Another daft aerial question

[NorthernRaider]

Can I stick a 1.5 meter long mag mount based loaded CB aerial in my loft? If so do I need to stand it on a metal plate to get an earth plane, if so how big a plate. and will I need to SWR it?

[Bug_out_Bag]

NR, for best results stick it on the biggest bit of metal you can. Add four groundplanes, For bugging out, I used a Dv27 on a magmount stuck on an old Roses choccy tin. I drilled four holes equadistant around the tin and attached bolts with washer and nuts to hold the ground planes. Make the GPs from something like speaker wire, you only need one strand for each GP and you need to cut each one to 2.75 meters. Insulate the ends of the GPs with some insulation tape as GP can generate a bit of heat while transmitting. Hope thos helps

[Paul]

The only daft question is the one that's not asked!

Yes you can, and yes you'll have to SWR it.
The plate, the bigger the better but ideally no less than 1.5m square. It should be 2.5 meters but that's all your roof space gone in one hit.

Having said that, you could mount it on a biscuit tin. It's going to be better to buy (I hate that word) a hole mounted aerial base. Drill the biscuit tin and mount it in the middle Solder onto each corner the thickest wire you can get and run it out in a star fashion from the biscuit tin edges each "leg" a minimum of 2.5 metres. That way the long wires become part of the aerial (aka radials).

I'm guessing you'll extend the coax with a long patch lead into a room.
Always use proper uhf connectors and as this aerial will be a "tad twitchy" to SWR, the extension cable should be in multiples of 3 metres.

For peace of mind, fit a TVI filter in the line.

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Don't mount it too close to your cold water tank or electrical wiring.

[Lightspeed]

(31 July 2012, 22:26)Bug_out_Bag Wrote: NR, for best results stick it on the biggest bit of metal you can. Add four groundplanes, For bugging out, I used a Dv27 on a magmount stuck on an old Roses choccy tin. I drilled four holes equadistant around the tin and attached bolts with washer and nuts to hold the ground planes. Make the GPs from something like speaker wire, you only need one strand for each GP and you need to cut each one to 2.75 meters. Insulate the ends of the GPs with some insulation tape as GP can generate a bit of heat while transmitting. Hope thos helps

Cool solution BoB!!!

Like it :-)

LS

[NorthernRaider]

Thanks guys, its for a young chap in our village who is housebound and fancies a CB , I'm planning on scrounging one for him or giving him mine as he needs one more than I do. I've got a piece of 3 mm steel about 20 inches by 20 inches and some flat steel bar i can make the GP with, so its got potential.