Low VHF interference

freeisforme

Thread Starter
SatelliteGuys Guru
Feb 21, 2017
136
26
south jersey
I can't find where you asked that question. Is it in this thread?

I don't quite understand your oclock references for an antenna. Are you talking about what the antenna looks like from above, or at eye level?

Looking at a dipole antenna from above, it is bi-directional. So, it should be aimed broadside (perpendicular) to the transmitter:

View attachment 147146

This is what my CH 3 indoor folded dipole looks like. It is 14 gauge wire on yardsticks:

View attachment 147150

View attachment 147147 View attachment 147148
View attachment 147149
Here are my crappy pictures. antenna1.jpg antenna2.jpg
 
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rabbit73

SatelliteGuys Family
Jul 17, 2020
56
38
S.E. VA
rabbitears.info owner " forget his name" should incorporate your answer here into the website.
His name is Trip on this forum. He is the webmaster for the rabbitears.info site and works for the FCC.

I have known Trip for a long time and have learned a lot from him. He checks my posts from time-to-time. When I say something that is right, he supports me; when I say something that is wrong, he corrects me. I appreciate both; I don't want to post bad advice.
 
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rabbit73

SatelliteGuys Family
Jul 17, 2020
56
38
S.E. VA

Thank you for the interesting antenna photos with notations.

freeisformeSatGuysAnt1_1.jpg

freeisformeSatGuysAnt2_1.jpg

freeisformeSatGuysAnt2_2.jpg


I see you are using a splitter in reverse to combine your VHF-Low twinlead antenna with your 4-bay bowtie antenna.

Sometimes that works OK, but not always. The correct device to use is a HLSJ (VHF-High/VHF-Low Separator-Joiner).

If the two antennas pick up the same signal, when they reach the combiner they might interfere with each other.

To see if using a splitter in reverse as a combiner for your two antennas is working OK, I suggest you make a TEMPORARY test by connecting just the VHF-Low twinlead antenna to the 7777 preamp to see if there is any improvement in your VHF-Low signals.
 
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johnnynobody

SatelliteGuys Pro
Pub Member / Supporter
Aug 2, 2009
4,365
767
42N 103W
I am using the twin lead as a simple folded dipole tv antenna. Is there a better radio or radio antenna to find other poles? Marine VHF radio? Don't have it but can borrow. I don't mind building a antenna. As always, cheap or free is best.

If you can pick up the noise without an external antenna then that'll help pinpoint the source. I've removed a "rubber duck" antenna on an FM transceiver to locate interference issues.
 

freeisforme

Thread Starter
SatelliteGuys Guru
Feb 21, 2017
136
26
south jersey
Thank you for the interesting antenna photos with notations.

View attachment 147584
View attachment 147585
View attachment 147586

I see you are using a splitter in reverse to combine your VHF-Low twinlead antenna with your 4-bay bowtie antenna.

Sometimes that works OK, but not always. The correct device to use is a HLSJ (VHF-High/VHF-Low Separator-Joiner).

If the two antennas pick up the same signal, when they reach the combiner they might interfere with each other.

To see if using a splitter in reverse as a combiner for your two antennas is working OK, I suggest you make a TEMPORARY test by connecting just the VHF-Low twinlead antenna to the 7777 preamp to see if there is any improvement in your VHF-Low signals.
correction: the twin lead is 96 inch. i cut it shorter for better reception on rf 6. i should make it longer. i dont watch 6 abc.

reverse splitter: i did try each antenna without the splitter. it seemed to make no difference on low vhf. hi vhf " one channel at the time of install" and uhf the difference was not enough to lose any channels. therefor i kept the reverse splitter. if you think the HLSJ will help some, i give that a try too.
 

freeisforme

Thread Starter
SatelliteGuys Guru
Feb 21, 2017
136
26
south jersey
If you can pick up the noise without an external antenna then that'll help pinpoint the source. I've removed a "rubber duck" antenna on an FM transceiver to locate interference issues.
i did try the AM radio. some pole are noisy next to my house. I should record the power line noise and post it. can i post just audio?
 

freeisforme

Thread Starter
SatelliteGuys Guru
Feb 21, 2017
136
26
south jersey
If both antennas are about 98 inches long, the 14 gauge antenna might do slightly better, but it is difficult to say for certain.

View attachment 147310
View attachment 147311
View attachment 147312
View attachment 147313
View attachment 147314

I think what will make the biggest difference in the reception of channel 2 is the location and orientation of the antenna. Your antenna has a power line in front of it. Channel 2 has circular polarization, so it has a vertical component. Part or all of the antenna might need to be vertical.
Build Day. I will take a picture of the single meter on the TV with the current twin lead antenna and the new 14awg antenna for channels 2, 6. directly connected no splitter. Thanks Rabbit73
 

freeisforme

Thread Starter
SatelliteGuys Guru
Feb 21, 2017
136
26
south jersey
Need more gain. A signal strengh of 40+ is needed to watch channel 2 on the TVs (4). The reverse splitter and Amp lower the strength to about 25-30. Channel 6 seems to work OK at 35.
 

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