Re: Topband: A Tale of a Successful 160 meter RFI Hunt
Mike and Frank, If interested, I can sent via direct E-mail the account and associated map image of my sleuthing and finding a bad one a few years ago. It was SIX miles from the station. As Frank says, NEVER presume anything in advance when you are sleuthing for sources of RFI. 73 de Milt, N5IA -Original Message- From: donov...@starpower.net Sent: Monday, February 15, 2016 5:33 PM To: topband@contesting.com ; r...@contesting.com Subject: Re: Topband: A Tale of a Successful 160 meter RFI Hunt Hi Mike, We never needed to use the loopstick antenna in the PL-660 receiver. Because I had a very accurate bearing from my 350 foot diameter 8-circle receiving array, we simply used the PL-660 S-meter as we searched for the RFI along the 325 degree azimuth. I had initially suspected a large school campus one mile from my home directly on the 325 degree azimuth, but we couldn't find an RFI source adjacent to any of their facilities. There was good reason to suspect the school campus, t here was a serious electrical fire in one of the buildings four weeks ago and a multi-million dollar high efficiency HVAC system installation last summer, As we continued along the 325 degree azimuth through a rural area beyond the school campus the signal strength of the interference increased dramatically as we approached the Travellers' Information Service transmitter at the far edge of a 200 acre county park. I had never suspected the TIS transmitter as a source of interference but you just never know. Its never a good idea to prejudge the interference source, just use good direction finding techniques and let physics guide you to the RFI source. The county turned off the TIS transmitter within a few hours of being notified of the problem. The sweet sound of silence! 73 Frank W3LPL - Original Message - From: "Mike Greenway" To: donov...@starpower.net Cc: "K4TEA" Sent: Tuesday, February 16, 2016 12:12:32 AM Subject: Re: Topband: A Tale of a Successful 160 meter RFI Hunt FB. I looked up your Tecsun and I have an Eton E10 here that look totally identical to it. Fryes Electronics sold them some years ago. I guess you were using the internal loopstick to DF with? 73 From: donov...@starpower.net Sent: Monday, February 15, 2016 6:51 PM To: topband@contesting.com Cc: Mike Greenway ; k4...@bellsouth.net Subject: Re: Topband: A Tale of a Successful 160 meter RFI Hunt Hi Mike, Ah... The sweet sound of silence! Now if only there were some Topband activity,,, My county Office of Emergency Management was very responsive and took their Travellers' Information Station off the air this morning. Their TIS transmitter has been trouble free for many years. Hopefully they will take due care with repairs and testing before activating it again. The on-line FCC database shows only one TIS station in the Atlanta area, but its at Atlanta International Airport far from Ken's QTH. https://www.fcc.gov/media/radio/travelers-information-stations-search I wouldn't limit your search to 1/2 mile, you should search at least two miles. A large loop antenna should serve your needs well. I've found the Tecsun PL-660 to be an excellent and inexpensive RFI hunting receiver. Good luck! 73 Frank W3LPL - Original Message - From: "Mike Greenway" To: topband@contesting.com Sent: Monday, February 15, 2016 11:06:25 PM Subject: Re: Topband: A Tale of a Successful 160 meter RFI Hunt That is interesting Frank as I was just at K4TEA’s QTH yesterday trying to find why he had more noise from one direction that had no signature of any type, just higher background from 1.7 Mhz up to around 2.5 Mhz. 80 M is fine. He is near an interstate so maybe there is something similar out there. I built a large DF loop for 160 I can haul on a pickup to use with my K3. We moved from location to location trying to triangulate on it but we felt it was going to be within .5 miles but I see your source was 2 miles away. Thanks for the input. Keep us posted on your success on getting it turned off. 73 Mike K4PI _ Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Tuner
_ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Remote Antenna Tuner
Gary,Check out Array Solutions - AT615, I believe it is. Only other I found was MFJ. Jimk2hn _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Antenna Tuners
As a point of reference, in the product manual for the Palstar auto tuner, they do mention developing a remote version of their auto tuner. PALSTAR will off er a fully remote version of the base version in the near future. However, in certain cases where there is DC power available at a reasonable distance you can operate this base version in the AUTO MODE. Other functions would of course not be available. I have e-mailed Palstar but, to date, they have not responded. I would love it if someone would come up with a high power, fully weatherized, remote tuner. On 2/15/2016 4:26 AM, Larry wrote: I have started looking at tuners myself and was mainly interested in auto tuners. There are some that claim to handle the legal limit except for RTTY. I have a Dentron MT3000A manual tuner and it doesn't seem to care. OTOH most of my antennas usually don't need a tuner as I have had solid state rigs since the early 1980's and they are not as tolerant of an SWR above 2:1. I recently switched to a solid state amp which is much more touchy about SWR than the radios. I am thinking the auto tuner may make the amp a bit happier. The choices are few however. 