RCA ANT3036XR question
 

I'm a new house and few months in I'm considering getting a better VHF range antenna to swap out the DB4e I have up with VHF add on since the UHF range is cover sufficiently by the Solid Signal HDB91X. I cant seem to find a listing for the separate VHF/UHF distance range just a 65 mile general, does anyone know the specs on this? It's on sale for $60 this week at Menards so this makes it a tempting replacement.

http://www.tvfool.com/?option=com_wr...e2cb38228a8e20

https://scontent-iad3-1.xx.fbcdn.net...31&oe=5874276A

I think that you can improve your VHF performance and save some money by using a Stellar Labs 30-2476 VHF high-band yagi instead of the RCA: It only does VHF, and can be added to your existing stack far more easily. The 30-2476 should outperform the RCA on VHF channels 7-13, and only costs $34.99 plus shipping.

Thanks, one of the ugliest VHF antennas I've seen :) but it seems to be a great performer, I'm assuming its +60 mile range from the reviews I've read? i only wish I could get it from Menard's as I got rebate credit with them but still costs a few bucks less.

With a rotator, you should be able to get all the Detroit stations, too.

Here, you can imagine what it the array will look like: HDB91X and 30-2476:

http://forum.tvfool.com/attachment.p...1&d=1475149860

http://forum.tvfool.com/attachment.p...3&d=1475150188

The 30-2476 may be more wind worthy than the DB4e and much more wind worthy than the RCA 3036XR, both are wind catchers.

I would hope, I get 2 (real 7) & 9 at night now regularly with the single dipole add on top on the DB4e, I would hope to get daytime reception with this but 2 is a pretty weak transmitter.

Yeah that's about how I planned to mount I was surprised the 30-2476 is only 5" shy of the HDB91X, any reason more forward mounting of the 30-2476? I have mine set to be more centered with the reflectors parallel, planning on about 3' spacing.

Yeah, its a bit of a sail but both are light & my top mast is less than 10'.

The only reason I mounted it forward is because the instructions show the mount there. And that's how it ended up on the mast. I know I thought the same thing later when I looked at it. And the funny thing is the ad picture of it shows the clamp between another set of elements than the instructions show.
Mine should probably be mounted even. I don't know if there's a rule on that or not. It may not matter.

I called Antennas Direct. Really excellent help there. I asked him about the VHF add-on kit and there are actually two different ones. One is slightly better then the other. You have to actually ask them fo it, they keep it in the office.

I understand it ships from another location than their regular antennas.. However, I believe the VHF add-on kit is barely a compromise. Even the Tech Guy said anything more than 35 miles his risky with that antenna meaning the VHF add-on kit.

I think the 30 - 2476 will open up New Horizons for you. It is a clean-looking antenna and well-constructed. Also during another conversation I had with an antenna Tech Guy, he said that when there is nothing they can do for their customer about VHF reception they actually recommend the 30 - 2476. Even though it is made by another antenna company.

The add on was the one dipole from the Antennas Direct ClearStream, they actually sent the reflector from that antenna in the kit order, its a jimmy rig basically.
I mounted pretty similarly with the HDB91X on top using the Stellar Labs UHF - VHF Antenna Combiner http://www.mcmelectronics.com/produc...-2230-/33-2230 this was a pain as the combiner case would not contain the high quality guarded cables I had been using due to the heads being too large for the case so I had to cut new traditional cables with twist on heads to fit the case.
The end result so far is that 2 is rock solid, not a single dropout since I scanned in the afternoon until I pointed east to get 24 Toledo around midnight, 9 was less good, only could get with a direct point (whereas a general ch 50 point will do) with a lot of breakup, the UHF reception has been pretty disappointing, I'm really hoping its the weather as its been storming in Detroit today but tonight (prime reception time) I scanned under 20 channels (poor in any weather) 20 & 7 haven't been seen at all & 4 ,62, 56 are only seen intermittently with lots of breakup, I thought in the first couple hours that ch 4 "seemed" rock solid & I was expecting it to stay. I was hoping for improvement with the height boost of the HDB91X but perhaps the DB4e was doing more than I thought when I consider it to be UHF overkill, it always was a very impressive antenna, I got the HDB91X for a more directional point but I'm not sure if it tops the fringe reception, I would hate to have to remount again soon as that was more of a pain than expected but if things don't improve something will have to change.

https://drive.google.com/open?id=0B2...m5pQzM4Y3BicE0

It might be that the DB4e worked better because it is not as directional since it looks like you are trying to pick up channels from some degrees apart.

