Pre-amp-Passive Splitter/Amplified splitter

[shoman94]

So I was finally able to get FOX after going thru 3 antennas.
Here is my report: http://www.tvfool.com/?option=com_wrapper&Itemid=29&q=id%3d51347570c1f198

I'm using the Clearstream 4v from BestBuy. I have 3 TVs I need to connect. With a single line and a single tv I have very good signal on all channels except FOX and WPME is about 50% but its nice and clear.
If I add a Pre amp (PA-18) all channels get pixels and are unwatchable....signal strength is the same.
So I removed the preamp..... tried to split and I lose signal across the board. I added a power splitter (http://www.bestbuy.com/site/rocketfish-bidirectional-mini-drop-amplifier-silver/9449135.p?id=1218106370284&skuId=9449135) and with 2 TV's the signal is still good and channels are good. When I add the third tv and see FOX and WPME start to degrade and I get some skips and pixel loss fairly consistent.


Do I need a stronger splitter amp? Would this be better(http://www.lowes.com/pd_79376-63374-VH140R_1z0vin1__?productId=3701514&pl=1&Ntt=signal+amplifier)? 10db gain vs 4db gain on the Rocketfish.
Will the preamp work if I also install the passive splitter?

Thanks in advance.
Jason

[ADTech]

The PA18 is probably overloading from nearby FM stations. Other than that, it appears to be an appropriate amp for your situation. You need an FM filter or two, not a stronger amp.

Call any remaining Radio Shack stores in your area and ask them if they have any FM filters still on hand, catalog number 1500321 (15-0321). You have to call, the item is not on their website. The filter must be installed between the antenna and the amp and you'll need a short jumper cable to do that.

If you strike out with RS and don't mind a bit of a wait, fill out the contact form on our website (https://www.antennasdirect.com/customer-help-service.html) with your information and I'll get a filter and cable mailed out to you for free.

FYI, I tested that amp from Best Buy a while back. Its noise figure is so bad (> 7 dB) that there is no reason for the product to even exist, certainly not for antenna signals. It's really not a 4 dB amp, it's a 12 dB amp with an integral 4 port splitter (~8 dB insertion loss). I haven't tested the RCA amp shown, but it's probably a 15-18 dB gain amp with the same type of splitter and corresponding insertion loss.

Will the preamp work if I also install the passive splitter?


Yes, as long as you don't make the common mistake of installing a non-power passing splitter between the preamp and its power inserter. If your cabling layout requires the splitter to be installed in that cabling segment, a power-pass splitter must be used.

[shoman94]

The PA18 is probably overloading from nearby FM stations. Other than that, it appears to be an appropriate amp for your situation. You need an FM filter or two, not a stronger amp.

Call any remaining Radio Shack stores in your area and ask them if they have any FM filters still on hand, catalog number 1500321 (15-0321). You have to call, the item is not on their website. The filter must be installed between the antenna and the amp and you'll need a short jumper cable to do that.

If you strike out with RS and don't mind a bit of a wait, fill out the contact form on our website (https://www.antennasdirect.com/customer-help-service.html) with your information and I'll get a filter and cable mailed out to you for free.

FYI, I tested that amp from Best Buy a while back. Its noise figure is so bad (> 7 dB) that there is no reason for the product to even exist, certainly not for antenna signals. It's really not a 4 dB amp, it's a 12 dB amp with an integral 4 port splitter (~8 dB insertion loss). I haven't tested the RCA amp shown, but it's probably a 15-18 dB gain amp with the same type of splitter and corresponding insertion loss.



Yes, as long as you don't make the common mistake of installing a non-power passing splitter between the preamp and its power inserter. If your cabling layout requires the splitter to be installed in that cabling segment, a power-pass splitter must be used.

I'll be calling at 11am when they open.....
Is this basically the same filter? http://www.amazon.com/RadioShack-RadioShack%C3%AF%C2%BF%C2%BD-FM-Trap/dp/B007Z82MF6/ref=sr_1_2?ie=UTF8&qid=1452439899&sr=8-2&keywords=fm+trap
It's a different number than you mentioned.

