The New Northern Central

[keeper]

(Attachment Link)

Where is that Leipzig number plate coming from?

Thomas 

[Ed Kapuscinski]

Where is that Leipzig number plate coming from?

Thomas 

Oh man, that used to be the front plate on my old Volvo when it was registered in PA.

Not sure if this will work.

[C855B]

Oh man, that used to be the front plate on my old Volvo when it was registered in PA.

Not sure if this will work.

It worked. Not so sure about that scanner antenna, tho' - too short for RR frequencies.   

[Ed Kapuscinski]

It worked. Not so sure about that scanner antenna, tho' - too short for RR frequencies.   

I disagree!

It was far better than the full length version that it had been before it was cut down.

[C855B]

If you mean by full-length, I think I recognize the base/magnet - was it originally a 5/8-wave ham antenna, ~4 feet long? If so, that particular design is notorious for narrow frequency response and they are fairly deaf outside of the design range. Again, if 5/8-wave, it should've been 42" for RR band.

If it was 1/4-wave, in untrimmed form it was likely to have been 22" and then resonant at 136 MHz, the upper end of the aircraft band. 161 MHz would put it at 18".

In either case, what you have there is what we call a "random wire" antenna <1/4-wave, which sometimes works OK, sometimes doesn't, depending on the receiver's "front end" and how well it tolerates impedance mismatch. In so many words, a random wire cut too short (but not way too short!) will work better than one that's too long.

Yeah, this is in the weeds. One of my "hats" was as an antenna designer. My specialty was direction-finding antennas. My working/test vehicle in the 1990s was a plain-jane white Explorer with steel wheels; it had 13 antennas on it. Even the local FCC official was impressed. Unintended, it was a hoot to merge onto a freeway and traffic would suddenly slow down. But I was hired on a couple of occasions by local PDs and other agencies to assist in locating stolen radios where some idiot thought it would be fun to get on their channel and raise hell. 

[Ed Kapuscinski]

If you mean by full-length, I think I recognize the base/magnet - was it originally a 5/8-wave ham antenna, ~4 feet long? If so, that particular design is notorious for narrow frequency response and they are fairly deaf outside of the design range. Again, if 5/8-wave, it should've been 42" for RR band.

If it was 1/4-wave, in untrimmed form it was likely to have been 22" and then resonant at 136 MHz, the upper end of the aircraft band. 161 MHz would put it at 18".

In either case, what you have there is what we call a "random wire" antenna <1/4-wave, which sometimes works OK, sometimes doesn't, depending on the receiver's "front end" and how well it tolerates impedance mismatch. In so many words, a random wire cut too short (but not way too short!) will work better than one that's too long.

Yeah, this is in the weeds. One of my "hats" was as an antenna designer. My specialty was direction-finding antennas. My working/test vehicle in the 1990s was a plain-jane white Explorer with steel wheels; it had 13 antennas on it. Even the local FCC official was impressed. Unintended, it was a hoot to merge onto a freeway and traffic would suddenly slow down. But I was hired on a couple of occasions by local PDs and other agencies to assist in locating stolen radios where some idiot thought it would be fun to get on their channel and raise hell. 

Haha. What you're actually looking at is the "$20 Radio-Shack Special" with one of the sections removed because someone said "it works better". In all the years of using it it's actually done ok. I actually have no idea where it is anymore, and I've been thinking about a replacement, but I also am nervous about hurting the paint of my current "instant classic".

[davefoxx]

@Ed Kapuscinski,

I just received that new Diamond RH77CA antenna for my old Radio Shack scanner.  I can't wait to get out there and see if it makes any difference.

DFF

[C855B]

OK, now I get it. There was a cheap brand of ham antennas that used the same base. Yeah, those RS jobbies were crap. You eliminated the center coil, which detuned the whole works so it would favor the 450 MHz police bands at the expense of "hi-band". Great for picking-up FREDs, tho'.    It worked OK with the mod because there was also a coil in the bottom, so the resonant length of the whip+coil was in the ballpark. Sort of like rubber-duck antennas on walkie-talkies.

Fear of scratching the paint with the magnet? Pish-posh! Those 13 antennae on my Explorer were drilled mounts! No fear! 

... Diamond RH77CA ...

Full geek mode!   

[Ed Kapuscinski]

OK, now I get it. There was a cheap brand of ham antennas that used the same base. Yeah, those RS jobbies were crap. You eliminated the center coil, which detuned the whole works so it would favor the 450 MHz police bands at the expense of "hi-band". Great for picking-up FREDs, tho'.    It worked OK with the mod because there was also a coil in the bottom, so the resonant length of the whip+coil was in the ballpark. Sort of like rubber-duck antennas on walkie-talkies.

Fear of scratching the paint with the magnet? Pish-posh! Those 13 antennae on my Explorer were drilled mounts! No fear! 

Full geek mode!   

Haha, yeah. But from what I understand, there might only be about 1000 copies of my Shark floating around out there, so I want to keep the speed hole applications to a minimum.

And Dave just got the same antenna I use on mine too when hand held. So far I've got no complaints.

[wazzou]

Haha, yeah. But from what I understand, there might only be about 1000 copies of my Shark floating around out there, so I want to keep the speed hole applications to a minimum.

And Dave just got the same antenna I use on mine too when hand held. So far I've got no complaints.

Just get one of those sheets that go between hamburger patties or cheese and use that between the magnetic base and the car.

[CRL]

Ah... Brings back memories we used to go on back in the 60’s as part of our county civil defense group using 20 meter band radios. One guy would set up a stationary broadcast somewhere in the county on a public accessible spot, then at an appointed time, would begin broadcasting, but only if the “hunters” were able to keep him talking.

A favorite technique was to park the transmitter vehicle on a railroad crossing because the signal tended to spread out down the tracks in each direction making it harder to get a fix.

Great fun.

[C855B]

Have you guys seen one of these?:



Sort of obvious, a mag-mount for hand-helds. Works great with that Diamond whip. (Though still a magnet, Ed.    )  Easy to pack for trips where we have to rely on rental cars. Available here.

Ah... Brings back memories we used to go on back in the 60’s as part of our county civil defense group using 20 meter band radios. One guy would set up a stationary broadcast somewhere in the county on a public accessible spot, then at an appointed time, would begin broadcasting, but only if the “hunters” were able to keep him talking.

A favorite technique was to park the transmitter vehicle on a railroad crossing because the signal tended to spread out down the tracks in each direction making it harder to get a fix.

Great fun.

I was no fun (for the others) on "foxhunts", as they were called. My equipment and software would find the "fox" in the time it took to drive there. It got to the point where the designated foxes were doing things specifically in attempts to foil my techniques. Didn't work.

[keeper]

That Volvo rocks.
Not like a SAAB, but cool enough.

Thomas 

[John]

If he does do full ctc with a JMRI interface then it is theoretically possible to have the through trains run on automated routines while the single operator handles the locals.

I use CATS with JMRI -- I have two panels built .. one for CTC, and the other for APB-2 .. so when I just want to run trains myself, the signals just work without me interfering .. the JMRI automation stuff is just too hard for a large layout -- time wise to set up

[Ed Kapuscinski]

That Volvo rocks.
Not like a SAAB, but cool enough.

Thomas 

I know. It's the one I regret letting get away. I had a lot of fun in that thing.

To this day, if I wanted a bespoke resto-mod it'd be that car with the heated/ventilated seats from my current ride, some modern infotainment, and an LS under the hood.