Railfan Technology > About radio antennas . . .

Since the question about radio antennas comes up so often, here is what I hope will be some helpful information:

First, some generalizations about both mobile and portable antennas. A bad antenna will hurt the performance of any radio, including a good one, but a good antenna will generally be of only marginal help in improving the performance of a low quality receiver. Why? Because most low quality receivers suffer most from poor selectivity--that is, they lack the ability to discriminate against unwanted interference--and a better quality antenna will strengthen the interference reception along with the desired signals. Second, if a radio is going to be used for transmitting--for example, a railfan using an amateur radio for listening to rail traffic, but also transmitting on the amateur band--then the antenna needs to be tuned for the transmit band. If it is not tuned to the transmit frequency, particularly on a high-wattage mobile radio, the transmit signal can be significantly compromised and, worse yet, the radio itself can be damaged from transmitting on a significantly out of tune antenna. If the user has no intention of using the radio to transmit, then the antenna will perform better if it is tuned to the "listening" frequency.

Now, let's talk about portable radio antennas. First, all "rubber ducky" portable antennas are pretty inefficient. That stems from the fact that they lack a ground plane. A good way to prove this is to hold a portable radio in the air away from your body and listen to a weak radio transmission. Next, set the radio on the metal hood or roof of a vehicle and listen to how much stronger the reception is--the metal hood or roof creates a ground plane. Having a portable radio next to your body on a belt clip compromises the reception of a portable radio a bunch more, especially if your body is between the radio and the transmitter antenna that you are trying to listen to. So, with a portable radio, for best reception of weak signals, one needs to equip the radio with the best reception antenna possible to overcome the inherent inefficiencies of a portable radio antenna. That generally means buying an "extended range" antenna tuned specifically for the railroad band, in the case of a railfanning radio. My two favorites, as I have noted several times in other posts, are the Laird EXH-160 series of antenna (the three letters following the EXH-160--e.g., EXH-160 MXI, indicate the antenna mount for the radio). The other is the Smiley Slim Duck extended range antenna. Both have their individual advantages and disadvantages. The Slim Duck generally uses a screw-on adapter to adapt the antenna to the needed antenna mount. There can be some loss of signal in that screw-on adapter. Worse yet, the antenna can become loose on the screw adapter and that will compromise reception and the antenna can actually fall off of the radio without the user noticing it. Other than that, the Slim Duck is a pretty tough antenna that rarely fails. The EXH-160 has an antenna mount specific for the radio where it will be used--no adapter--and that is good. The EXH-160's weak spot is at the mid-point of the antenna where the taper ends and the "straight" portion of the antenna begins. Under severe use, the antenna cable can break internally at that point, which severely compromises the antenna, and the break may not be readily visible to the user. I've seen a number of EXH-160's fail that way, but, again, those antennas were in daily severe duty use that a typical railfanning radio would generally not see. Both the Laird and Slim Duck antennas are longer than stock antennas--that is the price one must pay to have a more sensitive extended-range antenna. Also, if one buys a Kenwood commercial radio and buys the Kenwood extended range antenna, the antenna is almost always a re-branded Laird EXH. Very occasionally one will find a stock antenna that performs nearly as well as an extended range. One that I found was the stock antenna (and it's also fairly short) for the Wouxun UV-6X commercial radio--that is the best performing stock antenna that I've encountered. Comet and Diamond make several extended range portable antennas, BUT they are "wide band" antennas designed primarily for amateur radio use, so their tuning is not optimum for railfan use. They are a good choice for an amateur radio operator that uses his/her radio for railfanning, however.