From my antenna to the splitter in the house is about 35 feet then each run is 35 feet or less from there.

So in your opinion I'm better off to use an FM trap,the PA-18 and a passive 4 way splitter vs no FM trap,no preamp and a better splitter amplifier?

EDIT: I called RS and the 1500321 is an amplifier... So I'm assuming that you meant to use the part number I linked above. P/N-1500024.

My local RS has a few in stock at 1.97 on clearance! I'll buy a few in case something happens to it...lol

[ADTech]

Yes, I mis-quoted that part number from memory, you got the right one. Good catch.

So in your opinion I'm better off to use an FM trap,the PA-18 and a passive 4 way splitter vs no FM trap,no preamp and a better splitter amplifier?


Yep. You already have almost all the parts, just need the filter/trap(s).

[shoman94]

Yes, I mis-quoted that part number from memory, you got the right one. Good catch.



Yep. You already have almost all the parts, just need the filter/trap(s).


Why do you mention traps in multiple?

[ADTech]

In case you need two in series.

[shoman94]

In case you need two in series.

Heh..... How would I know that?

[ADTech]

Try one filter first. If the original problem is still there, try adding a second.

[shoman94]

Try one filter first. If the original problem is still there, try adding a second.

OK thanks... I bought 3...lol

Can i test this with 30 feet of coax to the antenna?

EDIT: So installing 1 fixed most except 2 channels... 6.x and 51.x

Then I installed 2.... 51.x is good but still fluctuates some signal wise... Channel 6.x is about the same... Maybe a touch better...

Then I installed 3.... 6.x still cuts out and pixelate, no real change. 51.x still fluctuates but no drop outs.

Any advice?

[ADTech]

Put the filter between the antenna and the amp, keeping all cabling before the amp to a minimum for best results.

[shoman94]

Put the filter between the antenna and the amp, keeping all cabling before the amp to a minimum for best results.

So installing 1 fixed most except 2 channels... 6.x and 51.x

Then I installed 2.... 51.x is good but still fluctuates some signal wise... Channel 6.x is about the same... Maybe a touch better...

Then I installed 3.... 6.x still cuts out and pixelate, no real change. 51.x still fluctuates but no drop outs.

Any advice?

EDIT: Looks like WMEA radio station freq 90.1 is in the same exact direction as WCSH 6.1. Is that the culprit?

[shoman94]

I'm also wondering now if I should be using the Antennas direct FM filter based on this chart...

http://forum.tvfool.com/attachment.php?attachmentid=1269&d=1436108763

[shoman94]

Ok now that I have spent a little time watching the channels with the family in bed.

My current setup: CS4V antenna aimed at 28DEG (TRUE) and 20' up and 5 feet above the peak of my metal roof.
2 RS FM traps, PA-18, PA-18 power inserter, 3 way splitter (5-1000mhz)

TVFOOL:
http://www.tvfool.com/?option=com_wrapper&Itemid=29&q=id%3d513421e7b3a772

FMFOOL:
http://www.fmfool.com/index.php?option=com_wrapper&Itemid=29

These issues only start after adding the PA-18 but is it tolerable (sort of) with the 2 FM traps. If I don't use the Pre-amp I cant split the signal to more than 2 tv's without issue and having the PA-18 also increases my weakest signal (23.1) by 5% to 10%.

This is all new to me. I just cut Directv! YAY! lol

6.1(Real-44)- Audio drops/skips randomly... not as bad as the others.
8.1(Real-8)- No issues
13.1(Real-38)- No issues
23.1(Real-23)- Audio drops/skips randomly every 5 to 15ish seconds (Sometimes video is effected but not pixel drops)
26.1(Real-45)- No issues
35.1(Real-35)- Audio drops/skips randomly every 5 to 15ish seconds (Sometimes video is effected but not pixel drops)

This evening,channel 51.1) has the most audio drops/skips.
51.1(Real-43)- Audio drops/skips randomly every 5 to 15ish seconds (Sometimes video is effected but not pixel drops)

[ADTech]

Try testing (same TV set) with a straight-through coupler instead of the three port splitter. Repeat testing with at least one of the other available TV sets and see what happens.

