I have a Uniden BC246T with an MFJ-1717 antenna on top of it. I am looking to improve my mobile reception range. Down here in Southeast Missouri with all the trees and such my reception definitely isn’t as good as I would like it to be.
I’m thinking of doing a couple of things. One idea is to buy a Diamond RH77CA and see if that improves my reception any. I know the MFJ-1717 I have is basically the same thing, but I would like to see if it would improve reception any at all. Of course it could just as easily make my reception worse.
Another thought is looking into something like this. http://www.antenex.com/index051206.htm
The TRAT1500 looks like it would hit just about the perfect 161.550 MHz band I need to pick up. My question is, would that antenna boost the reception more than my MFJ-1717? Again, we are talking about mobile scanning here.
I know you can buy a magnet mount antenna, but I would hate taking it on and off, and I can’t stand the vehicles with big antennas on them. This is why I’m interested in the short little Antenex antenna mentioned above. What would you do in my situation? Does anybody know of any other antennas that I might look into or have any suggestions on what I’m considering? Thanks for the help.
In radio reception, size matters. Antennas like the MFJ 1717 are “stub” antennas. They are shorter than 1/4 wave (about 46 cm or 18 inches) and use coils to appear the correct impedance for this frequency. The only way to get better reception is to raise and lengthen the antenna. The higher the antenna picks up signals from a longer distance. As you raise the antenna you move the horizon for signal reception out further. Put your antenna up on top of the house. Put it outside on a window sill. Out and up is good. For mobile operation, there is nothing that beats the magnetic mount on the roof of the vehicle. As you lengthen the antenna you make its reception pattern flatter (more like a horizontal pancake than a sphere). Since your signals come from the horizon, there is no use to have the antenna sensitive to signals high in the sky (or low in the earth, for that matter). A long antenna looks like many antennas stacked upon each other. The pattern for the long antenna is concentrated toward the horizon. Of course there is a limit to the length of the antenna. Normally a 5/8 wave colinear antenna is used with a magnetic mount on the automobile. Any ham radio 5/8 wave antenna can be tuned up in frequency (shorter in length) to the 161 Mhz railroad band. The MFJ 1729 is a magnetic mount antenna with coaxial cable and connector for your scanner. The Diamond RH77CA is a fine whip antenna for direct connection to your scanner. Since it is longer than the MFJ 1717 you will get a flatter sensitivity pattern and better reception. The TRAT1500 claims “unity” gain which is usually relative to a 1/4 vertical antenna. Most 5/8 wave antennae have 2.6 db gain relative to the 1/4 wave or the TRAT1500. It will not be a good reception antenna but will very compact and convenient for those who do not want a long antenna on the top of the car. Size matters, tall and long is good.
Ok, so the Diamond RH77CA would improve my reception a little, but not much, as I expected.
The Antenex TRAT1500 would not do any better than my MFJ-1717?
I really don’t know if I’d be interested in a magnet mount, but if you would send me some links to some of the top ones you would recommend for me I would really appreciate it. I am only needing to improve reception on the 161.550 frequency, so any other frequencies don’t matter to me.
If I decide I don’t want a magnet mount, then I guess I’ll just buy the RH77CA and see how much it helps. Do you think the small improvement it would make would even be worth the $40 or so to buy it?
This is kind of odd, because I was instructed in the beginning to get the MFJ-1717 over the RH77CA, so that’s why I have it. I wish I would have known when I bought the MFJ-1717 that it wasn’t as good (for my purposes) as the RH77CA. O well, I guess that person didn’t know what they were talking about.
I’m no expert on this topic, so anything you can tell me really does help me a lot.
There is a Forum member, whose name escapes me right now, but as part of his signature mentions he is in the antenna business…Maybe, somebody else can fill in my missing information, but that might be a source for resolving your antenna problems?
Personally, I use a 36" center-loaded magnetic-mount RS whip in the back end of my SUV – I stuck it to an old tie plate I found lying around near the tracks. Works great for me, better than the rubber ducky and better than a telescoping antenna that gets in the way when I’m driving (I keep my scanner in the center console drink holder and keep it plugged into a lighter receptacle.).
