Re: [Flexradio] RFI Issues
This is a good article: http://kc.flex-radio.com/KnowledgebaseArticle50426.aspx?Keywords=ground 73s-Erik-OZ4KK I think that in terms of the 3000 and 5000, the RFI exposure difference between these rigs and purely "discrete-component" rigs is that they have: 1. an inbuilt audio amp and speaker where we have an extra line going to a set of powered speakers, and 2. the firewire cable is a critical part of bus of the rig. I have a ground isolator going between my radio and my Bose Speakers from The Shaq http://www.radioshack.com/product/index.jsp?productId=3446917 left over from my SDR1K days. The firewire cable, since it is the "bus" of the radio, is particularly critical to work well and I would not even think of having a cable that didn't have two knucklebuster toroids on each end. You can buy a Granite Digital cable which has the toroids molded into place or buy a good quality firewire cable and doi it yourself. I have ordered several cables from this place ( http://firewirestuff.com/firewire6pin.html ) and they are very serious about not selling junky cables. Just get the length you want and get two knucklebuster black split toroinds from DX Engineering and put one on each end and you are in business. Then make sure you ground the rig to a single point that you also ground the computer. I use braided shield from coax and attach it to one of the screws that fastens the power supply of the computer. I make sure I use the same electrical outlet for the computer and power supply for the rig, as well as the separate power supply I use to power all of the 12v toys attached to the radio (antenna switch, wavenode box, etc.) so there is not potential difference in the power ground resistance. I also put a toroid on the power cord of the computer to try and avoid introducing noise on the power line. This is just what I do. 73 Neal Campbell Abroham Neal Software www.abrohamnealsoftware.com (540) 645 5394 NEW PHONE NUMBER Amateur Radio: K3NC Blog: http://www.abrohamnealsoftware.com/blog/ DXBase bug reports: email to ca...@dxbase.fogbugz.com Abroham Neal forums: http:/www.abrohamnealsoftware.com/community/ ___ FlexRadio Systems Mailing List FlexRadio@flex-radio.biz http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz Archives: http://www.mail-archive.com/flexradio%40flex-radio.biz/ Knowledge Base: http://kc.flex-radio.com/ Homepage: http://www.flex-radio.com/ ___ FlexRadio Systems Mailing List FlexRadio@flex-radio.biz http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz Archives: http://www.mail-archive.com/flexradio%40flex-radio.biz/ Knowledge Base: http://kc.flex-radio.com/ Homepage: http://www.flex-radio.com/
Re: [Flexradio] RFI Issues
Dudley, Thank you for good tips. Actually the RFI is not my problem - not any more. All my antennas are fed by coaxial cable with baluns and impedance matching done at the antenna terminals high up and far away from the shack. The cables are inside the metal tower and come to the house through an underground pipe. This solution is the result of "learning by errors". Most of the problems come from the leaking computers, but also those can be solved. As an evidence, below are some noise level measurements (SigAvg) of my SDR-1000 with antenna connector terminated to 50 ohm resistive "dummy load". The measurements are made at "High" position of the preamp, 500 Hz bandwidth and using the USB-to-PIO cable. MHzdBm 1.86 -137.6 3.6-142.9 5.4035 -138.1 7.1-142.0 10.11 -142.7 14.1 -143.3 18.1 -142.7 21.1 -140.1 24.9 -142.1 28.2 -142.1 (The last decimal is not meaningful, but is given only as an indication of the small differences between the different bands.) The average noise floor of the spectrum display is about -160 dBm. I think, these readings are typical to the accurately calibrated SDR-1000 (and I have three of them). If somebody has considerably better readings, please tell the trick, I want to try. 73, Ahti OH2RZ - Original Message - From: "Dudley Hurry" <[EMAIL PROTECTED]> To: "Ahti Aintila" <[EMAIL PROTECTED]>; ; "Wallace Watson" <[EMAIL PROTECTED]> Sent: Thursday, June 02, 2005 6:43 PM Subject: Re: [Flexradio] RFI Issues Ahti, RFI issues can really drive one to drink...HI HI One suggestion and one that I do here.Since you said that other rigs have your RFI problem also, you might make sure that there is not a large amount of RF in the shack.