[shoman94]

Try testing (same TV set) with a straight-through coupler instead of the three port splitter. Repeat testing with at least one of the other available TV sets and see what happens.

I'm 99% sure I did that before installing the splitter but I'll do it again when I get home from work.

Weird though that the channels in question are all on UHF and close to the same channel (23,35,43,44)

[shoman94]

Looks like both Panasonic TV's are better. No noticeable dropouts but the problem channels listed above have large signal fluctuation problems. Some as much as 20%.

On my XBox One I'm still having the same problems but just slightly better. WCSH isn't cutting out anymore but the rest are about the same. This tuner was connected to the 3.5db drop of the splitter originally. Unfortunately I cannot see signal strength on the XBox.


EDIT: I installed a different splitter and the Panasonic's seem to be doing OK and I also switched to a different COAX going to my XBox since I already had 2 lines running there. Nothing has changed with the XBox.... with or without the splitter. So it looks like maybe the splitter was doing something but it did not stop the slight dropouts on the XBox. Is the PA-18 too strong?

[shoman94]

I'm assuming by the amount of responses here I'm shit out of luck?

[ADTech]

I'm assuming by the amount of responses here I'm shit out of luck?
You should assume that more patience is required. A forum is not a medium for immediate responses.

You mentioned earlier that the antenna is above a metal roof.

As currently installed, is the antenna situated so that the incoming signals must cross the roof to arrive at the antenna or is the antenna mounted so that the signals hit it before crossing the roof?

[shoman94]

You should assume that more patience is required. A forum is not a medium for immediate responses.

You mentioned earlier that the antenna is above a metal roof.

As currently installed, is the antenna situated so that the incoming signals must cross the roof to arrive at the antenna or is the antenna mounted so that the signals hit it before crossing the roof?

Yes it goes across the metal roof. If you look at the attached image above you see where the antenna is placed. It is 5 feet above the peak of the roof attached by a gable end mount.

Just to reiterate though... I don't get these signal fluctuations without the PA-18.

EDIT: I don't expect immediate responses but I also don't see anyone else chiming in. My statement was based on limited responses that I have normally seen in other threads buy some very knowledgeable people as yourself. My post was in no way to insult anyone.

Another question, Can there signal fluctuations be the Pre-amp clipping?

[rickbb]

With a metal roof between the antenna and the transmitting tower you could be getting reflections of the signal from the roof. This can cause issues.

You may want to try a taller mast or move the antenna to the other side of the house to eliminate that reflection.

Of course none of that may work, but it needs to be eliminated and trial and error location testing is the only way to do it.

[ADTech]

I don't get these signal fluctuations without the PA-18......Can there signal fluctuations be the Pre-amp clipping?

Yes, it could be. I wanted to eliminate the very pronounced risk of FM overload first. Some of the stronger UHF signals are near the limit of vulnerability to PA18 overload. I made a very simple rule for our in-house sales and support staff: If the TVFool estimate shows stations "in the green", don't sell or recommend the PA18, it's really for rural locations only where everything is weak.

Shoot me your mailing info, either by PM or via email to info (at) antennasdirect.com and I'll send out a Juice. I KNOW it won't get overloaded whereas the PA18 might be, perhaps by something as yet unidentified.

rickbb already made the specific point that I was angling toward. His advice is spot on, but yI'd recommend that you try the Juice first before committing to a relocation of the antenna. BTW, I can't see any photo of the install, perhaps it got lost.

[shoman94]

Yes, it could be. I wanted to eliminate the very pronounced risk of FM overload first. Some of the stronger UHF signals are near the limit of vulnerability to PA18 overload. I made a very simple rule for our in-house sales and support staff: If the TVFool estimate shows stations "in the green", don't sell or recommend the PA18, it's really for rural locations only where everything is weak.

Shoot me your mailing info, either by PM or via email to info (at) antennasdirect.com and I'll send out a Juice. I KNOW it won't get overloaded whereas the PA18 might be, perhaps by something as yet unidentified.

rickbb already made the specific point that I was angling toward. His advice is spot on, but yI'd recommend that you try the Juice first before committing to a relocation of the antenna. BTW, I can't see any photo of the install, perhaps it got lost.

