I am really looking forward to playing around on digital chats on 630 meters assuming I am OK'd by the powers that be through the plc database thingee I just filled out yesterday. And of course when my 6400 shows up hihi
This one works well to get close to the correct impedance.
I use an auto transformer to match from 50ohm feed to about 25ohms.
In the shack I use a scope match.
Some SWR meters will work, give it a try.
My LDG Z100 tunes on 630m.
At the antenna I use a current meter or a simple field strength meter for fine tuning.
For more serious work the Tecsun PL365 (CountryCom GP5) or PL360 have a very linear field strength meter in dBuV for far field measurements.
VK5AI and I have measured the antenna factor of the accessory external loopstick that it comes with at 20dBuV/m at 475kHz so add that to the measurement. The internal antenna is about 40dBuV/m.
Many 630m ops are also using a ScopeMatch:
I used my F6300 last night on 630m WSPR with a G0MRF 300W amp kit running 40 watts (2 watts ERP) and the combo performed splendidly. Details on my blog for whoever's interested.
Recent posts on the LP500 Yahoo group below. Looks like the LP500/700 and LP100 should be fine on 630M using the stock HF couplers.
Do you have any data on the usability / accuracy of the LP-500 and LPC-501 coupler on 630M (475kHz+-)? Likewise for the LP-100 and LPC1 coupler on 630M? Several of us with these meters are constructing amps for 630M and would like to have a usable watt meter.
Yes. I have tested LPC501 down to 450 kHz, and it was accurate for both power and SWR. Measured insertion loss was 0.01 dB. These tests were at 10W output from an instrumentation amplifier, so I don't know about power handling, but I would guess it would be no problem unless the antenna is a piece of wet spaghetti ;-)
I checked an LPC1 and it was down 0.085 dB at 465 kHz, which is roughly 2%. The measured return loss at 475 kHz was 33 dB, and insertion loss was 0.08 dB. The insertion loss is higher on the LPC501 because it uses a transformer across the load to measure voltage, and the transformer has shunt inductive reactance, of course. The LPC501 uses a capacitive divider. I should point out that we have a number of special couplers available for LP-100A for frequencies down to 40 kHz. These are normally used for industrial applications.
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