ham Radio at a young age. As technology advances, so does the technology used in our hobby. We even have a nobel laureate, Joe Taylor K1JT who is a ham. Joe has developed weak signal digital communication modes that let us communicate by bouncing signals off the moon!
As technology has advanced, so has the use of it in Ham Radio. Most Ham Radio operators have one or more computers in their shack. Many also have a software designed radio (SDR), where much of the radio functionality is implemented using Software, we use sound cards to run digital modes, which are a lot like texting over the radio, and we use the internet extensively as part of operating. We can also make contacts through satellites orbiting the earth and even the International Space Station.
Most hams love do-it-yourself technical projects, including building a station, home brewing an antenna, building a radio or other station component. In my day job, I am a program manager for software development projects, but its been a while since I have built anything. As a Ham I taught myself how to code in Python and about the Raspberry Pi and I built the DX Alarm Clock.
One of the coolest things about being an amateur radio operator is that you can communicate with other hams all over the world. Ham Radio is an international community where we all have something in common to talk about – our stations and why we enjoy ham radio. The QSL card above is from a memorable QSO with Mal, VK6LC, from Western Australia, who was the last contact that I needed for a Worked All Zones award. I must have talked to him for 1/2 hour about his town in Australia and his pet kangaroos!
I have learned much about geography from being on the air and trying to contact as many countries as I can. There are 339 DX Entities, which are countries or other geographical entities and I have learned where each one is in order to understand where propagation will allow me make a contact. I have learned a great deal about world geography. Through exchanging QSL cards often get to see photos from so many areas of the world.
Achievement – DXing and Contesting
DXing and Contesting provide a sense of achievement and exciting opportunity for competition. Many Hams work toward operating awards. You can get an operating award for contacting all 50 states, contacting 100 or more countries, contacting Islands, cities in Japan, countries in Asia, or anything else you can imagine. Each of these operating awards provides a sense of accomplishment and helps to build skills. Contesting builds skills through competition among Hams to see who can make the most contacts with the most places in 24 or 48 hours. Contesting also improves our operating skills and teaches us to copy callsigns and additional data accurately.
Teaching Licensing Classes – Passing it On
Recently I have joined a team of club members who teach license classes to others who want to get licensed or upgrade their existing Amateur Radio licenses. Teaching provides a way to improve my presentation skills and also helps me to really understand the material that we teach about Amateur Radio. It is always a thrill at the end of the class to see so many people earn their licenses or upgrades.
There are so many interesting aspects of Ham Radio which is what makes is such a great hobby. Getting your license can open up a world of possibilities. Upgrading to a new license class provides more opportunities to communicate over longer distances. Ham Radio clubs, including our local club, the Nashua Area Radio Club, provide many resources to help you get your first license, upgrade to a new license class, and learn about the many aspects of our hobby.
Computers and Digital Signal Processing already play a big role in recent Amateur Radio transceivers. Many HAMs have a good understanding of these features and regularly use them for all manner of filtering, noise reduction and signal processing tasks while on the air. We’ve also seen more and more radios with Spectrum Scopes which make it easier to visualize what is on a given band in real time. Thanks to increasing volumes in color displays, Digital Signal Processor (DSP) applications and low-cost processors, these capabilities are now common – even on entry-level HF transceivers.
Software Defined Radios (SDRs) are the next logical step in this evolution. SDRs are not new, they have been around for some time now. SDR technology has continued to improve as the cost and performance of Analog to Digital Converters, Programmable Logic Devices and other processors that make up the hardware side of SDRs have improved. We are now to the point where it is possible to build an SDR for Amateur Radio applications which can directly sample RF at frequencies as high as 150 MHz.
Direct Sampling SDR receiver designs have some important advantages over more conventional single conversion and super-heterodyne receiver (i.e. multiple conversion) designs. These include:
- Higher dynamic range
- Low phase noise
- Ability to cover multiple bands simultaneously with multiple receivers
- Very high-quality spectrum displays
- Flexible, high-performance filters
- The ability to add new modulation schemes and other features via software updates
The first two items above (dynamic range and phase noise) are particularly important as they result in receiver performance which is significantly better than that which can be achieved with the best direct and superhet designs. Take for example a busy contest environment when a band is very crowded (ex. 40m at night in a worldwide DX phone contest). There are many strong signals crowded closely together on the band. Even the best conventional design receivers will have trouble hearing moderate and weak signals in this environment. The problem is that the strong signals tend to overload the analog circuitry in the conversion stages of conventional radios which produces a great deal of Intermodulation Distortion Design products. Phase noise also compounds this problem.
A direct sampling SDR converts the incoming RF signals with high dynamic range Analog to Digital conversion and then performs all of the filtering and demodulation of the incoming signals in software. This approach limits the potential for Intermodulation Distortion with an end result that all of the signals on the band (including the weaker ones) are much clearer. This approach also allows very high order filtering to be applied in the RF domain which results in greatly improved selectivity and rejection of closely spaced adjacent signals with minimal distortion.
By now some may be think that this all sounds great but I don’t want to have to use my computer to make QSOs. There is good news on this front as well. We are beginning to see the major transceiver manufacturers introduce direct sampling SDR technology in radios with conventional “buttons and knobs” interfaces.
New designs like the Icom IC-7300 can provide a way to gain the performance and feature advantages of an SDR in a radio which has a more conventional interface. The entry of the major manufacturers into the direct sampling space and the resulting competition should help to lower prices for all types of SDRs.
Want to give SDR technology a try without spending a lot of $? There are several very good SDR Dongles available along with SDR software at a minimal cost. Dongles are typically receive-only but some can also transmit as very lower power. The use of this technology in digital TV receivers and set-top boxes has made the cost of SDR Dongles very low and there is some very good SDR software available for free on the web. Dongles are generally broad coverage receivers and they can also be used to listen to signal outside the Amateur Bands.
It is interesting to follow the rapid evolution of SDR technology. We recently integrated a FlexRadio-6700 SDR into our station to enable us to operate remotely via the internet. You can read more about this project on our blog.
– Fred (AB1OC)