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Author Topic: Buddipole antenna  (Read 9924 times)
AB3QK
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Posts: 3




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« on: August 22, 2011, 12:41:59 PM »

I live in a condo, third floor, facing mostly due west.  I've been a General class ham since 2009, recently bought a new ICOM 718 HF transceiver, MFJ 940E tuner.  Frustrated is putting it mildly.!  Does anyone know anything about the buddipole?  Does it need to run thru a tuner (buddipole people say no), however, I am having problems tuning the radio and getting the swr to an acceptable level without blowing the finals.  I get a pretty reading if I tune it up on AM, pretty good being 1.5:1, but when I switch over to CW, seems the swr goes nuts. Do I watch the swr on the radio, which seems to read a little lower than the tuner meter.  I have been on 20mtrs recently, SSB all looked okay. Then over CW, swr up again around 2.5:1 even 3.0.  Anyhow can anyone offer some suggestions to a newbie who really loves the hobby, and wants to operate to the best of my ability, considering my condo restrictions.  I have to keep the buddipole inside the confines of my balcony..which is difficult since to operate on 20mtrs, 15mtrs I have to extend both sides of the antenna out to about a total of 14ft...Sorry this is so long, but looking for help.
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2E0OZI
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Posts: 269




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« Reply #1 on: August 22, 2011, 01:21:31 PM »

As far as I know mate you will find it very difficult to get a SWR reading of any meaning on SSB - you need to use CW or RTTY so that you get an output thats constant if you put the key down or press the PTT on the mic. On SSB if you dont make noise not a lot is going out, and if you do (hence the infernal "whistlers" from Italy!) its all over the place anyway.

I am sure the guys on here will tell you a Buddipole is a very compromised antenna, but then again I bet most of them don't live in a condo either! I wonder of it night you could not lower a wire out the window and feed it against a counterpoise?

all the best

Scotty
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Men can only be happy when they do not assume that the object of life is happiness.
George Orwell
KQ6Q
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Posts: 971




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« Reply #2 on: August 22, 2011, 03:00:26 PM »

If you're trying to use the Buddipole indoors, all kinds of things could be affecting the setup, including RF feedback into the rig - via the mike cord or the keying connection or even the power cables. To verify the setup, take the rig, tuner and antenna outdoors to an unobstructed location, and try it there - with a decent distance between the antenna and the rig.
Contact one of your local clubs for an Elmer to come over in person and work the problem with you.  Indoor operation can be very tricky.
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W0FM
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Posts: 2054




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« Reply #3 on: August 22, 2011, 03:03:44 PM »

Hi Lou,

I have several "resonant" dipoles and can assure you that on many of the hams bands it will be difficult to get the same SWR reading in the SSB portion as in the CW portion.  That much of a frequency move on most HF bands will require you to tweak the tuner (and/or the Buddipole settings) and, even then, you still may not achieve the same match moving from SSB to CW.

Your SWR could easily be affected by the proximity of the Buddipole to your building, railing, gutters, etc.  But, a compromise antenna can still work for you.  As stated, you need a steady carrier (like CW) when adjusting an antenna tuner for the best SWR on any part of a band.  Don't attempt it with SSB.  Simply find the SSB spot where you want to transmit, flip to CW temporarily, adjust the tuner, then switch back to SSB.  Again, don't expect a flat SWR everywhere.  I've had a lot of fun over 50 years with compromise antennas.  Have fun!

73,

Terry, WØFM
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AB3QK
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Posts: 3




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« Reply #4 on: August 22, 2011, 03:23:48 PM »

Thank guys for the quick responses.  I am not using the Buddipole indoors.  I set it up outside on the balcony of my condo, but of course the only clear path it has is to the west/southwest.  The building blocks it on the east side of the antenna, looking at it from the doorway. One of the ops in my ham club suggested I tune it up on AM..but I will try on CW next time.  Good suggestion, and maybe that will work better for me.  I am so into this hobby I get frustrated when I can't operate, but I am a patient guy for a 78 year old...and I'll get 'er done as the cable guy would say.  Hope to see some of you the bands...and thanks again for the help.

73

Lou KB3LJF
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K5LXP
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« Reply #5 on: August 23, 2011, 06:45:22 AM »

Antennas are easily influenced by any conductors less than a quarter wavelength away.  You didn't mention what bands you're messing with, but even on 10M I would hazard that there are conductors within a quarter wave surrounding your balcony.

I consider the buddipole an excellent solution in search of a suitable problem and normally wouldn't bother with one, but being on the 3rd floor, even a poor antenna stands a chance of doing something useful.  Odds are though you've got some external influences that might make tuning this or any antenna a challenge.

Do you have, or have access to, an antenna analyzer?  Tuning antennas with a transmitter and an SWR meter won't tell you how far off you might be, but an analyzer would make it easier to find out where it's actually resonant and let you "walk it in".


Mark K5LXP
Albuquerque, NM
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KQ6Q
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Posts: 971




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« Reply #6 on: August 23, 2011, 02:37:38 PM »

Have you tried various orientations with the Buddipole ? Horizontal is obvious, but also try it as a vertical sloped dipole, rabbit ears, etc.  You would change the coupling to whatever else is in the vicinity that way...
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WB6BYU
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« Reply #7 on: August 23, 2011, 06:02:48 PM »

I think part of your problem is that the output power varies between modes.  If you are looking at the
reflected power, of course it will go up and down when you switch from AM to CW to SSB, because
the forward power reading also changes.

If the SWR meter on the rig gives a relatively constant reading as you increase the output power, then
that probably is the best one to be looking at.