Re: [Flexradio] RFI Issues
Ahti, RFI issues can really drive one to drink...HI HI One suggestion and one that I do here.Since you said that other rigs have your RFI problem also, you might make sure that there is not a large amount of RF in the shack. I have a small field strength meter setting in my shack (happens to be an old Heathkit, but MFJ makes a couple of models) with the gain set at maximum. If anything goes wrong (loose connector, incorrect antenna selection, etc) the meter will come off of the "0" peg and then I see that I have a problem, in everything.If there is any RF floating around in the shack, you will have all sorts of strange issues with computers and radios that are connected to them. I running have my SDR setting on top of my Alpha 87A and the computer setting right next to the Alpha with no RFI issues at all on any band. Good luck and 73, Dudley WA5QPZ At 11:22 PM 6/1/2005 +0300, Ahti Aintila wrote: Wally and all, Since receiving the SDR-1000 in July 2003 I am fighting the RFI, spurious, noise and common mode issues and no final and universal solution yet! So far I try to manage with isolating transformers in I/Q lines (input and output), ferrite beads in parallel cable as well as the USB to Parallel cable, strictly a single point grounding system (star configuration) and on top of all I have a 7.5 kVA UPS system for powering my office/lab/hamshack. IMHO, these problems are related to the fact that no theoretically "clean" star groundings can be created and ground loops eliminated, mainly due to the common practice of connecting together the "Protective Earth" (PE) and "Signal Earth" already inside the electric/electronic appliances, especially the PCs. PLEASE, NOTE! The problems are not alone with the SDR-1000 only. My Yaesu and Icom equipmet suffer these problems, too, as soon as I connect the PC to them. Whatever systems I have had, a careful routing of cables, experimentation with the grounding points, common mode and differential mode filtering, signal line balancing and shielding were needed. When it comes to the RFI, keep all radiating wires and cables as far away from the hamshack as practical. A lot of "wonder" antennas may have essential part of radiation coming from the feedline - Carolina Windom included. Sorry Wally, I have no ready made solution for you. Believe me, all these requires good understanding of the theory, but that is not enough. Finding the optimal wiring in our wireless hobby is art that beautifies the science. Who would make the optical fiber interface for our SDR-1000 so that we don't need to be artists and scientists at the same time? 73, Ahti OH2RZ - Original Message - From: "Wallace Watson" <[EMAIL PROTECTED]> To: Sent: Tuesday, May 31, 2005 11:54 PM Subject: [Flexradio] RFI Issues Greetings All, I have had my SDR-1000 now for approximately 3 month and find the receiver very pleasurable to use. New additions are being made to the software for the radio adding to it's functionality. My computer is an HP/Compaq Celeron 2.4Ghz with 512Mb of RAM. I initially purchased a Creative Labs Audigy 2ZS card but I never installed it in the computer, instead when the M-Audio sound card was mentioned on TeamSpeak and posted in the forum I decided to purchase and install it instead. Prior to the Dayton Hamfest I ordered a Behringer UB802 mic preamplifier/mixer for SSB use vice installing a second sound card in the computer. I hooked up the Behringer mixer the day I returned home from the Dayton Hamfest. I also had switched to using the USB cable for use with the SDR-1000 prior to this. I have since begun making contacts on 80 and 40 meter bands on SSB and experimenting with CW using the automatic memory and keyboard modes with the SDR-1000 with the 100 watt amplifier. I have been experiencing RFI problems when I switched to using 30/20/15/10 meters with my primary antenna system, a Radio Works Carolina Windom. The antenna vertical radiator terminates immediately overhead my family room which serves as my ham shack. The RFI problem manifests itself as follows: When using the USB cable between computer and radio, when I transmit on 30 meters or above the radio begins by transmitting and then I get a High SWR indication on the display and the radio reverts to the Standby mode. I am unable to switch the radio back on via the software Standby/ON button, I must instead disconnect/reconnect the USB cable from the computer or reboot the computer. I have been semi-successful at reducing/partially eliminating this problem by reducing output power to approximately 35 watts. In an attempt to eliminate this problem I switched back to using the original parallel cable between the computer and radio, with this cable in place on 30 meters and above I am able to go into transmit at the 50 to 100watt level and the radio will transmit in SSB or CW but will shut down the 100watt amplifier while in operation, when I come out of transmit mode to rece
RE: [Flexradio] RFI Issues
