HF Antena Blues
Submitted: Saturday, Oct 28, 2006 at 19:22
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Noldi
I don't know if there is a HF whip (pardon the pun) out there but I'm having troubles with my radio.
I picked up a cheap
HF radio from a friend, but needed an AE.
Having not spent a lot on the radio, I do not want to spend a fortune on an AE. I made myself an UGLY Balun using 50 ohm CoAx, connected it to my radio via some more 50 ohm CoAx (approx 3 meters) and connected 2 wires (around 30 feet and 9 inches each) to the Balun (my calculations said 1/2 wave length of 8.022 MHz is 61.33 feet but I'm not sure this is right).
When I set it up I can generally hear VKS
Adelaide base 5/5 as
well as other VKS members around this great land. However when I transmit their reception of me is poor. Add to this a message on my radio that says "Antena out of tune".
So I purchased a Manual AE Tuner (MFJ-945E) situation seems worse, The rxed signal seems muted and I cant tune the AE in.
Would anyone have any idea where I'm going wrong All I know about the HF is what I've read over the least few weeks and a lot of it is as clear as the preverbial
Rgds
Ian
Reply By: Member - John (Vic) - Saturday, Oct 28, 2006 at 19:52
Saturday, Oct 28, 2006 at 19:52
Footloose is the bloke you want, he will be right along shortly I'm sure. LOL.
Are you a VKS member?
AnswerID:
201473
Follow Up By: Noldi - Saturday, Oct 28, 2006 at 19:56
Saturday, Oct 28, 2006 at 19:56
Thanks John, Yes Wiskey 1419 I'm amased how clear the reception is sometimes, itchin to be able to get the TX side workin
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460792
Follow Up By: Member - John (Vic) - Saturday, Oct 28, 2006 at 20:00
Saturday, Oct 28, 2006 at 20:00
Noldi what make and model is the set?
There is a Codan users group over on the Yahoo site which has some really switched on radio guys who could also be of real help link below.
Site Link
FollowupID:
460793
Follow Up By: Member - John (Vic) - Saturday, Oct 28, 2006 at 20:03
Saturday, Oct 28, 2006 at 20:03
Hmmm!! sorry copy and paste did not work try again hope this works.
Codan Group
If not just cut and paste Site Link
FollowupID:
460794
Follow Up By: Member - John (Vic) - Saturday, Oct 28, 2006 at 20:05
Saturday, Oct 28, 2006 at 20:05
OK I give up on the link think??? does not want to do anything.
Try Google to find the site. LOL.
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460795
Follow Up By: Member - John (Vic) - Saturday, Oct 28, 2006 at 20:08
Saturday, Oct 28, 2006 at 20:08
Ok hit me hard twice please!!! Now the link works.????
Noldi sorry for filling up your inbox with crap.
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460796
Reply By: Noldi - Saturday, Oct 28, 2006 at 20:08
Saturday, Oct 28, 2006 at 20:08
Thanks John,
I will go and have a look, its an old Barrett but I'll try google site anyway I may
well be doing something stupid but it would be nice to find out
AnswerID:
201475
Follow Up By: Noldi - Saturday, Oct 28, 2006 at 20:12
Saturday, Oct 28, 2006 at 20:12
P.S. john I don't know much about forums but both those links worked for me ;-)
FollowupID:
460798
Follow Up By: Member - John (Vic) - Saturday, Oct 28, 2006 at 20:54
Saturday, Oct 28, 2006 at 20:54
Yeah they worked for me second time round???
Not sure why they did not work straight away.
I first thought that maybe the recent site changes were playing funny buggers with the link settings, obviously not.
Anyway no hassles just gives you another option.
Cheers
FollowupID:
460805
Reply By: Mike Harding - Saturday, Oct 28, 2006 at 20:36
Saturday, Oct 28, 2006 at 20:36
Consider making a dipole antenna along these lines:
http://www.arrl.org/tis/info/pdf/9304064.pdf
make the arms as long as possible (the 80m length would be good) and use your antenna tuner to match it to your radio.
Mike Harding
AnswerID:
201481
Follow Up By: Mike Harding - Saturday, Oct 28, 2006 at 20:39
Saturday, Oct 28, 2006 at 20:39
This Amateur Radio club also make an excellent range of whip antennas - one of them is suitable for VKS737.
www.qsl.net/vk3frc/
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Follow Up By: Noldi - Saturday, Oct 28, 2006 at 21:04
Saturday, Oct 28, 2006 at 21:04
Thanks Mike,
will follow up on both of those, though the whip seems the easiest solution
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Follow Up By: Mike Harding - Saturday, Oct 28, 2006 at 21:10
Saturday, Oct 28, 2006 at 21:10
Whip antennas are not very efficient at the HF frequencies and a bit of wire up in the trees will beat a whip hands down - having said that; a whip is a lot easier to use especially in a daily changing situation. It can be a pain trying to get an inverted vee dipole set up but it will always out-perform a whip - ideal if you are in one spot for a few days. I take both - a FAMPARC whip and an 80m inverted vee and use them as appropriate for my situation.