Post 13 has an attachment that shows the satellite view of my home and I placed the marker right where my antenna is mounted.

So if it were in fact reflecting off the roof that way, wouldn't that fluctuation show up even without the amplifier?

I will PM you my info. Thanks!

[shoman94]

With a metal roof between the antenna and the transmitting tower you could be getting reflections of the signal from the roof. This can cause issues.

You may want to try a taller mast or move the antenna to the other side of the house to eliminate that reflection.

Of course none of that may work, but it needs to be eliminated and trial and error location testing is the only way to do it.

Thanks, I have read that the antenna should be installed 10 feet above the metal roof. Adding another 5 feet length is probably an easier change but my only concern there would be stability. Maybe I'd have to go to a larger mast.

I'm not seeing the fluctuation without the amp so I wasn't considering the roof being an issue. But I could be wrong.

[ADTech]

Some times I conclude that this stuff is some combination of black magic, voodoo, and blind luck, either good or bad... Some times I'm surprised it even works at all...

You should have the amp in a few days, let me know how it turns out.

[shoman94]

Some times I conclude that this stuff is some combination of black magic, voodoo, and blind luck, either good or bad... Some times I'm surprised it even works at all...

You should have the amp in a few days, let me know how it turns out.
lol, thanks I will!

[shoman94]

For shits and giggles I removed the PA-18 and purchased an RCA VH140R (Power splitter/amplifier at Lowe's.

My signal does not jump any more. I also have better signal on a couple channels. I'm still having the same skips with my XBox One and the Hauppauge tuner but it does it about half as much so its an improvement! Hopefully the Juice will will solve it 100%

[shoman94]

I'm starting to think that something with the XBOX is the issue. I took the tuner and plugged it into my Win10 Laptop and installed WinTV. No issues with stuttering!

[rabbit73]

I'm starting to think that something with the XBOX is the issue. I took the tuner and plugged it into my Win10 Laptop and installed WinTV. No issues with stuttering! That sounds like a good clue.

FMFOOL:
http://www.fmfool.com/index.php?option=com_wrapper&Itemid=29
That doesn't take me to your FM report, it takes me to the page to enter your location. FM reports don't link the same way that tvfool reports link. Based on an estimate of your location, this is your FM report. You can see how close I came:
http://www.fmfool.com/modeling/tmp/adfc006504/Radar-FM.png

[shoman94]

That sounds like a good clue.

That doesn't take me to your FM report, it takes me to the page to enter your location. FM reports don't link the same way that tvfool reports link. Based on an estimate of your location, this is your FM report. You can see how close I came:
http://www.fmfool.com/modeling/tmp/adfc006504/Radar-FM.png

I don't know what happened there..... I guess I can't post it the same way. See attached.

[shoman94]

I received the JUICE today.... its definately a better preamp and has a controlled signal. It also gave me a few more channels..... but .....I still have the same results. Last night I hooked the tuner directly to my Win 10 PC and everything was great. oh Microsoft!

[ADTech]

Did you leave the FM filter(s) installed? The Juice will pass FM amplified which can clobber tuners.

[shoman94]

Did you leave the FM filter(s) installed? The Juice will pass FM amplified which can clobber tuners.

Yes I left them installed. Like I posted above that I believe its something with the XBOX software causing the issue. I found other people complaining about it and that it happened after the last software update. Both my other TVs are not exhibiting these problems and the same tuner plugged into my WIN10 PC is just fine as well, so I'm returning the tuner and picking up and Tivo Roamio OTA box and BestBuy for 50 bucks. I'll post later tonight when I get everything setup. I also ordered a PCT 4 way power distributer which arrives today.

The Juice surely helped with stabilizing the signal and getting me another set of VHF channels I wasn't getting with the PA-18.

[shoman94]

Got my Roamio OTA DVR and all is well. Using 2 fm traps, the juice and a PCT 4 port distributer.