73, Larry W6NWS On 2/14/2016 10:11 PM, Robert Harmon wrote: Jim, You are undoubtedly going to get a variety of recommendations on a tuner. I guess the first thing to decide is if you really want an automatic tuner. Secondly it if you are going to use balanced line or not. And last but not least power level you will be using. I have a Palstar AT5K which works very well. Rated for our legal limit then some. Easy to tune up and takes full limit easily. It is a manual tuner though. I used a Dentron MT-2000 for years and it had switchable taps on the inductor. There were places where I couldnt get a nice match, needed another tap, hihi. My preference now is the rotary inductors like the Palstars. You can dial in a great match all the time, no switch settings to contend with. Bob K6UJ On 2/14/16 6:30 PM, Jim Murray via Topband wrote: Hello all,Would you have any recommendations for antenna tuners? Have been looking at the automatics, Palstar, Mfj, LDG At-1000Proii etc.. Have been using an old Dentron which doesn't have very close markings on the dials and getting tired of turning and adjusting. Another option would be another manual such as the At2k with more precise settings. I do quite of bit of band hopping and even on 160 my Inv. L is perfect on 1.830 but doesn't like going very far either up or down, hence the need for a little tuner loss. The automatics look pretty appealing but would appreciate any opinions from the group.Thanks Jim/k2hn _ Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband -- 73, Gary K9GS Greater Milwaukee DX Association: http://www.gmdxa.org Society of Midwest Contesters: http://www.w9smc.com CW Ops #1032 http://www.cwops.org _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: A Tale of a Successful 160 meter RFI Hunt
Hi Mike, We never needed to use the loopstick antenna in the PL-660 receiver. Because I had a very accurate bearing from my 350 foot diameter 8-circle receiving array, we simply used the PL-660 S-meter as we searched for the RFI along the 325 degree azimuth. I had initially suspected a large school campus one mile from my home directly on the 325 degree azimuth, but we couldn't find an RFI source adjacent to any of their facilities. There was good reason to suspect the school campus, t here was a serious electrical fire in one of the buildings four weeks ago and a multi-million dollar high efficiency HVAC system installation last summer, As we continued along the 325 degree azimuth through a rural area beyond the school campus the signal strength of the interference increased dramatically as we approached the Travellers' Information Service transmitter at the far edge of a 200 acre county park. I had never suspected the TIS transmitter as a source of interference but you just never know. Its never a good idea to prejudge the interference source, just use good direction finding techniques and let physics guide you to the RFI source. The county turned off the TIS transmitter within a few hours of being notified of the problem. The sweet sound of silence! 73 Frank W3LPL - Original Message - From: "Mike Greenway" To: donov...@starpower.net Cc: "K4TEA" Sent: Tuesday, February 16, 2016 12:12:32 AM Subject: Re: Topband: A Tale of a Successful 160 meter RFI Hunt FB. I looked up your Tecsun and I have an Eton E10 here that look totally identical to it. Fryes Electronics sold them some years ago. I guess you were using the internal loopstick to DF with? 73 From: donov...@starpower.net Sent: Monday, February 15, 2016 6:51 PM To: topband@contesting.com Cc: Mike Greenway ; k4...@bellsouth.net Subject: Re: Topband: A Tale of a Successful 160 meter RFI Hunt Hi Mike, Ah... The sweet sound of silence! Now if only there were some Topband activity,,, My county Office of Emergency Management was very responsive and took their Travellers' Information Station off the air this morning. Their TIS transmitter has been trouble free for many years. Hopefully they will take due care with repairs and testing before activating it again. The on-line FCC database shows only one TIS station in the Atlanta area, but its at Atlanta International Airport far from Ken's QTH. https://www.fcc.gov/media/radio/travelers-information-stations-search I wouldn't limit your search to 1/2 mile, you should search at least two miles. A large loop antenna should serve your needs well. I've found the Tecsun PL-660 to be an excellent and inexpensive RFI hunting receiver. Good luck! 73 Frank W3LPL - Original Message - From: "Mike Greenway" To: topband@contesting.com Sent: Monday, February 15, 2016 11:06:25 PM Subject: Re: Topband: A Tale of a Successful 160 meter RFI Hunt That is interesting Frank as I was just at K4TEA’s QTH yesterday trying to find why he had more noise from one direction that had no signature of any type, just higher background from 1.7 Mhz up to around 2.5 Mhz. 80 M is fine. He is near an interstate so maybe there is something similar out there. I built a large DF loop for 160 I can haul on a pickup to use with my K3. We moved from location to location trying to triangulate on it but we felt it was going to be within .5 miles but I see your source was 2 miles away. Thanks for the input. Keep us posted on your success on getting it turned off. 73 Mike K4PI _ Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: A Tale of a Successful 160 meter RFI Hunt
