[Elecraft] XV50 no output

[Dave Sergeant]

Danny

Decent BNC connectors have identical pin diameters in both 75 and 50 
ohms versions and are fully compatible (unlike N type which are 
definitely incompatible). But obviously these cheaper ready made up 
cables use cheap plugs so may well have fat pins.

As an interim measure I have taken a couple more of the cheap BNC/BNC 
leads and chopped one of the plugs off and fitted a phono plug, which 
at least gets round the problems of adaptors - still 75 ohms of course. 
A quick search shows that all made up BNC-phono leads are 75 ohms so to 
go to 50 ohm leads you really do need to make it up yourself - and I 
don't seem to have any BNC plugs in the spares box at the moment.

This has got it up and running again, but I have revealed another issue 
- the earthing of the phono sockets in the K60XV at the K2 end is not 
ideal. Only the output phono has a grounding lug, the input phono 
relies on earthing via the aluminium panel. Although there are crinkle 
washers both sides of the socket the socket tends to wear loose every 
time you put the plug in. The receive noise on the XV50 shows this, as 
you wriggle the cable at that end the noise goes up and down. It really 
needs a direct earth to the ground on the K60XV panel.

I guess now having got it going not much else will happen until the 
sporadic E season starts next May...

73 Dave G3YMC

On 21 Nov 2015 at 19:44, Danny Higgins wrote:

> I remember buying some cheap BNC patch leads at a rally which worked
> fine. After a swap around my RX went deaf and I couldn't work out what
> was wrong. After a lot of diagnosis I started to inject a large signal
> and worked all the way back to the BNC antenna input socket, where I
> found that the cheap leads were 75 Ohm video types with fat centre pins
> that had splayed out the centre of the socket so that while they worked,
> there was no connection to the centre pin of a thinner 50 Ohm plug. 
> They went straight in the bin after that.
> 
> Danny, G3XVR
> 


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