Distance Between Antennas
 

What is the minimum distance between two receiving antennas, not combined, pointed in the same direction?

I want to add another antenna below my current one that would feed to a second TV in a separate room. I'm trying to keep my set up very simple.

Thanks, forum!

Good morning sir I found this article:
https://www.jpole-antenna.com/2013/0...fuhf-antennas/

Thanks bobs for the link.

So, according to the article about 19 inches between two VHF Ham antennas, or for my purposes, roughly 2 feet. If you were attempting to do what I need, would you be comfortable with that minimum distance?

BTW, in a previous thread I saw a pic of your VERY COOL Bobs Garage!

I think the most difference would be made on transmitting antennas but multipart and resonate frequencies very important and not always measurable or definable by formulas etc sometimes u just have to try it and see. I personally would try 3 to 4 feet and see what happens.

Thanks for the input, kb4!

I'm hoping to stay as close as possible to my current antenna, as it's up as high as I can get it at 20 feet. So, as you know height is usually paramount. But I understand what you're advising. You're right, I'll have to trial and error somewhat.

I'm starting a fund drive to buy rabbit73 some new testing equipment of his choice, so he'll continue to post here. Can I count you in for a donation???

yes, I would donate. A better solution, though it seems unlikely would be for the owner to sell the site or form nonprofit etc or at least appoint moderators to be able to keep things on point and civil.

I guess since its not moderated perhaps a category in another forum such as AV forum etc. could be formed to do exactly same thing this does and just check the new posts here and refer them there. Buy surely someone is making money from the advertisements on this site.

I volunteered to become a moderator and it is now so. I will do my best to keep the discussion high-quality, constructive, and civil. I hope we don't lose ADTech, Rabbit73 and other high-quality contributors. But let's keep this thread, and others, on topic. Perhaps a new thread about ways to bring back key contributors is warranted.

I would need to get in touch with rabbit73 by PM. I have offered similar to him before, but I don't know how to get in touch by PM currently. And I hope he hasn't left here for good and ADTech as well. I'd buy them both an early Christmas gift if they start posting again ASAP!

Thanks again for another link regarding my issue here, bobs. Since I'm not combining antennas and they're for receive only, it appears around 3 feet might work, but I'm going to have to trial and error before permanently installing my second antenna below current one. I was hoping for a simpler answer, but I think from my reading of the links you provided, there is a bit more "math" to it. However, maybe I'll catch a break.

On the other hand, thanks to jrgagne99 for stepping up to moderate forum. I will always be polite and respectful (you can check my post history), and appreciate your extra effort to keep us on point.

Perhaps if the antenna gods smile on us here, rabbit73 and ADTech will chime in on my issue. My question probably would an easy answer for them???

April 12 we'll have two channels out here in SoCal LA/OC that will change frequencies and viewers will need to rescan their TVs. One of the stations, KWHY 22(virtual) will be dropping to real channel 4 on low VHF. One of their subs is RETRO TV, which is off the air at the moment here. If it returns, then I'll need to put up the Winegard HD7000R which is the slightly larger version of the RCA751, or smaller version of my current RCA3037X(R), which of course, enables me to receive low VHF. I want to continue to watch RETRO TV, if I can.

If RETRO TV doesn't return on KWHY 22, then I'll probably just put the RCA751 below my 3037X(R).

I cannot go up any higher on my roof. I'm already at 20 feet. I just don't have the materials or ability to install such a set up. I like to have something I can maintain without too much demand. Age is a factor here, if you know what I mean. Besides, I'm in a strong signal area about 35 miles south of Mt. Wilson LOS, 346 degree magnitude. And yes, my 25 year pole is actually good quality, thicker than what you get nowadays. Last year I sanded it down and cleaned out the inside and repainted it. Good for another 50,000 miles, I hope!

I'll shout out a BIG HORRAY if ADTech and rabbit73 start posting again. But any other ideas you have bobs, would be much appreciated by me regarding the issue I posted here. I'm just not sure what the dynamics are with two receiving antennas at a minimum distance from each other. I want to keep things simple. But I suppose I could add another pole further down on my eaves from my current antenna, if the minimum distance below my 3037X(R) would cause interference with another antenna. What do you think?

