Tram 1411 information

blues222

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What are the 2 adjustable radials used for? Any information on the antenna and info to get the maximum performance on the antenna ? Thank you.
 

Arkmood

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Radials would be adjusted to transmit... not a concern when used with a scanner. For good performance just your basic: decent coax - my preference is RG8 for "maximum performance" higher priced cables are available, shortest run, elevation, keep away from other objects,etc.
 

KEWB-N1EXA

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New Bedford,MA
What are the 2 adjustable radials used for? Any information on the antenna and info to get the maximum performance on the antenna ? Thank you.
The tram 1411 is the same as the 1410 except they add a dipole section for 26-27.5 Mhz for the CB band. This part operates seperate
of the discone section which is cut for 100mhz on up into uhf. Both the top whip and 2 lower radials are adjustable.

I have one and the CB performance marginal. It works but you will get far better performance with a 1/4 - 5/8 wave full size antenna.
The Discone section works great on the VHF Hi band but as you go up in Frequency the radiation angle increases too so using it for
700-900 for trunking at a real long range say 25 mile + is pretty poor. This radiation angle is great for VHF and UHF aircraft bands though
and that's why you see them used allot in that application.

Is it a good antenna yes at $50-60. Is it over advertised on what it can do, Yes ! It all depends what you want from it.

Peter N1EXA
 

blues222

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Southwest Missouri
I thought only the lower radials adjusted for 11 meters? does the top whip adjust too? Your reception is only 25 miles on 700-900mhz trunking?
'
 

KEWB-N1EXA

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I thought only the lower radials adjusted for 11 meters? does the top whip adjust too? Your reception is only 25 miles on 700-900mhz trunking?
'
11 Meters is CB - and the dipole section both top and bottom can be adjusted for what part of the band you want to use the most. As for the radiation angle and Understanding it you should Google ( DISCONE ANTENNA ) and understand how it works.

Basic Knowledge of Electronics such as OHMS and Impedance along with Some Ham Radio references to antennas can be looked up on the web.

The adjustments both top and Bottom For 26-27 mhz Has to do with Transmitting and Reflected Power ( SWR) Standing Wave Ratio which
can also be googled.

Hope this helps out Peter N1EXA
 
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KEWB-N1EXA

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Your reception is only 25 miles on 700-900mhz trunking?

This has to do with the Radiation angle of the antenna and looking over the horizon which at sea level is 14 miles.

Yes ! The Discone works at say 900 Mhz an Example Is the Local IC&E DMR system...If I Use Discone the range is only about 10-20 miles at 900mhz
where if I switch over to a multiband verticle which the radiation angle sits lower on the horizon I can pick of the DMR site 30 miles away. stronger.

The verticle works on say military UHF at 300MHZ but if I use the Discone I can get USAF and Coast Guard Aircraft Way out at 100 Miles.
Because the Radiation angle is not on the Horizon but looking at a Higher angle.

An Example based on experience.
Peter N1EXA
 

prcguy

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In the 100MHz to roughly 400-500Mhz range the radiation pattern of a scanner type Discone is more at the horizon and that is where you want it for aircraft reception. Your aircraft reception at 100mi would be a very low angle example. The low angle is also not a problem for aircraft up at high angles overhead because they are very close and generally unobstructed where you can pick those up with a paper clip on the end of your coax, so the Discone null overhead is not a problem.

but if I use the Discone I can get USAF and Coast Guard Aircraft Way out at 100 Miles.
Because the Radiation angle is not on the Horizon but looking at a Higher angle.

An Example based on experience.
Peter N1EXA
 

prcguy

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A Tram Discone will never give great results on weak 700/800 signals and will be noticeably worse than a simple 3 inch tall ground plane. Not long ago I took some readings at 900MHz on a typical size scanner Discone, although it was an unusual design by mp antenna, the Super-M Ultra. I swapped it for a tiny Discone rated something like 400MHz to 3200MHz where it had a good pattern at the horizon at 900MHz and my 900MHz test signals came up about 10dB. This was on the same mast with the same coax.