With mobile radios, having the antenna properly tuned for the transmit frequency is critical if one is going to use the radio for transmitting. As noted, failure to do so can severely damage the radio if it transmits with a poorly tuned antenna. For amateurs that use a dual or tri-band radio, there are antennas sold that try to minimize the "misfit" of antenna tuning necessary to accommodate multiple bands, but the performance is somewhat compromised to do it. For reception use only, the user can tune the antenna for the specific band being monitored and that will optimize performance. Most single band antennas are sold with a "mast" that must be cut to the proper length to perform best at a given frequency--with a "cutting chart" supplied to indicate the lengths. For a VHF antenna monitoring the railroad band, I generally cut the antenna to perform best at about 161 mHz. The performance "sweet spot" of an antenna generally extends about 1-2 mHz on either side of the cut length, so, in my example, the antenna would perform pretty darn well from 160-162 mHz. There are generally two levels or reception quality in mobile antennas--a "unity" antenna and a "gain" antenna. "Gain" antennas will have marginally better reception of weak signals than a "unity" antenna, but generally have to be a bit longer and, thus, may present a problem for vehicles that have get in or out of low clearance areas. My all-time favorite in gain antennas is the Larsen NMO-150 base load antenna cut to length for the railroad band--they have outstanding reception qualities. That said, I no longer have any vehicle using the NMO-150 because of the extra-length issue. For most use, a unity quarter-wave antenna will perform adequately if it is cut to the proper length and is mounted optimally--more about the mount location in a minute. There are numerous unity quarter wave type antennas available--I use mostly Comtelco brand unity antennas, just because I have a good supplier source for them. Another one that I use for vehicles that have to deal with low clearance garages, etc. is the Sti-co Flexi-whip unity antenna. That one can literally be tied in a knot and not break. The Flexi-whip is about the same length (around 15"-23" depending on frequency) of any of the unity quarter-wave antennas. Now, about mounting location. Remember my comment about ground planes? Well, a mobile antenna gets a bunch of its performance from a good ground plane. In a vehicle, there is no better one than the roof of the vehicle, with a mount in the center of the trunk of a sedan being in second place. A cowl mount on either side of the hood of the vehicle is a distant third--because the ground plane becomes fairly directional. Window mounts? Near total loser--generally no good ground plane. What about magnetics? They can be fine if the antenna itself is good quality, the cable is not compromised (i.e., not mechanically smashed in the window or door seal), and the antenna is placed where it has a good ground plane.

Now, if one is railfanning in an area where signal strength is always strong, none of this may matter that much. But, if one railfans in an area with relatively weak signals--and that is in a lot of places--then getting the best antenna and radio performance is critical if one plans on hearing the most transmissions. Finally, a radio and antenna is a communications system. Like most any system, it is only as good as its weakest part. A lousy quality radio with a good antenna is not going to perform well, neither will a high quality radio with a crappy antenna. Think of camera bodies and lenses--same thing.

One final note: I see frequent posts saying things like "My cheap scanner performs fine", "My window mount antenna does great", "I use my portable scanner inside the car and it performs fine", etc. Well, in high signal strength areas that may all be accurate, but I CAN GUARANTEE YOU that if you travel to an area with weak signals and/or a lot of RF interference, those setups will prove to be a huge disappointment. As an example, some years back, I was chasing one of those sort of "once in a lifetime" events way out in the middle of nowhere. I was using a high-quality amateur mobile radio at the time with the aforementioned Larsen NMO-150 antenna. I heard all the radio traffic associated with the movement. Knowing pretty much the exact location of the train, I was able to position myself well in advance to a location where I got the exact photo that I wanted as the train passed--right before it entered a long area with no vehicular access. As I was preparing to leave the location about 5 minutes after the train passed, another railfan hurriedly drove up to me and asked, "When will the train be here?" "It went by over 5 minutes ago," I said. "How did you know where it was?" he asked. I replied, "I've been listening to the Conductor on the radio all day." He looked dejectedly at his cheap portable scanner with a stock antenna, "I don't get it, I'm on the right channel and I never heard a thing." As we talked, I found out that he had taken over a week of vacation time and had driven over 1,200 miles to chase this train--and he missed the shot of a lifetime because he was using a $75 scanner with a stock antenna in an enclosed vehicle. Oh, and that is not the only time that has happened when I've been out photographing.



Edited 1 time(s). Last edit at 03/15/18 09:09 by WW.

What he said.

Rick2582 / Shasta Route
Redding, CA

Interesting and well said. Thank-you.

KG

For the practical railfan who wants great track side reception from their amateur HT a VHF gain antenna (Diamond, etc) suited for the HT it is connected provides all one needs. All the theory above may be useful to a few but in reality it is overkill. The practical benefit of an antenna resonant to 161 on receive is really null and serves to limit the use of your radio. To really keep things simple order a suitable gain antenna from the same outlet when purchasing the HT. The benefit of tuning a 2meter mobile whip for RX is also somewhat negligible IMO.

