[Flexradio] RFI Issues
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/
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/
[Flexradio] RFI Issues
Hello Wally, Try using 1/4 or 1/2 RFI snap-on cores from RadioWorks, see page 55 in the 2004 Catalog. Snap one or more ferrite cores unto the USB cable. 1/4 1/2 refers to the diameter of the cable you are snapping the ferrite core onto. Try a few on the DC power line or wherever you think RF is getting in. I have a 1/2 core snapped on the Delta Breakout box DB-15 cable and a few 1/4 cores on the Input#3 line. This solved an audio RFI problem here. The Isolator on the feedline should prevent RF from flowing on the outside of the coax shield and prevent RFI problem too. Because of skin-effect, RF sees 3 conductors on a coaxial line: the inner conductor, the inside surface of the shield (where it belongs!) and the outside surface of the shield. Don't allow RF to go there or it will gum up the works! 73, AlanK2WS Message: 7 Date: Tue, 31 May 2005 21:54:53 +0100 From: Wallace Watson [EMAIL PROTECTED] Subject: [Flexradio] RFI Issues To: FlexRadio@flex-radio.biz Message-ID: [EMAIL PROTECTED] Content-Type: text/plain; charset=us-ascii; format=flowed 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 install an additional multi-band dipole antenna at the boundary of my residence which is separated from a farmers pasture by a 12 foot security fence. My grounding system consists of a 12 foot copper ground rod approximately 1 in width driven into the ground outside my radio shack window. Only 6 of the ground rod is exposed above ground and I have attached to it via bolt, lock-washer and nut a 3/4 wide tinned copper flat ground cable approximately 5 feet long and terminating at my Kenwood manual matchbox. All radio equipment, including the SDR-1000 radio is connected in a star pattern to this single grounding point. Please advise if anyone has suggestions or recommendations for my installation? Thanks, Wally (M0ZAZ). -
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: FlexRadio@flex-radio.biz 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
[Flexradio] RFI Issues
I have been a Flex-Radio owner since just about the middle of this March (2005) and cut my teeth on the Audigy 2Zs sound card. I found the receive aspect spectacular, to say the least. However, just like everyone else I discovered the latency problems on transmit. Not only was there the latency issue with me, but if you did not some degree of delay in the set up I would find that there was a noisy tail just before your audio did actually transmit. However, I never experience any RFI problems or issues. Well, the M-Audio Delta 44 card certainly cured that transmit problem. However, whilst I was installing this new card and the required break-out box I was inherently concerned with the large cable between this box and the actual sound card. Having been into computer based RTTY back in the very early '80's, I have had to deal with all sorts of RFI, both computer generated and radio generated. I actually ran a Radio Shack TRS-80 Model III with an IRL FSK-1000 modulator/demodulator and all the accompanying unshielded ribbon cables etc. I could have sunk a small boat with all the ferrite beads and doughnuts that I purchased to wrap everything but the family pet around. Having this prior experience has served me well, let alone finding it particularly interesting to watch all the toroids now standard on most computer cabling. This brings me to one very important note regarding this Delta 44 card and the required external box. Why, pray tell, did the the manufacturers of this fine piece of kit fail to place a ferrite core on their enclosed cable? Let's face it folks, even if you are not an amateur radio operator we live in an RF environment now more than ever. Since those reading this I assume are transmitting amateurs. However, due to the present solar conditions, many hams probably are utilizing some sort of RF amplification and the current recommended set-up with this new Delta 44 card has created an exponential increase in the disruptive ingress of RF. I personally discovered this new RFI problem after installing the new Delta 44 card and attempted to transmit on 40 meters above 100 watts. This actually occurred whilst transmitting at around 650 watts PEP. I was using a headset/boom mic at the time, but, has also has occurred with an external mic as well. The manifestation of this problem was not just the typical RF distortion on the audio, but, an unusual feed back of sorts. If I just keyed the mic and said nothing there was just a dead carrier. However, if I attempted to speak or tapped the mic there was some of the typical aberrant RF noise, but, then there was a very syncopated continuous audio pulse that you could hear, watch on the station monitor, and even detect on the watt meter. If I decreased the power to some where around 100 watts this aberration would cease, for the most part. If I decreased the transmit output well below 100 watts there was no evidence of the aforementioned problem. Given my prior experience with RFI issues and my current experience I suspect the large cable between the audio card/computer and the break-out box. I have just about every other cable secured with a toroid bead/core. However, due to the large increase in wires and cables with this new installation I need to get more toroids, most especially for the audio card cable. One consideration that I am toying with is finding some sort of a large shielded metal box to collectively contain this new rat's nest of required wires. If anyone has experienced a similar problem and summarily cured it I would enjoy reading your results. My only answer is to coil the wires so as to inductively break-up the RFI or the use of a series of ferrite cores in various configurations and number. Harold KD5RD --- avast! Antivirus: Outbound message clean. Virus Database (VPS): 0522-1, 05/31/2005 Tested on: 5/31/2005 6:32:32 AM avast! - copyright (c) 1988-2004 ALWIL Software. http://www.avast.com
