Discussion:
300 or 450 Feeder
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Guy G4DWV 4X1LT
2018-04-06 23:54:53 UTC
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Hi,

Which is best to feed a boublet? 300 or 450 ladder feeder.

Many thanks
--
73 de Guy G4DWV/4X1LT
Graham.
2018-04-07 02:29:04 UTC
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Post by Guy G4DWV 4X1LT
Hi,
Which is best to feed a boublet? 300 or 450 ladder feeder.
Many thanks
600 ohm open wire maybe? I've got a reel of 450 ohm for my proposed
doublet project.

It's going to be a 40m band Inverted V and we will see how well it
performs on the higher bands.

I have built a genuinely balanced ATU, most people compromise with
what is really an unbalanced one with a balun thrown in.

I've got a 20ft pole, and now the good weather has arrived...

I must get a wideband TV aerial to replace the C/D one pointing at
Winter Hill, kill two birds etc.
I've got new co-ax for that.

If it all miraculously works we will have that shed I promised you
about a decade ago.

73,
G3ZVT
--
Graham.
%Profound_observation%
Guy G4DWV 4X1LT
2018-04-08 12:03:07 UTC
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On Sat, 07 Apr 2018 03:29:04 +0100, just as I was about to take a
Post by Graham.
It's going to be a 40m band Inverted V and we will see how well it
performs on the higher bands.
I'm hoping for am 80-10m doublet, as far off W-E as I can in my garden
of that direction. I live halfway down a hill (just like the old days
in Prestwich).

Do you think a ground wave or NVIS could schlep from North Manchester
to Barnet EN4 8QE? I could just make a sked on 17m with a relative in
Potter's Bar.
--
73 de Guy G4DWV/4X1LT
Guy G4DWV 4X1LT
2018-04-08 12:19:00 UTC
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On Sun, 08 Apr 2018 13:03:07 +0100, just as I was about to take a
Post by Guy G4DWV 4X1LT
I'm hoping for am 80-10m doublet, as far off W-E as I can in my garden
of that direction
Hope to get it up (snigger) before the Holyland Contest at the end of
the month.

Must also get the callsign I used last year for 23nd April, viz
GB2SGD.
--
73 de Guy G4DWV/4X1LT
Brian Morrison
2018-04-08 12:36:08 UTC
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On Sun, 08 Apr 2018 13:03:07 +0100
Post by Guy G4DWV 4X1LT
Do you think a ground wave or NVIS could schlep from North Manchester
to Barnet EN4 8QE? I could just make a sked on 17m with a relative in
Potter's Bar.
Would be surprised at that frequency...
--
Brian Morrison

"I am not young enough to know everything"
Oscar Wilde
Spike
2018-04-07 08:31:37 UTC
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Which is best to feed a doublet? 300 or 450 ladder feeder.
Many thanks
The nature of your question suggests your knowledge of doublets is
lacking. You may be doomed to disappointment as a result.

The most important thing about doublets is to ensure that both legs of
the feeder carry equal currents. Few Amateurs seem to bother to measure
this, but it can be done with two 20p light bulbs and one or two minor
non-electronic parts.

Ask yourself:

Why are equal feeder currents important?

If the currents are unequal, how could they be equalised?

What effect(s) would result from unequal feeder currents?

Why is the ladder-line feeder impedance largely irrelevant?
--
Spike

"RSGBTech is meant for everyone", or so the RSGB says. The group is
moderated 'to
ensure that the questions are on topic', but the group's own admissions
policy mention
(a pre-) 'vet', 'known', 'trouble', and 'maker', but not the vetting
policy! None of these are
'moderation' issues and none are mentioned in the RSGB's Guidelines.....
Jeefaw K Effkay
2018-04-07 08:36:32 UTC
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Post by Spike
Which is best to feed a doublet? 300 or 450 ladder feeder.
Many thanks
The nature of your question suggests your knowledge of doublets is
lacking. You may be doomed to disappointment as a result.
The most important thing about doublets is to ensure that both legs of
the feeder carry equal currents. Few Amateurs seem to bother to measure
this, but it can be done with two 20p light bulbs and one or two minor
non-electronic parts.
Why are equal feeder currents important?
If the currents are unequal, how could they be equalised?
What effect(s) would result from unequal feeder currents?
Why is the ladder-line feeder impedance largely irrelevant?
I'm asking myself where one can buy light bulbs for 20p?
Spike
2018-04-07 09:00:10 UTC
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Post by Jeefaw K Effkay
Post by Spike
Which is best to feed a doublet? 300 or 450 ladder feeder.
Many thanks
The nature of your question suggests your knowledge of doublets is
lacking. You may be doomed to disappointment as a result.
The most important thing about doublets is to ensure that both legs of
the feeder carry equal currents. Few Amateurs seem to bother to measure
this, but it can be done with two 20p light bulbs and one or two minor
non-electronic parts.
Why are equal feeder currents important?
If the currents are unequal, how could they be equalised?
What effect(s) would result from unequal feeder currents?
Why is the ladder-line feeder impedance largely irrelevant?
I'm asking myself where one can buy light bulbs for 20p?
I have receivers with 2.5V and 6V indicator bulbs, which are also ideal
for this kind of feeder task. I bought several strips of them at a rally
many years ago and I doubt they were even 10p each. I have enough to
last 50 to 100 years, so I guess they'll wind up in landfill when I pop
my clogs.

