5MHz NOV changes consultation

In reply to M0LEP:

For a long time radio amateurs in the UK have had the power at the feed point of the antenna limited to 400W. As the feedpoint is not where the PA stage is located for 99.999999999999999999% of transmitters we all use a feeder to get the RF to the antenna. As this feeder is lossy, UK amateurs will run their PA stages to greater than 400W to allow for the “lossy feeder”. It is for this reason why PAs capable of in excess of 1.5KW are often purchased or made. To overcome the “lossy feeder”. Even if the “lossy feeder” is LDF 7-50 complete with 7/16 DIN connectors and there is only a few metres of feeder in use, you still need a big enough PA to overcome the “lossy feeder”. At least 1.5kW. Or more if you want to be “sure”. (n.b. contest stations always seem to use the lossiest cable in existence hence their need for such enormous PA and generators.)

The problem of the maximum height of the antenna with regards to the proposed 5MHZ NOV is analagous to the power limit regulations and the effect of the limit can be handle quite nicely if you invest in a “lossy tape measure” for measuring the height of the antenna. Just as power is lost in a “lossy feeder”, cms (or inches for those of you using old money) can be lost when the height is measured with a “lossy tape measure”. When using a “lossy tape measure” you’ll find that most antennas will always measure to less than 5m AGL!

You see all problems have a simple solution when you have the correct tools.

:slight_smile:

Andy
MM0FMF

In reply to MM0FMF:

“if you invest in a “lossy tape measure” for measuring the height of the antenna.”

And I am certain thermal expansion plays it’s part too :wink:

Congratulations again, & Best 73,

Mark G0VOF

Lossy feeder is easy…

but give me a bit of time and i’ll find somone on Ebay doing the tape measures :o)

Carolyn

In reply to G6WRW:

Just don’t get fishermans’ tape measures… :wink:

In reply to M0LEP:

Well I can’t see what the problem is here…

My antenna is never going to be 5m above ground level. My house is at 250ft ASL and therefore I would need a mighty big tower to get it 5m above the highest bit of ground in Nepal…