# Antenna length on a track powered Te.



## smcgill (Jan 2, 2008)

O.K. I came across a TE reciever # 5471 with a short antenna.
Range **** not good!
How long can I make it by adding wire?
What is the best length from base of unit to the end of wire?
Can I put a loop @ top to hang it from above?
It's track powered, if that matters.
Thanks 
Sean


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## Greg Elmassian (Jan 3, 2008)

As long as you want on such a low frequency... up to 1/4 wavelength or even a full wavelength. The approximate length of 27 MHz is 36.4 feet. 

In your case, divide it by 4 for a 1/4 wavelength antenna, so it should be optimum around that length if stretched out straight to 9.11 feet... 

Regards, Greg


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## bottino (Feb 7, 2008)

That sounds pretty good Greg. I saw a thread on this about five years ago when I was setting up my first TE, I added 8 ft to the existing antenna, ran it through a hole in my garage wall outside, and it has worked quite well over the years. I have a second TE without the antenna extension, and it also has much less range. 
Paul


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## smcgill (Jan 2, 2008)

Thanks Greg!
I should of just e-mail you.
Sean


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## Greg Elmassian (Jan 3, 2008)

This information is probably helpful for all, so I think posting it was the right thing to do... it also encourages comments from others, so keep it up Sean! 

Regards, Greg


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## aceinspp (Jan 2, 2008)

And then we have Lewis answer over at AC.







Later RJD


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## toddalin (Jan 4, 2008)

My TE's are in the 27 MHz band, just like CB radios. Ergo, I just use a CB radio antenna to extend the range for my receivers. Works like a charm.


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## Jerry Barnes (Jan 2, 2008)

My TE Rx is in the garage, with the transformer, a good 100' from the track, my old TE and my new one work fine. No need to even extend the antenna any. The Rx has it's antenna extended up the wall vertically, but that is all.


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## Greg Elmassian (Jan 3, 2008)

Lewis knows less about RF than what dates his new stuff will arrive... I guess I need to get him a calculator.... you can look up the wavelength in feet on a number of online sites... 

Why does he keep doing this? 10 seconds on google would at least give him the wavelength... I don't expect him to understand 1/4 wavelength vs. 1/2 wavelength vs. full wavelength, but ... oh well... 

If you open your TE transmitter, you will see 2 adjustment pots, deviation (strength of modulation) and frequency... there are adjustments on the receiver too... that should explain why some have good range and others do not, even in a "clean" RF environment.... I just got a frequency counter and oscope so will be doing "tuning" for my friends... had to retune EVERY accessory receiver I had, which was SIX... 

Regards, Greg


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## Torby (Jan 2, 2008)

I measured one at 39 inches. On a receiving antenna, you can figure the longer the better.


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## Greg Elmassian (Jan 3, 2008)

Not really Tom, once you get close to the wavelength of the frequency used, then the proper sub multiples or multiples apply, just as in ANY antenna on ANY RF frequency.... Talk to an RF engineer, or take the word of someone who has actually designed antennas. 

Regards, Greg


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## SteveC (Jan 2, 2008)

Posted By Greg Elmassian on 04/08/2009 11:04 PM
{snip...}[/i] I just got a frequency counter and oscope so will be doing "tuning" for my friends... {snip...}[/i] 
There you go taking all the fun out of it, what's wrong with using a 4' florescent tube on a long-wire for adjusting?


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## Torby (Jan 2, 2008)

But he's not likely to go as far as 9 ft.


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## Greg Elmassian (Jan 3, 2008)

Yeah, I actually had a radio system (I'm a ham operator) in my car that would light a fluorescent bulb held in your hand! A lot of power there. 

On the length, you do what you can.. 

Regards, Greg


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## smcgill (Jan 2, 2008)

So Greg which is it !