Amazon have some for 34p each (pack of 10) but the current rating is a
little high.

http://amzn.eu/eKsiiIz

Still, much cheaper than an analyser, though.
--
Spike

"RSGBTech is meant for everyone", or so the RSGB says. The group is
moderated 'to
ensure that the questions are on topic', but the group's own admissions
policy mention
(a pre-) 'vet', 'known', 'trouble', and 'maker', but not the vetting
policy! None of these are
'moderation' issues and none are mentioned in the RSGB's Guidelines.....
Jim GM4DHJ ...
2018-04-07 09:46:23 UTC
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Post by Spike
Post by Jeefaw K Effkay
Post by Spike
Which is best to feed a doublet? 300 or 450 ladder feeder.
Many thanks
The nature of your question suggests your knowledge of doublets is
lacking. You may be doomed to disappointment as a result.
The most important thing about doublets is to ensure that both legs of
the feeder carry equal currents. Few Amateurs seem to bother to measure
this, but it can be done with two 20p light bulbs and one or two minor
non-electronic  parts.
Why are equal feeder currents important?
If the currents are unequal, how could they be equalised?
What effect(s) would result from unequal feeder currents?
Why is the ladder-line feeder impedance largely irrelevant?
I'm asking myself where one can buy light bulbs for 20p?
I have receivers with 2.5V and 6V indicator bulbs, which are also ideal
for this kind of feeder task. I bought several strips of them at a rally
many years ago and I doubt they were even 10p each. I have enough to
last 50 to 100 years, so I guess they'll wind up in landfill when I pop
my clogs.
Amazon have some for 34p each (pack of 10) but the current rating is a
little high.
http://amzn.eu/eKsiiIz
Still, much cheaper than an analyser, though.
better just swishing the vfo ......
Spike
2018-04-08 10:56:54 UTC
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Post by Jim GM4DHJ ...
Post by Spike
Post by Jeefaw K Effkay
Post by Spike
Which is best to feed a doublet? 300 or 450 ladder feeder.
Many thanks
The nature of your question suggests your knowledge of doublets is
lacking. You may be doomed to disappointment as a result.
The most important thing about doublets is to ensure that both legs of
the feeder carry equal currents. Few Amateurs seem to bother to measure
this, but it can be done with two 20p light bulbs and one or two minor
non-electronic  parts.
Why are equal feeder currents important?
If the currents are unequal, how could they be equalised?
What effect(s) would result from unequal feeder currents?
Why is the ladder-line feeder impedance largely irrelevant?
I'm asking myself where one can buy light bulbs for 20p?
I have receivers with 2.5V and 6V indicator bulbs, which are also
ideal for this kind of feeder task. I bought several strips of them at
a rally many years ago and I doubt they were even 10p each. I have
enough to last 50 to 100 years, so I guess they'll wind up in landfill
when I pop my clogs.
Amazon have some for 34p each (pack of 10) but the current rating is a
little high.
http://amzn.eu/eKsiiIz
Still, much cheaper than an analyser, though.
better just swishing the vfo ......
That won't help in measuring feeder currents.....
--
Spike

