Thanks all for help.
I'm making a spider antenna (Rothammel), 6 beams
10 m = 2x2.5
15 m = 2x2.38
20 m = 2x5.05
40 m = 2x10.1
80 m = 2x19.8 m
Will rig it in the attic with a 1:1 balun and RG-82 double shield down to
the input and north-south direction. A multiband dipol with other words.
What do you think? I've no idea about the Q and VSWR, nor Za
Inge
----- Original Message -----
From: "Ahne Oosterhof" <[log in to unmask]>
To: <[log in to unmask]>
Sent: Sunday, February 27, 2011 8:02 PM
Subject: Re: [TN] NTC: GEC BRT 400S
>I searched BING for "+Antenna +lf" and found small ready made antennas
> covering the band you mentioned for less than $200 and some descriptions
> of
> antennas like those on your ship.
> No idea regarding which is best or even acceptably useful.
>
> Have fun,
> Ahne.
>
> -----Original Message-----
> From: TechNet [mailto:[log in to unmask]] On Behalf Of Inge Hernefjord
> Sent: Sunday, February 27, 2011 10:38
> To: [log in to unmask]
> Subject: Re: [TN] NTC: GEC BRT 400S
>
> Thanks, Steve & Blair,
>
> the manual is excellent, thanks again. Unfortunately very little about
> antennas.
> When I look through the 56 ps manual, I realize this is a very advanced
> machine for its age. They are said to be one of the best for that time.
> Just
> wonder what they cost then? Nothing for the picnic, weight 75 pounds!
>
> A funny problem: it's almost impossible to get the old copper lines with
> porcelain isolators. Whoever I try look at me as being a Neanderthaler.
> So,
> seems as it will be a variable dipol of some kind. From what you say,
> Blair,
> it will be little of a monster to cover all bands. On the other hand, is
> there anything today at kHz bands? Beacons? Navigation buoys? Radio sonds?
> I
> guess my old receiver will be laughed at by the VHF/UHF/GHZ radios: "
> Have
> you seen, folks, a GEC BRT 400S...ho-ho-ho..it smells of stinky selenium
> rectifier and leaking electrolytes. Poor thing, got a frequency range like
> an elephant..ho-ho....use capacitors with blades and gear boxes..no, no,
> not
> kidding....and you should see the line transformer...my...weight as a six
> feet man...guys...let's help him back to the museum.."
>
> Inge
>
> On 27 February 2011 17:19, Steve Gregory
> <[log in to unmask]>wrote:
>
>> Hi Inge!
>>
>> Haven't heard from you in quite sometime! Glad to hear from you! I have
>> your pictures posted:
>>
>> http://stevezeva.homestead.com/Inge_s_Lab.jpg
>>
>> You have a nice little lab to work in! Here's your receiver:
>>
>> http://stevezeva.homestead.com/Inge_s_BRT400.jpg
>>
>> I know nothing about antennas, but I did find this. I don't know if you
>> have a manual for your receiver, but here's one for download:
>>
>> http://bama.edebris.com/manuals/ge/brt400
>>
>> But before you can see it, you will have to download this viewer:
>>
>> http://windjview.sourceforge.net/
>>
>> It's almost like an Adobe *.pdf viewer
>>
>> In the manual, it does talk about antennas (they are called aerials in
>> the
>> manual) on page 20 and 21.
>>
>> Steve
>>
>> -----Original Message----- From: Blair Hogg
>> Sent: Sunday, February 27, 2011 10:46 AM
>> To: [log in to unmask]
>> Subject: Re: [TN] NTC: GEC BRT 400S
>>
>>
>> Inge,
>>
>> I'll wait for the photos, but an antenna is an antenna. It can either be
>> resonant at a particular frequency or tuned by an antenna tuner as
>> needed.
>> Probably for a wide coverage receiver a long wire antenna is the easiest
>> place to start. The longer the better, up to a certain point.
>>
>> If you are interested in a particular band of frequencies, a dipole works
>> well, but tends to be directional - not necessarily a bad thing.
>>
>> For 28 MHz I've used dipoles that are roughly 5.8 meters on each leg. The
>> length varies inversely with the frequency, so at 3 MHz the dipole would
>> need to be 58 meters or so. But any piece of wire will work, some will
> work
>> better than others.
>>
>> Once I see the photo I'll refine my comments.
>>
>> Blair
>>
>> On Sun, 27 Feb 2011 14:57:42 +0100, Inge Hernefjord <
>> [log in to unmask]>
>> wrote:
>>
>> Hi, when I left the navy decades ago, I missed my radio equipments.
>>> However,
>>> I succeded to save one traffic receiver as you can see on the photo (if
>>> Steve can give a hand). This machine is of course stonaged and
>>> hopelessly
>>> behind technology of today, but of nostalgic reasons I would like to
>>> give
>>> it
>>> a try. I've spent some money for service and now the receiver can work.
>>>
>>> Now, I've little knowhow about aerial antennas for 380 Kc/s to 30 Mc/s.
>>> I
>>> remember I had a network of copper lines across the destroyer, but know
>>> nothing of the design.( Had to be repaired frequently after shooting
>>> with
>>> the anti-aircraft artillery).
>>>
>>> So, to the question: Anyone familiar with the GEC 400S? How would a
> modern
>>> antenna look like and what kind of tuning and compensation is necessary
>>> ?
>>> I've contacted some DX guys, but they know nothing about this antiquity.
>>>
>>> Wait for the photos.
>>>
>>> Inge
>>>
>>>
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