[balm]

I recently dismantled a tower, and its gear...The gear included this very large, long antenna...

http://s638.photobucket.com/albums/uu110/stanicet/vhf/

1. What type is this
2. Can this, or should this be reused
3. What channels is it for

Also I got this rusted bow-tie, it is very small, and very rusted...

http://s638.photobucket.com/albums/uu110/stanicet/bowtie/

not sure of the manufacturer...

1. should I reuse it

 

[PanaMark]

pretty sure the smaller one is an original Channel Master 4221 UHF antenna.
Should be still good. My understanding is that is a quite desirable antenna since the new one (4221 HD) is not as good; performance wise.

 

[balm]

It is very rusted, does that matter...I was thinking to replace the whiskers with new copper...

Also, the whiskers are about 5" long...is the CM 4221 that small..

 

[ota_canuck]

VINTAGE CM4221 UHF antenna

Good find !

It's made by Channel Master [when they were actually made in America] but it's a pre-generation 4221 design. A CM4221 has aproximately 7 3/4" 'V' elements and they are lighter gauge than what I see in the pic. The screen width of a 4221 is 20" and the one in the pic looks a little bit narrower. The wider CM4221's were made in China by the same people who now make the CM4221HD.

It would be worth your while to just clean it up a little and give it a shot. It may not work as well if you change the elements. Be careful handling the plastic element mounts as they will likely be quite brittle.

Or you could donate it to an antenna museum

 

[balm]

ota canuck,


how does one clean such an animal....


especially at the connections, the whiskers, and rivets are rusted together

...while the phase lines are not, in fact the phase lines seem to be of a different material...why would they do that...


also the reflector is very rusted, should that be sanded also....

 

[Jake]

I am not an OTA expert but I imagine that, like beauty, it is what is inside that counts. The conductive properties of the metals will have changed very little with the surface corrosion. It may be hard on the eyes though.

 

[balm]

Jake,

the corrosion is such that the rivet and whisker are essentially welded together, and I imagine the rusted whisker acting against the phase lines is similar...

 

[stampeder]

The big VHF/FM Yagi is definitely a Channel Master and it looks like one of the shorter range Crossfire 361x models probably from the mid-1980s. For Montreal-area people like yourself it would get ABC 13 from the U.S. beautifully.

Using old antennas is fine if they are designed to pick up the channels you desire and you take some precautions before mounting them. See "Is it okay to used an old antenna?" in Post #3 in the OTA FAQ

 

[300ohm]

Yeah, I would just straighten it out and reinforce it and use it, if you need vhf. I dont see any missing pieces from your photo. You would want to wire brush the balun connecting points.

 

[M.Satterfield]

Yes that is a CM VHF antenna

I had one that had 2 of those front wings on it when I was a kid.

Of course, I didn't know they made the "he-man" versions of the VHF model or parabolic UHF model (shown below) at that time, or I would have gotten both of them!

http://radioguy.googlepages.com/4251_3617b.jpg

 

[balm]

300 ohm,


I think its missing 1 element, I counted 19 brackets, and only 18 elements...

I assume I would point the small end towards transmitter...

not sure if its of much use for me, after 2011, we'll have channels 10 and up...but so far my bow-tie is catching these channels...when they go digital it may be another story...

Maybe I can use the materials to build a GH...

 

[balm]

1. does anyone know if the missing, 9th element (short one of the pair) from the narrow front end will make any difference in reception...

2. is this large VHF antenna completely useless for catching UHF channels...

3. how would this large VHF antenna compare to say a DBGH NAROD for VHF high

 

[stampeder]

1. the impedance of the antenna might be screwed up and channels 12 and/or 13 would probably be weakened. Make sure that the feed lines are not broken.
2. yes, it is completely useless for UHF
3. it would probably outperform the GH with NARODs on VHF-HI

 

[markdd]

I'm thinking the large VHF one is a log-periodic since I thought that one of the characteristics is that the rod electrical connections crisscross down the length of the boom. But it's hard to tell for sure since there's no top down view to observe the rod spacings.

 

[balm]

stampeder,

thanks for your comments...

I was thinking of setting it up at my BIL's but I would have to add the missing element, and then he still wont get the digitals...not much point eh...

another option could be combining this with a proper GH or mclapp, point the VHF at the strong locals (VHF) with the UHF one on top. I'm not sure if this worth while in comparison to using one unique antenna, namely the DBGH NAROD...

 

[balm]

oops, I just realized that if he points it for ABC #13, then it probably cant catch the other local VHF's which are at 70 degrees to #13...

 

[stampeder]

Yagis are very directional, but CFCF 12 in Montreal is very powerful too so he'd probably catch it off the side even if its pointed at the U.S. for 13, and I think he'd get the other Montreal analogue VHF channels that way as well.

Its too bad the smallest elements got damaged since they're the most important for 12 and 13.

 

[balm]

bow-tie

I cleaned up the bow-tie, used rust loosener, and mouse sander on most surfaces + connections...


http://s638.photobucket.com/albums/uu110/stanicet/vhf/bowtie/?action=view&current=IMG_0175.jpg

1.does it matter if the reflector mesh and/or whiskers are corroded, or rusty - I didnt think it did...

2. now that i've removed the loose rust, is worth while, or detrimental to coat the reflector, and/or the whiskers -note the phase lines didnt seem to corrode..

 

[stampeder]

Everything should be fine now. You might have a hard time finding paint that will stick to all that corrosion, and you need to make sure that the paint has no metallic properties.

 

[300ohm]

Naval jelly is very good for rust. I wouldnt put any coating on it.