Copper Talk » Ask The Tech » Ham Antennas » The least amount of wire for all-hf band dipole? « Previous Next »

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Mikefromms
Intermediate Member
Username: Mikefromms

Post Number: 346
Registered: 6-2003
Posted on Wednesday, December 29, 2004 - 9:48 am:   Edit Post Delete Post    Move Post (Moderator/Admin Only)

Just wondering what the least amount of wire I could use for an all-purpose dipole that would work well with my Kenwood TS850s internal automatic tuner? I would like to work some 160 meters but a resonant antenna there is looooong.

Any help is appreciated.

mikefromms
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Tech237
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Username: Tech237

Post Number: 124
Registered: 4-2004
Posted on Wednesday, December 29, 2004 - 10:38 am:   Edit Post Delete Post    Move Post (Moderator/Admin Only)

Mike,
Give me too the weekend and I'll check my files for suitable antennas. I know I have acouple that I have used in the past.
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Mikefromms
Intermediate Member
Username: Mikefromms

Post Number: 348
Registered: 6-2003
Posted on Wednesday, December 29, 2004 - 10:57 am:   Edit Post Delete Post    Move Post (Moderator/Admin Only)

Thanks Tech237, I have plenty of copper wire. There's no hurry.

Happy Holidays!

mikefromms
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Bob_p
Advanced Member
Username: Bob_p

Post Number: 618
Registered: 7-2004
Posted on Wednesday, December 29, 2004 - 10:58 am:   Edit Post Delete Post    Move Post (Moderator/Admin Only)

If you don't mind checking for something from 10 to 80 meters I would be happy too.

Any assistance would be greatly appreciated

Bob
CEF # 362
KG6POG
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Bob_p
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Username: Bob_p

Post Number: 619
Registered: 7-2004
Posted on Wednesday, December 29, 2004 - 10:59 am:   Edit Post Delete Post    Move Post (Moderator/Admin Only)

By the way mine would need to be as short as possible.

Thanks again
Bob
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Kirk
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Username: Kirk

Post Number: 264
Registered: 6-2002
Posted on Wednesday, December 29, 2004 - 11:14 am:   Edit Post Delete Post    Move Post (Moderator/Admin Only)

Mike you could try something with traps/coils like an Alpha Delta DXB or something. They are less efficient, but practical and not bad really. I've used a DX-CC before (not sure if that covers 160 or not) and liked it, although I opted for my homebrew monoband dipoles. I don't work much 160 at all. You may end up compromising somewhere given the fact you don't have a lot of room to work with and 160 requires lots of farm. GL and Happy New Year--Kirk
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Tech833
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Username: Tech833

Post Number: 928
Registered: 8-2002
Posted on Wednesday, December 29, 2004 - 5:59 pm:   Edit Post Delete Post    Move Post (Moderator/Admin Only)

Mike.

To specifically answer your question, 70 feet of wire is what you are looking for. Your internal tuner can tune any ham band with that length over a suitable ground plane.
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Geekster
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Username: Geekster

Post Number: 146
Registered: 6-2004


Posted on Wednesday, December 29, 2004 - 7:35 pm:   Edit Post Delete Post    Move Post (Moderator/Admin Only)

I use the DXCC as well. It works up to 80 meters but I can tune it to work on 160 with a DLP tuner. I have had great success with it so far as a flatop.
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Tech8541
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Username: Tech8541

Post Number: 253
Registered: 12-2003
Posted on Wednesday, December 29, 2004 - 10:53 pm:   Edit Post Delete Post    Move Post (Moderator/Admin Only)

it needs to be at least 1/8 wave or the ambient resistance will be too much to make the antenna really useable
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Mikefromms
Intermediate Member
Username: Mikefromms

Post Number: 350
Registered: 6-2003
Posted on Thursday, December 30, 2004 - 6:04 pm:   Edit Post Delete Post    Move Post (Moderator/Admin Only)

When I said dipole, I was just talking about stringing a regular horizonal dipole up to tune in from 160 meters to 10 meters. It would be hung over earth and concrete driveway. I plan on using mini 8x for coax with some coiled at the dipole connection.

mikefromms
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That ELCO Guy (Unregistered Guest)
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Posted on Thursday, December 30, 2004 - 6:54 pm:   Edit Post Delete Post    Move Post (Moderator/Admin Only)

A full size dipole for 160 M is an long piece of wire. That had better be a very long driveway.