I recommend a technician class HAM ticket to go along with your HT/mobile. In many areas testing is free. A little study will earn a passing grade and open up a new hobby or at the very least make you "legal" in those odd states with scanner laws.

JW



Edited 2 time(s). Last edit at 03/15/18 16:30 by ChessieSystem.

To further enforce what you are saying, I had an experience on Amtrak several years ago. I had a ham portable with me and it had the Diamond antenna on it. We were stopped for something, I don't remember what it was. The conductor or engineer was trying to talk to the dispatcher or a MOW foreman. Again, I don't remember the particulars. Anyway, the conductor was a few feet from me and he was having trouble receiving with his handy-talkie and a 6" antenna, what the other person was saying. Me, with my ham radio and a good antenna, was able to hear the other person without any trouble.

Antennas require a certain minimum length to be effective and making them shorter reduces that efficiency. You can coil that antenna or whatever you want to do to it to shorten it but any reduced length will reduce efficiency.

Good article.

John
WA4UMR

Good article, and we ought to bookmark it in some way, for use when those periodic queries show up here.

On a lighter note, while I am an Extra Class licensed amateur, I occasionally like to monitor Caltrain, between San Jose, where I live, and San Francisco. I use Scanner Radio Pro on my cellphone. :)

To add just a bit about John's note--these days I see very few portable radios in Class 1 railroad service that don't have an extended range antenna. One reason is that narrow-banding back in 2013 did have some negative effects on the signal range of radios. Unfortunately, narrow-banding also negatively affected many amateur radios in reception capability. Many of them have a narrow band function, but on some of the amateur radios that function only narrows the transmit side of the radio and doesn't really affect the receive side, so one is still essentially monitoring a narrow band transmission from a railroad radio with an amateur wide-band receiver. I do give the Uniden BC-125AT scanner credit for being a true narrow band receiver. Narrow banding is the main reason why I generally no longer use amateur equipment to monitor the railroad channels. One amateur radio that is an exception to the narrow-banding issue is the Kenwood TM-281A mobile. It is a true narrow band radio, as was the prior model, the TM-271A. Both were/are very good railfan radios, with the exception of being a bit susceptible to RF interference.

On antenna length, I do know that hassle of using an extended range antenna on a portable radio, but, for me, the results are worth the inconvenience. If I am railfanning where a longer antenna is just a big hassle (for example, riding on Amtrak), I will stow my commercial radio away and use either my Wouxun KG-UV6X with its strangely very good short stock antenna or my BC-125AT scanner with what is a very good fairly short antenna that performs very well. I didn't mention that antenna earlier because I don't know its pedigree. I acquired several of them several years ago from a railroad radio tech who no longer had any use for them. They had BNC mounts and the railroad no longer had any radios with BNC mounts. The antennas were tuned to the railroad band, but had no brand or identifying marks on them--I wonder if the railroad had them specially made. Since the BC-125AT has a BNC mount, I use one of those antennas on it and the combination works pretty well, nearly as well as the BC-125AT performed with a Smiley Slim Duck.



Edited 1 time(s). Last edit at 03/16/18 08:13 by WW.

All of the information is correct and should be observed for great reception, But there is one more thing that is of paramount importance. Use the best cable from the antenna to the receiver. The standard 50 ohm RG cables cause a lot of trouble in weak areas. I have found that on my airplane (120+ mhz) and with my railfan radio's, it is best to use double shielded larger cables like the Times microwave 400 series. (beldin has similar cables in standard fles and extra flex) The increase in signal strength is amazing I have doubled my tranmission and reception distance in both cases.

Like the comments about adapter connectors (there is significant loss) the larger cable and the fact that it is double shielded makes a world of difference especially when routing it from the roof to the interior of the car. True the larger and heavier cable requires special connectors (available from Times and other sourcesat reasonable cost--- both BNC and SMA). The cable connections have less standing wave loss and keep out the noise from our noisy planet. The larger cables may be a little more difficult to route, but they are not as prone to pinching (more standing waves).

r

^Very good information. Cabling and cable connections are critical. Compromising either even a little bit can crater the performance of an otherwise good setup.



Edited 1 time(s). Last edit at 03/16/18 08:16 by WW.