9.11' or 8.6'


"As long as you want on such a low frequency... up to 1/4 wavelength or even a full wavelength. The approximate length of 27 MHz is 36.4 feet. 
In your case, divide it by 4 for a 1/4 wavelength antenna, so it should be optimum around that length if stretched out straight to 9.11 feet... "
Greg


"The most efficient antennas are cut to either full-wave, half-wave or 1/4 wave. For 27 MHz, 1/4 wave is about 8Ft 6in, so if you add enough wire to make the total wire length about 8' 6" (or 102" which is the common length of the old CB Whip antennas), and stretch it as straight as possible, you should get optimum range"
Jon Radder

Thanks 
Sean


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## Greg Elmassian (Jan 3, 2008)

I only said 9.11 feet... now that is theoretical, so small differences in the case, metal around the antenna, whether it is completely straight, etc. could make a variation. 

From a practical aspect, there would be not a lot of difference between the 2 lengths. 

Also, I just use 27 MHz for the calculation. 

In reality, the frequency is 27.045 MHz for channel 1, and you can look at the end of this page: http://www.elmassian.com/trains-mainmenu-27/dcc-battery-rc-electronics-mainmenu-225/battery-power-remote-control-mainmenu-32/aristo-rc for the frequencies for each channel on your TE should you be using a different channel.

Also this measurement is for a 1/4 wave antenna, I think a 1/2 wave would be out of the question due to length, but it would work even better... 1/4, 1/2, and full wavelengths would work, and have increasingly better performance...

You can look up "calculate wavelength in feet" on google, and find several online calculators that will convert frequency to feet... 


Regards, Greg


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## smcgill (Jan 2, 2008)

So the length I'm using now is 70" or 5'10"
If I go with 104" or 8'8' ,I guess I should see an improvement!
I hope.
Sean


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## krs (Feb 29, 2008)

Wouldn't you also need to tune the circuit, ie get the SWR below 1.5 to get optimum reception? 

...........and don't shoot me, I know next to nothing about RF, never did any design work in that area.


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## smcgill (Jan 2, 2008)

One more question!
What gauge wire to use!
Sean


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## Greg Elmassian (Jan 3, 2008)

Gauge can be thin, very little current in the wire. Yes Knut, you could do that, although you normally only tune transmitting antennas for swr, since it is normally done under power. On receiving antennas, you measure gain pretty much, i.e. you would measure the level of the received signal, easier to do, and receiving antennas are sort of less finicky than transmitting antennas... if you want to class them that way. 

I do have several swr meters myself for my ham stuff, and an oscope and freq counter, and a real service monitor that is normally used to align radios... but that stuff is overkill... 

Sean, theoretically you should see an improvement, keep the wire pretty straight for comparison testing... solder the connection when you extend the antenna... 

Regards, Greg


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## GG (Jan 1, 2009)

Greg, do I really need to scold you like I do Semper and Nick....


Did you answer Smgilll's question?... 

do you have a gauge # here... ? 


I hate people who keep their students on the edge...










gg










PS: think you are about to be added to the Semper/Nick club.... not good I say


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## krs (Feb 29, 2008)

Why would the gauge matter? 
This is an *antenna* - it doesn't carry any current to speak of.


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## GG (Jan 1, 2009)

Posted By krs on 04/09/2009 9:00 PM
Why would the gauge matter? 
This is an *antenna* - it doesn't carry any current to speak of.





My apologies if I offended you on this attempt at humor... 

Unfortunately I am not an electrical engineer. 


Regrets, 

gg


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## krs (Feb 29, 2008)

I see that Greg actually answered the "gauge" question already - I just didn't see it because it was on the previous page. 

And I'm sorry - I didn't see the humour..........when it comes to even very basic concepts in electricity, some people have the wrong idea how things work. 
I just had a Large Scaler desperately looking for a 4.5 amp 24 volt power supply because his throttle could only handle 4.5 amps and he thought the 24 volt power supply rating had to be the same as the throttle rating. 
Turns out there weren't too many 4.5 amp 24 volt supplies around.


