HELLO! And question about Monitenna

[LIScanner101]

Hello All,

I posted on here many years ago under anther user name. I’m not new to scanning but I got out of it for a while and I’m considering getting back into it again.

I have TWO NIB Monitennas sitting in my garage, only taken out of the box to check for any shipping damage. I have always wanted to throw one of these babies up on my roof but the “boss” (a/k/a wife) seems a little cool on the idea of this monstrosity in plain view of the whole neighborhood. So – I figured, maybe an attic install? Problem is, there’s just barely enough room stand it up vertically right in the middle (we have a two-story ranch). The OTHER – and more recent issue – is the increasingly violent weather we’ve been seeing here in the Tri-State Area; I don’t want my prized antenna to get destroyed in the first storm!

Well, I toyed with the following idea and never asked about it, so here goes:

Looking down from inside the attic there are spaces between walls that are occupied by not much more than some insulation. Would it be possible for me to stick the LOWER dipole portion of my Monitenna into this space just deep enough for the UPPER dipole to clear the upper beams in the attic? Since the bottom dipole is not as active as the upper (this is my understanding, anyway) this seems like it would be OK.

Any ideas on whether this would be a good idea or not?

Thanks for any assistance here

[Rt169Radio]

What kind of antennas are NIB Monitennas? Your idea sounds like it would work, but there might be a fire hazard with a transmiting antenna next to insulation.

[LIScanner101]

Originally Posted by Rt169Radio

What kind of antennas are NIB Monitennas? Your idea sounds like it would work, but there might be a fire hazard with a transmiting antenna next to insulation.

NIB stands for "new in box".

The Monitenna is a discontinued base scanner antenna that has been considered the gold standard of base scanner antennas. I do not plan on doing any transmitting.

[LtDoc]

I'm afraid I've never heard of a 'Monitennas' either. I tried 'googling' it and only came up with a reference to an 'ST-2' antenna. Sort of doubt it they are the same things though.
I'm afraid your understanding of the 'bottom' part of an antenna not being as 'active' as the 'top' part isn't correct. Any antenna uses 'both' parts, not just one of them to 'work'. Placing that antenna in a wall isn't very common, but if that insulation doesn't have a metal 'backing', and there's no metal siding on the outside of that wall, then it should probably work as well as the whole thing being in the attic. (Hope the roof /roof insulation doesn't have any metal either.) Bunch of 'if's in that so it'd be up to you to make sure about that part.
I'm also assuming that you'd only be using this antenna for listening and not for transmitting. Using it for transmitting would definitely be a 'no-no' if it's near metal that can shield it. As for catching something on fire, that depends entirely on the amount of power being transmitted. No idea how to say what would be a safe power level, so it'd just be best not to do that.
And naturally, putting that antenna outside would be better than inside. But, sometimes you can't.
- 'Doc

[dmg1969]

I googled it and found some threads here in RR.

RR search for "Monitenna" The RadioReference.com Forums - Search Results

Also, I found a link that shows a drawing of one. Looks kind of like an ST2.

POLICE SCANNER RADIO ANTENNA for LOW, HI and UHF public service bands.

Dave

[n8zcc]

The Monitenna was made by Channel Master, likely the best broadband receiving antenna ever made but it was but ugly. You can see a picture of it here:

http://www.repeater-builder.com/othe...-monitenna.pdf

To the OP, I still run my Monitenna but I live well out in the country were no one cares how ugly the antenna is. Your installation method is fine (stay away from conductive materials and electric wires) just be aware that ice and snow on your roof will reduce the signal strength of higher frequencies. You didn't say what bands are your primary interest. Of course, the best mounting location is outside above the roof line.

[KZ9G]

Keeping them inside is a good idea. They had issues similar to the sc2 with breaking center insulators or the metal breaking near the insulator. The issue is that to get it to work properly you must have both sides. If you don't have the room in the attic look at another route for an antenna. What bands are you looking to monitor the most? These are basically the first version of what we see as the modern sc2.

[n8zcc]

Originally Posted by KZ9G

Keeping them inside is a good idea. They had issues similar to the sc2 with breaking center insulators or the metal breaking near the insulator. The issue is that to get it to work properly you must have both sides. If you don't have the room in the attic look at another route for an antenna. What bands are you looking to monitor the most? These are basically the first version of what we see as the modern sc2.