SWR and transmission line loss are not exactly one in the same.
Unless you have a really unique situation concern over transmission line loss on a short mobile run is totally unnecessary. Taking your airplane situation out of the equation, to suggest LMR 400 or similar for a railfan rover borders insanity unless of course you were a coax salesman lol.

JW


rhotond Wrote:
-------------------------------------------------------
> All of the information is correct and should be
> observed for great reception, But there is one
> more thing that is of paramount importance. Use
> the best cable from the antenna to the receiver.
> The standard 50 ohm RG cables cause a lot of
> trouble in weak areas. I have found that on my
> airplane (120+ mhz) and with my railfan radio's,
> it is best to use double shielded larger cables
> like the Times microwave 400 series. (beldin has
> similar cables in standard fles and extra flex)
> The increase in signal strength is amazing I have
> doubled my tranmission and reception distance in
> both cases.
>
> Like the comments about adapter connectors (there
> is significant loss) the larger cable and the
> fact that it is double shielded makes a world of
> difference especially when routing it from the
> roof to the interior of the car. True the larger
> and heavier cable requires special connectors
> (available from Times and other sourcesat
> reasonable cost--- both BNC and SMA). The cable
> connections have less standing wave loss and keep
> out the noise from our noisy planet. The larger
> cables may be a little more difficult to route,
> but they are not as prone to pinching (more
> standing waves).
>
> r

I've found that good quality "standard" cabling will work fine on short runs (say 10' or less) if the connectors are done properly and the cable is safe from mechanical damage (crimping, water, chafing, etc.). For longer runs--for example, connecting a base antenna on a tower or mast to a base station, then the line loss in standard cable becomes a big problem--that's where cable like 400 series becomes mandatory. Also, no matter which cabling or connectors are used, moisture and water are one of the biggest enemies--usually introduced at a connector. It takes very little moisture to foul up the performance of an antenna system. I've seen a couple of drops of water in a cable connector effectively compromise communications through a whole repeater setup. And, if the moisture/water infiltrates the cable itself, the cabling may have to be completely replaced.

About the STI-CO Flex antennas, our radio vendor turned us on to the Flex antennas and it has ended the issue of our FD ambulances snapping off their roof mounted antennas all the time. When I got a new SUV, I had him install Flex for both the UHF and VHF radios. And as mentioned, he tied the VHF antenna in a knot to convince me before the install. I had great reception on my railfan trip last month to NC.

I'll keep this a tad short, but there is some generalizations and not-as-accurate information floating around.

Longer antenna's on current issue Kenwoods for the RR are standard antenna's. It has NOTHING to do with narrowbanding, increased range, or the sort. Its a standard wideband antenna.

You do NOT need to cut an antenna for RX purposes. At the most for most 1/4 wave antenna's, its about an inch or three.

You cut for transmitter performance, if required.

Today, many multiband antenna's are available (as commercial public safety radios are somewhat SDR and covers VHF/UHF/700/800) with one transmitter. Most antenna's for these radios are approximately the same size as a standard 1/4 wave VHF antenna.

Not all "rubber duck" antenna's are not the same. Back in the olden days, we used them on HT220 UHF radios, and worked well. Its not necessarily a "ground plane" issues. The RF charactrics of a portable radio are much different than a mobile.

The use of "gain" or "extender" antenna's are something of ham radio use. Most are akward and have no real gain value (especially sitting in a vehicle) but some do provide some gain.

Again, your sacrificing real estate for function.

Motorola, Harris and Kenwood do not offer any "extended range" antenna's for their portable radios. They have offered wideband (136-174) but not gain (except for 800MHz with the elevated feed point antenna).

For vehicles, you want a NMO antenna drilled. That's is the best case. Also consider the different metals used in todays construction. Again, this mostly effects transmitters than receivers.

The comment on cheap scanners is generally correct. You get what you pay for. However, all scanners by design have a wide front end - and will take in much interference. The best performing ones are the most expensive one (Uniden HP series, TRX, etc). The $150 ones work, but don't expect the same performance as commercial radio. Same goes with ham radio equipment. By design, they do not typically reject interference very well.



Edited 1 time(s). Last edit at 03/17/18 19:28 by MP683.

