Just recently I have been having troubles with a neighbor while I am working the FM satellites(SO-50 and AO-27). The setup I am currently using is my mobile setup because I am unable to put a base station up for many reasons. I am using a FT8900 with 50 watts out into a 1/4 wave or 1/2 Larson mobile antenna.The 1/4 wave is mounted permanently via a hole in the roof of my truck an the 1/2 wave is mounted on a mount opposite the factory installed FM/AM radio whip. It doesn't seem to matter what antenna I use for the problem to occur. Then I use either the arrow antenna or my cju for the downlink.
The problem occurs while I am transmitting. The neighbor says that his tv receives the interference in that the picture is disturbed and sometimes cuts out completely. He is getting his tv from hdtv over the air. He has an antenna in the attic that goes to a powered splitter which then goes to several tvs. That is about all i know on his setup but I do know that if he cuts the power to the splitter he receives nothing. Also the problem seems to be on every channel.
Today I had another local ham over at the request of the neighbor and his mobile Kenwood radio did the same thing to the neighbors tv when he transmitted on 2 meter with 50 watts out. He also recommended that they get a filter. I did not see the specs on the filter nor do I know what bandwidth it was for.
If anyone has any ideas on what would solve this problem and could share that would be great.
Catch you on the birds
Wyatt AC0RA
Hi Wyatt,
How far away is your neighbor?
I TVI myself when I transmit on two meters, I have a Winlink station running 50W into a J-pole about 20 feet away from my TV antenna, in the attic. We are on the fringe of the OTA TV coverage, so I have a high gain TV antenna with a preamp. I also installed an ICE 437B filter. It appears that since the two are in such close proximity and the TV signals are so weak, that it doesn't take much to tile the picture or freeze it for a moment on some of the channels. Such is the nature of it. Most of our HDTV is on UHF, but channel 8 is on channel 9 (VHF). Some days the TV signal is stronger, and there are no problems. Most days, just the opposite. I have no big solutions, just an observation, but you may be able to mitigate the problem if you move off to the side of his antenna or further away from his antenna, or decrease your power. And maybe one other solution. Fox-1 will have the uplink on 70cm, so that might make you both happier!
73, Jerry N0JY
On 12/6/2011 9:17 PM, Wyatt Dirks wrote:
The problem occurs while I am transmitting. The neighbor says that his tv receives the interference in that the picture is disturbed and sometimes cuts out completely. He is getting his tv from hdtv over the air. He has an antenna in the attic that goes to a powered splitter which then goes to several tvs. That is about all i know on his setup but I do know that if he cuts the power to the splitter he receives nothing. Also the problem seems to be on every channel.
On Tue, 6 Dec 2011 21:17:55 -0600 Wyatt Dirks wyattdirks@msn.com wrote:
Just recently I have been having troubles with a neighbor while I am working the FM satellites(SO-50 and AO-27). The setup I am currently using is my mobile setup because I am unable to put a base station up for many reasons. I am using a FT8900 with 50 watts out into a 1/4 wave or 1/2 Larson mobile antenna.The 1/4 wave is mounted permanently via a hole in the roof of my truck an the 1/2 wave is mounted on a mount opposite the factory installed FM/AM radio whip. It doesn't seem to matter what antenna I use for the problem to occur. Then I use either the arrow antenna or my cju for the downlink.
Use 5W into a hand-held Yagi. You'll get far better results.
Today I had another local ham over at the request of the neighbor and his mobile Kenwood radio did the same thing to the neighbors tv when he transmitted on 2 meter with 50 watts out. He also recommended that they get a filter. I did not see the specs on the filter nor do I know what bandwidth it was for.
What you want is a highpass filter that will lop off everything below 500MHz. The chances are that your TX output is clean enough but the little amplifier in the splitter for the TV is causing all sorts of intermod - and probably covers from broadcast VHF radio to the top of the TV band.
HPF above 500 MHz? Then the TV would not be able to see anything but a few UHF channels.
What is needed is a stub filter. Just a piece of open ended coax 13" long "T"ed into the antenna lead....
The 13" is about 66% of a quarter wave at 2 meters.