Is there any reason why I should move the traps and juice up by the antenna? I have 2 channels (WENH and WPXG ) I get a 30% signal with.... I need 40% for it to play. I don't need them honestly but WPXG would be nice. I'm thinking keeping the traps and juice out of the weather is best. I'm about 30 feet from where the juice and traps are now indoors to the antenna.
Thoughts?

EDIT: For some reason tonight I had some issues (pixelation) with WGME and had to remove the JUICE preamp. This was the first time since getting the antenna I had this issue. For some reason this channel is also about 20% lower then its been since installing my C4V..... screwy!

Edit2: Re-aimed the antenna today. Rehooked the JUICE ... all good again.

[shoman94]

Just to update my progress in case my experience can help someone else.

This TVFOOL: http://www.tvfool.com/?option=com_wrapper&Itemid=29&q=id%3d51347570c1f198

I have my antenna 20 ft up on a gable mount and its 5 feet above my metal roof and pointed thru a huge pine tree 70 feet away. See image attached.

I have the antenna C4V pointed at 21 degrees magnetic and the VHF antenna mounted on top of the left reflector.

Channels I get 90 to 100% signal:
Real 8, 38, 43 and 35

Channels I get 60 to 89% signal:
Real 44, 45, 23 and 10

Channel 11 comes in sometimes and 33 is just to low to give me a picture.

Equipment:
Antennas Direct C4V, Antennas Direct Juice preamp, 2x Radio Shack FM Traps, PCT 4 Port amplified splitter going to 3 TVs (soon 4).

So I answered my original question with trial and error. I'm ok not using the amplified splitter with the preamp or no preamp and an amplified splitter. But using both together actually increased my signal strength on most channels so I'm keeping both.
My FM traps and Preamp are located indoors 30 feet from the antenna and the amplified splitter is within 18 inches of the preamp inserter.

[rickbb]

Assuming that channel 33 is real channel 3, then you will need to point your VHF element at 257 mag. and channel 11 will need the VHF pointed at 253 mag. If you have it pointed the same as your UHF at 21 mag then it's aimed the wrong way.

You might try to split the difference, but, channel 33, (3) has a NM value of only 1.8 and it's a 2 edge so you may never get it without a large old school VHF antenna. (If then.)

[ADTech]

Assuming that channel 33 is real channel 3, then you will need to point your VHF element at 257 mag. and channel 11 will need the VHF pointed at 253 mag. If you have it pointed the same as your UHF at 21 mag then it's aimed the wrong way.

You might try to split the difference, but, channel 33, (3) has a NM value of only 1.8 and it's a 2 edge so you may never get it without a large old school VHF antenna. (If then.)

Real channel 33 on his plot is WPXG, the ION affiliate from Concord, NH, virtual channel 21. It's off the back of the C4V and it would not be expected to be received at those forecasted levels off the back of any antenna than has any F/B ratio greater than 0.

WORK-LP is presumably still operating under their STA at a measly 58 watts ERP while they wait out the FCC's spectrum actions. That meager signal will never make it to this location.

My FM traps and Preamp are located indoors 30 feet from the antenna

You would improve your system noise margin by at least 2 dB if you put the amp immediately at the antenna as is customary.

[shoman94]

Assuming that channel 33 is real channel 3, then you will need to point your VHF element at 257 mag. and channel 11 will need the VHF pointed at 253 mag. If you have it pointed the same as your UHF at 21 mag then it's aimed the wrong way.

You might try to split the difference, but, channel 33, (3) has a NM value of only 1.8 and it's a 2 edge so you may never get it without a large old school VHF antenna. (If then.)

Real 33 is WPXG (ION) Which is on the back side as ADTECH mentioned. Without using a tinlee or a rotor or separate tuners... I highly doubt I'll get it. I don't need the channel I'm happy with it.
Channel 11 is another PBS and I already get 2 other PBS stations so I'm ok with not getting that one as well. The VHF are Di-pole's... I'm not sure it has any gain is any direction.

Real channel 33 on his plot is WPXG, the ION affiliate from Concord, NH, virtual channel 21. It's off the back of the C4V and it would not be expected to be received at those forecasted levels off the back of any antenna than has any F/B ratio greater than 0.

