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Author Topic: Just set up my first "real" shack after being inactive for years - difficulties  (Read 5883 times)
KB5SBM
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Posts: 14




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« on: December 04, 2010, 05:25:01 PM »

Hello All,

I became a ham at age 11, was active as a child, then time constrainsts and working in Fire and EMS kept me away for years. Recently my uncle, a long-time ham with an amazing station, gave me some gear to get on the air. It has been tough, as I live in a townhouse and have only a small attic crawlspace to hang a dipole. He has been very persistent and even mad because I am unable to copy him CW with him transmitting at 1kW via an antenna system 600' AGL from a distance of approximately 400 miles away, and he is unable to copy me CW at 100W. This is on 40 meters, using a standard 40 meter dipole.

I am getting frustrated because of the "pressure" he is putting me under and because I do not understand how my antenna can be almost perfectly resonant with 1.2:1 SWR either through my tuner or without. I am running an Icom IC-718 with LDG IT-100 Autotuner. I haven't been able to copy hardly any voice since I set up the station, and little CW.

Any ideas? I feel bad that he helped me out and is upset; but I have done everything I know and recently moved to a new area and cannot locate any active local hams. Thanks in advance.
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K1CJS
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« Reply #1 on: December 05, 2010, 12:58:42 PM »

Dipoles are somewhat directional antennas--is the dipole pointing at him?  Also, could well be that 40 meters just won't permit contacting him.  Have you tried any other bands?
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AA4PB
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« Reply #2 on: December 05, 2010, 03:22:05 PM »

The fact that an antenna has a low SWR doesn't necessarily mean that it is an efficient radiator. Remember, dummy loads have a very nice SWR across the whole spectrum but you don't make too many contacts with them.  Grin

Attic antennas often pick up a lot of noise from things inside the home (because they are close by) and that may be causing a poor signal to noise ratio on received signals. How the attic antenna radiates depends a lot on the building construction and roofing materials. There is usually a lot of metal flashing in the area plus aluminim gutters and perhaps aluminum siding.

The time of day on 40 meters has a lot to do with propogation. I used to run 5W CW to a 40M Hamstick dipole on a 5-foot mast setting on my deck about 10 foot above the ground. I reliably kept a Sat morning (9AM) schedule almost every Saturday between VA and MI.

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NN4RH
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Posts: 324




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« Reply #3 on: December 06, 2010, 03:43:30 AM »

If the uncle is really a long-time ham then he should know what's possible with your setup. Maybe he can log into eHam and tell us what's going on from his perspective to shed some light on this.

An attic dipole for 40m isn't going to be high enough off the ground to be very directional so orientation shouldn't be an issue.  It's practically NVIS and fairly isotropic. You should be able to easily hear a 1000 watt CW station 400 miles away during the daytime even if your antenna sucks. If the band "goes long" at night you might not be able to hear him, though.

That you're not hearing hardly anything at all is a clue.  

Questions that come to mind are:

- Is the roof made of metal or something else conductive?

- Is the noise level SO high that you're only making out the very strongest signals? Even if that's the case I would think you should be able to hear a 1000 watt station 400 miles away on 40 meters at least during some times of the day. Look up the callsigns of the few stations you can hear and see where they are.

- I don't know anything about the IC-718 but is it possible that you have an IF Shift so far out of whack that you're killing off your signals; and/or RIT or XIT so far off that you're no where near the frequency you think you are?
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K1CJS
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« Reply #4 on: December 06, 2010, 04:46:40 AM »

NN4RH, I brought up the directional issue because a townhouse is usually two floors, so the attic would actually be the third.
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NN4RH
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« Reply #5 on: December 06, 2010, 03:17:14 PM »

NN4RH, I brought up the directional issue because a townhouse is usually two floors, so the attic would actually be the third.

I missed the part about it being a townhouse but still that is only 30 feet up which is still pretty low for 40m.  So, ok, a little directional but not a big null like you would have if it were 60 feet.
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WX7G
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« Reply #6 on: December 07, 2010, 08:44:50 AM »

Are you and your uncle able to detect each other's signals? Can you contact any stations?

I suspect operator error and not an antenna problem.
« Last Edit: December 08, 2010, 06:16:27 AM by DAVE CUTHBERT » Logged
NO6L
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Posts: 179




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« Reply #7 on: December 07, 2010, 05:25:43 PM »


- Is the roof made of metal or something else conductive?


This is his problem. I've spoken with many, many people on even 75M using attic antennas at only 100 watts, on SSB!. So it's not the fact it's in the attic. But what may be a factor is the roofing/ceiling materials are foil backed, etc. Under certain conditions you could prune your antenna to a point where the complex impedances are at 50 ohms and you're firing all 100 watts straight into the ground or slab your apartment sits on. And, shielding the antenna from any usable signals.

And I concur, "A 1:1 VSWR does a good antenna make". Try this; Use a tuner and throw an insulated hank of green wire about 33 ft long over a tree at night so no one sees it and see if you hook up. Bet you will. Be sure to employ some kind of counterpoise, though. If you really want to buy something, consider a screwdriver antenna on an upstairs hand rail, for example. Won't work as good as the wire, but you will be heard and you'll still need a counterpoise if the rail is too small. Stay away from those 8' Hustlers with resonators, they are horribly low Q and the hamsticks lower than 20m are worse yet.