Done
Bob, WB4APR
-----Original Message----- From: amsat-bb-bounces@amsat.org [mailto:amsat-bb-bounces@amsat.org] On Behalf Of Gordon JC Pearce Sent: Wednesday, December 07, 2011 3:02 AM To: amsat-bb@amsat.org Subject: [amsat-bb] Re: 2 Meter TV Interference
On Tue, 6 Dec 2011 21:17:55 -0600 Wyatt Dirks wyattdirks@msn.com wrote:
Just recently I have been having troubles with a neighbor while I am
working the FM satellites(SO-50 and AO-27). The setup I am currently using is my mobile setup because I am unable to put a base station up for many reasons. I am using a FT8900 with 50 watts out into a 1/4 wave or 1/2 Larson mobile antenna.The 1/4 wave is mounted permanently via a hole in the roof of my truck an the 1/2 wave is mounted on a mount opposite the factory installed FM/AM radio whip. It doesn't seem to matter what antenna I use for the problem to occur. Then I use either the arrow antenna or my cju for the downlink.
Use 5W into a hand-held Yagi. You'll get far better results.
Today I had another local ham over at the request of the neighbor and his
mobile Kenwood radio did the same thing to the neighbors tv when he transmitted on 2 meter with 50 watts out. He also recommended that they get a filter. I did not see the specs on the filter nor do I know what bandwidth it was for.
What you want is a highpass filter that will lop off everything below 500MHz. The chances are that your TX output is clean enough but the little amplifier in the splitter for the TV is causing all sorts of intermod - and probably covers from broadcast VHF radio to the top of the TV band.
-- Gordon JC Pearce MM0YEQ gordonjcp@gjcp.net _______________________________________________ Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
At 05:24 AM 12/8/2011, Bob Bruninga wrote:
HPF above 500 MHz? Then the TV would not be able to see anything but a few UHF channels.
What is needed is a stub filter. Just a piece of open ended coax 13" long "T"ed into the antenna lead....
They work well, have had occasion to use them in the past to cure TVI.
73 de VK3JED / VK3IRL http://vkradio.com
I didn't think there were any vhf stations left. All the numbers on the channels now are virtual. All the tv antenna plans are for uhf bands. A quick look in the Boston market and the lowest channel is 19, channel 2@500MHz. Are there places that still use vhf?
Charles On Dec 7, 2011 1:38 PM, "Bob Bruninga" bruninga@usna.edu wrote:
HPF above 500 MHz? Then the TV would not be able to see anything but a few UHF channels.
What is needed is a stub filter. Just a piece of open ended coax 13" long "T"ed into the antenna lead....
The 13" is about 66% of a quarter wave at 2 meters.
Done
Bob, WB4APR
-----Original Message----- From: amsat-bb-bounces@amsat.org [mailto:amsat-bb-bounces@amsat.org] On Behalf Of Gordon JC Pearce Sent: Wednesday, December 07, 2011 3:02 AM To: amsat-bb@amsat.org Subject: [amsat-bb] Re: 2 Meter TV Interference
On Tue, 6 Dec 2011 21:17:55 -0600 Wyatt Dirks wyattdirks@msn.com wrote:
Just recently I have been having troubles with a neighbor while I am
working the FM satellites(SO-50 and AO-27). The setup I am currently using is my mobile setup because I am unable to put a base station up for many reasons. I am using a FT8900 with 50 watts out into a 1/4 wave or 1/2 Larson mobile antenna.The 1/4 wave is mounted permanently via a hole in the roof of my truck an the 1/2 wave is mounted on a mount opposite the factory installed FM/AM radio whip. It doesn't seem to matter what antenna I use for the problem to occur. Then I use either the arrow antenna or my cju for the downlink.
Use 5W into a hand-held Yagi. You'll get far better results.
Today I had another local ham over at the request of the neighbor and his
mobile Kenwood radio did the same thing to the neighbors tv when he transmitted on 2 meter with 50 watts out. He also recommended that they get a filter. I did not see the specs on the filter nor do I know what bandwidth it was for.
What you want is a highpass filter that will lop off everything below 500MHz. The chances are that your TX output is clean enough but the little amplifier in the splitter for the TV is causing all sorts of intermod - and probably covers from broadcast VHF radio to the top of the TV band.
-- Gordon JC Pearce MM0YEQ gordonjcp@gjcp.net _______________________________________________ Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
Rock Island, IL, where I used to live, still has a channel 4 on VHF channel 4.
73s John AA5JG
----- Original Message ----- From: "Charles Suprin" hamaa1vs@gmail.com To: "Bob Bruninga" bruninga@usna.edu Cc: amsat-bb@amsat.org; "Gordon JC Pearce" gordonjcp@gjcp.net Sent: Wednesday, December 07, 2011 9:48 PM Subject: [amsat-bb] Re: 2 Meter TV Interference
I didn't think there were any vhf stations left. All the numbers on the channels now are virtual. All the tv antenna plans are for uhf bands. A quick look in the Boston market and the lowest channel is 19, channel 2@500MHz. Are there places that still use vhf?