So this is going from an antenna that has maybe 0dBd gain at best with the sweet spot near the horizon and the larger Discone was about 10dB below that. These are not subtle differences and if you want to hear distant 700/800 stuff from towers over flat ground you need some height and gain. For 150Mhz the Tram Discone should be fine.

I want it for 7XX.XXX MHZ and 150.xxxmhz. talkgroups and dmr systems.
 

blues222

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Southwest Missouri
A Tram Discone will never give great results on weak 700/800 signals and will be noticeably worse than a simple 3 inch tall ground plane. Not long ago I took some readings at 900MHz on a typical size scanner Discone, although it was an unusual design by mp antenna, the Super-M Ultra. I swapped it for a tiny Discone rated something like 400MHz to 3200MHz where it had a good pattern at the horizon at 900MHz and my 900MHz test signals came up about 10dB. This was on the same mast with the same coax.

So this is going from an antenna that has maybe 0dBd gain at best with the sweet spot near the horizon and the larger Discone was about 10dB below that. These are not subtle differences and if you want to hear distant 700/800 stuff from towers over flat ground you need some height and gain. For 150Mhz the Tram Discone should be fine.
my 700mhz tower is only 15 miles down the road.
 

Ubbe

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The Tram1411 are special version to include CB27MHz frequencies. It will also affect the perfomance at other bands negativly. If you only need 150 and 700 bands and you cannot exchange the antenna for a 1410 model, then remove that big top element.

Check the measurements of the bottom elements and the horisontal elements. If you cut them to 150Mhz it will also help the 700MHz band.
The bottom elements should be 1/4 wavelenghts and the horisontals 70% of that. So for the bottom elements it's 300/150Mhz to get a full wavelenght, which is 2 meters or 200 centimeters, and 1/4 of that are 0,5 meters or 50 centimeters. The horisontals are then 0,7*50cm which is 35 centimeters.

It's probably the 150MHz band that you want to receive the best, so try and optimize the discone for that. The higher the frequency you optimize it for the better the 700-800 band will work. Almost all discones are designed to work from 90Mhz-100Mhz which is the FM broadcast band, you probably don't want that and often need to use a FM trapfilter when using a discone, so cutting the discone for higher frequencies will also attenuate the FM band a little more. if you do not need full reception at airband and the lower part of VHF then you can cut the discone to 155Mhz.

A discone usually have a workable band of 6-7 decades, 6 or 7 times its lowest frequency. So a standard 90Mhz discone goes up to 500-600Mhz. But if you cut it to 150Mhz it will work up to 900Mhz without pointing too much up in the sky and loosing 10db of signal at the horizon.

/Ubbe
 

blues222

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Southwest Missouri
The Tram1411 are special version to include CB27MHz frequencies. It will also affect the perfomance at other bands negativly. If you only need 150 and 700 bands and you cannot exchange the antenna for a 1410 model, then remove that big top element.

Check the measurements of the bottom elements and the horisontal elements. If you cut them to 150Mhz it will also help the 700MHz band.
The bottom elements should be 1/4 wavelenghts and the horisontals 70% of that. So for the bottom elements it's 300/150Mhz to get a full wavelenght, which is 2 meters or 200 centimeters, and 1/4 of that are 0,5 meters or 50 centimeters. The horisontals are then 0,7*50cm which is 35 centimeters.

It's probably the 150MHz band that you want to receive the best, so try and optimize the discone for that. The higher the frequency you optimize it for the better the 700-800 band will work. Almost all discones are designed to work from 90Mhz-100Mhz which is the FM broadcast band, you probably don't want that and often need to use a FM trapfilter when using a discone, so cutting the discone for higher frequencies will also attenuate the FM band a little more. if you do not need full reception at airband and the lower part of VHF then you can cut the discone to 155Mhz.

