Got this today for $50

[No Static At All]

I wonder if the CM antenna has any ability to pull in VHF channels?

At your distance, I doubt you will see anything on VHF with the 4251.

 

[chapelrun]

The antennas being so close is likely not helping either. If in your shoes, I would replace the RCA combo antenna with the lightweight/low windload VHF-Hi Antennacraft Y10-7-13 & mount it at least 1 foot above or below the 4251. This will really help improve the dynamic range of the 7777 which is likely suffering from some signal clipping due to the strong local FM's in the valley.

I just ordered the antenna you suggested. Only $38 plus shipping from SolidSignal. Many thanks for the good suggestion!! Most likely will not be able to install until next Saturday.

http://www.solidsignal.com/pview.as...d-vhf-tv-antenna--(y10-7-13)&sku=716079000994

 

[riffjim4069]

Perhaps high band VHF (some have experienced good results), but my experiences with using CM UHF antennas for VHF have not been very good - I'm batting .000

Thanks for the suggestion - - - question first. I wonder if the CM antenna has any ability to pull in VHF channels?

If so I could change the 7777 to combined and see if that makes any difference. No cost option and might be worth a try.

What do you think?

 

[chapelrun]

You may have to come back out to Berryville and help me fix this!!!

 

[Mr Tony]

I just ordered the antenna you suggested. Only $38 plus shipping from SolidSignal. Many thanks for the good suggestion!! Most likely will not be able to install until next Saturday.

I had one of those when I lived in the house...picked up VHF from 72 miles away (channel 12...thats the only reason I had that antenna)

 

[chapelrun]

Lots of Upgrades

Today I tested 3 different upgrades to my CM4251. Each time I recorded the signal levels for all UHF channels. Also, I must give credit to

http://www.digitalhome.ca/forum/showthread.php?t=96216&page=12

for most of the ideas used here. They had many good suggestions and the information was both technical and detailed.

OK, first try was just to make the bow-ties bigger by adding aluminum flashing to the existing bow-ties. I really didn't think this would help much but it did have a very small positive affect on the signal. (This is labeled CM4251-Test1 below)

Second was the same aluminum flashing with a larger reflect behind it. I made the larger reflector using an old combo antenna and then wiring this to the back on the assembly used in test 1. (This is labeled CM4251-Test2 below) More on this one later.

Third, I built a new one using copper flashing and stuff I found in the shed. This one was the most fun and took the most time. (This is labeled CM4251-Test3 and Test3a below).

So which one was the best?? Well everything is a trade off. I really thought the third one might end up best but it did not win. One problem with the third setup is that the wood blocks some side lobe signals and thus is not good for signals not on the bore-sight of the antenna.

The first test was good but with only limited increase in signal. So the best by far was Test2. Not only did it have the most signal - - - it also allowed me to receive all the channels that I want from Washington DC - - - including WETA 26-1 thru 26-4. One down side to Test2 was that it was very heavy but I don't think that should be a problem unless we get very high winds.

I currently have Test3 on the antenna - - - because I just too tired to go change it one more time. Maybe tomorrow.

Here are some PIX.

 

[chapelrun]

Also Upgraded the VHF antenna

The antennas being so close is likely not helping either. If in your shoes, I would replace the RCA combo antenna with the lightweight/low windload VHF-Hi Antennacraft Y10-7-13 & mount it at least 1 foot above or below the 4251. This will really help improve the dynamic range of the 7777 which is likely suffering from some signal clipping due to the strong local FM's in the valley.

Also, I replaced the very old VHF antenna with the AntennaCraft Y10-7-13 as suggested by "No Status At All" - - - thanks Man!!

Anyway, I like this antenna a lot because it allowed me to get channels 7, 9 and 11 reliably but not 13. I still need to check the FM trap setting on my CM-7777 but have not done that yet. This may be still causing my Channel 13 issue.

I put the antenna as I high on the mast as possible so as to have the UHF and VHF antenna's as far apart from one another as I could on this short mast.

Very happy with this antenna and for the money it is definitely a great VHF antenna for channels 7 thru 13. If you have deep fringe problems with 7-13 I would give this antenna a serious look.

Some PIX.

 

[riffjim4069]

Great Posts! I remember tweaking my deep fringe UFH antenna for an entire weekend so I could pick-up all the DC locals (ABC, CBS, FOX and NBC) as well as some of the Baltimore locals during the evening hours (80+ miles). However, I rarely use that antenna after the digital transition due to 7 and 9 moving back to the VHF band. Instead, I now use my Richmond UHF antenna (53-miles the other direction) to pull-in ABC, CBS and FOX and it also receives NBC from Charlottesville for whatever reason, which is perfect since Richmond NBC moved back to VHF 12. Offhand, I have been wanting to install a VHF antenna and point it toward DC. However, I will also have to replace the CM-7775 (UHF) preamp with a CM-7777 (UHF-VHF) model. It just hasn't been a high high priority, but your post does give me some motivation.

