1/2 wave resonant inverted v dipole ?

[Cold War Vet]

Guys
i thank you all for the input i think im going to abandon the all RG-6 multiband fan dipole and go with whats proven for now and experiment later ( i just want to get on the air after i pass my tests )( i had RG-6 on hand ) im still looking for a way to be able to do 80 - 10 meters on one dipole in limited space
using whatever i can to achieve this

thank you all for the input CWV

 

[Road Squawker]

save the RG-6,.... it will be useful for other antennas

as far as an 80 meter multiband antenna, you will be hard pressed to get an efficient one in your space without using loading coils.... do a search for linear loaded dipoles.... they do work well.. a dB(+/-) of loss isn't important for now.

also , good info here too https://www.google.com/url?sa=t&rct...w.k7mem.com/&usg=AOvVaw0Tku7H4SKuIhVrexCaWSNg

 

[Road Squawker]

I forget that I shouldn't make bad jokes here. Thank you for the much needed clarification.

No problem on my end, but,.... the OP is a self described newbie and is looking for good basic info.

if it were me, and I had the room, I would put up a 130 (ish) foot wire and feed it with 300 ohm L.

 

[543_Dallas]

No problem on my end, but,.... the OP is a self described newbie and is looking for good basic info.

if it were me, and I had the room, I would put up a 130 (ish) foot wire and feed it with 300 ohm L.

Why 300 ohm....or even 450 ohm window line? The conductors are so close together and there is so much material between them there are issues with rain and ice. Tuning changes and loss increases.

I used to use the 450 ohm stuff. Now mine is spaced 4 inches with an insulator every 12 to 18 inches. No noticeable change wet or dry. Having as little material as possible between the conductors makes a big difference.

 

[Cold War Vet]

save the RG-6,.... it will be useful for other antennas

as far as an 80 meter multiband antenna, you will be hard pressed to get an efficient one in your space without using loading coils.... do a search for linear loaded dipoles.... they do work well.. a dB(+/-) of loss isn't important for now.

also , good info here too https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&cad=rja&uact=8&ved=0ahUKEwigrOO6vNnWAhWDXiYKHa8QA-IQFggmMAA&url=http://www.k7mem.com/&usg=AOvVaw0Tku7H4SKuIhVrexCaWSNg

RS i just checked out the link wow !!!!!! thanks for the link several options in there for me once again thanks
CWV

 

[Road Squawker]

quite frankly, because that homemade spreaders look like cr@#

...and I ain't worried about a little loss in 300 ohm LL

 

[543_Dallas]

I suppose we all have different priorities. 300 ohm twinlead and rg6 are for television sets.

 

[BJ radionut]

It’s worth noting that ladder line exhibits substantially less loss on the HF bands than just about any other transmission line available. This means you can get away with SWRs on ladder line that would cause intolerable loss with coax.

The object of any antenna system is to get RF into the antenna, and out on the air. Your transmission line plays a critical role in getting this job done. When you shortchange yourself on transmission line, you shortchange your whole station. As long as an antenna tuner is used, ladder line offers some compelling advantages compared with coaxial cable in almost any medium- or high-frequency application. This is particularly true when you want multiband operation with a single antenna.
It's also worth noting that the loss difference between 300/450 or 600 ohm transmission twin-lead is negligible in comparison to each other.
MHO + 2 cents worth
All the Best
Gary

 

[543_Dallas]

It's also worth noting that the loss difference between 300/450 or 600 ohm transmission twin-lead is negligible in comparison to each other.
MHO + 2 cents worth
All the Best
Gary

I'm more concerned with conductor gauge than impedance. A small conductor can only carry so much current. I can't use store bought feedline with my doublet so building it was my only option.

If a person is running low enough power to get away with using 300 ohm twin lead or rg6 and plan to work the lower frequencies you need the antenna to be as efficient as possible. Those neglable losses throughout the system add up.

A person who has limited space can make good use of heavy duty feedline and a short antenna made of heavy gauge wire. It will take some work but no loading, traps or fans are needed. It will even have some gain on the higher frequencies.

 

[BJ radionut]

I'm more concerned with conductor gauge than impedance. A small conductor can only carry so much current. I can't use store bought feedline with my doublet so building it was my only option.