WORK-LP is presumably still operating under their STA at a measly 58 watts ERP while they wait out the FCC's spectrum actions. That meager signal will never make it to this location.



You would improve your system noise margin by at least 2 dB if you put the amp immediately at the antenna as is customary.

What would installing the FM traps after the preamp do? The FM trap don't appear to be very weather proof. lol

[Tim]

The VHF are Di-pole's... I'm not sure it has any gain is any direction.

A dipole antenna does have gain compared to an omni-directional antenna. It is directional. The maximum signal is received broadside to the antenna on each side making a dipole essentially bi-directional. A dipole receives very poorly off the ends of the antenna elements.

[shoman94]

A dipole antenna does have gain compared to an omni-directional antenna. It is directional. The maximum signal is received broadside to the antenna on each side making a dipole essentially bi-directional. A dipole receives very poorly off the ends of the antenna elements.

Ok I found the chart (see attached) and look like I would benefit to aiming the dipole separately from the panel. Thanks for that.

[ADTech]

What would installing the FM traps after the preamp do?

Typically, filtering is done prior to amplification to prevent the amplifier from creating distortion products with the amplifier itself.

However, in the case of the Juice, that thing is so tolerant of strong signals it will simply pass any FM signals though it (amplified, of course) without any discernible internally generated distortion. Unfortunately, that would then shift the risk of distortion to the active devices further down the chain such as tuners or any subsequent amps.

In your specific situation [emphasis added], you can readily install the tramps downstream of the Juice's power inserter and still keep any strong FM signals out of the downstream signal path. Since you're filtering post-amplification, you'll essentially need an extra trap in order to knock down the already-amplified FM signals.

[shoman94]

Typically, filtering is done prior to amplification to prevent the amplifier from creating distortion products with the amplifier itself.

However, in the case of the Juice, that thing is so tolerant of strong signals it will simply pass any FM signals though it (amplified, of course) without any discernible internally generated distortion. Unfortunately, that would then shift the risk of distortion to the active devices further down the chain such as tuners or any subsequent amps.

In your specific situation [emphasis added], you can readily install the tramps downstream of the Juice's power inserter and still keep any strong FM signals out of the downstream signal path. Since you're filtering post-amplification, you'll essentially need an extra trap in order to knock down the already-amplified FM signals.

Can the Juice be place in a weather tight box? I notice it does get warm. If its recommended it be outside then I'll get a smaller enclosure for just the traps.

[shoman94]

Moved the Juice and FM traps on the mast. FM traps are inside a weather tight box. I did move the VHF dipole from being clipped to the upper reflector to just under it and attached it to the mast so I can aim it. Now I can't get a lock on channel 10 anymore but I gained channel 11. I think the reflector was helping with that VHF channel when it was clipped to the reflector.

@ADTECH; I was wondering if you could provide me with a couple things....
What would the gain graph look like if I removed the reflectors or even just one reflector?

What would the gain graph look like if I rotated the C4V 90 degrees so they were aligned vertically vs horizontal?

Thanks!

[ADTech]

The Juice is already weatherproof. Just don't mount it upside down. ;)

With both reflectors removed, the gain would drop by 2-3 dB across the UHF band. Of course, the F/R ratio would drop to 0 as the antenna would then become bi-directional. I have no idea what the specific effects might be with a single reflector removed. As far as I know, that has never been modeled and I know I haven't tested it.

Rotating the antenna is not recommended unless you're in an area that uses vertically polarized broadcast signals as there's approximately 20 dB cross-polarization rejection. We've made the current production models capable of this rotation as we've been contemplating an entry into the UK market. Please note, there are some TV stations in North America that utilize circular or elliptical polarization so those stations would not be affected by the rotation of the antenna.

