• Effective immediately we will be deleting, without notice, any negative threads or posts that deal with the use of encryption and streaming of scanner audio.

    We've noticed a huge increase in rants and negative posts that revolve around agencies going to encryption due to the broadcasting of scanner audio on the internet. It's now worn out and continues to be the same recycled rants. These rants hijack the threads and derail the conversation. They no longer have a place anywhere on this forum other than in the designated threads in the Rants forum in the Tavern.

    If you violate these guidelines your post will be deleted without notice and an infraction will be issued. We are not against discussion of this issue. You just need to do it in the right place. For example:
    https://forums.radioreference.com/rants/224104-official-thread-live-audio-feeds-scanners-wait-encryption.html

NMO antenna questions, Please read and respond

Status
Not open for further replies.

skoobyj

Completely Banned for Stupidity
Banned
Joined
Jun 16, 2006
Messages
45
#1
Hi, I have some questions about NMO (Motorola style) mounts and antennas.

First question,
I have been looking for a CB band NMO mount antenna and on ebay there is one for like $20 but it says it is not recommended for magnet nmo mounts. I contacted the seller and he said something about no magnet mounts arent good because of high SWR's. But that a low profile trunk lip clamp on mount is okay. I asked him to explain that and he never responded.
there is another seller with one for $40 and his says any NMO mount is fine including magnets. I am confused.

Second question,
Chevy put my car radio antenna in the back window and reception sucks big time. When I turn on the defrost, all I get is static. Can I buy or Modify a NMO antenna that I can screw onto my nmo mag mount and use a nmo mount antenna as my car's FM stereo antenna?
I have a pl259 on the end of one of my nmo mag mounts and I was thinking I can use a pl259 to motorola adapter and all will be good?
I just need to find an antenna that will work good for FM stereo reception (if there is one).

Any and all help and comments will really help. i am serious about this and need some good advice.
 
Joined
Jun 21, 2007
Messages
161
#2
question 1)

seller is a moron. UNLESS this is a "no ground plane" antenna, or something like that - there are SOME antennas that actually require a DC ground as well, but i've never seen an NMO antenna like this.

Magnets are not typically your best option because the ground is mostly capacitive (or your radio, depending on a number of things). you can tune an antenna like that on your mag mount, but it may be unstable at higher speeds (I've had antennas go crashing down in excess of 70 MPH - lucky me, it was a rental). The trunk lip mount has a DC ground... moving an antenna between a magnet and a trunk lip mount may yield different SWR readings at the same frequency, but that's because it needs to be retuned (theoretically, it SHOULDN'T need retuning, but reality and theory vary a LOT).

question 2)

yes, you can put a physical whip on your car for FM radio. I would reccomend something a little longer than a 2M amateur radio antenna, but even a ham radio antenna would work fine - anything about 2.5 - 4 feet long would yield fair results. you can even use the adaptor of which you speak, though i'm curious as to whether or not you really have space behind the radio itself to fit that stuff....
 

skoobyj

Completely Banned for Stupidity
Banned
Joined
Jun 16, 2006
Messages
45
#3
Hi! thanks for your time!!

Here is the auction I speak of Seller states "Capacitor Matching Base Load Not Recommended For Magnet Style Mounts".
http://cgi.ebay.com/10-METER-HAM-CB...oryZ4672QQssPageNameZWDVWQQrdZ1QQcmdZViewItem
He said I cant use it with mag mount because of high swr's

Here's one they say is for any mount:
http://cgi.ebay.com/Antenex-26-28-M...ZWD1VQQ_trksidZp1638.m118.l1247QQcmdZViewItem

One more for any mount:
http://cgi.ebay.com/Larsen-27-31-MH...ZWD1VQQ_trksidZp1638.m118.l1247QQcmdZViewItem

As far as the FM radio reception I can fit the adapters in there,my car is newer GM so I will have to use a reducer and it's just long enough to tuck the Motorola pl259 adapter out of the way beside the radio.
But your saying a simple nmo antenna like this: http://cgi.ebay.com/Antenex-152-162...ZWD1VQQ_trksidZp1638.m118.l1247QQcmdZViewItem
but longer? will work for me?
Or This? http://cgi.ebay.com/Tram-VHF-134-17...ZWD1VQQ_trksidZp1638.m118.l1247QQcmdZViewItem
Wouldn't I need one to be a specific length to receive properly?

Thank you!! Much appreciated!!
 
Last edited:
Joined
Jun 21, 2007
Messages
161
#4
for the CB Antenna -

http://search.cartserver.com/search...ts=1200&keywords=larsen&go.x=25&go.y=13&go=GO!

Search for a Larsen NMO27B or NMO27C. these should work with any type of mount. I've used them succesfully with many different mounting methods.

as far as your FM antenna - you want something that's 2.34 feet long (1/4 wavelength = 234/F(MHz) )if it's going to be TUNED for the FM band, but anything that's vertical will work better than what you have now, it sounds like.
 
Joined
Mar 31, 2007
Messages
1,843
Location
Jackson Square, East Weymouth, MA.
#5
I highly recommend looking for a local dealer. Ordering stuff on ebay can be a real bad experience and you may end up with a lemon. At least if you are going to buy something, get it from one of the reputable ham radio stores which are online. Try Ham Radio Outlet, Universal Radio, R and L, and theres a few more that have what you need. There are a few other good CB stores online, too. If I want an antenna, or anything radio, I call HRO and be sure it's there and drive there. It's just an hour away and I'm guaranteed not to be disappointed.
 

skoobyj

Completely Banned for Stupidity
Banned
Joined
Jun 16, 2006
Messages
45
#6
The closest shop to me is 2 hours.
I prefer ebay, any more they protect the buyers. Did you know that sellers no longer have the option to leave buyers bad feedback? It's true. You can pretty much count on the bad sellers and scammers to fall off the ebay map.
Now adays if I buy something off ebay and don't like it, I send it back and demand a full refund and if the seller won't respond, I contact paypal, give them the tracking number for the item I returned and they give me a full refund. Ebay is a buyers world now. also if a seller forgets to add tracking or delivery confirmation to your package, he has no proof you got it and you can say you didn't then the seller has no choice but to refund.
Of course I wouldn't do that.
 
Status
Not open for further replies.
Top