GH with NARODs for VHF-HI & UHF

[lenl]

I have given in and bought a YAGI style VHF only antenna. My GH with tophat does a decent job pulling in the 4 VHF channels but 3 of them pixilate. The solution for better VHF is to elevate this antenna. However it is in the sweet spot for me for UHF at my location. Plus I have a CM 4228 much higher up to complement my home built GH and I can't have both on the chimney.

So given my issues, what I would like to do is feed both the GH antenna and the Yagi VHF into the house (they both have CM7777 preamps) and then combine the VHF feed and the GH feed to the TV. So how do I shut down the VHF signal from the GH antenna? I think if I simply combine the feeds the VHF will not necessarily be taken from the YAGI. So do I need to strip the VHF signal from the GH and then use a combiner to bring it back in from the YAGI?

Suggestions?

[Ndnile]

The cm7777 should have seperate inputs for vhf and uhf. If you have one of the bunk new ones that does not have this you can get a vhf/uhf joiner from antennas direct and then feed the joined line into a single cm7777.

[lenl]

The Cm4228 and the YAGI VHF will be on different masts at different locations. So I can't combine them at one CM7777 preamp. I have to combine them in the house before I send the signal up to the TV.

Also even if I could do it the way you suggest the CM777 preamp would now be split between 2 antennas and it could result in less signal getting to the TV. I'm already dealing with problematic reception.

[majortom]

a UVSJ (aka diplexer), for $1.79 will pass VHF on the VHF port and block UHF, and pass UHF on the UHF Port, while blocking VHF. Net result seperate VHF/UHF antennas combined to one coax with minimal insertion loss.
So connect ur VHF yagi path to the VHF port, and the GH (or CM4228) path to the UHF port.

[lenl]

Sounds like that would work for my situation. I have to see where I can get this device.

[majortom]

google 'pico uvsj'.
last time I bought locally at a local radio / electronic parts supplier they only had one in the bin
which they had inadvertantly mixed in with their line Taps, or I woulda bought several just to have layin around.
ya may as well get a couple of em they're so cheap.

[lenl]

The UHF.VHF band separators worked!

The Antenna Craft Y5-7-13 VHF YAGI antenna's resting place was decided at the last minute to be on the same mast as the CM4228 with its own preamp and it is doing what I had hoped for. It proved the CM4228 was not good at pulling in VHF.

I then decided to get a dedicated UHF antenna, the Winegard HD 9075P to replace my Grey Hoverman. I thought for sure my GH would be out performed by a commercial Yagi antenna. I was having trouble getting some of my local UHF stations. I was also needing to take it down for repairs (rusting washers and bolts).

Well the Wingard is in the exact same location and the results are in. The GH performed just as well for UHF. Almost the exact same results. I'll do the repairs on the GH and keep it ready to go back up as a spare. The GH proved once again it is a great design.

[gcd0865]

lenl:

I also have the CM4228 (the old 4228A version, same as yours), mounted on my chimney similar to how you have yours, but on a rotator. I also have troubles with some distant VHF-high stations, and found your improvements with the separate Y5-7-13 interesting. I checked out your TVFool report from your earlier post, and your signal strengths for your problem channels 11 and 13 are a bit higher than those for my problem channels (mine are around +5.0 dB NM). Was wondering (if you happen to know from your tv's signal strength meter) how much more signal strength the Y5-7-13 provided on those VHF-high stations relative to how the CM4228 did.

My tv's tuner will lock any station with a signal strength above 35 on the tv's signal meter, and my two problem VHF channels rise above 35 in the evenings (often into the 40's), making them watchable then. But they fall below the 35 threshhold in the daytimes. If I thought I could add 10 points of signal strength on those VHF-high stations by adding a small dedicated VHF-high antenna below my CM4228, I might consider doing that.

Thanks in advance for your comments...

[lenl]

I have a problem location that I don't think TVfool accounts for which makes good reception a problem for me given that I am only about 30 miles from the broadcast towers at the Empire State Building. I'm 750 feet above sea level but on the back side of a hill about 100 feet below the top of the hill and my antennas have to face the top of the hill which unfortunately is the direction of the transmitters.

I have the original CM4228a combined with the CM7777 preamp. I never got 11.1 or 13.1 but in the low 60s. At times I got 7.1 in the 90's but it has been lower lately. In all fairness the GH with the tophat that I built might have done better than the CM4228 if I could mount it that high. Not sure about that since I did not do it but I suspect it might have. But I was basically using the GH to fill in the holes where I was not getting good UHF with the CM4228 which was basically UHF 2.1 and 9.1 for me. So I mounted it lower in a sweet spot for channel 2.1. Vhf reception was marginal. At times I could lock in a signal but there would be some pixelation and occasional lost signal. BUt I understand that VHF reception is very much dependent on height and of course the right antenna.

