Cutting a 5/8 Wave VHF-HI antenna for railroad frequencies

[TechTwo]

I have just purchased an Averonic VHF 5/8 Wave NMO antenna.

This antenna will be used with a scanner only to receive railroad frequencies.

Since the US railroad frequency coverage is 160.215MHz - 161.565MHz, my question is what is the length that I should cut the whip?

The antenna came with a cutting chart.listing 160MHz as 42.187" and 162MHz as 41.437".

I am planning to use this antenna with a magnetic base NMO mount on the roof of my truck.

Thanks!

Michael

 

[cmdrwill]

Cut a little long, 43 inches from the dimensions you posted.

 

[majoco]

If you can cut a whip to a thousandth of an inch you'll be doing pretty well - those are totally theoretical figures - I'm afraid radio is not an exact science at the moment - cut it to 42 inches - you'll never notice the difference!

 

[SteveC0625]

I have just purchased an Averonic VHF 5/8 Wave NMO antenna.

This antenna will be used with a scanner only to receive railroad frequencies.

Since the US railroad frequency coverage is 160.215MHz - 161.565MHz, my question is what is the length that I should cut the whip?

The antenna came with a cutting chart.listing 160MHz as 42.187" and 162MHz as 41.437".

I am planning to use this antenna with a magnetic base NMO mount on the roof of my truck.

Thanks!

Michael

Let's keep in mind that antenna cutting charts are much more important for transmitting quality. Installers fine tune the antenna's performance by reading the SWR (standing wave ratio) of the antenna when the radio is transmitting. Thus the sage advice to cut it a bit long at first.

The precise measurements in the cutting chart are important for transmit. Approximate measurements are fine for receive only. Plus or minus a quarter or even half inch at 161 MHz. is not going to make a bit of difference in your receive capability.

FWIW, many antennas come with a cutting chart which is a simple XY graph of frequency vs. length. There's no way one could achieve the precision mentioned in your cutting chart, and yet thousands of antennas are sold and installed with only that simple graph and work just fine.

 

[iMONITOR]

I have just purchased an Averonic VHF 5/8 Wave NMO antenna.

This antenna will be used with a scanner only to receive railroad frequencies.

Thanks!

Michael

If it's not too late, and you haven't cut your new antenna, you might want to check these out:

DPD Productions - Railroad Base & Mobile Antennas: TrainTenna, Voice Communications, ATCS, Data

DPD Productions - Railroad Base & Mobile Antennas: TrainTenna, Voice Communications, ATCS, Data

 

[TechTwo]

Thanks for all the help, I will give it a try.
Michael

 

[FFPM571]

If it's not too late, and you haven't cut your new antenna, you might want to check these out:

DPD Productions - Railroad Base & Mobile Antennas: TrainTenna, Voice Communications, ATCS, Data

DPD Productions - Railroad Base & Mobile Antennas: TrainTenna, Voice Communications, ATCS, Data

Nothing special there. Just hyped up for foamers..all they are is standard 2 way commercial products.

 

[spongella]

RR Ant.

Have fun monitoring RR freqs. Here with a discone ant. usually hear NJ train traffic but don't understand the lingo hi hi.

Guess this antenna would bring in the NOAA wx channels pretty well also, 162.4 - 162.55 mHz.

 

[mmckenna]

Nothing special there. Just hyped up for foamers..all they are is standard 2 way commercial products.

Wow, $70 bucks. Must be made of solid gold and magic antenna dust.