Thanks again bobs for your help!

Copy that, bobs.

I will sleep better tonight knowing ADTech and rabbit 73 are back on the front line of this forum!

Semper fi!!

Younger brother was in the Corps, we live about 80 miles from Lejenue.
Small world.

Distance Between Antennas
 

OK, after reading everyone's post above again and further written research along with advise from some of my radio Buds locally, I climbed back on my roof Memorial Weekend and put up a Winegard HD7000R below my existing RCA ANT3037X(R). (jrgagne99 posted he also was climbing up on his neighbors borrowed 60' lift to adjust his antenna in the tree(s) Memorial Weekend as well. I'll be interested to see how he came out too).

It seems that when it comes to receiving antennas, distance between them is not as critical as with transmitting ones. That opinion was prominent in all the literature I read. So, after some experimenting and scanning my TV for signal strength and checking for interference on my other TV, I finally found that even 1ft below my RCA 3037 gave me optimal performance. And my Winegard 7000 is about 19 feet in the air above area rooftops and foliage. To repeat, no interference between my two TVs has been viewed! (If I'm missing something, you good Techs here tell me what I need to look out for going forward, please. Thanks!)

I have tried repeatedly to attach a photo to this post so you could see how my set up now looks, but to no avail. No matter what I do, my photo lays on its side at about a 240 degree angle. I've tried flipping the photo every which way but loose, but no luck. I've had some minor issues lately posting on TV Fool, so maybe the site is having some technical issues. If this issue resolves itself, I'll post the pic. (If anyone has advise here, please chime in, thanks!)

In the meantime, try to imagine a Winegard 7000 tucked 1ft neatly below and in parallel with its bigger brother the RCA 3037. So far, my project has exceeded my expectations.

Thanks to all you good folks here at TV Fool for your help!

Glad to hear that you got good results. You did exactly the right thing: tried it to see how it works.

Post your photo as an attachment; maybe I can straighten it.

Distance Between Antennas
 

So glad you replied, rabbit73! Hopes and prayers your wife and you are doing better.

I have been posting as attachment, including right now, but still not straight as previous pic in my original post on this thread.

Fingers crossed, you can work your magic rabbit!

Thanks again!

original photo, nice and sharp:

https://forum.tvfool.com/attachment....1&d=1559443929

Thanks for the second image.

Very odd. When I downloaded it with Firefox, it was vertical, but when I downloaded it with IE11, it was on its side.

I converted it to a jpg, made it vertical, enlarged it a little, and rotated it a little clockwise. I couldn't make it any sharper because your file size was very small.

Is that a different location, or just a different camera angle?

https://forum.tvfool.com/attachment....2&d=1559443058

Distance Between Antennas
 

Same location, just a different angle. My new Winegard 7000 seemed to be more distinguishable from the side. And yes, I downsized the pic this time (probably too much) because of TV Fool site requirements I found out from posting my original pic.

A friend of the family suggested I try a different browser, but I did not have any issues with my original pic/browser, other than I had to downsize several times before TV Fool accepted the attachment. So, very odd indeed.

I'm still learning TV Fool's posting format and appreciate your patience and help, rabbit! But my learning curve is improving, certainly from when I first started several years ago now. Much due to your tutelage and others here!

A couple further observations after a week now with my new outdoor antenna setup.

The Winegard 7000 feeds 75' rg6 cable to my second Samsung 32" (2017 Best Buy Exclusive 1080p) TV, properly grounded, of course, by National Electrical Code parameters. Across UHF it matches or beats by a dB or two my main Living Room 40" Samsung TV (2013), which is fed by 90' of rg6 cable, again properly grounded. But on VHF the 40" has the edge and can "see" real channel 8, just over the "digital cliff," 16-17dB SNR. The Winegard does not pick up channel 8 at all. So, the RCA probably has more gain given its larger boom, especially for weak channels like 8. Interesting and puzzling. Also, my Channel Master 94444 balun leads on both antennas were cut to 2 1/2" each, according to rabbit73s' lab test. I found a couple dBs improvement!