Charles On Dec 7, 2011 1:38 PM, "Bob Bruninga" bruninga@usna.edu wrote:
HPF above 500 MHz? Then the TV would not be able to see anything but a few UHF channels.
What is needed is a stub filter. Just a piece of open ended coax 13" long "T"ed into the antenna lead....
The 13" is about 66% of a quarter wave at 2 meters.
Done
Bob, WB4APR
-----Original Message----- From: amsat-bb-bounces@amsat.org [mailto:amsat-bb-bounces@amsat.org] On Behalf Of Gordon JC Pearce Sent: Wednesday, December 07, 2011 3:02 AM To: amsat-bb@amsat.org Subject: [amsat-bb] Re: 2 Meter TV Interference
On Tue, 6 Dec 2011 21:17:55 -0600 Wyatt Dirks wyattdirks@msn.com wrote:
Just recently I have been having troubles with a neighbor while I am
working the FM satellites(SO-50 and AO-27). The setup I am currently using is my mobile setup because I am unable to put a base station up for many reasons. I am using a FT8900 with 50 watts out into a 1/4 wave or 1/2 Larson mobile antenna.The 1/4 wave is mounted permanently via a hole in the roof of my truck an the 1/2 wave is mounted on a mount opposite the factory installed FM/AM radio whip. It doesn't seem to matter what antenna I use for the problem to occur. Then I use either the arrow antenna or my cju for the downlink.
Use 5W into a hand-held Yagi. You'll get far better results.
Today I had another local ham over at the request of the neighbor and his
mobile Kenwood radio did the same thing to the neighbors tv when he transmitted on 2 meter with 50 watts out. He also recommended that they get a filter. I did not see the specs on the filter nor do I know what bandwidth it was for.
What you want is a highpass filter that will lop off everything below 500MHz. The chances are that your TX output is clean enough but the little amplifier in the splitter for the TV is causing all sorts of intermod - and probably covers from broadcast VHF radio to the top of the TV band.
-- Gordon JC Pearce MM0YEQ gordonjcp@gjcp.net _______________________________________________ Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
Charles,
I didn't think there were any vhf stations left. All the numbers on the channels now are virtual. All the tv antenna plans are for uhf bands. A quick look in the Boston market and the lowest channel is 19, channel 2@500MHz. Are there places that still use vhf?
The Phoenix area still has 3 TV stations on the high VHF channels 7-13 (KAET/PBS on 8, KSAZ/Fox on 10, KPNX/NBC on 12), but none on the low VHF channels 2-6. The Tucson area still has one station on the high VHF channels, and southwestern Arizona around Yuma has 3 - also on high VHF channels. There are many low-power TV stations and translators around Arizona still operating on both low and high VHF channels. Many of these are still broadcasting in analog, as these stations were not required to make the change to digital TV along with the full-power stations. Some translator stations are now being moved to digital TV in rural Arizona.
An explanation on why many TV stations are now on UHF channels instead of VHF in the USA is at:
http://en.wikipedia.org/wiki/DTV_transition_in_the_United_States#VHF_frequen...
73!
Patrick WD9EWK/VA7EWK http://www.wd9ewk.net/
On Wed, 7 Dec 2011 16:48:49 -0500, Charles Suprin wrote:
I didn't think there were any vhf stations left. All the numbers on the channels now are virtual. All the tv antenna plans are for uhf bands. A quick look in the Boston market and the lowest channel is 19, channel 2@500MHz. Are there places that still use vhf?
I have channel 8 and channel 10 VHF locals in my area. I use a Channel Plus DA-500A preamp in my system. It was recommended by a VHF guru as a high-power preamp that is more overload immune. I have a K1UFH 144.200 notch ahead of it to keep my APRS digi out, and had to throw a coulple of FM traps on the input still, to keep out herringbone from strong local FM stations (back in analog days), but it was still much better than the cheapo consumer stuff even without the extra filters.
73
-Jim
-- Ham Radio NU0C Lincoln, Nebraska, U.S.S.A. TR7/RV7/R7A/L7, TR6/RV6, T4XC/R4C/L4B, NCL2000, SB104A, R390A, GT550A/RV550A, HyGain 3750, IBM PS/2 - all vintage, all the time!
"Give a man a URL, and he will learn for an hour; teach him to Google, and he will learn for a lifetime."
