Low VHF interference

[freeisforme]

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:

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Here are my crappy pictures.

 

[rabbit73]

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.

 

[rabbit73]

Here are my crappy pictures. View attachment 147536View attachment 147537

Thank you for the interesting antenna photos with notations.

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.

 

[ZetaMale]

Got the balun connected to the twin lead then rg6 25ft to the tv. No amp or splitter. I have a noisey pole about 200ft away on a AM radio.

Have you reported this to the power company?

 

[ZetaMale]

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]

Thank you for the interesting antenna photos with notations.

View attachment 147584
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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]

Have you reported this to the power company?

no. i dont have proper test equipment and dont want to look foolish.

 

[freeisforme]

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]

If both antennas are about 98 inches long, the 14 gauge antenna might do slightly better, but it is difficult to say for certain.

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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]

I hope the strightness of the wire donsent matter to much. It seem to be better then the twinlead. Im still testing it out. Its on a 1x3x8.

 

[rabbit73]

I hope the strightness of the wire donsent matter to much. It seem to be better then the twinlead. Im still testing it out. Its on a 1x3x8.
View attachment 148365

Thank you for the photo of your folded dipole.

I don't think the straightness is real critical. I just used masking tape on mine.

Glad to hear you notice some improvement.

 

[freeisforme]

Thank you for the photo of your folded dipole.

I don't think the straightness is real critical. I just used masking tape on mine.

Glad to hear you notice some improvement.

Before and after. RF channels 2, 4, and 6.

 

[freeisforme]

Both antennas were connected directly to a converter box. I use the converter box for the meter. No splitter , No Amp.

 

[freeisforme]

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.

 

[rabbit73]

Before and after. RF channels 2, 4, and 6.

Thank you for the photos. Big improvement on CH2.

 

[rabbit73]

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.

Your SDR image for CH2 on a good day:

 

[freeisforme]

Your SDR image for CH2 on a good day:

View attachment 148401

I will check the SDR after dinner. Channel 2 should be watchable by then. Thanks Rabbit73.

 

[freeisforme]

Im waiting for it to come in. last time channel 2 was watchable was Friday morning.

 

[freeisforme]

Also when channel master updates the LTE filter in JOINtenna im going to buy it.

 

[freeisforme]

Rabbit73: How do you calculate the length of a folded dipole using 14AWG? Thank you.