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Vintage Radio (domestic) Domestic vintage radio (wireless) receivers only.

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Old 26th Jul 2021, 4:25 pm   #1
pentoad
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Default Bush A.C.91 aerial question

Is this set sensitive enough to work without a long aerial and earth (not mains ground but the socket marked "earth" or true earth in the diagram) connected?
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Old 26th Jul 2021, 5:25 pm   #2
DonaldStott
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Default Re: Bush A.C.91 aerial question

Although the Bush AC91 has the same valve line up as the DAC90 and an Autotransformer instead of a Dropper there is no internal aerial.

So the short and simple answer to your question is NO.
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Old 26th Jul 2021, 6:50 pm   #3
G6Tanuki
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Default Re: Bush A.C.91 aerial question

The number of MW/LW stations broadcasting is diminishing, and many of those that remain are reducing their transmit-powers.

There's also the growth of 'hash' from SMPS and other such things that raises the local noise-floor.

Both these mean that MW/LW reception without a proper antenna [either an outdoor long-wire erected well clear of the house, tuned against a clean earth-connection, or some sort of tuned magnetic-loop] is becoming much more difficult.

It's well over a year since I listened to anything much on MW/LW - and I live in a rather-rural location. City-dwellers have a noise-floor at least 10dB higher, which must make things a lot harder for them.
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Old 26th Jul 2021, 8:51 pm   #4
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Default Re: Bush A.C.91 aerial question

Personally, I think it has got to the point where the only sounds on AM of acceptable quality (at least in Bristol) are those piped in via the Minimod. At least then you have the choice of connecting the minimod to streamed digital radio (the world's your oyster), podcasts, DAB services or MP3 music. With the minimod or other pantry transmitter, you don't need a long aerial which has the added benefit of less hash pickup, unless you're unlucky enough to suffer mains-borne interference. Or else "cut out the middle man" and plug in Bluetooth and simply use the set as an amplifier. Cheers, Jerry
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Old 27th Jul 2021, 10:57 am   #5
pentoad
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Default Re: Bush A.C.91 aerial question

Quote:
Originally Posted by DonaldStott View Post
Although the Bush AC91 has the same valve line up as the DAC90 and an Autotransformer instead of a Dropper there is no internal aerial.

So the short and simple answer to your question is NO.
The reason for my question is that my other old valve radios without any form of aerial can receive a clear signal from Stagshaw (50KW) mast which is 8 miles away.
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Old 27th Jul 2021, 4:43 pm   #6
cathoderay57
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Default Re: Bush A.C.91 aerial question

I'm not surprised if you are that close to the transmitter. The reception without an aerial wire plugged in will depend on the internal length of wire from the radio's aerial socket to the coils, and the amount of shielding provided by the metal chassis and any internal foil shield. All radios without either a ferrite rod or frame aerial were intended to use an external aerial wire, the longer the better. You could also consider active loop antennas about which there is info elsewhere on this Forum. Cheers, Jerry
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Old 27th Jul 2021, 5:41 pm   #7
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Default Re: Bush A.C.91 aerial question

That all dry battery Bush radio I created uses the coil pack assembly from a SUG3 and is similar to the coil pack in the AC91.
That radio works extremely well with the mains power unit, ten usual ten feet of wire for the aerial is all that's needed for reception on all three wavebands.
However, when connected up the internal batteries the performance was found to be absolutely hopeless. It was found that a good earth connection is essential. With a ten feet of aerial wire and and an earth connection once again excellent results.
Next, the receiver was connected to the tunable frame aerial and things really started to happen. Here in Gateshead Talksport is received on 1071Khz and is flanked by two other distant Talksport transmitters which are normally very weak reception. No so with the Bush radio, because of AGC action all three stations were coming through equally loud, the only difference the distant stations were producing a strange echo effect, something I've noticed with distant medium stations. Could this be the result of receiving two distant transmitters on the same frequency? Effects of phasing.
So it follows those three waveband Bush receivers such as the AC91 and SUG91 must have a good aerial and earth to work properly.
Make yourself a tunable loop aerial and be amazed at the results.

DFWB.
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Old 27th Jul 2021, 5:55 pm   #8
bobhowe
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Default Re: Bush A.C.91 aerial question

Hi David my AC91 is useless without an earth even so its a mains set ok on SW & LW but MW is out of alinement kind regards Bob
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Old 27th Jul 2021, 6:19 pm   #9
FERNSEH
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Default Re: Bush A.C.91 aerial question

Hi Bob,
It's most likely the Bush BA91 when working on batteries will need a good aerial and earth connection. The Bush receivers have proper aerial input transformers which demand a proper earth connection to work correctly.
The mains receivers will have the earth connection through the mains neutral.

DFWB.
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Old 27th Jul 2021, 6:47 pm   #10
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Default Re: Bush A.C.91 aerial question

No circuit no current.

Lawrence.
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Old 27th Jul 2021, 7:46 pm   #11
FERNSEH
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Default Re: Bush A.C.91 aerial question

That's it.

DFWB
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Old 29th Jul 2021, 12:10 pm   #12
pentoad
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Default Re: Bush A.C.91 aerial question

Quote:
Originally Posted by FERNSEH View Post
That all dry battery Bush radio I created uses the coil pack assembly from a SUG3 and is similar to the coil pack in the AC91.
That radio works extremely well with the mains power unit, ten usual ten feet of wire for the aerial is all that's needed for reception on all three wavebands.
However, when connected up the internal batteries the performance was found to be absolutely hopeless. It was found that a good earth connection is essential. With a ten feet of aerial wire and and an earth connection once again excellent results.
Next, the receiver was connected to the tunable frame aerial and things really started to happen. Here in Gateshead Talksport is received on 1071Khz and is flanked by two other distant Talksport transmitters which are normally very weak reception. No so with the Bush radio, because of AGC action all three stations were coming through equally loud, the only difference the distant stations were producing a strange echo effect, something I've noticed with distant medium stations. Could this be the result of receiving two distant transmitters on the same frequency? Effects of phasing.
So it follows those three waveband Bush receivers such as the AC91 and SUG91 must have a good aerial and earth to work properly.
Make yourself a tunable loop aerial and be amazed at the results.

DFWB.
Good advice, I'll have a crack at that
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