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## Semper Vaporo (Jan 2, 2008)

Posted By Greg Elmassian on 04/08/2009 11:04 PM
Lewis knows less about RF than what dates his new stuff will arrive... I guess I need to get him a calculator.... you can look up the wavelength in feet on a number of online sites... 

Why does he keep doing this? 10 seconds on google would at least give him the wavelength... I don't expect him to understand 1/4 wavelength vs. 1/2 wavelength vs. full wavelength, but ... oh well... 

If you open your TE transmitter, you will see 2 adjustment pots, deviation (strength of modulation) and frequency... there are adjustments on the receiver too... that should explain why some have good range and others do not, even in a "clean" RF environment.... I just got a frequency counter and oscope so will be doing "tuning" for my friends... had to retune EVERY accessory receiver I had, which was SIX... 

Regards, Greg 




Greg, being a HAM, you know of these things and take them in due course, but there are those reading these forums that may not understand it at all.

Before anyone opens the TE transmitter (or any "transmitter") and starts fiddlin with those adjustement pots...

1. You MUST have some good test equipment to measure the results of your twiddling.

2. You MUST have some good knowledge of RF electronics and some specific knowledge of the circuit you are working on.

3. You MUST have an FCC license before you attempt any repairs or adjustments to a TRANSMITTER. These particular R/C transmitters may be of such a low power that just anybody can fiddle with their innards, but you'd better KNOW that for sure before you take it apart and possibly incur FINE$ from the FCC when your fiddlin' interferes with another person's devices (TV, Radio, garage door opener, pacemaker, etc.)

Also, please note, just becaue you see that the pot is maybe pointing off at about 2:00 o'clock, if you move it to the left a little bit or to the right a ways, you will probably NEVER get it back to that EXACT setting of "about 2:00 o'clock" such that the transmitter will be working the correct way... TRUST ME! Without knowledge of what you are doing and the appropriate test equipment to SEE what you are doing, you WILL just mess up the transmitter and then you will need to PAY someone who has that knowledge and test equipment to reset it back to where it goes.

I have tuned enough transmitters and receivers to know that just wiggling an adjustment can alter its characteristics such that it may need to be set to some different position to attain the same value it had before I put my claws near it.


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## Greg Elmassian (Jan 3, 2008)

Yep, the "I have a 10 amp power supply, will it be too much" question is often asked... we really need a FAQs section to explain these things... it's a tough concept at first.. 

The limits on how fine a gauge of wire is what is practical to keep from breaking.. I would use something like 22 gauge or 24 or whatever is lying around. 

To clarify: DO NOT OPEN YOUR TRANSMITTER OR RECEIVER AND PLAY WITH THE TUNING CONTROLS.

Even though I did not recommend anyone to do this, and I hope that it is clear I understand these things, I guess it is still possible for people to misinterpret.


My point was that these items have to be tuned to work, and they are not always tuned correctly.




Regards, Greg


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## Dan Pierce (Jan 2, 2008)

If adjusting the innards of a transmitter, a non-metal device is needed to turn the so called pots (should have been rf tuning coils). 
Metal instruments will change the tuning of the coils. 

If it is not broke, then do not fix it!!!!! 

Leave the tuning to the experts. 

If in the country, maybe we should feed the TE to a CB transmitter where the final power input is 5 watts. We could run trains several miles away, however illegally. Marty and Jen are almost there and need this.


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## Madstang (Jan 4, 2008)

Heres another thought maybe try using the anttenna attached to one side of a ball bearing wheel set as they use on their Aristo battery car, I had a lot of distance problems trying to get the antenna figured out.

I switched to the aformentioned way and now I have NO problems..just point the handheld at the track and wa'la. Easier then having to deal with ANY length of wire at all...that is a hassle.

Also if you have a rubber antenna, buy the metal ones from aristo, that will make a marked improvement!

IMHO

Bubba


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## Greg Elmassian (Jan 3, 2008)

From the first post, the item is a 5471 which is a trackside TE receiver. So, he's not talking about the transmitter, but Bubba's comment about adding a metal telescoping antenna to the transmitter is well taken. 