If a person is running low enough power to get away with using 300 ohm twin lead

I fully understand your concerns.
I think this a commonly shared concept. I think most people who look at 300 Ohm twin-lead cable, are old enough to remember when 300 Ohm "TV Ribbon" was used for receiving systems, and was available in every grocery, drug and hardware store in North America.
This is not the products we are discussing.
The 300/450 Ohm twin-lead (Ladder Line) has been used by Military and Amateur's since before WWII.
The product I am presently using is 300 Ohm. This is used not only on my phasing harness between my "Phased Dipoles" (see Lazy H / but laying Horizontal).
I also use it as feedline from the tuner on my bench to antenna array.
This and similar products are available from several sources that serve the Amateur community.
This product consists of 2/18 AWG stranded/(19) copper clad steel conductors with a PVC/Teflon coating.
This product has a V.F.of 0.88% and a Power Rating of 2500 watts CCS.
(CCS)Continuous Commercial Service, for those that do not recognize that term.
This equates to roughly between 3-4+ KW PEP. IARS
This is certainly acceptable for most Amateurs in the North American region.
(even CK)
These type of products are light, easy to terminate and only have minor effects from weather conditions, (if I do not make a large frequency change or bands I can go days without ever retweeking the tuner)
The 450 Ohm products are similar in spec's and are also easily acquired.
I have zero issue with anyone building their own EVER!...but for me ease of use, weight and Windload were the determining factors.
All the Best
Gary

 

[543_Dallas]

I fully understand your concerns.
I think this a commonly shared concept. I think most people who look at 300 Ohm twin-lead cable, are old enough to remember when 300 Ohm "TV Ribbon" was used for receiving systems, and was available in every grocery, drug and hardware store in North America.
This is not the products we are discussing.
The 300/450 Ohm twin-lead (Ladder Line) has been used by Military and Amateur's since before WWII.
The product I am presently using is 300 Ohm. This is used not only on my phasing harness between my "Phased Dipoles" (see Lazy H / but laying Horizontal).
I also use it as feedline from the tuner on my bench to antenna array.
This and similar products are available from several sources that serve the Amateur community.
This product consists of 2/18 AWG stranded/(19) copper clad steel conductors with a PVC/Teflon coating.
This product has a V.F.of 0.88% and a Power Rating of 2500 watts CCS.
(CCS)Continuous Commercial Service, for those that do not recognize that term.
This equates to roughly between 3-4+ KW PEP. IARS
This is certainly acceptable for most Amateurs in the North American region.
(even CK)
These type of products are light, easy to terminate and only have minor effects from weather conditions, (if I do not make a large frequency change or bands I can go days without ever retweeking the tuner)
The 450 Ohm products are similar in spec's and are also easily acquired.
I have zero issue with anyone building their own EVER!...but for me ease of use, weight and Windload were the determining factors.
All the Best
Gary

Those ratings are good when terminated into what impedance? I did not know there was a better 300 ohm version available than what was used for television antennas years ago. I am familiar with the 450 ohm window line and have used it but it is still not an option for me if I use 80 meters. My situation is not the norm. I use a 70 ft doublet on 80 - 6 meters often at legal limit AM on 75 meters. Believe it or not it works very well for what it is. My ladder line is made from #8 thhn, the first 5 feet of the doublet is #8 and the rest is #10. The link coupled tuner is rolled from 1/4" copper tubing and my balanced L is 3/8" copper. The impedance of a 1/4 wave dipole is very low so the feed line and tuner has to deal with some serious current. Maybe one of the smarter members can do the math for how much current at X watts.

I understand the frustration of an operator with limited space like the OP. I have tried loading coils, linear loading and all of the common recommendations to overcome my limitations. They worked but were never that impressive. A fellow ham suggested I try the heavy duty doublet and home brew tuner approach. I was amazed with the outcome and can't thank him enough for the advice. I'd love to see others with limited space put the information to good use and get out of the static. It is not plug and play but the end result was well worth it.

 

[BJ radionut]

Dallas: Yes I can see using what essentially is a 40 meter dipole and loading it for 80m might be considered a special problem. Then add AM service to the loop!
Please do you have any pictures you can post that shows your antenna set-up...curiosity is my plague.
I would also love to see pictures of your tuners...I enjoy the art of American Engineering.
I have several that I use, one is a HB Double "L" built from parts and case from a Dentron MT2000A...also have a PALSTAR AT4K, both serve me well for my set-up.
All the Best
Gary

 

[543_Dallas]

Dallas: Yes I can see using what essentially is a 40 meter dipole and loading it for 80m might be considered a special problem. Then add AM service to the loop!
Please do you have any pictures you can post that shows your antenna set-up...curiosity is my plague.
I would also love to see pictures of your tuners...I enjoy the art of American Engineering.
I have several that I use, one is a HB Double "L" built from parts and case from a Dentron MT2000A...also have a PALSTAR AT4K, both serve me well for my set-up.
All the Best
Gary

These are the tuners. No tuner needed for 17 and part of 6. I use the choke rolled with the mini 8 for that. There is a 70pf cap across the so239 to get a better match.


The spreaders for the ladder line are 4" electric fence insulators. I bought them at Tractor Supply Co.



This is #10 ladder line made with the same spreaders.

 

[wavrider]

Pictures

 

[wavrider]

Pictures are worth a thousand words.
Then again some would prefer to say a thousand meaningless words and make claims that can not be backed up with pictures.