HyGain 3750 User's Group - http://groups.yahoo.com/group/HyGain_3750/ http://incolor.inetnebr.com/jshorney http://www.nebraskaghosts.org
I have one still on RF channel 3 (KDLO). West of me is one on RF channel 2 (KOTA).
73, Joe kk0sd
-----Original Message----- From: amsat-bb-bounces@amsat.org [mailto:amsat-bb-bounces@amsat.org] On Behalf Of Charles Suprin Sent: Wednesday, December 07, 2011 3:49 PM To: Bob Bruninga Cc: amsat-bb@amsat.org; Gordon JC Pearce Subject: [amsat-bb] Re: 2 Meter TV Interference
I didn't think there were any vhf stations left. All the numbers on the channels now are virtual. All the tv antenna plans are for uhf bands. A quick look in the Boston market and the lowest channel is 19, channel 2@500MHz. Are there places that still use vhf?
Charles On Dec 7, 2011 1:38 PM, "Bob Bruninga" bruninga@usna.edu wrote:
HPF above 500 MHz? Then the TV would not be able to see anything but a
few
UHF channels.
What is needed is a stub filter. Just a piece of open ended coax 13" long "T"ed into the antenna lead....
The 13" is about 66% of a quarter wave at 2 meters.
Done
Bob, WB4APR
-----Original Message----- From: amsat-bb-bounces@amsat.org [mailto:amsat-bb-bounces@amsat.org] On Behalf Of Gordon JC Pearce Sent: Wednesday, December 07, 2011 3:02 AM To: amsat-bb@amsat.org Subject: [amsat-bb] Re: 2 Meter TV Interference
On Tue, 6 Dec 2011 21:17:55 -0600 Wyatt Dirks wyattdirks@msn.com wrote:
Just recently I have been having troubles with a neighbor while I am
working the FM satellites(SO-50 and AO-27). The setup I am currently using is my mobile setup because I am unable to put a base station up for many reasons. I am using a FT8900 with 50 watts out into a 1/4 wave or 1/2 Larson mobile antenna.The 1/4 wave is mounted permanently via a hole in the roof of my truck an the 1/2 wave is mounted on a mount opposite the factory installed FM/AM radio whip. It doesn't seem to matter what antenna I use for the problem to occur. Then I use either the arrow antenna or my cju for
the
downlink.
Use 5W into a hand-held Yagi. You'll get far better results.
Today I had another local ham over at the request of the neighbor and
his
mobile Kenwood radio did the same thing to the neighbors tv when he transmitted on 2 meter with 50 watts out. He also recommended that they
get
a filter. I did not see the specs on the filter nor do I know what bandwidth it was for.
What you want is a highpass filter that will lop off everything below 500MHz. The chances are that your TX output is clean enough but the
little
amplifier in the splitter for the TV is causing all sorts of intermod -
and
probably covers from broadcast VHF radio to the top of the TV band.
-- Gordon JC Pearce MM0YEQ gordonjcp@gjcp.net _______________________________________________ Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
_______________________________________________ Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
Charles, Our Channels 8 & 10 moved the digital channel from UHF to VHF at the end of the conversion period. Since they had to give up one channel and the operating costs for the same coverage are considerably less on VHF it was a easy decision to make. I doubt this is what FCC had in mind, but that is how it worked out.
UHF has less noise (Very little galactic noise) and significantly smaller antennas,(shorter wavelength) making the UHF segment more desirable for portable operations. Best policy is to use the VHF band for TV and save UHF for other uses.
Interesting enough a 5 Watt "S" Band link transmitter carries the video signal to the local cable TV companies that serve 90% of the viewers. Only 10% receive their TV signals over the air!
That is how it is done in Southern California.
73, Art KC6UQH
-----Original Message----- From: amsat-bb-bounces@amsat.org [mailto:amsat-bb-bounces@amsat.org] On Behalf Of Charles Suprin Sent: Wednesday, December 07, 2011 1:49 PM To: Bob Bruninga Cc: amsat-bb@amsat.org; Gordon JC Pearce Subject: [amsat-bb] Re: 2 Meter TV Interference
I didn't think there were any vhf stations left. All the numbers on the channels now are virtual. All the tv antenna plans are for uhf bands. A quick look in the Boston market and the lowest channel is 19, channel 2@500MHz. Are there places that still use vhf?
Charles On Dec 7, 2011 1:38 PM, "Bob Bruninga" bruninga@usna.edu wrote:
HPF above 500 MHz? Then the TV would not be able to see anything but a
few
UHF channels.
What is needed is a stub filter. Just a piece of open ended coax 13" long "T"ed into the antenna lead....