The formula for a dipole in Feet is 468 divided by the frequency in mhz. Figure out the length of the antenna wire by plugging in the the LOWEST FREQUENCY you will be using.

Might I suggest that you feed the antenna NOT with coax but rather with 450 ohm ladder line running the ladder line into a tuner. The SWR on the antenna will be out of sight and that much feedback demands a balance feedline aka 450 ladder line be used to feed your dipole. By using ladder line you will make the dipole a multiband antenna.

For a 160 meter antenna at 1.90 mh in the 160 meter band the length of the dipole would be right at 246 feet long...468 divided by 1.9.

IF you make the dipole for 160 meters might I suggest that you use no smaller than #12 copper wire due to the stress the sag will be putting on the wire. A good place to find that much wire fairly inexpensive is at the Home Improvement Stores or electrical contractor supply houses in your area. Look for the contractors bulk spools of wire.

In parting, remember to keep all parts of the antenna OUT OF REACH when installing the antenna.





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Mikefromms
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Username: Mikefromms

Post Number: 352
Registered: 6-2003
Posted on Friday, December 31, 2004 - 6:57 am:   Edit Post Delete Post    Move Post (Moderator/Admin Only)

Thanks. I know the formulas. I really don't want to put up an antenna that long. I could live with a 100ft. I use mini 8x on my 10,11 meter dipole and it works well without a tuner. Less than 1:1 on channel 38, 39.

I have considered ladder line but where does it hook up in the back of the Kenwood TS850S?

mikefromms
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Mikefromms
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Username: Mikefromms

Post Number: 356
Registered: 6-2003
Posted on Saturday, January 01, 2005 - 5:32 pm:   Edit Post Delete Post    Move Post (Moderator/Admin Only)

Hey, this is a good question. Is there an adaptor? Never used ladder line.

mikefromms
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That Elco Guy (Unregistered Guest)
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Posted on Sunday, January 02, 2005 - 12:18 am:   Edit Post Delete Post    Move Post (Moderator/Admin Only)

Re Mike...

Relpy to statement of 100 ft. A dipole for 80 meters is approx 120 to 130 feet long if you do not use a trap to electricly shorten it. I wish I could tell ya better news but physics are physics.

HOWEVER you can use that coax IF you purchase one of those commercial made vertical antennas. Some even go as low in frequency as 80 meters. Just remember to follow manufacturer recommendatins on assembly, installation and the need for counterpoises.

As to your question on adaptor its not about adaptor, do they have one? The question you need to ask: is the radio made for a 450 ohm input. In all modern ham rigs that I know of the answer is a simple no. You have to tune the input down to 50 ohms using some kind of tune device such as an antenna tuner.

In Closing, if you acquire a half decent antenna tuner you could possibly "Tune" that 80 meter dipole to 160 meters. The results will of course not be optimal but at least you are able to go there (on 160 meters). Better than nothing.





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Mikefromms
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Username: Mikefromms

Post Number: 357
Registered: 6-2003
Posted on Sunday, January 02, 2005 - 7:14 am:   Edit Post Delete Post    Move Post (Moderator/Admin Only)

What about the 70 ft all hf-band dipole they sell? It claims to do it all, but has ladder line.

mikefromms
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Tech833
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Username: Tech833

Post Number: 932
Registered: 8-2002
Posted on Sunday, January 02, 2005 - 11:42 am:   Edit Post Delete Post    Move Post (Moderator/Admin Only)

"What about the 70 ft all hf-band dipole they sell? It claims to do it all, but has ladder line.

mikefromms"

That would ge the G5RV. It works O.K., but is certainly NOT the most high performance thing out there. They still require a tuner, BTW.
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Bob_p
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Username: Bob_p

Post Number: 657
Registered: 7-2004
Posted on Friday, January 21, 2005 - 2:24 pm:   Edit Post Delete Post    Move Post (Moderator/Admin Only)

I see above a post saying that the length of wire for resonate properly has to be at least 1/8ths of a wave length to work, and another that says an 80 meter dipole will work on 160m with a tuner. So how about a shortened 40-meter dipole? Will it work on 80m with a tuner? If it will work on 80m will the performance be at least reasonable? Or should a 40-meter dipole be used as a mono-bander only?