Not to be snarky, but maybe you should read Kenwood's own website. Look up the KRA-25 antenna, quoted there as a "VHF High Gain Antenna." It's a re-branded Laird EXH-160, also marketed as a "high gain" antenna. This antenna IS used extensively on the railroads. Where I found out about them over a decade ago was from a BNSF radio tech. In weak signal areas, they WILL perform better in reception than a standard antenna. I've tested both standard antennas and the Laird EXH-160 (and KRA-25) on the same radio and there is a performance difference. The difference won't be notable in strong signal areas, but it will be in weak signal areas.

If one has to use a multi-band radio--and many public agencies now have to use them--there are two choices: use a multi-band antenna that sacrifices some performance on any given band (and the sacrifice can be significant in weak reception areas), or use a radio setup that uses different radios and different antennas for the different bands optimized for performance for the particular band. Where I live (in a fairly remote rural area), it is not uncommon to see some public service vehicles with radios in a stack, and 3-5 antennas on the roof, thereby trying to wring every bit of performance out of the radios (e.g. VHF, UHF, and 800 mHz).

The "wide-open" architecture of scanners does make them very susceptible to intermod interference. That's one reason that they are not my primary choice for railfanning. Even dual-band VHF-UHF amateur radios can suffer some of the same issues. That is why I generally forego using a dual-bander just to be able to hear EOT transmissions on the UHF band (my one exception is my Wouxun KG-UV6X dual-bander, but it is not my primary railfanning radio, either). I would rather use a single band radio that is a top performer on the VHF band where railroad voice traffic lives.



Edited 2 time(s). Last edit at 03/17/18 20:10 by WW.

And....had a nice detailed reply, and I accidentally zapped it. Will try again before called back on duty.

Posted from iPhone

^I feel your pain--I've had that happen more than once. Hit a wrong key, and--poof--the whole post is gone forever. One other note--you are absolutely correct that a the big major benefit of a gain antenna is on the transmit side, much less so on the receive side, but they do help some on receive. And, as everyone might surmise, where I live and work requires getting the absolute most out of a receiver--it's a place where radio signals are coming from long distances over difficult terrain.

Now that I am in front of a laptop for a moment...

Prior to coming to the RR, I was a comm guy for a large state police agency. After that, went to the RR as a Telecom guy and then into train service. I still manage a few fire districts comms in my area in my free time.

A couple of comments...

The "many antenna's" on top of public safety vehicles is not to "squeeze" every bit of any band. Prior to the introduction of the Motorola APX8500 radio, the Motorola APX7500 required two antennas (it is only a dual band radio). The APX8500 can be used with a triplexer or as a single antenna installation. Out of the box, it is single antenna only. This allowed for installing antennas on various vehicles as needed, if required due to spacing, materials or the such. The Harris Unity only sports two antenna ports. One for lowband, the other for V/U/8.

Prior to all this, and the advent of FCC type accepted multiband commercial radios, all radios were single band only.

Every department has its own RF requirements, as well as taking into account their mutual aid/neighboring departments - if they so choose to. Also these days, you have to take into account with multiband trunked radio systems. In my area, we use VHF for wide area coverage, and 800 for the metro areas. Same radio, same system, two bands - and its transparent to the user. One recuse truck sports one multiband antenna, the other sports two - due to the radio model.

The rescue using the multiband antenna has the same operational range as the 5/8 antenna that replaced it (more on that later).

Even with this, multiple modulations may be required, but only one public safety radio that I know of supports this - the Kenwood NX5000 series. So if you need DMR and P25 in your vehicle, its two radios or one that supports both. But operationally, you still may need to radios to talk and listen to who you need to. Hence, more antenna's.

My vehicle sports 6 (technically 9) antennas feeding 5 actual radios. The installed scanner is connected to a Comtelco Multiband antenna. The rest are 1/4 antenna's from Lowband to 800.

BNSF does things a little different. They have custom firmware from Kenwood to allow direct dial of all the AAR channels. Everyone else uses zone/banks for the analog, NXDN and location specific channels. Due to this, there are certain limitations on what the BNSF radios can do functionally then "off the shelf". In a way, its doing what the JEM/NEXTRMA locomotive radios do.

In testing, we determined that the advantage of the Kenwood KRA-25 antenna does, is bring the signal out more from the body (ie elevation) compared to the KRA-26. RF wise, they tested out to be about the same on the monitors and basic field testing. We also found a higher failure rate with the -25 due to people using them as handles/radio holder, zipped in zippers for grips, fly swatters, etc. They took a little more abuse.