Back to your question. That Yagi brought in 7.1 above 90, and 11.1 and 13.1are in the 80s. About 20 point higher than they were. I am very very happy with the results. It was not that expensive either.

[gcd0865]

lenl:

Thank you - that's what I was hoping to hear. I knew that the 4228A provided decent performance on VHF-high, and I was trying to get away without a second antenna up there, but adding a small dedicated VHF-high antenna now sounds like it will improve reception for me.

[undefined]

Hi 300ohm,

Referring back to posts 506 through 514 of this forum, I've finally got around to finishing the DBGH with your feedback. This included the use of 3/8", 1/4" and 1/8" aluminum rods for the reflectors, driven elements and narods, and feedlines respectively. With my new antenna, I'm able to capture the same channels as before without the 10db amplifier 50-450MHz, but still no ABC (20.4 NM, WVNY). Being that the antenna is in the attic, is the 6 to 25+ db loss due to the limited height location of the antenna (roughly 25'), VHF band issue or the shingles, flashing, nails, etc.? I had a SNR=27 when viewing FOX WFFF at 23.7NM. Not sure if that helps. Would a preamp at this point be my solution? I'm thinking about connecting the amplifier to perhaps give me an idea as to whether a Mid-Gain or High-Gain preamp is the next best option. Do you have any other recommendations to the antenna at this point besides welding the joins?

By the way, the bargain I got on the aluminum was lost on botching a few driven elements when bending.

Thanks

[300ohm]

Being that the antenna is in the attic, is the 6 to 25+ db loss due to the limited height location of the antenna (roughly 25'), VHF band issue or the shingles, flashing, nails, etc.?

Yes, all of the above.

To try:
Yes, try the amplifier you have on it.

Make sure there isn't any big metal near the antenna in the attic (or at least in front of it).

Make sure there is a surface to surface air distance of 1/4" between the NARODs and the stubs of the GH. (you did use a NAROD length of 28 inches for channel 13, and a NAROD to NAROD reflector distance of 10 inches correct ?)

I had a SNR=27 when viewing FOX WFFF at 23.7NM.

SNR and signal meter values vary greatly between devices.
But do you get FOX steady without any breakups ?
FOX and ABC look like they could be on the same tower.

By the way, the bargain I got on the aluminum was lost on botching a few driven elements when bending.

Heh, but still cheaper than goofing up the more expense stuff.

[undefined]

Thanks for the quick reply

Make sure there is a surface to surface air distance of 1/4" between the NARODs and the stubs of the GH.

I did make end spacers to ensure that the distances were indeed respectful to the 1/4" between everything you did described. However, I did lose one when bringing it up to the attic. I'll make a new one to rule that out.

Though the frame is wood, I did ensure that all contacts with any of the aluminum was either with acrylic or pvc.

did use a NAROD length of 28 inches for channel 13, and a NAROD to NAROD reflector distance of 10 inches correct ?

Yes and yes.

do you get FOX steady without any breakups ?
FOX and ABC look like they could be on the same tower.

Yes, it was without breakups and both are broadcasting from the Mount Mansfield


Where I've placed the antenna, there's no flashing. The antenna is above the eavesdrops and about 10' away. I'll try the amplifier later on tonight, but if that doesn't help, do you think I have to move it to a different location and find a sweet spot for that last WVNY channel?

All these initial tests are with me working in the attic with a 3' RG-59 cable. I've passed 14/2 wiring around the attic in order to light and work in the attic. The wire does pass above the antenna, say 6" or less. Could that be the cause of my interference? Normally, the power won't be there. I'll place the connectors on my RG-6 from the basement to attic to rule that out.

Thanks again for your help.

[undefined]

Hi 300ohm,

So I did manage to test the antenna with the amplifier last night. It seems that all it did was give the Hauppauge WinTV software the "kick in the pants" it needed in order to detect the channel (WVNY). The breakup of the channel signal was the same with or without the amplifier at that point. I think it's safe to say that the antenna's well built that a pre-amp will likely solve the issue. Now I just got to figure out if I need a mid-gain or a high-gain pre-amp.

With regards to the direction of my DBGH, do I point it at 143° true north or 157° magnetic north? My TVFool is at post 506 of this forum.

Thanks

[300ohm]

With regards to the direction of my DBGH, do I point it at 143° true north or 157° magnetic north?

Well, your compass points to magnetic north. But if there are reflections, youll have to experiment.

Now I just got to figure out if I need a mid-gain or a high-gain pre-amp.

Get a low noise, quality name brand preamp like from Channel Master or Winegard.

A preamp only takes care of losses after the antenna terminals (or in rare cases, makes up for a bad TV tuner RF amp)

Figure 1 db loss for every 18 ft of RG-6 coax. A good two way splitter loses about 3.5 db, a good 4 way splitter loses about 7 db.
And figure about .5 db insertion loss for every connection.