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 Post subject: RS DX-160 with alot of ground floor noise..
PostPosted: Mar Tue 06, 2018 11:11 pm 
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Joined: Dec Tue 08, 2015 12:53 am
Posts: 414
Location: shirley NY...Long Island
Is this the way the radio is...or am I not doing something right??

I can tune in any broadcast band signal...and if its is a strong signal it completly covers the, what I call, ground floor noise..

I have went thru and replace all 20 of the electrolytes, and done the alignment over and over at least 3 times..like it says to do..

SSB voice get covered up...

I have noticed that on the RF gain control...when turning up..I can feel a slight bump at like 3/4's the range...now also two of the switches above this control were broken when I bought it...which was 3 days ago...the control gets to this 'bump" and the signal goes from very weak to way to loud...at just past this bump..I know this is not right, but until I get another control this is going to have to work this way..


Thanks to all that respond

Kenny KE4HVE


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 Post subject: Re: RS DX-160 with alot of ground floor noise..
PostPosted: Mar Wed 07, 2018 12:29 am 
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Do you have another receiver for comparison? It sounds like the receiver is picking up a lot of local noise (computer, switching power supplies, etc.). What type of antenna are you using for the shortwave bands? Do you have the receiver grounded? Is there a jumper from the A2 terminal to the ground terminal (unless you are using a balanced feedline)?

Put it on a shortwave band with the antenna disconnected and note the S meter reading. Now connect your antenna but tune the receiver in-between stations. What does it read on background noise/interference with the antenna connected?

It could be a receiver issue but in typical modern listening environments this is more likely an antenna/noise pickup issue.

Rodger WQ9E


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 Post subject: Re: RS DX-160 with alot of ground floor noise..
PostPosted: Mar Wed 07, 2018 7:35 pm 
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Joined: Dec Tue 08, 2015 12:53 am
Posts: 414
Location: shirley NY...Long Island
Thanks for the replay....I checked it against a Grundig G3 and there is no comparison, night and day difference,
Im using a long wire, about 30 feet long...

The receiver is grounded to a copper pipe 3 foot in the ground, and I have the G and A2 connectors connected together.

Thanks...I have done a little more alignment on it...and it seems a little better..but the noise is there...will try to disconnect the antenna and get back to you...

Thanks.

Kenny


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 Post subject: Re: RS DX-160 with alot of ground floor noise..
PostPosted: Mar Wed 07, 2018 11:57 pm 
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Joined: Dec Tue 08, 2015 12:53 am
Posts: 414
Location: shirley NY...Long Island
I dont know why but I tried hooking the ground to the A2 connection and the normal antenna to A1 and it is working waaaaaayyyyyyy better...


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 Post subject: Re: RS DX-160 with alot of ground floor noise..
PostPosted: Mar Sat 10, 2018 10:25 pm 
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Joined: Dec Wed 25, 2013 7:57 am
Posts: 2980
Location: USA
Kenny,

That's how you're supposed to connect the antenna. I'm glad you got it working. Enjoy your radio :)


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 Post subject: Re: RS DX-160 with alot of ground floor noise..
PostPosted: Mar Mon 12, 2018 4:05 am 
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Joined: Aug Fri 29, 2014 6:17 pm
Posts: 2564
Location: Vincennes Indiana
These are pretty hot for ambc dx.


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 Post subject: Re: RS DX-160 with alot of ground floor noise..
PostPosted: Mar Mon 12, 2018 1:07 pm 
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Joined: Jan Thu 01, 1970 1:00 am
Posts: 20035
Location: Utica, NY 13502 (USA)
Kennynva wrote:
I dont know why but I tried hooking the ground to the A2 connection and the normal antenna to A1 and it is working waaaaaayyyyyyy better...
I assume that you mean that you removed the A2-to-G jumper...is that correct? That's the way I use my radios in order to reduce noise from the house wiring. A1 is connected to the antenna while A2 is connected to a ground rod which I call a "counterpoise" (not ground). There is controversy about this method because most electrical codes say that all ground rods on a property need to be tied to electrical ground but that defeats the purpose for eliminating noise. (In order not to violate electrical codes, you can get a large piece of roof flashing and just lay it on the ground as a counterpoise.) When A2 is tied to G, power line noise is fed to the antenna circuit through the radio's line bypass cap(s) which, in today's world of high power line noise levels, work in reverse.

Dave


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 Post subject: Re: RS DX-160 with alot of ground floor noise..
PostPosted: Mar Wed 14, 2018 7:57 am 
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Joined: Sep Thu 23, 2010 6:37 am
Posts: 10466
Location: Powell River BC Canada
If the DX 160 RF gain control has a bump, it may have burnt by a
high voltage (lightning).

And the protection diodes will not help.

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 Post subject: Re: RS DX-160 with alot of ground floor noise..
PostPosted: Mar Wed 14, 2018 8:49 pm 
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Location: Ashhurst, New Zealand
But the schematic shows A2 connected to ground, so no wonder it works better. I bet the instructions say use A1 and A2 for a dipole.
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 Post subject: Re: RS DX-160 with alot of ground floor noise..
PostPosted: Mar Thu 15, 2018 1:28 am 
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Joined: Sep Thu 23, 2010 6:37 am
Posts: 10466
Location: Powell River BC Canada
With jumper off, the DC resistance of all primaries may be measured. Turn the control up full.



I have two DX-160 radios. Each is connected to a different aerial, battery,
and audio system. The objective was diversity reception.