I always tune up at the lowest possible power - typically a couple watts.  With some meters you
may need as much as 10 watts, but it shouldn't be any more than that with a 100 watt radio.
When in doubt, try driving full power into an untuned antenna:  the rig will shut back the output,
of course.  Then roll back the output power control until you see the output power drop a bit more
and use that output power for tuning.  That way you don't get confused when the reflected power
INCREASES as you get close to a match because the rig has increased output power.

The SWR shouldn't change with output power, but the reflected power will.  But if you are
too close to the bottom of the meter range the SWR will get worse with output power due to the
barrier voltage of the detector diode.  You could also have problems such as RF getting into the
transmitted audio or other things - a choke on the feedline may help in such situations.

You should be able to tune the Buddipole to resonance and get a reasonably low SWR without
a tuner, at least on the higher bands.  On 80m and perhaps 40m the feedpoint impedance will be
rather low, and a shunt coil across the feedpoint will help raise it to improve the match.  The key
is to get the dip in the SWR centered on your desired operating frequency:  if the SWR is still
high, then you have an impedance matching problem.  If the SWR is high because the dip is out
of band, then you don't have it tuned properly.

If you don't have a good balun at the feedpoint, the exact orientation of the feedline and stray
accessories in the shack can both affect the tuning of the antenna.
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K6TTE
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Posts: 70




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« Reply #8 on: August 24, 2011, 07:25:42 AM »

I too have to deal with the apartment/condo balcony location.  I use a Buddipole, but because I can't elevate it high enough, I find that the dipole configuration is less than optimal.  It functions as a NVIS antenna if you can't get enough elevation above ground level.  Instead I use it as a vertical and I've had good success with it in that configuration.  I find it's easier to tune in the vertical configuration as well.

The Buddipole folks have some helpful documents on their website that you may want to review.

Good luck!  -- Dale.
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AE5J
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Posts: 27




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« Reply #9 on: August 29, 2011, 08:21:57 AM »

Others have mentioned antenna issues, so I will mention the neatest thing since sliced bread for tuning. AES, HRO, and others all sell what is called a "one touch tune control" module for your rig. I have a 718 with one on it. It plugs in where an automatic antenna tuner would plug in on the back of your radio. (You cannot use most auto tuners with it unfortunately)

Follow the easy instuctions to install and set up the rig for it. Then, when you press the TUNER button on the front panel of the 718, the rig automatically changes to the correct carrier mode and reduces output power to 10 watts so that you can tune the antenna safely. Release the TUNER button and the rig reverts to your mode and power level you had set prior to tuning. Great.

I think the little module goes for about $33 or so. AES part number is 706TUNECONT.
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KJ6BBS
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Posts: 18




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« Reply #10 on: September 08, 2011, 04:37:54 PM »

I use a buddipole at my apartment/condo, and the first place I considered was my deck, but the it was completely walled in on all sides, and I had no effective place to set up my rig. So I decided on opting for the street level, at my garage entrance. First, I must ask, do you have a garage? If so, why not set up a mast just outside of it? The two-story complex has the gutter-line at 17 ft. high. The roof apex is another 10 ft. or so, but getting above the gutter is enough for me. I bought myself, KC1RA's 21 ft. aluminum mast, and sent my Buddipole up on that in a slight 'V' configuration (in other words each arm is set one notch above horizontal). The roof is an issue so I angle the antenna 45 degrees perpendicular to it, with the negative side of the dipole over the roof, and the positive out over open ground. I can tell you this configuration has gotten me to Japan, the East coast, and the Cook Islands on 50 watts SSB phone, and all over the globe on lower power digital modes.

I can't emphasize it enough, that getting away from the ground (height) and above the walls of the condo (escaping nearby RFI) has made a world of difference. Another aspect is stability of the mast. Keep it still or you will have high SWR jumping all over the place. I bought 2 corkscrew doggie leash holds, they go about a foot into the ground, and stabilize two sides of the mast. The third side I use a 75 lb. bounce-house sand bag with a metal latch for clipping the guy-wire to.

If you're on a covered balcony, I would suggest a tripod with a boom mounted to it, that would extend off the deck, and rig a vertical pole off the boom for mounting the antenna. Are you on the top floor? If so, then send that boom vertical up. The Buddipole is so lightweight, you could use two bounce-house sandbags to counter the horizontal load of the boom extension.

Best of luck, and 73
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WA6MJE
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Posts: 71




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« Reply #11 on: September 17, 2011, 06:01:11 PM »

I use the Buddypole system with great success.  HOWEVER, much of that success is from always using a good antenna analyzer each time I setup or QSY to another spot.  Depending on how much inductance you use with the Buddipole coils, you will have extremely small bandwidth with an acceptable SWR.  I had one of the MFJ antenna analyzers for awhile, and upgraded to a RixExpert AA-54 because it will graph your SWR so you can easily see which way to go with Buddipole tuning. I put a two port manual coax antenna switch with one port going to the RigExpert, the other to my transceiver, so I can switch over to the analyzer in a second.  Buddipole seems to suggest that once you get it all tuned up, it will work the same over and over, and I never found that to be the case.  Every day it is slightly different than the day before.  Not a problem for me. I switch to the analyzer, tweak, and then switch back to the rig. Zero problems with this. Also if you are low, then verticals work better than the Buddipole dipole configuration. When I am vertical, I use a mobile screwdriver coil that I can adjust from inside the house instead of the Buddipole coils. High-Q Antennas (and others) sell these remotely adjustable coils. So, in that configuration, I switch to the antenna analyzer, push a button on the screwdriver coil until the SWR is spot on, and never have to go out into the cold. I spent a couple of years experimenting with Buddipole in order to come up with the above configuration. I would have far less success with the Buddipole system without a good antenna analyzer at my side. Once Buddipole is at resonance, you should not have any problems. Life is good!   
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