That is a nice combiner.
http://forum.tvfool.com/attachment.p...1&d=1475237536

For about $14 more there is a RCA PREAMP1R available and it is a great UHF/VHF combiner. I used it to combine my UHF VHF antennas. it has about 20bd boost and lower noise. There were some issues reported a while back, but I haven't read anything lately and both of mine work well:

ttps://www.amazon.com/RCA-TVPRAMP1Z-Preamplifier-Outdoor-Antenna/dp/B003P92D9Y/ref=sr_1_1?s=electronics&ie=UTF8&qid=1475238081&sr=1-1&keywords=RCA+PREAMP1R
That preamp couldn't hurt looking at the distances you are working with...

Anyhow, I hope one of the experts can offer some help here for you.

I tried to comb a number of the specific magnetic points (at least for 7 & 20), didn't seem to differ much.
I'm limited to a preamp designed for powering by +17 VDC at less than 50mA using a single cable connection in conjunction with the Eagle ROTR100 I'm not sure if that one will work, I'm presently using none, I have a Juice but its incompatible, I'm not sure which ones are, I wrote the company for suggestions.

There are exactly ZERO current preamps on the market that are compatible with the ROTR100's One-Cable system. The RCA is NOT compatible with it. FWIW, I suspect that feature wasn't even enabled in the product the last time it was manufactured back around 2011. I tried several of the rotors with amps that met their specs and none of the rotors would work with any of the amps

Run two cables, there is no alternative unless you can find one of the really old CM or Winegard amps that were supposed to compatible with it.

I'm not convinced a preamp is even needed or would help reception, the cable run from the highest antenna to the point of entry into the house is only around 30 feet, the work & inconvenience of running another cable doesn't seem worth the gamble.

I'm sorry I did not realize you were running a one wire rotor system. Personally, I would run a separate cable. If it were me, I would be trying it a different idea like some sort of pre amp system...I hope one of these other guys chimes in, maybe someone has a better idea...

I would like to see you succeed, I hope you can figure out what is wrong with your system. I guess possibly you could get a larger antenna like a DB8e for your UHF.

Again, it seems too much work for a relatively short cable run that may or may not need it, the DB8e is basically two DB4e's pinned together, the DB4e is a really good antenna but I have one already so buying a DB8e at over triple what I payed is not very tempting (house funds are tight as is). I've been considering the Stellar Labs (30-2415) http://www.mcmelectronics.com/produc...-2415-/30-2415
but though the gain is listed at a high 18dB from what I've been reading its being said to be a lessor of the HDB91X, I'm not sure if that is bias, personally in my experience the HDB91X has been a lessor to the DB4e (with the exception of receiving ch4 slightly better, the goal of using it, though the loss in 0 reception of ch20 & ch7, even at night presently, among others is not worth that.) If HDB91X is the best, as claimed, for fringe UHF I'm not sure where to go, it hasn't been my experience, the DBs are claimed to be "ideal for suburban and rural areas where heavy foliage or roofing materials reduce the incoming signal". this is certainty my circumstance so perhaps that's why it outperforms. I actually have the lessor Solid Signal HDB4X, so I could conceivably jimmy together with the DB4e for a equivalent of the DB8e but I think that is rather top heavy for that stack, I would hope for a single UHF antenna solution ideally.

Well, if you can ever achieve a good signal without a preamp and you add at TV or two, you may be back in the same position, unless you get a distribution amp.

I think that is a copy of this antenna:
http://www.solidsignal.com/pview.asp?p=149881
It is on sale right now. It has a variable strength pre-amp. I already know, you don't want a pre-amp, but you can use it without and it is there should you need it and want to run separate cable to your rotor.



Like all antennas, especially Chinese copies, (in this case the 91 XG was copied), they are usually overrated.

Yes, but aren't most of the stations you are trying to get close to 60 miles? With any trees, that's a double whammy.

I have seen cases where two antennas were made into one by adding a section of the other. I was going to do that with my HDB91X, by buying another and adding the front section to another and still have what amounts to an HDB43X.

AD Tech has done it with an 91XG and picked up some gain, but it was minimal.