I was pretty much sold on the Gap Titan DX, but have read some pretty negative reviews on it's over all performance, and particularly on 40 and 80 meters, so I’m looking at some alternatives.

Thanks in advance
Bob

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Tech833
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Username: Tech833

Post Number: 962
Registered: 8-2002
Posted on Friday, January 21, 2005 - 7:55 pm:   Edit Post Delete Post    Move Post (Moderator/Admin Only)

The Gap antenna is not a full-size performer on 40 or 80, so if you compare it to a full-length wire dipole, surprize! The wire will work better than the Gap. Go figure... However, if you compare the Gap to a 'screwdriver' antenna or some other shortened antenna on 40 or 80, the Gap will perform better.

Length is everything, do not forget that. A 9 foot whip will work better than a 2 foot loaded whip on CB, right? Same thing, no matter how fancy you make the 2 foot antenna, the 9 foot whip will still work better. Same thing on any band, even 40 or 80m.
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Tech833
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Username: Tech833

Post Number: 963
Registered: 8-2002
Posted on Saturday, January 22, 2005 - 2:53 pm:   Edit Post Delete Post    Move Post (Moderator/Admin Only)

BTW, my dad has a Gap Titan DX and he loves it. Although it really shines on 20m and up, it does work O.K. on 40 and 80 too. I have been to his house and DXed on 40 and 80 with it. Worked pretty well from what I could tell. I did not have a full-length wire antenna to A-B compare, so it is entirely subjective. I prefer to only report facts to you here. Keeping that in mind, I can tell you for a fact that the Gap does work DX on 40 and 80. Oh, and for some of you.... It worked very well on 11m!
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Kid_vicious
Intermediate Member
Username: Kid_vicious

Post Number: 168
Registered: 9-2004
Posted on Sunday, January 23, 2005 - 11:36 pm:   Edit Post Delete Post    Move Post (Moderator/Admin Only)

hey mike, if i understand your post correctly, you have the built in tuner installed in your 850. if you have the manual, check what it says about using dipole antennas. you might be able to make the ladder line work using a balun. i used to run a G5RV, and it had a certain length of ladder line connected to a balun, and the other end of the balun had an SO-239 on it. you can run any length of coax from there back to the station. this should allow you to feed your tuner properly. BTW, my G5RV was quite inexpensive and i used it on 80 meters with a tuner.
matt
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Bob_p
Advanced Member
Username: Bob_p

Post Number: 661
Registered: 7-2004
Posted on Thursday, January 27, 2005 - 1:21 am:   Edit Post Delete Post    Move Post (Moderator/Admin Only)

Tech833 Thank for the report on the TitianD X. It's great to hear good reports from soneone I trust that has actually used the antenna, rather than reading reviews by people who might or might not know what the heck they're talking about.
I really liked the idea that I could mount the Titan on top of the house, and not have to worry about running a bunch of radials since I have the problem with space limitations.

I'm thinking the take-off angle on the Titan DX would be better for DX than it would be on a 1/2 wave 40 meter dipole. Mounted broad side facing north and south along the roof top at about 30 feet at the high end sloping down to about 20 feet at the low end, and DX is what I am most interested in.

Bob
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Honkytonkman593
Intermediate Member
Username: Honkytonkman593

Post Number: 163
Registered: 12-2001
Posted on Saturday, January 29, 2005 - 6:10 pm:   Edit Post Delete Post    Move Post (Moderator/Admin Only)

well im ready to get flamed but i bought the all band internet auction special with 70ish feet of dipole and half 450 ohm ladderline and half rg8x. it works well for a basic antenna. but i use a mfj tuner not an internal one of the radio cause most transcievers cant tune over 150 ohms of resistance verses the 50 ohms it wants. mine works 10/11/12/15/17 a lil arcing but does tune there/ 20/40 and i havent tried higher. this antenna works not 100 percent efficient but what does anymore( or ever did for that matter).good luck with your choice and adventures in antennas......
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Tech833
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Username: Tech833