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 Post subject: Re: RS DX-160 with alot of ground floor noise..
PostPosted: Mar Thu 15, 2018 1:31 am 
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Joined: Jan Thu 01, 1970 1:00 am
Posts: 660
Location: dayton oh usa
the rf gain pot is open at the "bump".
replace it.


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 Post subject: Re: RS DX-160 with alot of ground floor noise..
PostPosted: Mar Thu 15, 2018 6:11 pm 
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Joined: Dec Tue 08, 2015 12:53 am
Posts: 414
Location: shirley NY...Long Island
Majoko I removed the A2 to g jumper...This radio still has alot of white noise hiss on all bands...I thought maybe a transistor or jfet might have a problem also..someone said it is normal to connect the ground wire to the A2 connector, how is this..???


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 Post subject: Re: RS DX-160 with alot of ground floor noise..
PostPosted: Mar Thu 15, 2018 8:29 pm 
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Posts: 5894
The DX-160 input is like several of the early solid state radios where some RF gain control is done via a variable resistance between the antenna input terminals. Depending upon how your antenna and radio grounding is done you may have reduced the effectiveness of this part of the RF gain control circuit and you may have also reduced the effectiveness of the protective diodes that are designed to protect the RF stage from nearby lightning strokes are strong nearby transmitters.

Unless you are using a balanced (i.e. 300 ohm twin lead) feedline then A2 should be shorted to chassis ground via a link between the A2 and ground terminals. For example with a coax feedline the center conductor connects to A1 and the shield goes to A2 with the strap between A2 and ground in place.

It sounds like you have it connected where the chassis is floating above ground which isn't generally desirable and can be a safety hazard.

Rodger WQ9E


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 Post subject: Re: RS DX-160 with alot of ground floor noise..
PostPosted: Mar Thu 15, 2018 8:47 pm 
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Joined: Mar Mon 17, 2008 5:05 am
Posts: 5477
Location: Ashhurst, New Zealand
The jumper from A2 to the ground lug has to be in place or else there is no circuit through the primary of the antenna coils. I also suspect, as other have said, that the RF gain control element is open circuit. Two faults that give the same symptoms are always harder to find, as you change something expecting an improvement and there is none. You could try disconnecting the wire from the centre tag and connecting it to the top tag if you can't find a spare. This will mean that the AGC will have to work a bit harder but hopefully will be OK.

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 Post subject: Re: RS DX-160 with alot of ground floor noise..
PostPosted: Mar Thu 15, 2018 9:37 pm 
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Joined: Dec Tue 08, 2015 12:53 am
Posts: 414
Location: shirley NY...Long Island
I did just that...BUT....the antenna wire went to one side of the rf gain control..not to the center tag as you said...but same difference...I removed the antenna wire from the RF gain control and connected it to the middle wire..and put back the A2 to G wire...and will let everyone know how that works later...

Thanks..


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 Post subject: Re: RS DX-160 with alot of ground floor noise..
PostPosted: Mar Thu 15, 2018 10:18 pm 
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Joined: Jan Thu 01, 1970 1:00 am
Posts: 20035
Location: Utica, NY 13502 (USA)
To test if the radio is at fault, connect a wire between A1-A2-G and don't connect an antenna or a ground. Turn the RF gain control fully CW. If the noise is the same as you had with your previous antenna/ground connections, then the radio, itself, is the noise source.

Dave


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 Post subject: Re: RS DX-160 with alot of ground floor noise..
PostPosted: Mar Thu 15, 2018 11:53 pm 
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Posts: 5477
Location: Ashhurst, New Zealand
Quote:
the antenna wire went to one side of the rf gain control..not to the center tag as you said.


I didn't say the antenna wire - I said THE wire that is on the center tag - disconnect that wire and reconnect it to the top tag which of course IS the antenna wire - now you have removed the potentiometer from the circuit and the signal is going from the antenna directly to the switch.

You had this...
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You want this...
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 Post subject: Re: RS DX-160 with alot of ground floor noise..
PostPosted: Mar Fri 16, 2018 3:24 am 
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Joined: Sep Thu 23, 2010 6:37 am
Posts: 10466
Location: Powell River BC Canada
The RF gain pot is a dual section type. Pay heed to what the other section does. Also there are two versions of DX-160..

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VE7ASO VE7ZSO
Amateur Radio Literacy Club. May we help you read better.
Steve Dow
ve7aso@rac.ca


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 Post subject: Re: RS DX-160 with alot of ground floor noise..
PostPosted: Mar Fri 16, 2018 2:31 pm 
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Joined: May Wed 01, 2013 10:05 pm
Posts: 1975
Location: Rayleigh, BC, CANADA
That's right, it's a dual section pot.

I saved my DX-160 from the landfill. I'm sure it also got hit by lightning, the outer section of the pot has a dead spot at the end of the CW position.

It also had a blown trace further down the line, the diodes didn't do anything to protect the rest of the circuit.

I try to keep it away from all those household noise makers and it seems to be quiet enough to enjoy DX

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 Post subject: Re: RS DX-160 with alot of ground floor noise..
PostPosted: Mar Fri 16, 2018 4:25 pm 
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Joined: Jun Mon 24, 2013 3:00 pm
Posts: 1189
Location: Champaign IL 61822
rsingl wrote:

Unless you are using a balanced (i.e. 300 ohm twin lead) feedline then A2 should be shorted to chassis ground via a link between the A2 and ground terminals.


That's not necessarily true. With circuits like that one, there is both inductive and capacitive
coupling from the antenna to the tuned RF coil. It may work best with a2 grounded, or better with
it not connected. Its a very bad design ... you have to experiment.


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