 

[chapelrun]

Now that I have this all setup

With my newly upgraded OTA setup - - -I just cancelled Dish to save about $48 dollars a month. :up

I now have OTA using a Tivo HD with Lifetime, FTA, NetFlix, Roku and computer streaming. The Tivo with Lifetime was the real key that allowed me to drop Dish. I still have a real DVR and my ROI is about 6 months of Dish payments.

I have not completely cut the cord but I'm much closer and the wife is very happy about saving extra money every month.

 

[riffjim4069]

I would love to do the same thing (have 2 Tivos with Lifetime and lived several years without cable) but, unfortunately, we're being help hostage by the sports programmers. Perhaps one day...

With my newly upgraded OTA setup - - -I just cancelled Dish to save about $48 dollars a month. :up

I now have OTA using a Tivo HD with Lifetime, FTA, NetFlix, Roku and computer streaming. The Tivo with Lifetime was the real key that allowed me to drop Dish. I still have a real DVR and my ROI is about 6 months of Dish payments.

I have not completely cut the cord but I'm much closer and the wife is very happy about saving extra money every month.

 

[Bob2011]

Today I tested 3 different upgrades to my CM4251. Each time I recorded the signal levels for all UHF channels. Also, I must give credit to

http://www.digitalhome.ca/forum/showthread.php?t=96216&page=12

for most of the ideas used here. They had many good suggestions and the information was both technical and detailed.

If you follow that thread through to the end the members there modeled some other replacements for the bowties that may work better. The best one seemed to be a short Log Periodic antenna as it was easy to mount near the focus and still have great gain.

For your bowtie experiments I would try to shorten the gap between the small reflector and the bowties. Also replace that wood with plastic as it does reduce gain. The sheet metal can be replaced with tubing or heavy gauge wire bent to V shape. The elements could be lengthened to 8 or 9 inches depending on how low your UHF channels are.

 

[chapelrun]

If you follow that thread through to the end the members there modeled some other replacements for the bowties that may work better. The best one seemed to be a short Log Periodic antenna as it was easy to mount near the focus and still have great gain.

For your bowtie experiments I would try to shorten the gap between the small reflector and the bowties. Also replace that wood with plastic as it does reduce gain. The sheet metal can be replaced with tubing or heavy gauge wire bent to V shape. The elements could be lengthened to 8 or 9 inches depending on how low your UHF channels are.

I will do some additional research as you suggest - - - but for now I'm very happy with the result so far. I love to tinker with stuff so I'm sure I will not be able to leave it alone for long.

Many parts of the digitalhome thread were intriguing and I did not understand it all (not by a long shoot). Anyway on Sunday after church - - - I went back and installed the Test2 configuration and recorded UHF signals again. In all cases except two the signal was better than the XG91 or the other tries with the CM4251.

I'm really a newbie when it comes to Antenna Theory - - - it seems to be a bit of a black art to me - - - but I enjoy trying different things.

As this is now my primary UHF TV antenna I may only be able make changes on the weekend when I have large blocks of time.

 

[No Static At All]

Anyway, I like this antenna a lot because it allowed me to get channels 7, 9 and 11 reliably but not 13.

Nice pix!! Glad to hear of your success!! Not sure how important channel 13 is to you??(good late night offerings & a few Ravens games not carried on 9) Unfortunately 13 is only beaming about 6000 watts in your direction. Their directional antenna limits power output to the west due to an interference agreement with channel 12 in Martinsburg. An FM trap from Radio Shack before the preamp may help if the internal trap isn't enough. Exactly how close are you to the WXBN transmitter?

 

[chapelrun]

Exactly how close are you to the WXBN transmitter?

I can see it from my house - - - - as the crow flies I would say about a mile. 13 is really not too important to me - - and does not even showup on a TV-Fool plot. I was amazied I even get channel 11. Both 7 and 9 have signal in the high 60's on the Signal strength meter on my Tivo HD and 11 is in the high 50's which seems to be enough to have no breakups at all.

Thanks again for you help - - - this AntennaCraft Y10-7-13 rocks!!!

 

[No Static At All]

this AntennaCraft Y10-7-13 rocks!!!

Hope Antennacraft doesn't discontinue it. Winegard just discontinued the YA-1713, so now it's the only game in town.