Jim et.al. Here Here. Why in the heck not! I have posted several times an SDR dedicated board/link between the radio and the computer, others have already posted the connections to the DB 15. We can take a connector to the db 15 and do whatever we want! Filter, preamp, isolation FO or otherwise. Tony, has already said he would produce the interface PC board. For less than the cost of the 3 pounds of sprawling Hosa cables box and umbellical! Let's brainstorm our custome 44 or 92 interface. I sort get tired of all the interference issues, when we have so many good AF/RF designers, and the capability to pump out cheap well manufactured circuit boards! Eric - AA4SW Anyone up for this conversation and brain storming on 0100 Saturday TS forum? Looks like the Delta 44 is a winner, just the cabling and us are the losers! -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Jim Lux Sent: Wednesday, June 01, 2005 6:00 PM To: Ahti Aintila; FlexRadio@flex-radio.biz; Wallace Watson Subject: Re: [Flexradio] RFI Issues At 01:22 PM 6/1/2005, Ahti Aintila wrote: >Wally and all, > >Believe me, all these requires good understanding of the theory, but that is >not enough. Finding the optimal wiring in our wireless hobby is art that >beautifies the science. Who would make the optical fiber interface for our >SDR-1000 so that we don't need to be artists and scientists at the same >time? > You know, this isn't that far fetched. A lot of relatively inexpensive audio equipment has "TOSlink" connectors these days. If the DVD player sells for $100, the total parts cost inside can't be much more than $10-15, so the optical interface is going to be a very, very small part of that. These links are relatively low speed and low performance compared to the ones used in the telecom industry. They use 1mm (aka 1000 micron) plastic fiber. Perhaps rather than fooling around with USB, etc, interfaces, the next generation SDR should use a digital optical interface. I think the optical audio interface has provisions for control data as well as the digitized audio stream(s). >http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz James Lux, P.E. Spacecraft Radio Frequency Subsystems Group Flight Communications Systems Section Jet Propulsion Laboratory, Mail Stop 161-213 4800 Oak Grove Drive Pasadena CA 91109 tel: (818)354-2075 fax: (818)393-6875 ___ FlexRadio mailing list FlexRadio@flex-radio.biz http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz
Re: [Flexradio] RFI Issues
Yes, the IC-7800 introduced toslink to the ham hobby and it seems to work wonders on digi modes. One hopes that similar optical (read: NO RFI EVER) links will see their way into the hobby over time. Maybe some vendors will offer toslink adapters for USB and audio lines? de Ken Jim Lux wrote: At 01:22 PM 6/1/2005, Ahti Aintila wrote: Wally and all, Believe me, all these requires good understanding of the theory, but that is not enough. Finding the optimal wiring in our wireless hobby is art that beautifies the science. Who would make the optical fiber interface for our SDR-1000 so that we don't need to be artists and scientists at the same time? You know, this isn't that far fetched. A lot of relatively inexpensive audio equipment has "TOSlink" connectors these days. If the DVD player sells for $100, the total parts cost inside can't be much more than $10-15, so the optical interface is going to be a very, very small part of that. These links are relatively low speed and low performance compared to the ones used in the telecom industry. They use 1mm (aka 1000 micron) plastic fiber. Perhaps rather than fooling around with USB, etc, interfaces, the next generation SDR should use a digital optical interface. I think the optical audio interface has provisions for control data as well as the digitized audio stream(s). http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz James Lux, P.E. Spacecraft Radio Frequency Subsystems Group Flight Communications Systems Section Jet Propulsion Laboratory, Mail Stop 161-213 4800 Oak Grove Drive Pasadena CA 91109 tel: (818)354-2075 fax: (818)393-6875 ___ FlexRadio mailing list FlexRadio@flex-radio.biz http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz
Re: [Flexradio] RFI Issues
At 01:22 PM 6/1/2005, Ahti Aintila wrote: Wally and all, Believe me, all these requires good understanding of the theory, but that is not enough. Finding the optimal wiring in our wireless hobby is art that beautifies the science. Who would make the optical fiber interface for our SDR-1000 so that we don't need to be artists and scientists at the same time? You know, this isn't that far fetched. A lot of relatively inexpensive audio equipment has "TOSlink" connectors these days. If the DVD player sells for $100, the total parts cost inside can't be much more than $10-15, so the optical interface is going to be a very, very small part of that. These links are relatively low speed and low performance compared to the ones used in the telecom industry. They use 1mm (aka 1000 micron) plastic fiber. Perhaps rather than fooling around with USB, etc, interfaces, the next generation SDR should use a digital optical interface. I think the optical audio interface has provisions for control data as well as the digitized audio stream(s). http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz James Lux, P.E. Spacecraft Radio Frequency Subsystems Group Flight Communications Systems Section Jet Propulsion Laboratory, Mail Stop 161-213 4800 Oak Grove Drive Pasadena CA 91109 tel: (818)354-2075 fax: (818)393-6875