It is often to experiment wit the physical location of the VHF dipole. Moving it a few inches or a foot or so can make or break reception, depending on the immediate peaks and nulls present in any signal in any given point in space. Patience is a virtue. ;)

[shoman94]

The Juice is already weatherproof. Just don't mount it upside down. ;)

With both reflectors removed, the gain would drop by 2-3 dB across the UHF band. Of course, the F/R ratio would drop to 0 as the antenna would then become bi-directional. I have no idea what the specific effects might be with a single reflector removed. As far as I know, that has never been modeled and I know I haven't tested it.

Rotating the antenna is not recommended unless you're in an area that uses vertically polarized broadcast signals as there's approximately 20 dB cross-polarization rejection. We've made the current production models capable of this rotation as we've been contemplating an entry into the UK market. Please note, there are some TV stations in North America that utilize circular or elliptical polarization so those stations would not be affected by the rotation of the antenna.

It is often to experiment wit the physical location of the VHF dipole. Moving it a few inches or a foot or so can make or break reception, depending on the immediate peaks and nulls present in any signal in any given point in space. Patience is a virtue. ;)

Well I found it odd with channel 10 because it is mounted on the same tower as Fox (channel 23) Plus if I remember correctly I was getting channel 10 and channel 8 even with the Dipoles not hooked up! I thought that was strange.

So removing the reflectors would effectively give me the same gain as a C2V? With the C2V I wasn't able to catch FOX (channel 23) reliably. The C4V gave me about 20-30% greater signal strength. Does it change what the graph looks like much besides the DB loss on the forward side?

I also wondered why the C4V wasn't vertical stacked like the DB4E?

[ADTech]

Well I found it odd with channel 10 because it is mounted on the same tower as Fox (channel 23)

Doesn't matter. Each frequency will have it's own signal path which can be filled with minor anomalies which, when the signal finally arrives at any given random point in space (where you happened to put the reception device), can result in the signal getting pushed off the edge of the "digital cliff". When using a simple dipole, the issue can be aggravated by the dipole's reception pattern which can easily admit either reflections or other interfering signals. It is a mistake to assume that all signals from any given area or tower, even from the same antenna on a tower (there are transmitting antennas which broadcast multiple channels simultaneously) will arrive at any give point is space (where you planted the antenna, for example) with uniformity, there are always differences which are frequency-specific and those differences are the reason we put in big red letters at the top of every installation sheet the phrase "Before attaching the antenna to any surface, TEST RECEPTION in that area." Such peaks and nulls on UHF frequencies can be as little as 6-12 inches apart.

So removing the reflectors would effectively give me the same gain as a C2V?

Peak boresite gain will drop as indicated. The reception patterns will also change, especially side lobes, but I've never seen any simulations that show it, I just know it will happen. My guess is that the pattern of a reflector-less C4 would look something like a typical bidirectional antenna with observable side lobes fore and aft.

I also wondered why the C4V wasn't vertical stacked like the DB4E?

It depends on the design goal. Stacking two double loops vertically would indeed increase the peak boresite gain by about the same as stacking them horizontally while maintaining the ~70° HPBW instead of halving the HPBW as does the implemented design.. However, you would have to have a much longer mast to accommodate the vertical stack and this particular products was designed with retail (B&M) store shelf space in mind. It would also make assembly more complicated.

[shoman94]

Doesn't matter. Each frequency will have it's own signal path which can be filled with minor anomalies which, when the signal finally arrives at any given random point in space (where you happened to put the reception device), can result in the signal getting pushed off the edge of the "digital cliff". When using a simple dipole, the issue can be aggravated by the dipole's reception pattern which can easily admit either reflections or other interfering signals. It is a mistake to assume that all signals from any given area or tower, even from the same antenna on a tower (there are transmitting antennas which broadcast multiple channels simultaneously) will arrive at any give point is space (where you planted the antenna, for example) with uniformity, there are always differences which are frequency-specific and those differences are the reason we put in big red letters at the top of every installation sheet the phrase "Before attaching the antenna to any surface, TEST RECEPTION in that area." Such peaks and nulls on UHF frequencies can be as little as 6-12 inches apart.



Peak boresite gain will drop as indicated. The reception patterns will also change, especially side lobes, but I've never seen any simulations that show it, I just know it will happen. My guess is that the pattern of a reflector-less C4 would look something like a typical bidirectional antenna with observable side lobes fore and aft.