The 13" is about 66% of a quarter wave at 2 meters.
Done
Bob, WB4APR
-----Original Message----- From: amsat-bb-bounces@amsat.org [mailto:amsat-bb-bounces@amsat.org] On Behalf Of Gordon JC Pearce Sent: Wednesday, December 07, 2011 3:02 AM To: amsat-bb@amsat.org Subject: [amsat-bb] Re: 2 Meter TV Interference
On Tue, 6 Dec 2011 21:17:55 -0600 Wyatt Dirks wyattdirks@msn.com wrote:
Just recently I have been having troubles with a neighbor while I am
working the FM satellites(SO-50 and AO-27). The setup I am currently using is my mobile setup because I am unable to put a base station up for many reasons. I am using a FT8900 with 50 watts out into a 1/4 wave or 1/2 Larson mobile antenna.The 1/4 wave is mounted permanently via a hole in the roof of my truck an the 1/2 wave is mounted on a mount opposite the factory installed FM/AM radio whip. It doesn't seem to matter what antenna I use for the problem to occur. Then I use either the arrow antenna or my cju for
the
downlink.
Use 5W into a hand-held Yagi. You'll get far better results.
Today I had another local ham over at the request of the neighbor and
his
mobile Kenwood radio did the same thing to the neighbors tv when he transmitted on 2 meter with 50 watts out. He also recommended that they
get
a filter. I did not see the specs on the filter nor do I know what bandwidth it was for.
What you want is a highpass filter that will lop off everything below 500MHz. The chances are that your TX output is clean enough but the
little
amplifier in the splitter for the TV is causing all sorts of intermod -
and
probably covers from broadcast VHF radio to the top of the TV band.
-- Gordon JC Pearce MM0YEQ gordonjcp@gjcp.net _______________________________________________ Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
_______________________________________________ Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
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----- Original Message ----- From: "Bob Bruninga" bruninga@usna.edu To: "'Gordon JC Pearce'" gordonjcp@gjcp.net; amsat-bb@amsat.org Sent: Wednesday, December 07, 2011 7:24 PM Subject: [amsat-bb] Re: 2 Meter TV Interference
HPF above 500 MHz? Then the TV would not be able to see anything but a few UHF channels.
What is needed is a stub filter. Just a piece of open ended coax 13" long "T"ed into the antenna lead....
The 13" is about 66% of a quarter wave at 2 meters.
Done
Bob, WB4APR
Hi Bob, WB4APR
If the "open stub" is tuned to the 2 meters band and attached to the TV-set of one's neighbour a reduction of the 2 m signals of 25 to 30 dB may be expected.
At the same time all odd harmonics of the design frequency (3f, 5f, etc will be attenuated as well.
Since the UHF amateur is particularly concerned with f and 3f this "open stub" is usefull as well when one transmit in 432-435 MHz
On the other side if the quality of the previously good and clear TV-picture is reduced upon correct insertion of the "open 1/4 wave stub" one should investigate whether 3f, 5f, or 7f fall into the television frequency band. If this is the case it may become necessary to tune to a different TV channel or turn the antenna to a different TV-station.
I have just received a suggestion from James VK6FJA that I agree because of my previous experience in solving my TVI problems in HF and VHF in my condo.
"Nothing can be done to the Tx, better to offer a working filter to the Rx side! "
http://www.rjmb.net/vk6fja/tvi-filter/index.htm
This 144 MHz Stop-Band TVI Filter is based on a QST article found online.
VK6FJA says to me "it works just fine - and it can be aligned without the test gear, there's only 2 trimmers in it."
73" de
i8CVS Domenico
----- Original Message ----- From: "Wyatt Dirks" wyattdirks@msn.com To: amsat-bb@amsat.org Sent: Wednesday, December 07, 2011 4:17 AM Subject: [amsat-bb] 2 Meter TV Interference
Just recently I have been having troubles with a neighbor while I am working the FM satellites(SO-50 and AO-27). The setup I am currently using is my mobile setup because I am unable to put a base station up for many reasons. I am using a FT8900 with 50 watts out into a 1/4 wave or 1/2 Larson mobile antenna. Today I had another local ham over at the request of the neighbor and his mobile Kenwood radio did the same thing to the neighbors tv when he transmitted on 2 meter with 50 watts out. He also recommended that they get a filter. I did not see the specs on the filter nor do I know what bandwidth it was for.
If anyone has any ideas on what would solve this problem and could share that would be great.