A magmount antenna from Radio Shack works quite well for me…With a hand held scanner along with the standard telescoping antenna, I was lucky to get a 5 to 8 mile range. Now, that range has at least doubled. When I railfan the Johnstown West Slope in Pennsylvania, I can sit at South Fork, MP 266 on the NS Pittsburgh Line and hear chatter all the way up to MP 248-Gallitzin. Using the regular telescoping antenna that comes with the scanner instead, I would be lucky to hear as far East as Portage…MP 258. I found a similar scenario when railfanning around the Enola area of Pennsylvania. The handheld antenna might get me a 10 mile range. With the Magmount, I was hearing all the Harrisburg Dispatcher chatter from 30 miles West of Harrisburg.
For my Scanner I use the Railcom whip connected to a GRE Signal booster. Railroad reception is 100% like anything I have ever dreamed of. I can hear UP crews talking well over 25 to 30 miles away. I was over at Willett,Ia one day and heard a Train calling the Council Bluffs STO. And that was well over 35 to 40 miles away. I even heard the detector at milepost 332.0 all the way from milepost 315.0. Allan.
I have a $72 Railcom (the one that advertises in Trains magazine) magnetic mount antenna on the roof of my pickup and I can hear dispatchers up to 40 miles away. I pick up locomotive radios 25-30 miles and handheld radios over 10 miles away. I can even hear defect detectors 20 plus miles. I’m happy without spending a bunch of money.
Good Radio reception is a result of lots of factors working together. A chain can be no stronger than its weakest link…and radio reception can only be as good as the weakest element. Sometimes you can imporve the elements, it just takes money…
Remember that the 160Mhz band in nominally “Line of Sight”. That is, if you are in a valley, mot of the signals will pass over you…the radio signals dont bend well at that frequency. So if you are looking for a spot for best reception, find the crest of a hill instead of the valley…
A GOOD antenna is a pre requisite for GOOD reception. As stated previously, longer and higher is better. A second, but less important factor, is number of elements. If you have two elements, stacked on top of each other, it’s called a “Co-Linear”, and it will work in all directions. If they look a little like an old type TV antenna, it’s called a Yagi, and it is Directional…it works best in the direction perpendicular to the shortest element. Short antennas, as stated previously, area design compromise between good reception and easy to use/convience. SOme stubby’s are better than others.
Also, the antenna should be sized for your frequency. If you get the right kind, the elements can be trimmed for the exact center of the band you are interested in. That generally means a 2-M ham antenna, which is designed for 144-148MHZ, can be shortened to work at the 161 Mhz band. If you have an antenna designed for the Ham bands, you are losing about half the reception effectiveness at 160Mhz. The “Bandwidth” is typically calculated for a “Half Power Point”, so if you have an antenna designed for 144-148 Mhz, that means that usually at 148 Mhz, you get a 3Db loss from the best possible frequency. And that means the further you get from that frequency, the more attenuation (decrea
And don’t forget the coax. I have to replace the cable on my fire radio in the truck from time to time as moisture gets into it - and will creep all the way to the plug at the radio. Proper terminations are important. If you are doing a base installation, consider going “big” - RG8 vs RG58. Which reminds me - make sure you do have the right cable. The stuff the cable TV people use may look similar, but it is a different impedance, so will affect your reception, too.
You can get a sealant to wrap around your outside connections to help stop that…it looks like a thinck piece of black tape…kinda like a “Putty” tape. Pack it all around the connector, to stop moisture seepage. Kind of sticky if you have to remove the stuff, but keeps the moisture out pretty well. Try a google search on COAX SEAL, and you’ll get lots of hits…ONE EXAMPLE
I just buy a new base (or rather, the fire department does), which is pre-connected with coax. Since it isn’t a body mount (it’s an L bracket that sticks out between the fender and the hood), it doesn’t get a good seal.
I think one of the biggest factors affecting reception is the amount of traffic on adjacent bands – or on the same channel. I get far better reception away from busy metro areas like Chicago. Those of you in less-busy rural areas will hear signals from farther away.
Does weather have anything to do with reception? It seems on cloudy days, I have better reception than on bright sunny days. Or is that just coincidence with the location I’m at?
As a general rule, rain will “attenuate” or decrease signals. Having said that, at 160Mhz, the rain effect is minimal. Howevrer, often weather fronts associated with rain also brings a mile temperature inversion, which creates something of a “Trapping Layer”; UHF signals which ordinarly would go out to the horizon are "bent (refracted) back to earth. I once chatted on a similar ham frequency(149mhz) from Norfolk, VA to NYC…