Post Number: 979
Registered: 8-2002
Posted on Sunday, January 30, 2005 - 10:58 am:   Edit Post Delete Post    Move Post (Moderator/Admin Only)

Honky,

If you bought the G5RV (the real one) you would not be having these problems. The cheapie internet copies of the G5RV design have always been disappointing. Sorry.
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Karatebutcher
Senior Member
Username: Karatebutcher

Post Number: 1944
Registered: 7-2002
Posted on Friday, April 22, 2005 - 9:23 pm:   Edit Post Delete Post    Move Post (Moderator/Admin Only)

A good base antenna for 2 meter vertical M2800 Yeasu, or should I get a 2meter 70cc.
Thanks guys and especially Lon
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Jms656
New member
Username: Jms656

Post Number: 5
Registered: 5-2005
Posted on Saturday, May 28, 2005 - 9:34 am:   Edit Post Delete Post    Move Post (Moderator/Admin Only)

I currently run an Alpha Delta DX-LB and it works pretty good, even on 160 meters and the cost is not to bad. If you are going to start running multi-band dipoles, I highly suggest that you invest in a decent antenna tuner. Normally I believe, your antenna should be a quarter wave in height above the ground. You need to be way up there on 160 meters for optimal performance.

I am currnetly looking a the following design for 160 meters. It only requires about 132' of space and the height can be as low as just under 40'

http://members.tripod.com/~KE4UYP/80m_160m_Antenna.html

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Mikefromms
Advanced Member
Username: Mikefromms

Post Number: 777
Registered: 6-2003
Posted on Tuesday, October 04, 2005 - 12:45 pm:   Edit Post Delete Post    Move Post (Moderator/Admin Only)

I ended up using a horizonal loop antenna tuned to 75 meters but my interior tuner on my Kenwood TS-850s made it very usable up thru 17 and 20 meters.

mikefromms
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N8fgb
Junior Member
Username: N8fgb

Post Number: 31
Registered: 5-2002
Posted on Friday, October 14, 2005 - 10:47 pm:   Edit Post Delete Post    Move Post (Moderator/Admin Only)

My favorite hf antenna has always been a half wave dipole cut for 80/75 meter.Use about 100ft twin lead feedline.I use an external turner for open feedline.Will tune 80-10 meter.For 160 tye both feddline leads to single wire terminal and a counterpoise cut as long as possible.I doubt the internal tuner will have the range you are looking for.
Rich
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Rldrake
Junior Member
Username: Rldrake

Post Number: 49
Registered: 1-2006
Posted on Sunday, February 05, 2006 - 9:23 pm:   Edit Post Delete Post    Move Post (Moderator/Admin Only)

Best for 160 meters and up...either the longest loop that will fit your property, fed with open wire feeder (450 or 600 ohm), through a GOOD high power tuner...or through a good tube amplifier with a wide loading network. If it must be a dipole...again the longer the better. You can't make it too long (same with the loop). If there is not enough real estate, make it as long as space allows. Feed it in the same manner as the loop. Third choice...fan dipole fed with real 213 (mil spec) unbalanced feedline. Fourth choice (if not running high power)...either the longest dipole or loop possible, fed with 213, with an autocoupler AT THE ANTENNA'S FEEDPOINT. The fan dipole will give the best all band coverage if you insist on using the transceivers internal auto-tuner.
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Mikefromms
Senior Member
Username: Mikefromms

Post Number: 1107
Registered: 6-2003
Posted on Wednesday, December 14, 2011 - 6:04 pm:   Edit Post Delete Post    Move Post (Moderator/Admin Only)

After several years of learning and experimenting, I reread this thread and there is some really good information here. There's nothing like experimenting and discovering what many have known for years!
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Tech237
Moderator
Username: Tech237

Post Number: 1503
Registered: 4-2004


Posted on Friday, December 16, 2011 - 8:48 am:   Edit Post Delete Post    Move Post (Moderator/Admin Only)

A 80m fullwave loop (72ft per leg) works well on all bands, including 160.
Tech237
N7AUS

God made me an athiest, who are you to question his wisdom?

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