So yes the argument could be made they could be a better antenna, but its all a level playing field when its stuck in a back pocket, under a coat, top missing, or anywhere else which is not a standard radio carry position. When I was on the ground, I used my APX7500 of Thales Liberty with their stock antennas and it out performed all the Kenwoods.

Still, nothing is really going to overcome trying to talk to the headend of a train when your 8000ft+ back, thru cuts, valleys and mountain curves. For that, we installed radio repeaters so that conductors radios would have reach. They were installed at dispatcher towers and work well (when conductors know how to use them).

Now back to antenna's.

The ham radio dual band mobile antenna's, though some good ones, do not get real world testing/use/etc as much as commercial ones do. I personally like the Diamond NMO series for the ham stuff. I found those to work really well, but its at a cost of height.

Since we had all the gear, we testing various ones out - and always came back to the commercial stuff for ham and public safety. Our last recent testing was with the Motorola All Band antenna, Comtelco Multiband, Panaorama, Sti-Co solid, Sti-Co Flex, Larsen with spring and without and Laird.

The Laird (popular with hams) without the spring performed the worse overall. The spring version (150/400/500) actually did much better. All antenna's were performed well around 160, but had performance hits from 144 to 160, then again to 174. Same with UHF. Now when I say hits, most were on the transmitting side, but all worked pretty well on reception. Motorola, Comtelco and Sti-Co solid all came out about the same - and had the same overall height. I didn't have the Harris multiband at the time to test, but in the field, it appears to fit into above.

Compared to 1/4 wave counterparts, they faired the same. Motorola and Comtelco came out on top.

Where I operate on the fire side, my closest site is 20 air miles away - and we are required to operate on the state trunked system and conventional. In between are a few valleys, peaks and to the west, mountains. (Why can't I just live in Kansas?)

For my personal ride, I tried out the Antennex series antennas (now owned by Laird I believe) and they work awesome.

Getting back to an earlier point, using ham radios and scanners for dedicated railroad monitoring, you must decide on cost vs performance. ICOM, Kenwood, Baufung/Wuxon etc all have generally weak filters and must accommodate the band spread they were designed for. We have beaten that to death at this point. Its economics and design. Any commercial radio will generally do a much better job - as its what the radio *was* designed for. Of course there are cheap versions as well, but its performance will still generally be better. But now you get into having specific programming equipment, limitations, and some knowledge of how they work in order not to be *that guy* who wants to xmit on channels not licensed for.

So back to patrol vehicles - the city I do some side work for - operates primarly on the VHF trunked system. One antenna for that. However, we also install dedicated GPS, WiFi, LTE and RF mics for the body mic for the car cam. One true LMR antenna, but a bunch. We have generally switched over to the multiband antenna's for the aux equipment, but your still looking at 2-3 antennas minimum. That I have been using, and use on my vehicle is the Panorama Sharkee OEM lookalike - GPS, Wifi, cell with the RF antenna option. All the size of Chevy XM radio/GPS antenna.

As I keep thinking as I am editing - back to mobile installs -

If you are going to be mobile with whatever radio you want to use, just drill the damn hole.

BUT

Know your vehicle. There are some lightweight metals being used, and they do not play well. A good radio shop will know the vehicle and metal and recommend a best mounting option. As a general rule of thumb: Drill (NMO mount), "L" or lip mount bracket with correct metal/electrical bonding, magnet mount, then the dreaded cell lookalike. Each has its uses, but for performance and industry standard - that's what you are looking at. In any case, don't be that guy who runs the radio cable thru the window, door jamb and any other place that things get pinched/cut/destroyed.

We have seen them all, and its not pretty.



Edited 4 time(s). Last edit at 03/18/18 10:00 by MP683.

Great post! Yes, drill the hole. With the exception of one personal vehicle that I almost never use for railfanning, my vehicles all have NMO mounts. Now, I recommend having a professional radio shop do the mount and the cable install. Why? As I've mentioned a long time back, if a radio is used for transmitting, it can cause electronic problems in some vehicles, depending on where the antenna is located. On one pretty popular SUV a few years ago, mounting a transmitting antenna near the back of the vehicle would cause the rear wiper to run every time the the mike was keyed up to transmit.

