Comms: Where are we now?

[Lightspeed]

(28 June 2013, 11:29)Tarrel Wrote:

(28 June 2013, 09:38)Highlander Wrote:

(27 June 2013, 23:16)Tarrel Wrote: Or, use a simple long wire, again mounted close to ground, and connect to radio via an antenna tuner. It is the closeness to the ground that makes it NVIS.

I was lead to believe that to have the antenna too close to the ground would not give good results, because of the fluctuation of the wetness in the ground

If that's a problem, you could bury a layer of chicken wire or similar in the ground beneath the antenna, to provide a more reliable earth. Opinions vary about how low to the ground an NVIS antenna needs to be. General view seems to be around 1/8 wavelength or less.

Agreed. The generally accepted concept is that NVIS Antennas must be horizontal, and around 1/8 wavelength or less above the ground. The NVIS technique uses the ground to reflect transmitted signal Nearly Vertical.

So:-
For 3.5Mhz band (80m) antenna should be less than 10m (30ft) from the ground
For 7Mhz band ( 40m) antenna should be less than 5m (15ft) from the ground

This means that for most ground conditions,3.5Mhz and 7Mhz antennas less than 3m (15ft) off the deck will perform well for NVIS

HL I agree with you that getting the antenna too close to the ground may introduce problems as well as making it a trip hazard. I've found that mounting an end fed wire along the top of 6ft to 8ft WOODEN fence posts works pretty well and is very inconspicuous. The wire can follow the fence line around boundaries, it does not have to be straight at all, as long as it is approximately horizontal.

[Highlander]

Thanks for the above, I cant say that the information about being too close to the ground is from my knowledge, it was AL who first brought my attention to the problem after showing him a fence line I have

[Lightspeed]

I'm Bumping this in the hope of additional replies please????

[Binnie]

quick question,

I've got CB and 446, but i'd love the flexibility of the UV5R too,

BUT, there are so many to choose from on ebay, can anyone point me in the right direction?

[Lightspeed]

(26 July 2013, 12:43)Binnie Wrote: quick question,

I've got CB and 446, but i'd love the flexibility of the UV5R too,

BUT, there are so many to choose from on ebay, can anyone point me in the right direction?

Binnie

We're using the UV5r +Plus model. Its the last of the first generation and has maximum low cost accessories available.

[Binnie]

Ok, i see the second generation also has a plus model with a greater frequency range.

I'll order a 1st gen so i'm on the same playing field

[Lightspeed]

(26 July 2013, 13:58)Binnie Wrote: Ok, i see the second generation also has a plus model with a greater frequency range.

I'll order a 1st gen so i'm on the same playing field

That's news to me Binnie. Thanks for pointing that out.

I know some variants of the first version had a slightly extended range, but for my purposes that isn't too important as I have to work to lowest common denominator in our groups various radios.

Extra frequency range may be more important to you though. Its kind of subjective.

I think the frequencies on the previously proposed programming protocol will be supported by all variants.