Mike Harding
FollowupID:
460811
Reply By: Footloose - Saturday, Oct 28, 2006 at 21:20
Saturday, Oct 28, 2006 at 21:20
It seems when you called I was out :))
The reason you're having problems on 8022 is that you have an impedance mismatch. Ditch the balun and feed a 29ft 6" piece of wire directly into the centre of your so239 aerial socket. The other end should be strung up as high as you can get it. Run it in the general direction of the required 737 base.
If you're still not happy, follow Mike hardings advice.
AnswerID:
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Follow Up By: Member - John (Vic) - Saturday, Oct 28, 2006 at 21:37
Saturday, Oct 28, 2006 at 21:37
Sorry Footy, hope I didn't upset your dinner. LOL. ;-)
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Follow Up By: Noldi - Saturday, Oct 28, 2006 at 21:48
Saturday, Oct 28, 2006 at 21:48
Thanks footloose, sorry to be a bit slow, but are you sayng just a single piece of wire, no coax no balun and no tuner? In this modern world it sounds way to simple
Rgds
Ian
FollowupID:
460827
Follow Up By: Footloose - Saturday, Oct 28, 2006 at 22:30
Saturday, Oct 28, 2006 at 22:30
Thats it mate. The actual impedance at the end of the wire has to match the output impedance of the set (50 ohms). But the actual impedance (lets call it "Z") varies with the length of the wire, diameter, how close it is to the car body, how far above ground etc . I find the length I gave to be accurate enough. You can always experiment by shortening or lengthening it by say 6 ". Or by varying its height.
(I make it easy by using an aerial analyzer).
You can also run a bit of 50 ohm coax outside and use a whip base, attaching the wire to the centre of its so239 connector.
Just stay away from the burnee bits when transmitting. Oh and try and earth the set chassis if possible (car chassis ?)
FollowupID:
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Follow Up By: HJ60-2H - Sunday, Oct 29, 2006 at 09:50
Sunday, Oct 29, 2006 at 09:50
111.5' for the random wire seems to be a good length. If its a dipole the 2x67' should work.
A counterpoise ( wire of the same length or longer to the antenna atatched to the outer sheath of the antena plug) may also help.
FollowupID:
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Follow Up By: Mad Dog - Vic - Sunday, Oct 29, 2006 at 19:31
Sunday, Oct 29, 2006 at 19:31
Footy, how do you arrive at the impedance mismatch, looks like he's using a dipole with a 1:1 balun, if it's all made ok the impedance should be pretty much alright, if the length is ok it'll work ok without the balun with some stray radiation as you know.
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Follow Up By: Footloose - Sunday, Oct 29, 2006 at 19:35
Sunday, Oct 29, 2006 at 19:35
Mad dog, you are right. But I was advising him to use a 1/4 wave, not a 1/2 wave.
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Follow Up By: Mad Dog - Vic - Sunday, Oct 29, 2006 at 19:59
Sunday, Oct 29, 2006 at 19:59
yeah I know but I was curious as to how you arrived at the mismatch, if it's built correctly it should be ok but yes these problems can difficult to diagnose at a distance. I thought he must have stuffed the balun up or his diople length was crook but he may like me be in a bad position for HF.
My home is shocking, I spent a lot of time mucking around with antennas before coming to that conclusion, my ute HF with a whip does better 300 metres down the road than a wire strung up 10 metres at
home....RF black hole :)
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Reply By: Sign-man - Sunday, Oct 29, 2006 at 13:11
Sunday, Oct 29, 2006 at 13:11
I'm the operator on
Adelaide base this arvo.
If you wish to do radio checks- I would be more than happy.
Don't forget he Winter (daylight saving) schedule...
AnswerID:
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Follow Up By: Sign-man - Sunday, Oct 29, 2006 at 13:12
Sunday, Oct 29, 2006 at 13:12
ps...I do mean Sunday!!
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Reply By: Noldi - Sunday, Oct 29, 2006 at 21:22
Sunday, Oct 29, 2006 at 21:22
Thanks everyone, its great to get the huge cross section on thoughts and idea's on this.
My plan of attack with this is;
1, make a new 1/4 AE as sugested (29' - 6").
2, try it at
home and out in the bush (to make sure the location is not a factor). 3, try and see if I can find someone in
Perth that has a working setup and ask if I can connect my Barret to their AE to double check the radio.
4, come back here and hopfully tell you all is
well, or give you an update on whats happening.
I will try
Adelaide base but not tonight, just got
home from a great day in the sand with a mate thats just bought his first 4WD, he's hooked and I'm knackered.
Again Thanks and I will get back to you all and let you know how I get on.
Rgds Ian
AnswerID:
201672
Follow Up By: Member - Jerry C (WA) - Tuesday, Oct 31, 2006 at 00:54
Tuesday, Oct 31, 2006 at 00:54
Hi Noldi,
If you are in the Bibra Lake area drop into Barrett Communications, I am sure that their service section would do a check on your radio, or in East
Perth try WACB in Lord St, or Canning Vale there is Terlin Outback Antennas, there may not even be a charge for a quick check.
Best of luck, Jerry.
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Reply By: Noldi - Tuesday, Oct 31, 2006 at 10:07
Tuesday, Oct 31, 2006 at 10:07
Thanks Jerry will do
AnswerID:
202008