Putting two dissimilar antennas together will be the biggest challenge you have faced, it probably won't work, you will most likely be disappointed. I have been there, I know. On the other hand, it can't hurt to try it though, who knows you might get lucky. :)

The Winegard HD7698P is a one antenna solution for UHF and VHF, but it is highly directional. And in the $130+ range + shipping, so that's out I'm sure. So is that Televes DAT709 LR Mix, which is available without VHF (minus the "mix")

Did you ever try an FM filter? Your local FM transmitters are even stronger at your new location and might interfere with VHF reception of 7 and 9.
http://www.fmfool.com/modeling/tmp/9...a/Radar-FM.png

WWWM-FM is 64.1 dB stronger than WJBK and 68 dB stronger than CBET.

Yes, I use a FM filter, I broke down & tried a separate rotor cable & hooked up the Juice preamp, I have to eat my words as I went from 16 the afternoon to 32 channels with preamp pointing 22 degrees magnetic (the Detroit sweet spot), still no 20 though which is strange as that is usually one of the easiest pull prior to the recent setup. I haven't watched 7 too much but the little I watched in the afternoon was pretty intermittent still.
WJBK has been rock solid, zero break up all times of the day up since the 30-2476 install, even w/o the preamp, 9 is better post preamp with slight break up.

Glad to hear you tried the preamp. Was this all done with the HDB91X & 30-2476 ?

How did you combine the two antennas, with MCM combiner still ?

Also, I am assuming you are using the "real" channels numbers, not the virtual number, it appears to be the case.

Same stack to combiner to FM Filter to Preamp, yeah real channels to magnetic point, still no WMYD 20, even last night at a close to 50 channel peak where I was pulling ION & WADL-DT, I find this really bizarre.

WMYD is not real channel 20, it is real channel 21 and VIRTUAL channel 20.1. If you are going to use a virtual channel number, please use the decimal form to avoid confusion. Giving the callsign, as you just did, is even better.
So do I. There is a reason; we just haven't discovered it yet. They might be having transmitter trouble, or you might have interference to that channel.

In conversation I always refer to the channel number the station is identified with rather than the real (assuming its different), I understand the difference, regardless I tried the direct 20.1 point of 29 degrees magnetic this morning & I was surprised that I lost all but 6 channels of 36 (with the 22 degree point), I know its directional but that is a really an extreme blackout point, even local WNWO-TV 49 (24) dropped which I get with a 22 degree point with preamp even though its 98 degrees magnetic, anyhow WMYD is still a mystery.

I refer to the channel by its real channel number because

1. it is the real channel number that determines the antenna needed.
2. the real channel number is always listed on the report, but the virtual channel number isn't always listed.
3. sometimes two channels will have different real channel numbers, but the SAME virtual channel number.

You might understand the difference, but the way you state it isn't clear.

Using the callsign avoids that ambiguity and uncertainty.

Why don't you call the WMYD station engineer?
This is the time of year for tropospheric propagation when you will receive channels that you will not usually receive.

I might if I find the time & it nags me enough, none of the channels received in the sweet 22 degree range are highly unusual for any time of the year in this general location in the last 4 or so years of OTA usage. I find this selection to be the norm rather than the exception if not perhaps a bit lower than average from the sandwich days of DB4e with a working preamp at my old Apt a couple years ago. Improved stability for WDIV has its costs I guess.

WDIV on real channel 45 has adjacent channel interference from WUPW on real channel 46. A tuner is not expected to reject adjacent channel interference that is more than 33 dB stronger. WUPW is 49.6 dB stronger than WDIV.

5.4.2 Adjacent Channel Rejection

The receiver should meet or exceed the thresholds given in Table 5.2 for rejection of first
adjacent-channel interference at the desired signal levels shown above the columns therein.

https://forum.tvfool.com/attachment....8&d=1434754883

When you overload a tuner with local signals, it makes reception of weaker signals more difficult, because spurious signals are created in the tuner from IMD (Intermodulation Distortion) that damage the weak signals.

WUPW -29.1 dBm + 13 dB ant + 18 dB preamp = +1.9 dBm; tuner overload

ATSC Recommended Practice:
Receiver Performance Guidelines

Document A/74:2010, 7 April 2010

RECEIVER PERFORMANCE GUIDELINES

5.1 Sensitivity

5.2 Multi-Signal Overload

Sometimes the combiner you are using has problems. What happens to WMYD when you connect the UHF antenna to the tuner with and without the preamp, bypassing the combiner?

UHF Ant > FM filter > grounding block > tuner

UHF Ant > FM filter > preamp > grounding block > power inserter > tuner

Which FM filter are you using?

In short this is why I opted for a more directional antenna to address this, there has been improvement.

