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SIGMA EUROCOMM COBRA HY-GAIN VENOM 1/2 Wave silver rod cb base 11 - 10 METER

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markbooth

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Apr 24, 2022
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Hi,

I have installed this antenna but not sure if it is faulty or not.
I checked the cable with my multimeter and no continuity between screen and centre.
I then checked the input on the antenna and I am reading 0.9 ohms between screen and centre, I was expecting to see open circuit?
 

N1EXA

FT8 Huntin Mudd Duck on the deep end of the pond !
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There is a coil in the base of the antenna and its DC coupled to ground.
There is also a capacitor in there too.
I own the Sigma 5/8 wave Silver rod.

You can use a DC Ohm Meter to checks Coax cables for bad solder joints or shorts but not antenna's that are in the AC impedance world.

What is your SWR reading on this antenna ?

1659366806975.png

Peter N1EXA
 
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markbooth

Newbie
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Apr 24, 2022
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Hi Peter, thanks for the reply.

SWR on UK CB is 1, when I go to transmit on 10 m it is as high as 3, I have not tried to adjust it yet.
 

N1EXA

FT8 Huntin Mudd Duck on the deep end of the pond !
Joined
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Location
Acushnet Heights New Bedford MA - GRID FN41 mp
Your going to have to find a sweet spot . I tuned my antenna for 27.385 CH38 for the lowest SWR and I can get away with
it up to 28.5 using an antenna Matcher just to keep the SWR low But Its usless up on 29.6 for FM 10 Meter.
A CB Match box will buy you some wiggle room by changing the impedance and getting the antenna to a lower SWR
but it not going to make the antenna A "Broad Banded Does It All" as advertised.

Use some thin aluminum Metal Shims to tighten up the joints on the antenna using SS hose clamps and I put a piece of electrical conduit
inside the lower 2 sections so the antenna handle A Big Wind Load - They bend pretty easy !



Peter N1EXA
 

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prcguy

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So Cal - Richardson, TX - Tewksbury, MA
Hey EXA, do you ever get on 38 LSB with some locals around Woburn, Andover and Lawrence areas? If so have you ever heard a guy come on 38 LSB using a remote repeater system that repeated the locals to So Cal and other areas?

Your going to have to find a sweet spot . I tuned my antenna for 27.385 CH38 for the lowest SWR and I can get away with
it up to 28.5 using an antenna Matcher just to keep the SWR low But Its usless up on 29.6 for FM 10 Meter.
A CB Match box will buy you some wiggle room by changing the impedance and getting the antenna to a lower SWR
but it not going to make the antenna A "Broad Banded Does It All" as advertised.

Use some thin aluminum Metal Shims to tighten up the joints on the antenna using SS hose clamps and I put a piece of electrical conduit
inside the lower 2 sections so the antenna handle A Big Wind Load - They bend pretty easy !



Peter N1EXA
 

N1EXA

FT8 Huntin Mudd Duck on the deep end of the pond !
Joined
Mar 3, 2022
Messages
312
Location
Acushnet Heights New Bedford MA - GRID FN41 mp
Hey EXA, do you ever get on 38 LSB with some locals around Woburn, Andover and Lawrence areas? If so have you ever heard a guy come on 38 LSB using a remote repeater system that repeated the locals to So Cal and other areas?
I'm 50 Miles South of Boston - I hear some High Power guys on 38 LSB In Boston Calling CQ but never heard the Remote Repeater with the
California Guys on it. WOW World Link On CB that will make the DMR guys Cringe !
Most of my Ground wave Comm's are with the Guys on Cape Cod / Falmouth Area or heading out to Providence RI.

Pete N1EXA
 

prcguy

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Aah, I missed the "New" part of Bedford, sorry.

I'm 50 Miles South of Boston - I hear some High Power guys on 38 LSB In Boston Calling CQ but never heard the Remote Repeater with the
California Guys on it. WOW World Link On CB that will make the DMR guys Cringe !
Most of my Ground wave Comm's are with the Guys on Cape Cod / Falmouth Area or heading out to Providence RI.

Pete N1EXA
 

N1EXA

FT8 Huntin Mudd Duck on the deep end of the pond !
Joined
Mar 3, 2022
Messages
312
Location
Acushnet Heights New Bedford MA - GRID FN41 mp
Aah, I missed the "New" part of Bedford, sorry.
Bedford is the other way !

Hey your a Tewksbury Guy - Remember "CB City" 1980s out on Route 9 and 20 in Auburn MA - Place had a Moonraker 6 on the roof and big
CB CITY Red Plastic letters on the Side of the Building ? It now a Used car dealer But ill say the place looks the same.
The only hard core CB shop left is Lou's In Bridgwater MA.


Pete N1EXA
 

prcguy

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Joined
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Messages
17,174
Location
So Cal - Richardson, TX - Tewksbury, MA
I'm part time and for maybe the last 10yrs, so I missed seeing CB City. Don't get south of Boston much these days.


Bedford is the other way !

Hey your a Tewksbury Guy - Remember "CB City" 1980s out on Route 9 and 20 in Auburn MA - Place had a Moonraker 6 on the roof and big
CB CITY Red Plastic letters on the Side of the Building ? It now a Used car dealer But ill say the place looks the same.
The only hard core CB shop left is Lou's In Bridgwater MA.


Pete N1EXA
 
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