Hi Mike, Ah... The sweet sound of silence! Now if only there were some Topband activity,,, My county Office of Emergency Management was very responsive and took their Travellers' Information Station off the air this morning. Their TIS transmitter has been trouble free for many years. Hopefully they will take due care with repairs and testing before activating it again. The on-line FCC database shows only one TIS station in the Atlanta area, but its at Atlanta International Airport far from Ken's QTH. https://www.fcc.gov/media/radio/travelers-information-stations-search I wouldn't limit your search to 1/2 mile, you should search at least two miles. A large loop antenna should serve your needs well. I've found the Tecsun PL-660 to be an excellent and inexpensive RFI hunting receiver. Good luck! 73 Frank W3LPL - Original Message - From: "Mike Greenway" To: topband@contesting.com Sent: Monday, February 15, 2016 11:06:25 PM Subject: Re: Topband: A Tale of a Successful 160 meter RFI Hunt That is interesting Frank as I was just at K4TEA’s QTH yesterday trying to find why he had more noise from one direction that had no signature of any type, just higher background from 1.7 Mhz up to around 2.5 Mhz. 80 M is fine. He is near an interstate so maybe there is something similar out there. I built a large DF loop for 160 I can haul on a pickup to use with my K3. We moved from location to location trying to triangulate on it but we felt it was going to be within .5 miles but I see your source was 2 miles away. Thanks for the input. Keep us posted on your success on getting it turned off. 73 Mike K4PI _ Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: A Tale of a Successful 160 meter RFI Hunt
That is interesting Frank as I was just at K4TEA’s QTH yesterday trying to find why he had more noise from one direction that had no signature of any type, just higher background from 1.7 Mhz up to around 2.5 Mhz. 80 M is fine. He is near an interstate so maybe there is something similar out there. I built a large DF loop for 160 I can haul on a pickup to use with my K3. We moved from location to location trying to triangulate on it but we felt it was going to be within .5 miles but I see your source was 2 miles away. Thanks for the input. Keep us posted on your success on getting it turned off. 73 Mike K4PI _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Tuner
Many thanks to all for your input on possible tuners. I decided to get a Ten Tec 238 and give it a try. A gentleman on Ebay was selling a complete TT station and was good enough to sell me the tuner alone at a reasonable price. It seems to be a long time favorite and with a little modification it should tune 160 fairly well. Oddly enough, years ago I had one of these and remember putting a new dial cord on it. Don't recall what happened to it. I know I didn't pay $800+ as I see TT new parent company is getting for the latest version. The prices these days for the high power tuners is unbelievable. I paid $325. for the 238 which electronically is very similar probably to the new version.From correspondence with the seller I am confident the tuner is ok. Thanks again Jimk2hn _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Antenna Tuners
I have been successfully using the MFJ-998RT successfully on a 2 el 80M phased wire array. The 2 el wire beam has great performance but is very narrow banded (about 100khz) so I decided to try this tuner mounted on the tower at the feed point of the connection to the 2 phasing cables. It works successfully. I have it set up with a switchable 12V power line to be able to reset it from the shack in case it locks up. What I like about this unit is that it will NOT tune with more than 200W so if it goes into tune mode while running high power, it simply shuts down and waits for power to be removed and then exciter power retunes it and away you go again. It's a race by the millisecond to see whether my amp clicks off or the MFJ does in that case. I have not tried it on any other band but have been very impressed with it at 1.5kW on 80M in a complex tuning scenario with the phased wire beam. 73 Ed N1UR _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Antenna Tuners