It depends on the design goal. Stacking two double loops vertically would indeed increase the peak boresite gain by about the same as stacking them horizontally while maintaining the ~70° HPBW instead of halving the HPBW as does the implemented design.. However, you would have to have a much longer mast to accommodate the vertical stack and this particular products was designed with retail (B&M) store shelf space in mind. It would also make assembly more complicated.

Maybe I can play around with them one day to see what they do. Try the one reflector on and one off as well.... There is one channel (ION) on the back side that I see signal but its not quite strong enough to lock on. It would be interesting to see if I could gain that and not lose quality on the front side with (FOX).

One other channel on the back side I'd like is channel 9 (WMUR VHF).. I think I'd need to get a CS5 to get that but its a bit pricey for one channel that I don't need...lol.

[shoman94]

It depends on the design goal. Stacking two double loops vertically would indeed increase the peak boresite gain by about the same as stacking them horizontally while maintaining the ~70° HPBW instead of halving the HPBW as does the implemented design.. However, you would have to have a much longer mast to accommodate the vertical stack and this particular products was designed with retail (B&M) store shelf space in mind. It would also make assembly more complicated.

SO are you saying that if I kept the UHF elements the same orientation but stacked vertically I would end up with the same gain but keep the 70 degree HPBW? I think that would suit me based on my report!
Looking at the installation manual I think I can stack the loop elements and have the combiner bar connections on the loops facing each other and maybe this would still allow the combiner bars fit right up?

[ADTech]

SO are you saying that if I kept the UHF elements the same orientation but stacked vertically I would end up with the same gain but keep the 70 degree HPBW? I think that would suit me based on my report!

Yes, more or less the same.

Looking at the installation manual I think I can stack the loop elements and have the combiner bar connections on the loops facing each other and maybe this would still allow the combiner bars fit right up?

No. You cannot do it with the C4 combiner without really messing up the engineering of the phasing bars.

You'd either have to start with two C2 antennas and make a combiner (out of coax cables and a two port splitter, for example) or, if you have a C4, use standard baluns (matching transformers) to match to the same homemade combiner.

[shoman94]

Yes, more or less the same.



No. You cannot do it with the C4 combiner without really messing up the engineering of the phasing bars.

You'd either have to start with two C2 antennas and make a combiner (out of coax cables and a two port splitter, for example) or, if you have a C4, use standard baluns (matching transformers) to match to the same homemade combiner.

I guess my view is a little fuzzy at the moment. I see what you're saying but I'm not sure without trying that it cannot be done with the current phase bar/combiner.
I say this because the two loop elements are the same so if you flip one of them 180 so the connections are at the bottom then place that one on top of the other so the connection face each other, the orientation for the connections should be the same for the phase bars. See my sketchy 2 min sketch of what I mean attached.

Like I said, dimensionally I don't know until I try it. Maybe you have some parts and pieces you can try?...lol

About channel 10 and 11... I think that is being picked up by the loop antennas. I haven't raised it yet but last night I tried rotating it in different positions and some matter what position I put the dipoles in, the only signal that were effected was channel 8. No matter what position I placed the dipole, the signal strength remained the same for channel 10 and 11 (32-35%).

[ADTech]

Like I said, dimensionally I don't know until I try it. Maybe you have some parts and pieces you can try?...lol

It won't work without mangling both metal and performance. Forget it.

About channel 10 and 11... I think that is being picked up by the loop antennas. Not if you have the VHF module installed. It rejects any VHF from the loops by at least 15-20 dB and replaces it with the VHF from the dipoles. Vice versa for UHF from the dipoles.

[shoman94]

It won't work without mangling both metal and performance. Forget it.

Not if you have the VHF module installed. It rejects any VHF from the loops by at least 15-20 dB and replaces it with the VHF from the dipoles. Vice versa for UHF from the dipoles.

Vertical stacking the C4 loops didn't work. FOX was gone and WPXT and WPME were weakened.....

I raised both antennas 5 feet now and placed the dipoles on top. I'm now getting WCBB and WENH solidly.