A discone usually have a workable band of 6-7 decades, 6 or 7 times its lowest frequency. So a standard 90Mhz discone goes up to 500-600Mhz. But if you cut it to 150Mhz it will work up to 900Mhz without pointing too much up in the sky and loosing 10db of signal at the horizon.

/Ubbe
so this antenna won't work for me ?
 

Ubbe

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so this antenna won't work for me ?
All metal in the air will work to receive frequencies. The difference are how well you want it to receive. As prcguy points out you could loose 10dB, that's ten times less, at 700-800Mhz using a standard discone compared to a 4 inch steel rod. Your special discone with that 27MHz arrangement could loose more than that at 700Mhz. But if you only need to receive that single transmitter site down the road then it will probably work to that.

/Ubbe
 

blues222

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All metal in the air will work to receive frequencies. The difference are how well you want it to receive. As prcguy points out you could loose 10dB, that's ten times less, at 700-800Mhz using a standard discone compared to a 4 inch steel rod. Your special discone with that 27MHz arrangement could loose more than that at 700Mhz. But if you only need to receive that single transmitter site down the road then it will probably work to that.

/Ubbe
So take the 27mhz whip of the top and that should help on 700 and 800 mhz?
 
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lbashaw

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Technical question? I have the Tram 1411. Would it be effectively functional if I removed the top mast (don't really need Cb range), and replaced the top section with a 3 inch rod for 700MHZ? I listen to air a lot, but also enjoy VHF conventional and 700-800 some 15 miles away eminating from TXWARN in College Station, TX. I'm rural about 12-15 miles west of there. (BC536)
 

blues222

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Southwest Missouri
Technical question? I have the Tram 1411. Would it be effectively functional if I removed the top mast (don't really need Cb range), and replaced the top section with a 3 inch rod for 700MHZ? I listen to air a lot, but also enjoy VHF conventional and 700-800 some 15 miles away eminating from TXWARN in College Station, TX. I'm rural about 12-15 miles west of there. (BC536)
good question , i monitor Moswin on 700mhz.
 

Ubbe

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Analyzing discones show that the top whip could deterioate other frequency bands than the whip are tuned to.

The way a discone works will put the signal from the horisontal elements out of phase with the top whip and as they are connected to the same point they will more or less fight with each other and reduce the signal level. Only if the discone works very badly at a frequency, it doesn't produce any noticable signal strenght, will the top whip add any signal strenght to the antenna.

When the top whip are high impedance, when out of tune in some bands, will it not affect the function of the normal discone design, but if it starts to resonate and go low impedance, maybe at some multiple of its tuned frequency, will it reduce the signal strenght compared to a discone without a top whip.

/Ubbe
 

blues222

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Southwest Missouri
Analyzing discones show that the top whip could deterioate other frequency bands than the whip are tuned to.

The way a discone works will put the signal from the horisontal elements out of phase with the top whip and as they are connected to the same point they will more or less fight with each other and reduce the signal level. Only if the discone works very badly at a frequency, it doesn't produce any noticable signal strenght, will the top whip add any signal strenght to the antenna.

When the top whip are high impedance, when out of tune in some bands, will it not affect the function of the normal discone design, but if it starts to resonate and go low impedance, maybe at some multiple of its tuned frequency, will it reduce the signal strenght compared to a discone without a top whip.

/Ubbe
So it would be best to leave top whip off?
 

blues222

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Southwest Missouri
All metal in the air will work to receive frequencies. The difference are how well you want it to receive. As prcguy points out you could loose 10dB, that's ten times less, at 700-800Mhz using a standard discone compared to a 4 inch steel rod. Your special discone with that 27MHz arrangement could loose more than that at 700Mhz. But if you only need to receive that single transmitter site down the road then it will probably work to that.

/Ubbe
could i tune the top whip too 700mhz? or cut it too 700mhz?
 
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