I have started looking at tuners myself and was mainly interested in auto tuners. There are some that claim to handle the legal limit except for RTTY. I have a Dentron MT3000A manual tuner and it doesn't seem to care. OTOH most of my antennas usually don't need a tuner as I have had solid state rigs since the early 1980's and they are not as tolerant of an SWR above 2:1. I recently switched to a solid state amp which is much more touchy about SWR than the radios. I am thinking the auto tuner may make the amp a bit happier. The choices are few however. 73, Larry W6NWS On 2/14/2016 10:11 PM, Robert Harmon wrote: Jim, You are undoubtedly going to get a variety of recommendations on a tuner. I guess the first thing to decide is if you really want an automatic tuner. Secondly it if you are going to use balanced line or not. And last but not least power level you will be using. I have a Palstar AT5K which works very well. Rated for our legal limit then some. Easy to tune up and takes full limit easily. It is a manual tuner though. I used a Dentron MT-2000 for years and it had switchable taps on the inductor. There were places where I couldnt get a nice match, needed another tap, hihi. My preference now is the rotary inductors like the Palstars. You can dial in a great match all the time, no switch settings to contend with. Bob K6UJ On 2/14/16 6:30 PM, Jim Murray via Topband wrote: Hello all,Would you have any recommendations for antenna tuners? Have been looking at the automatics, Palstar, Mfj, LDG At-1000Proii etc.. Have been using an old Dentron which doesn't have very close markings on the dials and getting tired of turning and adjusting. Another option would be another manual such as the At2k with more precise settings. I do quite of bit of band hopping and even on 160 my Inv. L is perfect on 1.830 but doesn't like going very far either up or down, hence the need for a little tuner loss. The automatics look pretty appealing but would appreciate any opinions from the group.Thanks Jim/k2hn _ Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: What have I done?
Hi Carl, Does not appear anyone has answered you, so let me give it a quick shot while between flights in Japan. I'm somewhat confused with your final L network configuration because you mentioned one capacitor, and then a second capacitor without mentioning if you still had the first capacitor in your configuration, etc. You also did not mention what L network configuration you used (see below). Therefore I started from scratch to see what a 64 foot vertical wire would look like at 7.050 Mhz to see what kind of L network would be required to convert its impedance to a pure 50 ohms resistance. Using EZNEC demo, I approximate a 64 foot vertical wire on 7.050 Mhz has an input impedance of approximately 1274 +j1436 ohms when just using a ground rod with medium soil (because this antenna has such a high input impedance it really does not matter what I use for ground conductivity). Then using an online L network calculator I come up with the following two different L network configurations you could use to match to a 50 ohm resistive source. *L network with inductor between bottom of 64 foot vertical and ground.* L = 10.18 uh C = 59.9 pf *L network with capacitor between bottom of 64 foot vertical and ground.* L = 8.5 uh C = 67.6 pf Not sure what L network configuration you used, but does it sound like I closely replicated what you have based upon one of the above mentioned L network configurations? If not, then please better describe your configuration. Please advise so we can better answer your question, and hopefully I have not messed something up with my quick analysis/approximation. Don (wd8dsb) On Sat, Feb 13, 2016 at 4:53 PM, Carl Braun wrote: > I have revised my question to correct the length of the antenna in question > > > Topbanders > > In the past, I've posted some questions related to making my 80 meter > verticals (64' tall ground mounted) work on different bands. The pair is > spaced at ¼ wl on 80m and then I switch in base loading to resonate the > same pair on 160m which are then effectively spaced at 1/8 wl. Now I want > to make them work on 40m which would have them resonate as ½ or 5/8 wl and > would have an effective spacing at ½ wl. > > So this is what I did...I installed an L network off of the vertical > effectively tuning a 64' stick of aluminum to 7.050. It took me a couple > of tries as the first 1500pF (monster) variable capacitor wouldn't get down > low enough to get me flat. I had another 50-150pF Johnson variable cap > available so I tried that and got the antenna to tune to 46 ohms at j+0. > Inside the shack I see 1.0:1 Vswr from 7.000 to 7.290...wow! > > I measured the cap and it came to 70pf. My cheapie Chinese meter doesn't > register anything on the L scale but I have 7 turns on a 3 ½" inductor. The > full coil is 33 uH at 25 turns so I estimate 8-12 uH of inductance. > > But what have I done? Have I resonated a ½ wl antenna or have I resonated > something else like a 5/8 wl antenna with the added inductance? > > I plan on treating them as ½ wl spaced phased verticals on 40 and feeding > them with equal lengths of ¾ wl feedlines for broadside phasing and then > adding an additional 2/4 wl to get my 180 degree shift for end fire. > > Please share your comments. > > thanks > > Carl de AG6X > > _ > Topband Reflector Archives - http://www.contesting.com/_topband > _ Topband Reflector Archives - http://www.contesting.com/_topband
