Sounds like RF flowing on the outside of the coax due to the increased path
through the amp when the amp is added to the chain. The SWR meters are
being confused by these circulating currents. This says the SWR of the
antenna is probably 1.4:1 and the Orion meter is being confused by
circulating currents. Not an uncommon condition. What happens when a dummy
load is added to the output of the amp? Probably all is OK. Then check
all coax connectors and jumper to make sure they are clean, tight and are
properly soldered. And yes, it could be inside the amp with the routing of
input and output lines and associated switching relays.
Be sure each piece of station equipment is connected by a dedicated ground
wire to a common point for the station. Typically either the antenna tuner
or the transceiver power supply.
73
Bob, K4TAX
----- Original Message -----
From: "Rick Williams" <rick.williams@telus.net>
To: <tentec@contesting.com>
Sent: Monday, February 06, 2006 5:14 PM
Subject: [TenTec] Hercules II anomaly?
> Well I have a new one? I have recently noticed a discrepancy between the
> SWR measured by my Orion (internal tuner disabled) and by my LDG DWM-4
> wattmeter. I've checked the LDG meter with my Bird and all seems okay.
> So
> I've tried to isolate the problem.
>
> The problem disappears when I take the Hercules II out of the circuit. My
> problem occurs on 20 metres with the rig showing an SWR of about 2.5 : 1
> and
> the external meter about 1.4 : 1. When I remove the Herc input and output
> coaxes from the amp and connect them together with an Amphenol barrel
> connector both meters read an SWR of about 1.4 : 1? With power, control
> and
> keying loop cables removed the problem still exists.
>
> Of course all of this is happening with the Herc off and the only
> components
> I can see in the circuit are the input relay - K1 and the vacuum relay.
> Both are unenergized and normally closed with a DC resistance of less than
> 0.5 ohms. I have checked 80 metres, 17 metres and 15 metres and the
> problem
> does not occur there. It seems confined to 20?
>
> Thoughts appreciated. Thanks.
>
> 73,
>
> Rick
> VE7TK
>
> Website: http://www3.telus.net/ve7tk
>
>
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> TenTec@contesting.com
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>
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