Catch you on the birds
Wyatt AC0RA
----- Original Message ----- From: "Wyatt Dirks" wyattdirks@msn.com To: amsat-bb@amsat.org Sent: Wednesday, December 07, 2011 4:17 AM Subject: [amsat-bb] 2 Meter TV Interference
<snip>
Just recently I have been having troubles with a neighbor while I am working the FM satellites(SO-50 and AO-27). The setup I am currently using is my mobile setup because I am unable to put a base station up for many reasons. I am using a FT8900 with 50 watts out into a 1/4 wave or 1/2 Larson mobile antenna.
<snip>
Today I had another local ham over at the request of the neighbor and his mobile Kenwood radio did the same thing to the neighbors tv when he transmitted on 2 meter with 50 watts out. He also recommended that they get a filter. I did not see the specs on the filter nor do I know what bandwidth it was for.
If anyone has any ideas on what would solve this problem and could share that would be great.
Catch you on the birds
Wyatt AC0RA
Hi Wyatt, WC0RA
WOW.....50 watt out working the FM satellites SO-50 and AO-27 ? ?
Reduce your power to maximum 5 watt ( 10 dB less than 50) and see if you can solve the TVI problem using a decent directional antenna enstead of a 1/4 wave or 1/2 Larson mobile antenna.
73" de
i8CVS Domenico
On Wed, 7 Dec 2011 13:45:52 +0100 "i8cvs" domenico.i8cvs@tin.it wrote:
WOW.....50 watt out working the FM satellites SO-50 and AO-27 ? ?
Reduce your power to maximum 5 watt ( 10 dB less than 50) and see if you can solve the TVI problem using a decent directional antenna enstead of a 1/4 wave or 1/2 Larson mobile antenna.
Hang on, hang on, do I still need 1kW ERP to hit VO52 with CW? ;-)
I must admit I *always* run full QRO on the FM sats - a whopping 4.5W into a 6dB yagi.
This is probably front end overload on a TV without a front end. Can you spell SDR? The TV may now be using this technology.
A digital TV MUST receive all of the packets to display a useable picture. If it looses enough packets, it will not decode anything.
You probably cannot fix the problem with this TV.
73 Glenn WB4UIV
At 10:17 PM 12/6/2011, Wyatt Dirks wrote:
Just recently I have been having troubles with a neighbor while I am working the FM satellites(SO-50 and AO-27). The setup I am currently using is my mobile setup because I am unable to put a base station up for many reasons. I am using a FT8900 with 50 watts out into a 1/4 wave or 1/2 Larson mobile antenna.The 1/4 wave is mounted permanently via a hole in the roof of my truck an the 1/2 wave is mounted on a mount opposite the factory installed FM/AM radio whip. It doesn't seem to matter what antenna I use for the problem to occur. Then I use either the arrow antenna or my cju for the downlink.
The problem occurs while I am transmitting. The neighbor says that his tv receives the interference in that the picture is disturbed and sometimes cuts out completely. He is getting his tv from hdtv over the air. He has an antenna in the attic that goes to a powered splitter which then goes to several tvs. That is about all i know on his setup but I do know that if he cuts the power to the splitter he receives nothing. Also the problem seems to be on every channel.
Today I had another local ham over at the request of the neighbor and his mobile Kenwood radio did the same thing to the neighbors tv when he transmitted on 2 meter with 50 watts out. He also recommended that they get a filter. I did not see the specs on the filter nor do I know what bandwidth it was for.
If anyone has any ideas on what would solve this problem and could share that would be great.
Catch you on the birds
Wyatt AC0RA
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On Wed, 07 Dec 2011 09:20:19 -0500 Glenn Little WB4UIV glennmaillist@bellsouth.net wrote:
This is probably front end overload on a TV without a front end. Can you spell SDR? The TV may now be using this technology.
Even TV frontends that *do* use SDR use extensive filtering and a downconverter to go from the UHF input to a fairly "normal" 40MHz-ish IF.
A digital TV MUST receive all of the packets to display a useable picture. If it looses enough packets, it will not decode anything.
You probably cannot fix the problem with this TV.
I don't see why you couldn't. You just need to get rid of that grubby little splitter, and fit a highpass filter to keep the VHF signal out. I do this all the time.
What ever you do DO NOT TOUCH his TV in anyway.
You are covered by FCC rules already.
Tell him to call a TV repair service.
check the ARRL web site.
Been there done all this before.. John, W0JAB
Wyatt,
In all the replies that I read so far I have not seen much help for you. Here are a few tips.
The problem is your neighbor's amplified splitter can't handle a strong nearby signal. Your neighbor has to fix the problem.
