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View Full Version : Channel Master 4251- 7' Parabolic - Considering Installing



PCTools
08-08-2016, 05:49 PM
Well, I have one of the so-called legend parabolic antennas, and wanted to inquire to the team if this would be worthwhile to install over my existing stack of 91XG's.

Here is a quick link to a simple video I made to share.

https://youtu.be/oxv8gkWZcaE

Gary Hickerson
08-13-2016, 12:11 PM
You bet, IF you can keep it in the air..... An outstanding antenna.


Gary H.

antennanut
08-13-2016, 11:53 PM
i had one back in the 70s, and it was awesome. As Gary said - IF you can keep it in the air, because unfortunately mine was a victim of wind twice, in spite of using plumbing pipe as a mast the second time. But it's definitely a super performing antenna.

Tommy

indysteve
08-14-2016, 11:54 AM
I would say go for it and install your CM 4251. Mike G. and I replaced a horizontal stack of 91XGs with a Finco P-7 (a 7 ft. parabolic that rivals the 4251) at our remote controlled DTV DX site near Milford, IL, 85 miles south of Chicago in May. At this rural site both antenna setups work very well but I do believe some of the new DTV logs since the P-7 was installed are partially due to it having a little better directivity. About two-thirds of the P-7 is lined with chicken wire to help improve its F/B ratio.

DTV DXer Ed in KY also uses the P-7. There are several DTV DXers using the 4251. Please keep us posted on your decision.

19482

PCTools
08-14-2016, 04:21 PM
Gents,

This little project of mine, has turned into an "addictive" hobby. In fact, I have really enjoyed refurbishing this antenna. I replaced the metal rivets which attach the bow ties to the feed as they were not allowing perfect contact for full signal transfer (corroded). I drilled out all the rivets and wanted to replace with aluminum hardware, which I was unable to find. So, I went with stainless steel. Also, replaced the hardware where you connect the 300 ohm to balun.

My existing system has a stack of 91XG's and a Funke 1922 from Greg B.

http://jmp.sh/8yOi7cr

Here is a link to my project: http://jmp.sh/b/p6qBCC4rHQRHUHpgxe88

Any feedback would be great, as I am uncertain if the parabolic will outperform my existing system. (Then, I have the added wind load of the parabolic at 50')

Damon Hill
08-14-2016, 06:01 PM
The parabolic should be even more directional.

Gary Hickerson
08-16-2016, 08:24 PM
In your picture, how high are the 91XG's ? If you install, the 4251, I would suggest, that you use 1" I.D. Black pipe. Might have to use bigger U-bolts and it is heavy, but, much less likely, to bend !

Gary H.

PCTools
08-20-2016, 10:01 AM
At this time, I think I am going to just sell it.

Anyone interested, PM me.

indysteve
09-04-2016, 03:34 PM
After seeing the great condition of this completely reworked Channel Master 4251 by Chad, I contacted him. I used to DX with the 6 ft. version, the 4250, back in the 1970s while I was in college, and I really wanted to get this unit. Chad and I came to an agreement and when we met at KAS Satellite and Antenna, Inc., Angola, IN for an antenna shoot out https://www.facebook.com/chad.bryan.90 a week ago Saturday, Chad brought the antenna with him. I installed it on the tower at my house in Indy Friday afternoon. It was almost as good as a new one I helped a friend install in July 1975. A few pictures installing the 4251 are attached. My house is not in the most favorable location for DTV DX, but the 4251 was receiving Detroit DTV at around 230 miles this morning. Thanks to Chad for this great antenna and all the time and effort he put in making it look and work so great again. Some special TLC.

196201962119622

indysteve
09-27-2016, 03:57 PM
Has anyone actually tried and tested the results of vertically stacking two Channel Master 4251 parabolics? I would like to test this sometime.

http://www.rocketroberts.com/cm4251/images/cm4251_2stack.jpg

PCTools
03-15-2017, 01:27 PM
Well, I am at it again...

Project Parabolic is on its way with another total refurbishment of the "classic" parabolic. Stay tuned for pictures...

Gary Hickerson
03-16-2017, 06:34 PM
Do you have 2- 4251's ? If so, WHERE did you find them ?

Gary H.

PCTools
04-08-2017, 01:38 PM
Hi Gary,

I just completed the refurbishment of another Parabolic, and listed it in the Buy/Sell section. In fact, I placed some of my other (new) antennas in there as well. I just have too much, and decided to see if any of the members had an interest.

I really enjoy working on these vintage antennas, as it is a wonderful hobby to see a beautiful antenna at the end of the process.

Robert Grant
04-10-2017, 05:01 PM
I regularly see UHF parabolic antennas by rural houses between about Wauseon and the Indiana State Line.

Someone really should get with roofers and recyclers in the region to have them recovered intact and buy them from the climbers.

NN2E
04-10-2017, 06:02 PM
I know of two 4251's, here in the county, that I suspect are no longer in use. (Little satellite dishes in the yard) If I were 30 years younger I'd see about obtaining them. (I'm gettin' old and tired of climbing towers)

A 7 ft parabolic is not easy to keep in the air...

http://forums.wtfda.org/showthread.php?11234-Uh-Oh

... so, the installation needs to be as 'bomb-proof' as possible.

What I really need is a new Channel Master 3617B VHF to replace my broken Antennacraft CS-1100.

73, Ed NN2E
Owner / Operator - Murphy's Law Test Site & Thunderstorm Proving Grounds