Yes, using any antenna with the cable run through a door jam, window seal, etc. is just asking for problems. One serious crimp and you've basically got a radio without an antenna.

Since you brought it up about Kenwood radio models (and Icom has them, too) with special railroad firmware, I'm quite familiar with them. Bluntly, they are not suited for railfan use--partly because the firmware usually makes the radio non-programmable using the standard programming software for the radios. Most radio dealers do not carry the railroad firmware and railroad specific software, unless they work on railroad radios, and even then they are not likely to use it to program a "civilian" radio. Most of the railroads also password protect their radios such that the only way that they can be programmed without the password is to completely wipe the software and firmware off of the radio--then you have, at best, a radio that is no longer a railroad radio and, at worst, an expensive paper weight. So, if you see a used "railroad" version of an Icom or Kenwood late model mobile or portable radio listed for sale on the usual "sell-anything" type websites, it is a ) probably a stolen radio (I've seen a couple for sale by individuals on one website with the railroad's name clearly embossed inside next to the manufacturer's plate in the photos of the radio) and/or b ) it's likely not going to be re-programmable.

Cost vs. benefit is a big consideration. The simple cost array is that better performance costs more money, and the curve can be steep. A radio that will do OK up to hearing about, say, 70% of what would be possible to hear might cost $100, 85% might cost $200, and 95% might cost $900. The other consideration is this: improvements in technology and new technologies are going to significantly reduce the amount of railroad voice communications conducted over the radio system. Though it seems counter-intuitive, that means railfans need even better monitoring equipment. Why? Well, if, say, a train crew is communicating with the dispatcher over the radio every half-hour or so, you might be able to miss a communication here and there and still know pretty much what is going on, but, if that crew is only talking to the dispatcher once every four hours over the radio, then you better be able to hear that transmission or you'll be lost as to what's going on.

WW Wrote:
-------------------------------------------------------
> Great post! Yes, drill the hole. With the
> exception of one personal vehicle that I almost
> never use for railfanning, my vehicles all have
> NMO mounts. Now, I recommend having a
> professional radio shop do the mount and the cable
> install. Why? As I've mentioned a long time
> back, if a radio is used for transmitting, it can
> cause electronic problems in some vehicles,
> depending on where the antenna is located. On one
> pretty popular SUV a few years ago, mounting a
> transmitting antenna near the back of the vehicle
> would cause the rear wiper to run every time the
> the mike was keyed up to transmit.
>

Quoted the first paragraph in your response with a personal note.
I drive a Honda Ridgeline truck; my dealer strongly suggested
to not drill through the roof. He showed me the layout of the
various wires and related including airbag triggers in
the roof area of my specific truck.
I tend to keep my vehicles for a long time usually for
10-15 years so a proper installation for me would be ideal.
Also spoke to two different local radio shops who
made a similar comment "the newer trucks and automobiles
not specifically designed to accommodate antennas
can be a nightmare if the drill breaches the wrong
piece of infrastructure." I mounted the antennas on
L-brackets equipped with NMO connectors on the mudguards.

And too the name/company Laird appeared (if that is the correct
term) in regard to the long standing Larson brand of products.
Laird purchased Larson?

Laird is still an independent company as far as I know ( https://www.lairdtech.com/product-categories/antennas ). Larsen is part of the Pulse Electronics group ( https://productfinder.pulseeng.com/productList/WIRELESS%20INFRASTRUCT/ANTENNAS-1%20MHz%20TO%20512%20MHz ).

Yes, current generation vehicles can be a nightmare for antenna mounting. That is why I strongly recommend that antenna installation be done by a reputable radio shop. Mounting a radio, even temporarily in a vehicle, has also become a challenge. Keeping the radio from becoming a missile if the air bags deploy is a challenge with today's multiple airbag vehicles. Space is also limited for radios because seating areas have been contoured to offer maximum seating place in limited areas, leaving little room for much else. Radio shops generally have lots of experience in dealing with those issues.

Of course, drilling holes for antennas and mounting brackets can be a problem for people who trade vehicles often or have leased vehicles. I don't have that issue with mine because I keep my vehicles a long time--usually 10 to 20 years (the ones that I have now will probably outlast me).