The only solution is for your neighbor to remove the powered splitter from the antenna system. All consumer type powered TV splitters are broadband and will amplify everything from 50 mhz to 700 mhz. That is the problem, since your two meter signal is in the middle of the amp's passband. Any strong signal in the range from 50 to 700 mhz will swamp the transistors in the amplified splitter and block TV signals from being received. After he removes the amplified splitter, he can replace it with a passive splitter. Hopefully he is close enough to the TV stations that he doesn't need amplification. If not, he may need to consider a proper high gain antenna outside.
The only other solution (as your local ham friend suggested) would be to get a stopband filter(blocking 144 to 148), and have your neighbor place it in between his antenna and TV amplifier. The problem is that these type of special filters are not cheap. And the neighbor might blame you if something happened to his TV..... ICE has a filter for this application. Not sure if they are still in production. http://www.iceradioproducts.com/filtersrf.html
At my QTH I have to newer HDTVs connected to a high gain directional antenna pointed to stations 30 miles away. They are fed by coax with a PASSIVE type two-way splitter. (No amplified splitters, no special filters.) My two meter or 70 cm radios do not bother reception on either TV.
Your problem is similar to the problem that I run into when camping with my RV. The 'batwing' type antennas that are on most RV units have a built in amplifier in the head outside. ANY signal, even down to 1/2 watt, overloads my amplified TV antenna in the RV and any other RV close to my 2 meter or 70 cm antennas.
To the guys who say he is running too much power... that isn't a fix. There are other uses for his 'power' other than talking to satellites. This problem will prevent him from using his two meter radio any time at his house.
Ernie W8EH
On 12/6/2011 10:17 PM, Wyatt Dirks wrote:
Just recently I have been having troubles with a neighbor while I am working the FM satellites(SO-50 and AO-27). The setup I am currently using is my mobile setup because I am unable to put a base station up for many reasons. I am using a FT8900 with 50 watts out into a 1/4 wave or 1/2 Larson mobile antenna.The 1/4 wave is mounted permanently via a hole in the roof of my truck an the 1/2 wave is mounted on a mount opposite the factory installed FM/AM radio whip. It doesn't seem to matter what antenna I use for the problem to occur. Then I use either the arrow antenna or my cju for the downlink.
The problem occurs while I am transmitting. The neighbor says that his tv receives the interference in that the picture is disturbed and sometimes cuts out completely. He is getting his tv from hdtv over the air. He has an antenna in the attic that goes to a powered splitter which then goes to several tvs. That is about all i know on his setup but I do know that if he cuts the power to the splitter he receives nothing. Also the problem seems to be on every channel.
Today I had another local ham over at the request of the neighbor and his mobile Kenwood radio did the same thing to the neighbors tv when he transmitted on 2 meter with 50 watts out. He also recommended that they get a filter. I did not see the specs on the filter nor do I know what bandwidth it was for.
If anyone has any ideas on what would solve this problem and could share that would be great.
Catch you on the birds
Wyatt AC0RA _______________________________________________ Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
The only solution is for your neighbor to remove the powered splitter from the antenna system.... The only other solution would be to get a stopband filter(blocking 144 to 148)... these type of special filters are not cheap.
Again, a 5 cent piece of coax cut as a 1/4 wave stub at 2 meters will knock the signal at the input of that amp down by 10 to 20 dB. That is always the first approach for eliminating TVI and is cheap and cost effective and fully viable.
Bob, Wb4APR
Wyatt. Ernie has given you some good suggestions. It probably is the amplifier it self... But back in the day of analog TV a neighbor was having similar issues and I solved it by finding the power supply to his amp and doing some ferrite bead work with it..the signal was running up the power cord. Robert Oler WB5MZO
Sent from my iPad
On Dec 7, 2011, at 15:31, Ernie Howard w8eh.ernie@gmail.com wrote:
Wyatt,
In all the replies that I read so far I have not seen much help for you. Here are a few tips.
The problem is your neighbor's amplified splitter can't handle a strong nearby signal. Your neighbor has to fix the problem.
The only solution is for your neighbor to remove the powered splitter from the antenna system. All consumer type powered TV splitters are broadband and will amplify everything from 50 mhz to 700 mhz. That is the problem, since your two meter signal is in the middle of the amp's passband. Any strong signal in the range from 50 to 700 mhz will swamp the transistors in the amplified splitter and block TV signals from being received. After he removes the amplified splitter, he can replace it with a passive splitter. Hopefully he is close enough to the TV stations that he doesn't need amplification. If not, he may need to consider a proper high gain antenna outside.