Finally, don't run more than 100 watts or so in that wire in the tree, unless you like the idea of your own personal forest fire, especially if the tree is a conifer, (pine tree).

Good luck and 73.
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VE3FMC
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WWW

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« Reply #8 on: December 08, 2010, 04:14:17 PM »


- Is the roof made of metal or something else conductive?






Finally, don't run more than 100 watts or so in that wire in the tree, unless you like the idea of your own personal forest fire, especially if the tree is a conifer, (pine tree).

Good luck and 73.

I have run 1000 watts PEP through insulated wires (as you mentioned) through trees since 1995 and there has been no fires in those trees  Grin

I do agree, if the OP is using the tuner to get a good SWR on that attic antenna that does not make it a good antenna.

I'd be curious as to what the SWR is without the tuner in line. A good tuner, (and those LDG's are pretty good at tuning out high SWR's) does not make it a good antenna.

Double check the antenna swr without the tuner. If it is above 3:1 then you need to do some work on it to lower the swr.

I have worked guys on 40 meters SSB who were running 100 watts to attic antennas and had no problems copying them from 400 + miles away. A 1000 watt CW signal can be copied on my dummy load which sits on the basement floor under my desk.
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NO6L
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« Reply #9 on: December 09, 2010, 12:59:33 AM »



I have run 1000 watts PEP through insulated wires (as you mentioned) through trees since 1995 and there has been no fires in those trees  Grin

I do agree, if the OP is using the tuner to get a good SWR on that attic antenna that does not make it a good antenna.

I'd be curious as to what the SWR is without the tuner in line. A good tuner, (and those LDG's are pretty good at tuning out high SWR's) does not make it a good antenna.

Double check the antenna swr without the tuner. If it is above 3:1 then you need to do some work on it to lower the swr.

I have worked guys on 40 meters SSB who were running 100 watts to attic antennas and had no problems copying them from 400 + miles away. A 1000 watt CW signal can be copied on my dummy load which sits on the basement floor under my desk.

I'm just using 100W as kind of a rule of thumb. Gotta remember, in a pine tree though, there is a huge amount of hydrocarbons. That's why they burn like gasoline, and, why they are by nature "gross polluters". Other trees wouldn't be a problem though.

As for a dummy load being heard in DX, many times it's "bleed through" in an antenna switch, but it's still fun to tell people in DX you're on a dummy load.

Hear, Hear! on all you said, though.

KB5SBM, please get back to us to let us know how it worked out!

73
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K8KAS
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Posts: 569




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« Reply #10 on: December 11, 2010, 06:59:31 AM »

You or I missed it, forgot to mention what time of day you were trying to use 40 meters for 400 mile skip. This is a big factor in your comm's . Conditions are getting better and afternoon skip should be fine at 400 miles but not every day. Our chat group had to QSY to 75M because we had trouble with each other on 40M at our 6 Oclock sked, were all running good antennas and 1 KW plus and we had trouble.
Keeping trying 40M is getting better as the sunspot conditions improve the short skip on 40M. 73 Denny K8KAS

PS, dipoles at 30 feet are not directional and even at 65 feet only have a 6 db endfire null, not much at all.
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W6RMK
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« Reply #11 on: December 11, 2010, 08:44:45 AM »

Can you hear WWV? 5 and 10 MHz..  What about all the 39m and 41m SW broadcast stations?

That gives you a quick "does my antenna work at all" check.  As others have pointed out, you might have noise problems or something similar.

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KE7FD
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« Reply #12 on: December 13, 2010, 09:44:38 AM »

You're gonna get tons of opinions and sage advice...  Cheesy

For what it's worth, after trying all sorts of antennas over the past 38 years, the one which gave me the most bang for the buck is the venerable horizontal loop.  An 80m loop laid out the best one can is actually in most cases better than the idealized ones in the books and modeling software.  If hung over irregular terrain the pattern distorts from the idealized reditions and can provide some amazing DX.  These things are reportably only good for "local" stuff within a few hundred miles but that's where bending the rules when installing these actually helps.  From Pittsburgh, I would routinely work into Europe, Central and South America as well as points west.  I fed the antenna with a SGC tuner which allowed me to using it on every band from 80 to 6 meters.

So why am I not using it now?  After about 8 years of being exposed to the elements I found the copper coating on the copper-weld wire had worn in places and needed to be replaced.  Down it came.  It was counter-weighted at various places which made it a good player in the wind except when trees would fall on it.  Aside from a few repairs which you would have no matter what is used, it was a great antenna.  Presently, I have a vertical up, but I hope to get the loop back up when the weather is warmer.

Welcome back and good luck,

Glen - KE7FD
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KC9MXC
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Posts: 25




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« Reply #13 on: December 18, 2010, 06:09:05 AM »

I'm sorry to hear your uncle is pressuring you so much.  This is a hobby and hopefully your uncle won't make it so distasteful that we lose you again!

All the advice here is valid in that so many factors affect our signals.  It sounds like your noise floor is extremely high in your area and that could be overpowering many signals.

Check here to see how G4ILO had a problem similar to yours:

http://www.g4ilo.com/mfj1026.html

I also have a high noise level in the shack and I know it can be pretty aggravating.  By the way check the physical condition of your feedline connectors too.  It just might be that the signal is getting waylaid somewhere between the antenna and the rig.

Merry Christmas, welcome back to the hobby and thanks for being a fireman.  Folks like you are one of the blessings of our society!

73 - Phil KC9MXC     












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