Re: [Flexradio] RFI Issues
Wally and all, Since receiving the SDR-1000 in July 2003 I am fighting the RFI, spurious, noise and common mode issues and no final and universal solution yet! So far I try to manage with isolating transformers in I/Q lines (input and output), ferrite beads in parallel cable as well as the USB to Parallel cable, strictly a single point grounding system (star configuration) and on top of all I have a 7.5 kVA UPS system for powering my office/lab/hamshack. IMHO, these problems are related to the fact that no theoretically "clean" star groundings can be created and ground loops eliminated, mainly due to the common practice of connecting together the "Protective Earth" (PE) and "Signal Earth" already inside the electric/electronic appliances, especially the PCs. PLEASE, NOTE! The problems are not alone with the SDR-1000 only. My Yaesu and Icom equipmet suffer these problems, too, as soon as I connect the PC to them. Whatever systems I have had, a careful routing of cables, experimentation with the grounding points, common mode and differential mode filtering, signal line balancing and shielding were needed. When it comes to the RFI, keep all radiating wires and cables as far away from the hamshack as practical. A lot of "wonder" antennas may have essential part of radiation coming from the feedline - Carolina Windom included. Sorry Wally, I have no ready made solution for you. Believe me, all these requires good understanding of the theory, but that is not enough. Finding the optimal wiring in our wireless hobby is art that beautifies the science. Who would make the optical fiber interface for our SDR-1000 so that we don't need to be artists and scientists at the same time? 73, Ahti OH2RZ - Original Message - From: "Wallace Watson" <[EMAIL PROTECTED]> To: Sent: Tuesday, May 31, 2005 11:54 PM Subject: [Flexradio] RFI Issues Greetings All, I have had my SDR-1000 now for approximately 3 month and find the receiver very pleasurable to use. New additions are being made to the software for the radio adding to it's functionality. My computer is an HP/Compaq Celeron 2.4Ghz with 512Mb of RAM. I initially purchased a Creative Labs Audigy 2ZS card but I never installed it in the computer, instead when the M-Audio sound card was mentioned on TeamSpeak and posted in the forum I decided to purchase and install it instead. Prior to the Dayton Hamfest I ordered a Behringer UB802 mic preamplifier/mixer for SSB use vice installing a second sound card in the computer. I hooked up the Behringer mixer the day I returned home from the Dayton Hamfest. I also had switched to using the USB cable for use with the SDR-1000 prior to this. I have since begun making contacts on 80 and 40 meter bands on SSB and experimenting with CW using the automatic memory and keyboard modes with the SDR-1000 with the 100 watt amplifier. I have been experiencing RFI problems when I switched to using 30/20/15/10 meters with my primary antenna system, a Radio Works Carolina Windom. The antenna vertical radiator terminates immediately overhead my family room which serves as my ham shack. The RFI problem manifests itself as follows: When using the USB cable between computer and radio, when I transmit on 30 meters or above the radio begins by transmitting and then I get a High SWR indication on the display and the radio reverts to the Standby mode. I am unable to switch the radio back on via the software Standby/ON button, I must instead disconnect/reconnect the USB cable from the computer or reboot the computer. I have been semi-successful at reducing/partially eliminating this problem by reducing output power to approximately 35 watts. In an attempt to eliminate this problem I switched back to using the original parallel cable between the computer and radio, with this cable in place on 30 meters and above I am able to go into transmit at the 50 to 100watt level and the radio will transmit in SSB or CW but will shut down the 100watt amplifier while in operation, when I come out of transmit mode to receive the receiver is no longer receiving signals, I must switch off the radio and back on using the Standby/ON button on the SDRConsole. If I reduce power to an approximate 35 watt level, the radio functions normally. I have a second antenna, a tape 40 meter dipole, this antenna is usable on 40 and 15 meters only. With this antenna I have completely normal operation on 40 meters and with the Carolina Windom, I have completely normal operation on 80 and 40 meters. I have 3 other radios at my location, a Kenwood TS-440S, a Kenwood TS-450S and an old Yaseau FT-101EX and have experienced no problems on the air utilizing any of these radios. I believe my next step is to order and install the Radio Works ground isolators in the hopes that this will eliminate my apparent RFI/ground loop problem which are interfering with my operation of the SDR-1000 radio. I have no option to move the Carolina Windom antenna. I do intend to insta