Thanks again rabbit, you're the best.....

normally it is suggested a minimum of 1 meter between antennas
reasoning being that the reflectors off of one antenna can obscure that of the other

your smaller antenna is tucked under the larger one and the dipoles on the top one could act as a reflector or in this case a deflector and not allow signal to get to the bottom antenna


It would depend on the frequency of the wave of the station and 14 real and over it would probably not be as much of an issue but low vhf it might be an issue

when building an antenna the distance of the reflector to the dipole can be critical in inches especially on bay type antennas that use a rear reflector to both improve reception from the front and reduce interference from behind

but why didn't you just use a splitter or a distribution amplifier?
weak signal might not be good with a splitter to feed 2 tvs but you could use a distribution amp .. even an 8 port that is very weak would just pass signal without much power boost if your signals are very high on some stations.. a 4 port could actually give you a decent boost in strength to get channels that are marginal.

anyway .. good that you got it working but if you have signals from other directions you might want to turn one of them and then bind them and feed both tvs to get more stations.

I have two 110 inch RCA antennas .. both have CM7777 amps.. they come to a 2 port splitter that is bidirectional and power passing both ways on all ports.. and that goes to a 8port distribution amp in my basement where I pass it across the basement ceiling up into the outlets and coax to each tv ... this gets me stations from two different markets because I am in a fringe location 60+ miles out.. I actually have more markets I could grab from but.. too much effort for too little payback...

I won't be playing with my setup until the end of august when philly changes its broadcast stations for the repack.. just not worth it .. at that point i will have a couple years until the last of the stations move and I will have to see what fun cochannels I get from this.

Good Luck

These are the TVFool max attachment sizes for file size, pixel width, and pixel height. Anything larger will not be accepted as an attachment. I like to keep the width of jpg photos to no more than 750 pixels so that the posts don't get too wide. If the posts are too wide, the type in a post gets too small when trying to view the whole image.

https://forum.tvfool.com/attachment....4&d=1559500846

I crop and resize using a photo editor or Paint.

Using a splitter or a distribution amp and a splitter might be a good simple solution, but I would want to see a TVFool report and know the exact address and exact coordinates of the antenna (by PM for security) before making a recommendation about improving the reception of channel 8.

My wild guess is that the Winegard 7000 doesn't have enough gain for 8. Adding more amplification doesn't compensate for a poor quality signal coming out of the antenna terminals. The signal will be stronger, but not better quality (SNR and errors); GIGO.

Distance Between Antennas
 

Thanks for the tip, rabbit73! Next time I post a pic I think I'll get it right because of your kind help, once again. But at least folks can see what my set up looks like now.

And thank you ZippyTheChicken for your input on my antenna set up. I appreciate you taking the time to share your experiences with my issues. I will keep them in mind going forward if any interference between my antenna's develops.

I seriously considered your recommendation before deciding on my current set up. But I wanted to keep it very simple and both TVs distinct from each other, IF the antenna's did NOT interfere with each other. And as I mentioned above, so far they have not. Other considerations were possible future problems with amplifiers and I wanted to monitor signal strengths on each TV for reference in my learning process of what I call this "great hobby," and of course good, free entertainment of various sorts.

I think rabbit73 hit it on the nail in above quote, though. Before I put up my Winegard 7000, I pointed my RCA 3037 a bit left and right of the recommended 346 degree magnitude for optimal reception at my location 35 miles south of Mt. Wilson. I found that when I pointed it towards LA proper, I could increase the signal strength on my living room 40" Samsung to around 19dB SNR from the current 16-17dB SNR. But I lost a few dBs from MeTV KAZA 54-1 (virtual) real channel 22. And since I watch a lot more of MeTV than channel 8's lineup, I deferred to approximately 346 magnitude. Also, it's common knowledge here in SOCAL LA/OC that channel 8 is a weak and "choppy" station, although there are a few viewers who seem to get fairly good reception. I spoke with the owner of channel 8 several years ago by email about said issues, and he said he was "hemmed in" by the FCC with low power so as not to interfere with border stations. I have little knowledge about what it takes to run a TV station, but my take on it was that it probably came down to economics and a business decision. After all, he is the owner. But for us viewers in TV Land, channel 8 viewing is problematic.

