Railfan Technology > Scanner Antenna

After reading quite a few threads on the advantages of an antenna cut to the specific length for the RR band, I decided to get one. I went to a local radio business that sells equipment to my employer for maintenance, security, etc. After I described what I wanted and showing him my RS Pro 97 scanner, he talked me out of the sale. He explained that if I was transmitting, yes, a tuned antenna would improve the transmission signal. While receiving, however, he said it would make little if any difference, and he said I thought I would be wasting my $$.
Any thoughts on this?

If you could pick up a used antenna, cut to the RR band, I think it would be worth it (especially a 5/8th wave antenna). I've used one for years and if the railroads are all you listen to, it would be well worth it to get a 5/8th wave antenna cut to the railroad band. See if the radio shop has any used ones. You could buy a new one but frequently they sell used ones cheap or give them away (the radio shop where I work gives me a few every now and then).

The person at the shop is mis-informed.
To operate properly, an antenna must be tuned.
The same loss of signal caused by a mis-tuned antenna in transmit mode is present when the
antenna is used to receive.

Be Well,

Tim Colbert K3HX

30+ years in the 2-way radio industry
44+ years in amateur radio

I had the same experience the first time I went to a local radio shop. I had done my research and knew what I wanted and why. I was a little more forceful and insisted on getting what I wanted. The radio tech was still scratching his head as I walked out with my antenna.

The antenna was one of the best purchases I ever made. I now have 3 antennas, one on each car and one on the house.

Call these people http://www.smileyantenna.com/index.php and tell them what kind of antenna mount you have on your scanner and what you want to monitor. It will take about two weeks and cost you around $25, I think. Sometimes they have a few in stock tuned for railroad bands and it goes faster.

K3HX Wrote:
-------------------------------------------------------
> The person at the shop is mis-informed.
> To operate properly, an antenna must be tuned.
> The same loss of signal caused by a mis-tuned
> antenna in transmit mode is present when the
> antenna is used to receive.
>
>
Tim is right on this one. It's just harder to measure the effectiveness of a receive antenna if you don't have the equipment to test it. A properly cut antenna WILL work better. The question is "how much better" and "how can I evaluate it's performance?" It's hard to do by ear, especially when so many of the signals are moving.

It's kind of like hooking a hose up to a pipe. If both are 1" inside diameter and you're pumping water through them, then both operate at maximum efficiency. However if you change one to a 1.5" inside diameter, then the efficiencies are not equal and it doesn't matter which way the water is going. Either the 1" diameter segment will be over pressured or the 1.5" part will be under pressure. The mis-match is less than 100% efficient.

That's an odd way of thinking about it but the idea is the same with radio signals and systems. Antennas that don't match (tuned to) the operating frequency are less than 100% efficient. If they are mis-matched in the transmit direction, they are also mis-matched for the receive function. Instead of water volume and pressure, you're dealing with voltages, current, and impedances.

That's the over simplified version of what's happening. The idea of getting an old antenna is a great idea. You might have to wait a week or two to get one and the shop may just give it to you. You might have to buy some coax and connectors but just about any antenna you would find would be cut for 150MHz range. See if you can get a chart for that antenna to know exactly where to cut the whip for 160MHz.

John

Not wasting your money at all - a tuned antenna can make a great deal of difference, particularly in areas where you have marginal reception today. You'll be maximizing the amount of signal you're feeding to the scanner, getting as much as you can out of your gear.

Not sure who you are buying from, but the local commercial dealer I buy from stocks pre tuned kits(Antenna Specialist is the brand)for rr band. At least this is the case for 1/4 wave. No cutting needed just attach to the base. They also aren't more than 8 or 9 bucks(antenna only), so even plus a base for it you aren't talking more than $35 plus tax. Don't see how that could be a grand waste of money since you'd pay close to that for anything at a Ham shop or RS.

Just a thought, but you could also realize a significant benefit with an upgrade in your rig(radio)as well. Amateur handhelds like the Yaesu VX-170 are running what, like $125? If you are interested in primarily rr radio communications, then one of these coupled with a good external antenna is about as good as it gets at the entry level, and is a big step up from a scanner. Of course, if you listen to a lot of trunked communications or ATCS then the pro 97 is a better option(don't know much about the 97 but I assume it does trunking and other wide band stuff, whereas the VX-170 won't do those things period). Then again, not suggesting you get rid of the 97, just pointing out that if you are really serious about grabbing rr radio signals then there is a "next step" in the progression, and no laws exist pertaining to how many receivers one may have ;')

Bottom line is a good receiver, like a good antenna, will always be a good investment.

You were misled as stated by others here. The law of reciprocity applies. What is proper for a transmitting antenna is equally proper for a receiving antenna.

An antenna cut to resonance at a given frequency will radiate the maximum radio wave at that signal and inversely capture that wavelength and deliver the maximum electrical signal to your receiver.

I have an MFJ-259 Antenna Analyzer and have cut my magnet mount antennas while mounted right on my two vehicles.

Even though I had gotten very close by following the antenna manufacturers cutting guide prior to owning the MFJ-259, fine tuning with the analyzer provided a marked improvement in performance.

Remember, we are trying to capture relatively low power, line-of-sight signals, mostly transmitted from moving vehicles while in a moving vehicle ourselves.

I have two Antenex 5/8 wave antennas and 2 Yaesu VX-170 radios. The Yaesu's allowed me to retire my two Regency HX-1500 antiques.
The Yaesu's actually pick up more transmissions than the HX-1500s and that is saying a lot. Both the Yaesus and the old Regencys provide remarkable performance and blow the doors off of any Bearcat or Radio Shack radios I have ever been around.

I can't begin to tell you how many times I've had a group of railfans gather around my radio at trackside with their scanners mute in their hands while mine is talking up a storm.

Thanks everyone for the comments. I have some good options to look into. I was trying to "buy local," but it looks like I won't in this case.