How to figure err.

[WA9CFK]

I know from my mobil antenna tinkering that short antennas are not very efficient.

The erp or effective radiated power is just a fraction of the power input.

My question is, if I use my 160 m inverted L which is up 40 ft with a loading coil at the base, is there a easy way to estimate the erp or percent of radiated power?

For receiving would a simple tuned tank circuit work just as well as a base loaded coil? Us old timers have a few 455 IF transformers and capacitors in the junk box.

I have been listening and have heard a few CW signals just by plugging the inverted L into the back of the transceiver. I think a tuned antenna would work better.

[AA2UK]

Here is an on-line spreadsheet for determining EIRP at 630 meters. It's specific for short verticals which is probably the mode your dipole is operating as on 630 meters.
http://wg2xsv.webs.com/antenna-info
https://www.dropbox.com/s/pafykhftdwoxzm5/Rr%20draft2%20for%20630m%20dot%20net.xls?oref=e

Your back to back junkbox 455 IF filter idea is in use by many as an RX filter.

Tnx, Bill
AA2UK

[K0OD]

WA9CFK: I have been listening and have heard a few CW signals just by plugging the inverted L into the back of the transceiver. I think a tuned antenna would work better.

To answer your question, I doubt your reception will benefit. If you can hear QRN increase when you plug in your inverted L then a better match, while boosting your S-meter reading, wont help you copy more or farther signals. But try it and report back. Everything I'm seeing about 630 has been amazing.

I'm thinking hams gave up too easily in 1912.