Back to what was asked, since he was talking about lengthening the antenna, I made the assumption it is really trackside, not in a car. So, if you connected the antenna from a trackside to a ball bearing wheelset, you would have about 9 feet of slack and then it would pull the cars off the track ha ha ha! 

So, I've been proceeding on the assumption it is trackside. 

As bubba says, if it is onboard, then sometimes connecting it to one of the rails helps... some people get great increases in reception, and some do not. (I suspect those who do not improve have on-board interference problems) 

OK, so covered all 3 situations, trackside receiver, on board receiver, and handheld transmitter. 

Regards, Greg


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## Madstang (Jan 4, 2008)

Posted By Greg Elmassian on 04/10/2009 8:26 AM
From the first post, the item is a 5471 which is a trackside TE receiver. So, he's not talking about the transmitter, but Bubba's comment about adding a metal telescoping antenna to the transmitter is well taken. 

Back to what was asked, since he was talking about lengthening the antenna, I made the assumption it is really trackside, not in a car. So, if you connected the antenna from a trackside to a ball bearing wheelset, you would have about 9 feet of slack and then it would pull the cars off the track ha ha ha! 


Teach me not to pay TOTAL attension!
Anyway what would running trains be without train wrecks?
You can tell I am NOT track powered....everything for me reverts to battery power...my bad!








Bubba


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## Greg Elmassian (Jan 3, 2008)

Like I said, I ASSUMED something... so you know what they say about that word! Between you and I, I believe we covered all the antenna possibilities... and yes, if it was not clear, part of "bad reception" could be "bad transmitting" so I meant what I said about "well taken" on the transmitter side!!! 

Regards, Greg


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## Dan Pierce (Jan 2, 2008)

Sean's (SGill) layout has all 3 receivers in a metal cabinet. This was mentioned in his post. 

None in engines or cars!! 

He questioned the antenna length as his trackside receivers and his accessory receiver did not have the same length antennas. 

I also use a metal cabinet to house my receivers and I do not have any range issues. 
Power supplies are 1 foot from the receivers. 
Antennas hang down past the power supplies. 
Just because it works for me does not mean it will work this way for others, RF can have a mind of its own and not obey the rules!! 

PS, I live 2 miles from Sean and have visited his layout many times.


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## smcgill (Jan 2, 2008)

So I've learned that 1/4 length of 27mgh is 9.11' +/- 
So what length is the original antenna and what length of 27 mgh were they shooting for?
Sean


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## Greg Elmassian (Jan 3, 2008)

Thanks Dan, that clears any confusion about which units in what type of usage! 

I have not had problems with power supplies close to the receivers, but some power supplies have been known to emit interference. I think that's very rare nowadays. I believe that caution from Aristo is something that's not necessarily well proven to help, as an aside. 

If I had a metal cabinet, I would find a way to get the antenna "outside" without running near a lot of metal while doing so. Also the length of the antenna would be affected if the first foot, for example, was near a lot of metal. 

After asking this question on 3 forums, Sean, what have you done and what results do you have? 

If it's a real problem, then you might want to go about this scientifically. 

Regards, Greg


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## Torby (Jan 2, 2008)

Original Length is 39 inches. I guess they're going for 1/11 wave. I don't see anything that might be a loading coil here.


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## krs (Feb 29, 2008)

Posted By Torby on 04/11/2009 8:59 AM
Original Length is 39 inches. I guess they're going for 1/11 wave. I don't see anything that might be a loading coil here.



Only Aristocraft knows what fraction of the wavelength they were shooting for - my guess is "none".
The assumption probably was that the transmission range required is very short, so any reasonable length of "antenna" will do.
I put antenna into quotation marks - all it is is a length of wire - calling that an antenna is stretching the definition of the word (although that is the intended function of the wire).

My TE "wire antenna" just lies with random twists on the ground and for the distances I have between transmitter and receiver, that works fine most of the time.