This crossed my mind but I would have to take down the whole stack to access the combiner & I don't have another afternoon to forfeit doing that right now, too much other house stuff to do, recabling ate a whole afernoon yesterday I had planned for other work.
The FM Filter was bought at radio shack a 3-4 years ago, not sure of the model, it resolved the issue I had with WTOL 11 breakup I had at the time.

Good, a more directional will help that because they are in different directions.
Also good.
Understood

It's not a factor at this point since I recabled to a separate rotor connection but a FYI to anyone who might want to attempt a single cable connection with the ROTR100 from ProBrand support: " Channel Master Spartan series Pre Amps draw less current so 0068DSB, 0268DSB are good ones and 0065DBS and 0265DSB come without the power supply so may be a cost saving as well.. I am not sure if they still have these lower voltage, lower current draw units but that is where to check."

I also contacted WMYD & they verified that there have been no changes on their end so at this point I have conclude that the loss of DB4e from the stack or the combiner are the cause, not a lot of time to verify this in the next couple weeks.

That sounds like the same list I got from them 5 or so years ago when we were selling that rotor. Only problem is that all of those Spartan models were discontinued some 5+ years ago. That makes it a pretty tough proposition to score one unless you get lucky.

Double rescan
 

Double rescan

Have you tried a double rescan? It is possible that the tuner memory has become corrupted by, for example, WHNE on real channel 20 at the same azimuth.

https://www.google.com/?gws_rd=ssl#q=fcc+double+rescan

That got me wondering about the UHF antenna change. It wouldn't be gain, so maybe it is a slight change of antenna location or the form factor of the antenna.

I did a terrain profile that shows how the curvature of the earth blocks the direct signal and causes it to graze the surface and be subjected to ground clutter interference.

http://forum.tvfool.com/attachment.p...1&d=1475689113

The ground clutter interference will cause scattering of the signal so that it presents a non-uniform wave front to the antenna. This non-uniform field makes the location of the antenna very critical, because there will be hot spots and cold spots.

http://forum.tvfool.com/attachment.p...5&d=1466633825

http://forum.tvfool.com/attachment.p...6&d=1446858514

http://forum.tvfool.com/attachment.p...1&d=1475692853

It is also possible to have a non-uniform field in the vertical direction. Moving a UHF antenna a little as 6 inches up or down can make a difference. That would be easier for you to do than moving it in a horizontal direction. I wonder how the DB4e would do now?

http://www.hdtvprimer.com/antennas/siting.html

I was having trouble receiving CH 42 because my antenna was facing the wrong direction. The signal was strong enough, but the signal quality was poor; the tuner was not able to pick it up during a scan.

http://i496.photobucket.com/albums/r...pscp5alww7.jpg

As you can see, the top of the signal is not very flat, which probably indicates a multipath reflection problem. That's not surprising, because the antenna is aimed in the opposite direction and only reflections off the objects in front of the antenna are picked up; there is no direct signal from the transmitter.

I went across the street and setup a 2-bay UHF antenna, my Sadelco DisplayMax 800 signal level meter, and a CM7777 (original) preamp. I was able to get a nice scan and a stronger signal with the antenna aimed at the transmitter for CH42.

http://i496.photobucket.com/albums/r.../CH42setup.jpg

Interestingly, when I moved the antenna a few feet left or right, without changing the height or azimuth, there was a big difference in the signal strength and scan quality. This is most likely because of the tree line in front of the antenna about 200 ft away which created the non-uniform field.

I was able to get a nice scan and a stronger signal with the antenna aimed at the transmitter for CH42.

http://i496.photobucket.com/albums/r...pstck7kriy.jpg

My 8-inch Audiovox TV in the car was able to pick up CH42 WCVE; the 22-inch Sony was too big to bring along.

http://i496.photobucket.com/albums/r.../CH42found.jpg

Great explanation of multipath by Rabbit, who else?
 

Rabbit,

I have to hand it to you, that was the best explanation I've ever seen of multi path. I for one didn't get it to be honest. I think I'm getting the hang of what multipath means now.

Using those illustrations sealed the deal for me. Is Ken Nist still active?

Thank you for your kind words; I'm still learning so that I can make clear explanations.
I have learned a lot from Ken's website.
http://www.hdtvprimer.com/
His website is still up most of the time, but he doesn't add to it anymore and has only retained the essential parts. I don't know about the "active " part. His ham license is still active, and was renewed in 2013:
http://wireless2.fcc.gov/UlsApp/UlsS...?licKey=621708