AR8200Mrk2B insensitivity problem

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Vambo

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Feb 8, 2007
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My AR8200Mrk2B Started having sensitivity issues soon after I got it in late 2001. I have read that the 8200 was just not that good on the HF bands so I wrote my issue off. However, after finding I was having a problem selling a 8200 for anything close to the depreciated value because serious DXers have not spoken well of the unit, I decided to look into why the 8200 was not a good HF radio.

The unit needed about 300uv to make audio on the speaker as measured with the sig-gen. I opened the radio, placed it on the bench in a position to look at the RF board and started testing. I found that the unit was making audio at 2uV, close to the rated measurement. That is when I found I was having a 75-50ohm connector problem. Resolving that, I found that the sensitivity was still intermittently going between 300uv and 2uv. That is when I found the hairline air gap on the BNC connector.

I assume the connector had been pressed together to allow a lower soldering temp threshold for the wire alone and later the connector was pressed shut. I removed the tin shield to gain access to the connector, heated the connector and soldered the black hairline crack shut. I re-soldered the shield and tested to confirm the repair. I also cleaned the BNC connector center pin while I was there.

Pics of repair are here -> http://www.vambo.org/pictures/AR8200Repair/

---warning---
Repair at your own risk! If you are not technical, don't proceed with the repair without help from someone able to perform surface-mount component level repair

Hope this helps someone!

Vambo aka-K0BO
 
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Fast1eddie

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Joined
Mar 4, 2004
Messages
561
Location
Crafton Pennsylvania
Job well done!! I enhance my 82K's HF performance by clipping a short ground lead to the outside of the supplied whip antenna connector. The radio was not designed to work with large antennas but the whip or a short wire not longer than 6-8 feet seems to offer optimal performance. I keep thinking of experimenting with different wire lengths and my tuner.
 

Vambo

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Joined
Feb 8, 2007
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The front end is pretty conventional on this radio. The first thing in line is a pair of diodes to protect the front end. the bad part is the radio develops IM at anything over a volt or so. One could almost remove this but I would use a band-pass filter before to remove commercial FM and AM stations which will be the first thing to create IM with the diodes in place. I live on a mountain with a few commercial FM stations and using the cheap RS FM broadcast band block filter works great at reducing all my IM with this radio. With this, I've had great luck with a T2FD antenna and this radio.
 

BertaRobinz

Newbie
Joined
Dec 18, 2012
Messages
1
Clipping surely work well. I tried once to repair the device myself but it did not happen as it should've been. By the way looking at the pictures it looks that you had a neat setup for the repair process. Well Done. :)
 
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