Knut


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## Greg Elmassian (Jan 3, 2008)

The "loading coil" is most likely a tunable transformer (small metal can with screw slot on top) to help resonate at the basic frequency band... 

Greg


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## smcgill (Jan 2, 2008)

Between working late & rain and Easter I will get back with my findings!
Sean


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## George Schreyer (Jan 16, 2009)

a quarter wave antenna, with a proper ground plane, presents a characteristic impedance of roughly 50 ohms at it's base. A quarter wave wire doesn't have the ground plane AND the TE input is tuned and isn't a 50 ohm load. 

That being said, a longer wire does work better, it's not really critical how long it is as long as some of it is out in the open and not parallel to the chicken wire typically found behind stucco. 

The gauge of the wire doesn't matter much either. Small wire has less surface areas (where RF current flows) and therefore presents slightly higher losses. However, we're not dealing with really marginal links here so that any wire will work.


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## Greg Elmassian (Jan 3, 2008)

George, the metal case/pcb can act as a ground plane. Can, not must. When you talk about the input is tuned, that's the tunable transformer/inductor at the antenna input, right? My understanding is it gives you the ability to tune the circuit to resonate at the desired frequency, thus improving gain. Right so far? 

Regards, Greg


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## Torby (Jan 2, 2008)

That being said, a longer wire does work better, it's not really critical how long it is as long as some of it is out in the open and not parallel to the chicken wire typically found behind stucco. 




But Greg corrects me whenever I say that


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## barnmichael (Jan 2, 2008)

Posted By Semper Vaporo on 09 Apr 2009 09:46 PM 


3. You MUST have an FCC license before you attempt any repairs or adjustments to a TRANSMITTER. These particular R/C transmitters may be of such a low power that just anybody can fiddle with their innards, but you'd better KNOW that for sure before you take it apart and possibly incur FINE$ from the FCC when your fiddlin' interferes with another person's devices (TV, Radio, garage door opener, pacemaker, etc.)




I know this is an old thread, but I need to make a little correction here. An FCC license is NOT required to make repairs or adjustments to a transmitter. That changed about 20 years ago. About the only thing you need a license for anymore is aircraft radios and marine radar. For R/C transmitters, garage door openers, 2-way radios (police, fire, taxi, plumber, etc.) all the way to 100,000 watt broadcast transmitters, NO FCC license is required.


That doesn't mean you should go in and play around if you don't know what you're doing. You should have proper knowledge and test equipment to do such things. You just don't need an FCC license. Personally, I've been in the business for around 40 years now. Be glad you don't have to fool with tubes


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## noelw (Jan 2, 2008)

Posted By SteveC on 09 Apr 2009 08:43 AM 
Posted By Greg Elmassian on 04/08/2009 11:04 PM
{snip...}[/i] I just got a frequency counter and oscope so will be doing "tuning" for my friends... {snip...}[/i] 
There you go taking all the fun out of it, what's wrong with using a 4' florescent tube on a long-wire for adjusting?








I didn't know you could light up a florescent tube with a Aristo TE TX... No enough RF even if i put the ant around a small tube.. lol.. but i use to be able to light up a 8 foot tube about 6 to 10 feet from my Mobile ant. using my 12 watt TX on 75 meters. Ran mostly here Sac-cra-tomato on 39.75 hz. 
Greg is right on Long wire.. I'm just using a C B ant. with center coil. and run both TM Rec. w/ ag. clips to it thu a 10uf small cap from each ant of the TM .. short coax to
C B ant. to to keep within the Fre. of 27 mhz. 
Grag..We need to make a pocket 25 watt Linear for our TM's . hahahaha Then I can compete with the skip. Least I could used that on my layout..I can't see or reach the other end of my layout. hahahhaaha 
Sometime in Northern Calif from back East my Remote Tug get bleed over skip so bad on 27 mhz that it will start up in rev. or rudder will turn or squirt water with the fire gun top deck at you..