"RSGBTech is meant for everyone", or so the RSGB says. The group is
moderated 'to
ensure that the questions are on topic', but the group's own admissions
policy mention
(a pre-) 'vet', 'known', 'trouble', and 'maker', but not the vetting
policy! None of these are
'moderation' issues and none are mentioned in the RSGB's Guidelines.....
Jim GM4DHJ ...
2018-04-08 16:26:01 UTC
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Post by Spike
Post by Jim GM4DHJ ...
Post by Spike
Post by Jeefaw K Effkay
Post by Spike
Which is best to feed a doublet? 300 or 450 ladder feeder.
Many thanks
The nature of your question suggests your knowledge of doublets is
lacking. You may be doomed to disappointment as a result.
The most important thing about doublets is to ensure that both legs of
the feeder carry equal currents. Few Amateurs seem to bother to measure
this, but it can be done with two 20p light bulbs and one or two minor
non-electronic  parts.
Why are equal feeder currents important?
If the currents are unequal, how could they be equalised?
What effect(s) would result from unequal feeder currents?
Why is the ladder-line feeder impedance largely irrelevant?
I'm asking myself where one can buy light bulbs for 20p?
I have receivers with 2.5V and 6V indicator bulbs, which are also
ideal for this kind of feeder task. I bought several strips of them
at a rally many years ago and I doubt they were even 10p each. I have
enough to last 50 to 100 years, so I guess they'll wind up in
landfill when I pop my clogs.
Amazon have some for 34p each (pack of 10) but the current rating is
a little high.
http://amzn.eu/eKsiiIz
Still, much cheaper than an analyser, though.
better just swishing the vfo ......
That won't help in measuring feeder currents.....
best power out or lowest shwaaaaar....
--
Resistance is not futile ...
Spike
2018-04-08 11:20:29 UTC
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Post by Spike
Post by Jeefaw K Effkay
Post by Spike
The most important thing about doublets is to ensure that both legs of
the feeder carry equal currents. Few Amateurs seem to bother to measure
this, but it can be done with two 20p light bulbs and one or two minor
non-electronic  parts.
I'm asking myself where one can buy light bulbs for 20p?
Amazon have some for 34p each (pack of 10) but the current rating is a
little high.
http://amzn.eu/eKsiiIz
These are a massive 87.5p each, but have the advantage of being 3.5V 0.2A:

http://amzn.eu/7l6wJYa

So much cheaper than an analyser, though.
--
Spike

"RSGBTech is meant for everyone", or so the RSGB says. The group is
moderated 'to
ensure that the questions are on topic', but the group's own admissions
policy mention
(a pre-) 'vet', 'known', 'trouble', and 'maker', but not the vetting
policy! None of these are
'moderation' issues and none are mentioned in the RSGB's Guidelines.....
Stephen Thomas Troll
2018-04-08 11:39:24 UTC
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Raw Message
Post by Spike
Post by Spike
Post by Jeefaw K Effkay
Post by Spike
The most important thing about doublets is to ensure that both legs
of the feeder carry equal currents. Few Amateurs seem to bother to
measure this, but it can be done with two 20p light bulbs and one or
two minor non-electronic  parts.
I'm asking myself where one can buy light bulbs for 20p?
Amazon have some for 34p each (pack of 10) but the current rating is a
little high.
http://amzn.eu/eKsiiIz
http://amzn.eu/7l6wJYa
So much cheaper than an analyser, though.
Burt, I reckon you've proved, Burt, proved beyond any doubt AT ALL, Burt,
that you are the man for finding bulbs. Burt. Burt, Bulb Finder General,
Burt.


Burt, Thanks, Burt.
Stephen Thomas Cole
2018-04-08 14:12:03 UTC
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Post by Spike
Post by Spike
Post by Jeefaw K Effkay
Post by Spike
The most important thing about doublets is to ensure that both legs of
the feeder carry equal currents. Few Amateurs seem to bother to measure
this, but it can be done with two 20p light bulbs and one or two minor
non-electronic  parts.
I'm asking myself where one can buy light bulbs for 20p?
Amazon have some for 34p each (pack of 10) but the current rating is a
little high.
http://amzn.eu/eKsiiIz
http://amzn.eu/7l6wJYa
So much cheaper than an analyser, though.
I find it fascinating that Burt spent an entire day Googling for cheap
light bulbs just so he could try (but fail) to save face. Amazing scenes.
--
STC / M0TEY /
http://twitter.com/ukradioamateur
Bernie
2018-04-08 15:04:51 UTC
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On 8 Apr 2018 14:12:03 GMT
Post by Stephen Thomas Cole
Post by Spike
Post by Spike
Post by Jeefaw K Effkay
Post by Spike
The most important thing about doublets is to ensure that both
legs of the feeder carry equal currents. Few Amateurs seem to
bother to measure this, but it can be done with two 20p light
bulbs and one or two minor non-electronic  parts.
I'm asking myself where one can buy light bulbs for 20p?
Amazon have some for 34p each (pack of 10) but the current rating
is a little high.
http://amzn.eu/eKsiiIz
http://amzn.eu/7l6wJYa
So much cheaper than an analyser, though.
I find it fascinating that Burt spent an entire day Googling for cheap
light bulbs just so he could try (but fail) to save face. Amazing scenes.
It got me googling balanced RF ammeters - surprisingly rare (nothing
interesting on ebay) and even the cheap ones are quite dear:

https://www.hamradio.co.uk/accessories-aerial-tuning-units-mfj-aerial-tuning-units/mfj/mfj-835-balanced-line-rf-ammeter-pd-8415.php
Kid A
2018-04-09 12:22:04 UTC
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Post by Stephen Thomas Cole
I find it fascinating that Burt spent an entire day Googling for cheap
light bulbs just so he could try (but fail) to save face. Amazing scenes.
When it comes to bulbs Burt knows his onions.

Gareth's Downstairs Computer
2018-04-07 09:47:43 UTC
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Post by Spike
Why are equal feeder currents important?
They're not, in the case of the G5RV where the ladder
section is used on some bands as part of the tuned
lengths.

OK, they are equal, but of opposite polarity.
Bernie
2018-04-07 12:06:50 UTC
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On Sat, 7 Apr 2018 09:31:37 +0100
Post by Spike
The nature of your question suggests your knowledge of doublets is
lacking. You may be doomed to disappointment as a result.
Some questions are like that, Burt.
Stephen Thomas Troll
2018-04-07 13:23:32 UTC
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Post by Spike
The nature of your question suggests your knowledge of doublets is
lacking.
Burt, don't all questions arise as a result of a lack of knowledge, Burt?
Burt, apart from Gareth's questions, of course, Burt, which arise as a
result of showboating and fat-arsed attention seeking, Burt.


Burt, Thanks, Burt.
Gareth's Downstairs Computer
2018-04-07 09:38:23 UTC
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Post by Guy G4DWV 4X1LT
Hi,
Which is best to feed a boublet? 300 or 450 ladder feeder.
Many thanks
Either, except that the 300 ohm ribbon's plastic breaks up
after exposure to sunlight.
Ian Jackson
2018-04-07 09:59:56 UTC
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Post by Gareth's Downstairs Computer
Post by Guy G4DWV 4X1LT
Hi,
Which is best to feed a boublet? 300 or 450 ladder feeder.
Many thanks
Either, except that the 300 ohm ribbon's plastic breaks up
after exposure to sunlight.
What do expect when you buy stuff with too few ohms in it?
--
Ian
Gareth's Downstairs Computer
2018-04-07 12:20:28 UTC
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Post by Ian Jackson
Post by Gareth's Downstairs Computer
Hi,
 Which is best to feed a boublet? 300 or 450 ladder feeder.
 Many thanks
Either, except that the 300 ohm ribbon's plastic breaks up
after exposure to sunlight.
What do expect when you buy stuff with too few ohms in it?
Please don't make ad ohminem remarks!
Bernie
2018-04-07 13:58:26 UTC
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On Sat, 07 Apr 2018 00:54:53 +0100
Post by Guy G4DWV 4X1LT
Hi,
Which is best to feed a boublet? 300 or 450 ladder feeder.
Many thanks
A discussion of exactly this question on eham:

http://www.eham.net/ehamforum/smf/index.php?topic=42108.0
Guy G4DWV 4X1LT
2018-04-08 11:58:07 UTC
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On Sat, 7 Apr 2018 14:58:26 +0100, just as I was about to take a herb,
Bloody hell fire! A thread with useful answers that pertain to the
question! FFS, what next? Nurse, keep on compressing my chest!
--
73 de Guy G4DWV/4X1LT
Bernie
2018-04-08 12:57:12 UTC
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On Sun, 08 Apr 2018 12:58:07 +0100
Post by Guy G4DWV 4X1LT
On Sat, 7 Apr 2018 14:58:26 +0100, just as I was about to take a herb,
Bloody hell fire! A thread with useful answers that pertain to the
question! FFS, what next? Nurse, keep on compressing my chest!
Once Burt has settled on a trope he seems to have difficulty in moving
away from it until he's completely exhausted it - you just happen to
have caught him when his light bulb trope is to the fore. Further down
the thread you've asked a question the relates to ground conductivity
and waves - he'll be better with that one.
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