Well, that is probably more than you wanted to know about the background of my current antenna set up. But I really enjoy free TV and what has turned out to be a great hobby for me. I've learned so much from this forum thanks to people like you and rabbit73 and too many others to mention (apologies to everyone)!

Um, you keep mentioning real channel 8, but I don't remember you giving a callsign for it. Is it KFLA-LD?

Does this look anything like your report?
http://www.tvfool.com/?option=com_wr...90381088e7c829

https://forum.tvfool.com/attachment....5&d=1559521942

Distance Between Antennas
 

I was just thinking about this rabbit and realized I probably should have included real channel 8 callsign, KFLA-LD. Thanks for reminding me!

And yes, that is my TV Fool report. I was looking at KFLA-LD real channel 8 at RabbitEars with the Longley-Rice map. It showed me again what I remembered about the reception in my area. Indeed, the "hot spot" is over LA and weakens as it permeates my area. So, my RCA 3037 confirmed the Longley-Rice map, or visa-versa. I probably would need an even larger antenna boom to improve reception. But at my age, what I have on my roof is my limit! LOL!

However, if you have any more suggestions, I'm all ears.....

Thank you.

Yes, KFLA-LD IS a low power station, but I don't consider it the fault of the FCC. Low power stations are supposed to run at low power, hence the name.

Not only is it running low power, but it has a very directional antenna that sends only 0.366 kW out of 3 kW ERP in your direction, That is 366 Watts out of 3,000 Watts:
http://www.tvfool.com/?option=com_wr...ALLTV%26n%3d26

https://www.rabbitears.info/tvq.php?...ms&facid=28566

Any suggestion that I can think of now would probably exceed your limit.

Distance Between Antennas
 

If my memory serves me right, I believe KFLA-LD Channel 8's very directional antenna is what the owner was referring to when I contacted him several years ago by email. But he did say the FCC did not want any interference with border stations??? Again, memories are not often the best evidence in a court of law, but I would stand by my recollection today.

The main reason I was trying to receive KFLA-LD initially was they used to air RETRO TV. Now, that RETRO has moved to KWHY 22 (real channel 4) and will air June 15 according to their Facebook page, I replaced my other RCA 751 with my two new antenna's capable of receiving low VHF. KFLA-LD's line up is not a priority for me presently, especially since they continue to be low powered. I can watch Channel 8 most of the time when needed, but hopefully they will update their power with the FCC sometime in the future.

Anyway, if you're ever out here in SOCAL LA/OC rabbit, let me know and you can help an Old School Guy put a bigger antenna that will rival the best here on the West Coast! LOL!

That is correct. The US has non-interference border agreements with Canada and Mexico. The antenna patterns of the US transmitters are designed to minimize interference with border countries. Your location is between the transmitter and the border.

https://forum.tvfool.com/attachment....7&d=1559606401

The problem is especially critical at the US-Canadian border. Many Canadian viewers want to receive US channels, but the US channels are very weak because of the directional antenna patterns. Repack has made the problem even worse because of increased co-channel and adjacent channel interference.

The worst location for a Canadian viewer is just North of his local transmitters. When he aims his antenna South for the weak US channels, his local channels overpower the US channels.

This one has nothing to do with the agreements between the US and Mexico regarding non-interference.


For channel 8 in LA, the "problem" (for them) is that they are licensed as a "low power digital" stations that is required by the rules to not interfere with stations that are licensed as "full power" (or class A). In this case, San Diego station KFMB is the station that has an interference protected contour that KFLA is not allowed to interfere with.

Ah, so; KFMB in San Diego, also on 8.

Thank you for the clarification.

https://forum.tvfool.com/attachment....8&d=1559614361