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## Greg Elmassian (Jan 3, 2008)

I used to run high enough power in my mobile ham rigs that you could get a burn from the 440 MHz transmitter. If you held a florescent bulb in your hand and approached the car while in transmit, then it would light quite nicely. 

The 2 meter rig used to overload the systems in the highway patrol and come in on their radios... got lots of dirty looks... it would also get into most of the Becker radios in Mercedes. 

Regards, Greg


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## SteveC (Jan 2, 2008)

Noel

I was referring to using a fluorescent tube on a long wire antenna, roughly gauging SWR from brightness of the tube at various points along the antenna.


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## RioShay (Feb 26, 2009)

another question/clarification, can one hook up the end of a TE RX antenna to the center wire of the coaxial cable coming from a CB antenna to help extend the system's range? (i'm trying to convince linda into using an extra 500ft down the fence line)


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## Greg Elmassian (Jan 3, 2008)

well, coaxial cable is shielded.... so it will just "conduct" the signal from one place to another... and you have to be careful of the impedence. 

Are you trying to use the coax as an antenna? That just won't work. Just use bare wire. (you could hook the antenna to the shield though.) 

Regards, Greg


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## noelw (Jan 2, 2008)

Posted By SteveC on 08 Aug 2009 11:09 PM 
Noel

I was referring to using a fluorescent tube on a long wire antenna, roughly gauging SWR from brightness of the tube at various points along the antenna.









Oh.... ok Steve.. 
Was thinking you we're trying using a Aristo TM. to get it lite..

Back in the 50ths I got my fisrt house and put up an enverted "V" ant. my property line was small so had to go from corner to corner of a 50 X 100 lot. I got a bunch of guy together to help me get it up with a pully on top of yup.. 2'x 4's to make of 40 ft. mast. laf.. It busted a couple time before I findly got it guide wired up like a TV roof ant. Anyway that's how I use to ck out the resonate to see if my transmitter was loading up on 75 meters. I held a 8 foot tube up on a 12 foot laddar just after it got dark on the loaded side. And them before I knew it, Nabors call the cop that I was take the juice out of the naborshood. After that I wasen't a good nabors being I was a Ham in the naborhood..No mater what went wrong there, it was my fault if any thing happen to TV's or lights.. But I got even and lived there for 14 yrs.. laf..


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## RioShay (Feb 26, 2009)

Thanks Greg, we're not having any range problems now (in fact i'm pleasently surprised that the TE works from our patio deck), and i am kinda use to spectrum quality radio control ( i enjoy flying quarter scale warbirds). we have a CB magnetic based antenna with a long coaxial cable on it , and since the TE is around 27mhz, we thought that hooking the two together might give us rock solid range, but we're probably better to use our system just like it is, thanks. we have a couple RC ground systems, ESC's w/ reverse, and all kinds of lipo n nimh battery packs hanging around in the garage , so we're gonna put together some kind of RC loco this winter( we just have to find a loco to use), and we've got the signal bridge out on the layout, it looks good, but we haven't hooked it up yet till we get a fire extinguisher on standby ...and we'
re pretty excited about riding the Hood River Scenic R/R up in the dome car, this week


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## toddalin (Jan 4, 2008)

Posted By RioShay on 09 Aug 2009 01:14 AM 
another question/clarification, can one hook up the end of a TE RX antenna to the center wire of the coaxial cable coming from a CB antenna to help extend the system's range? (i'm trying to convince linda into using an extra 500ft down the fence line) 



I have the antenna wires from my two TEs and one RCS attached to the base nut of a CB antenna and it works fine. But I actually get better range extension by swapping out the "rubber duck" antennae with telescopic antennae in the transmitters.

For years I had the excess antenna wire coiled around the base of the CB antenna (ala, center loading). Big mistake and this actually cost me some range. I found it better just to run the excess wire up along the antenna (as high as it would go) and back down to the base and just tape the wire to the mast.


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