The only other solution (as your local ham friend suggested) would be to get a stopband filter(blocking 144 to 148), and have your neighbor place it in between his antenna and TV amplifier. The problem is that these type of special filters are not cheap. And the neighbor might blame you if something happened to his TV..... ICE has a filter for this application. Not sure if they are still in production. http://www.iceradioproducts.com/filtersrf.html
At my QTH I have to newer HDTVs connected to a high gain directional antenna pointed to stations 30 miles away. They are fed by coax with a PASSIVE type two-way splitter. (No amplified splitters, no special filters.) My two meter or 70 cm radios do not bother reception on either TV.
Your problem is similar to the problem that I run into when camping with my RV. The 'batwing' type antennas that are on most RV units have a built in amplifier in the head outside. ANY signal, even down to 1/2 watt, overloads my amplified TV antenna in the RV and any other RV close to my 2 meter or 70 cm antennas.
To the guys who say he is running too much power... that isn't a fix. There are other uses for his 'power' other than talking to satellites. This problem will prevent him from using his two meter radio any time at his house.
Ernie W8EH
On 12/6/2011 10:17 PM, Wyatt Dirks wrote:
Just recently I have been having troubles with a neighbor while I am working the FM satellites(SO-50 and AO-27). The setup I am currently using is my mobile setup because I am unable to put a base station up for many reasons. I am using a FT8900 with 50 watts out into a 1/4 wave or 1/2 Larson mobile antenna.The 1/4 wave is mounted permanently via a hole in the roof of my truck an the 1/2 wave is mounted on a mount opposite the factory installed FM/AM radio whip. It doesn't seem to matter what antenna I use for the problem to occur. Then I use either the arrow antenna or my cju for the downlink.
The problem occurs while I am transmitting. The neighbor says that his tv receives the interference in that the picture is disturbed and sometimes cuts out completely. He is getting his tv from hdtv over the air. He has an antenna in the attic that goes to a powered splitter which then goes to several tvs. That is about all i know on his setup but I do know that if he cuts the power to the splitter he receives nothing. Also the problem seems to be on every channel.
Today I had another local ham over at the request of the neighbor and his mobile Kenwood radio did the same thing to the neighbors tv when he transmitted on 2 meter with 50 watts out. He also recommended that they get a filter. I did not see the specs on the filter nor do I know what bandwidth it was for.
If anyone has any ideas on what would solve this problem and could share that would be great.
Catch you on the birds
Wyatt AC0RA
Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
----- Original Message ----- From: "Ernie Howard" w8eh.ernie@gmail.com To: "Wyatt Dirks" wyattdirks@msn.com; "'AMSAT-BB@amsat.org'" amsat-bb@amsat.org Sent: Wednesday, December 07, 2011 10:31 PM Subject: [amsat-bb] Re: 2 Meter TV Interference
On December 07, 2011 10:31 PM "Ernie Howard" , W8EH writes:
Wyatt,
< snip>
The only other solution (as your local ham friend suggested) would be to get a stopband filter(blocking 144 to 148), and have your neighbor place it in between his antenna and TV amplifier. The problem is that these type of special filters are not cheap. And the neighbor might blame you if something happened to his TV..... ICE has a filter for this application. Not sure if they are still in production.
http://www.iceradioproducts.com/filtersrf.html
Ernie W8EH
Hi Ernie, W8EH
I agree with you that the neighbor might blame you if something happened to his TV but if they are not against Wyatt's technical intervention he can try the following stopband filter (blocking 144 to 148), placed just at the TV antenna input or just at the input of the amplified splitter if necessary.
http://www.rjmb.net/vk6fja/tvi-filter/index.htm
I have just received this advice from James ,VK6FJA that I agree because of my previous experience in solving my TVI problems in HF and VHF in cooperation with the neighbor in my condo.
This 144 MHz Stop-Band TVI Filter is based on a QST article found online and is easy to be duplicated and tuned without special instruments as shown in Fig-2 of the above QST article.
73" de
i8CVS Domenico
Why are we still talking about this?
participants (16)
-
Art McBride -
Bob Bruninga -
Charles Suprin -
Ernie Howard -
Gary "Joe" Mayfield -
Glenn Little WB4UIV -
Gordon JC Pearce -
i8cvs -
Jim Shorney -
John Becker -
John Geiger -
N0JY -
Patrick STODDARD (WD9EWK/VA7EWK) -
Robert G Oler -
Tony Langdon -
Wyatt Dirks