Batboard

here are some pics check it

here is the antenna i installed this past sat 6/30/07

it is mounted









Radio is now installed 95% of the way. The shop crew has to get the dynamo going and check its polarity to wire up the inverter/battery charger






more here http://s32.photobucket.com/albums/d20/k ... loco%2040/

I once used one of those antennas. Found the VHF antenna was very sensitive to cable
length and how the SWR turned out. Don't be surprised if you have an issue trying to
match to that antenna.

It will take several tries with different length cables to fine one that will work with a
low SWR. When you remove the power meter, expect everything to change again.

Jim

We used the UHF version in australia and they worked great except for the odd wheat silo chute that took them off.

christ. really?

From the looks of that thing, it appears to be rather well attached (do i see four bolts on it?)...my guess is any kind of wheat silo that lopped that thing off was also doing a fair amount of damage to the locomotive as a whole.

no it mainly if the engine was in reverse or and the chute would catch the rear end and snap the blade off. The base was still attached.
If the silo operators had stowed the chutes properly it would not happen. I'm also certain it was only one or two silos gave the problem but with hundrereds in Victoria never foumd which ones.

it is a standard Railroad antenna and i have done 2 and never had a bad match. this one tuned up nice across all the RR channels. if they were such and issue like that then they would no be used by Railroads as much.seeing how Railroads like easy to use products

it has 6 screw holes. and is Supplied with self tapping screw. i used only 4 1/4 20 stainless bolts and we do not go aboive 30 mph

we did hundreds of UHF (400-420) ice skates in oz and I never recall a bad one out of the box but did replace one or two due to bad VSWR mot including the physically damaged ones from the chutes.
If I remember correctly we SS bolted all antennas rather than use screws. The UHF was 4 holes

Jim202 wrote:I once used one of those antennas. Found the VHF antenna was very sensitive to cable
length and how the SWR turned out. Don't be surprised if you have an issue trying to
match to that antenna.

It will take several tries with different length cables to fine one that will work with a
low SWR. When you remove the power meter, expect everything to change again.

Jim

You obviously had a bad or improperly installed antenna and you were just tuning the coax to match a bad load.

Those antennas need a good ground plane. You need to remove the paint from the roof in the contact area and bolt it securely.

I don't know about current practice on the major RRs but, back in the Penn Central days, the Radio Maintainers were not allowed to install or replace those antennas. It was considered a locomotive safety appliance and had to be done by the shop mechanical people. All the Maintainer could do was connect the coax.

KitN1MCC wrote:
it has 6 screw holes. and is Supplied with self tapping screw. i used only 4 1/4 20 stainless bolts and we do not go aboive 30 mph

I am surprised it is supplied with self tapping screws. My understanding of FRA locomotive safety appliance rules is that anything like that antenna that someone may attempt to use as a handhold when climbing on the roof has to be securely bolted to support the weight of a man.

also with these antennas if you don't take all the paint off the vehicle to be painted under the antenna it will not work

i coat the underside of the ones i did with Fredick seal copper never seize

Buses around here used to use the VHF midband (72MHz) version. Same sort of design, but about three feet long.

i had to remove the External Volumn control and Horn speaker and replace it with a Midland Comm speaker i had laying it around

the Volumn control was causing audio distortion

Nice install you have there! i like the weather proof boxes you have put the equipment in. defiantly have never seen that before, but its a good idea.
Ill have to take pics of the install we did on our 2-8-2T (the brawny beetle as trains mag likes to call her) up at the mount rainier scenic railroad. we have a 128 channel a4 spectra in her.

i have a Dual head a9 in our dual Control 80toner ge

i only have one channel programmed due to the fact that the drawer is set up weird and the F/R swich does not work and both Control heads are on at the same time i need to get a new drawer