Don't tell my antenna that, it has been outside since 1993 and on its third house.

[FD5722]

I have to say I didn't know what one of these antennas was either by the name but now seeing a picture of it we still have one on top of Salisbury (North Carolina) FD Station 1 that is still in use and has been there since the early 80's. At least that's as far back as I can remember.

I know that's a little off topic but I thought it may speak a little to the durability of it.....

[LIScanner101]

Thanks everyone for the great info!! I really appreciate it.

Yeah – it’s an ugly beast! That’s what’s holding my wife back from giving me the “green light” on an outside install. I am, admittedly, also VERY concerned about the weather – we had Hurricane Sandy last year, and just last week we got nearly 3’ of snow and winds in the Tri-State Are were up to 83MPH!! So I’ll trade-off some loss due to roof tiles, rafters, insulation etc for durability.

I will DEFINITELY not be transmitting with it, just scanning.

There is still a TON of 46.xxMHz FD around here, also VHF-hi PD and some FD. Nassau County PD is on UHF, and Suffolk County is now on an 800MHz digital trunked system. However, I have my most fun listening to low band, high band and UHF.

Thanks again for the info. I will TRY to see if there is any difference between 1) sticking the lower element down in between two sheetrock walls and 2) tipping the antenna slightly sideways to clear the attic, and see which one works best.

-John

[LIScanner101]

Would (GULP!) bending the lower element sideways cause any ill effects? I'd only be able to bend it ONCE, because it's thin-wall aluminum which will surely crack if I ever try to bend it back the othe way...

[RadioDaze]

It would probably crack and/or weaken even on the first bend.

[Rt169Radio]

Originally Posted by LIScanner101

Would (GULP!) bending the lower element sideways cause any ill effects? I'd only be able to bend it ONCE, because it's thin-wall aluminum which will surely crack if I ever try to bend it back the othe way...

I wouldn't try that, it would probably crack.

[lep]

I have had a Channel Master all-band Monitoring antenna up on a "push up" pole for more than 20 years,Works fine. Haven't seen one advertised for a very long time. With the growth of cable TV, satellite TV etc. I'm affraid the outlook for Channel Master (primarily a maker for TV antennas) was pretty bleak.

I agree it is an Ugly looking antenna but it has plenty of company since I have quite a few anennas.
I've not tried any 'bending' and expect the observation about thin-wall tubing is correct.

[LIScanner101]

Thanks for all the replies!

[Rt169Radio]

Originally Posted by LIScanner101

Thanks for all the replies!

So what did you decide to do? Did you put the antenna outside or inside?

[W2NJS]

Originally Posted by LIScanner101

Would (GULP!) bending the lower element sideways cause any ill effects? I'd only be able to bend it ONCE, because it's thin-wall aluminum which will surely crack if I ever try to bend it back the othe way...

Not a good idea at all. It looks as the basic design is a vertical dipole, and the bottom half that you want to bend is part of the active antenna. The two parts, top and bottom, taken together make up a balanced antenna of some certain design impedance, somewhere between 50 and 300 ohms. Bending one half of the thing destroys this relationship and causes a mismatch among the antenna, the feedlilne, and the receiver that you don't want or need.

[LIScanner101]

Originally Posted by Rt169Radio

So what did you decide to do? Did you put the antenna outside or inside?

Well, I know what I’m GOING to do (now I just have to do it…!)

I’m going to put it in the attic. It’s just not going to see the outside world anytime soon due to its “ugliness factor”. I’m thinking I’ll have about a 35’ run of coax down to a den where the scanner will be most of the time. I think quad shield RG-6 will be fine for this but a little voice in my head keeps telling me to “UPGRADE THE COAX!!!”

[LIScanner101]

Originally Posted by W2NJS

Not a good idea at all. It looks as the basic design is a vertical dipole, and the bottom half that you want to bend is part of the active antenna. The two parts, top and bottom, taken together make up a balanced antenna of some certain design impedance, somewhere between 50 and 300 ohms. Bending one half of the thing destroys this relationship and causes a mismatch among the antenna, the feedlilne, and the receiver that you don't want or need.

I've decided that I'm definitely not going to bend the elements and instead I'll either a) tip it slightly so it will fit or b) stick the bottom half down into a crevice between two walls. I'm sure neither is a good option as far as signal capture goes but it's all I can do here...I'll try both arrangements and see which one is the lesser of two evils.