Hi Joe and Laurence, It depends what power you design for, there can be
ahell of a lot of current flowing through it .....I remember measuring 12A
running100W or so. I had this current fusing the connection between some od
the capacitor foil and the lead wires, hence the suggestion of "pulse rated"
caps for C1 and C2. I guess this might warm 0.5mm wire a bit. I am a
believer in using the maximum supply voltage the Fets will stand and not
trying to get everything to work off 12v !!
It's an age thing y'know :-))
Andy G4JNT and I are at a microwave do this weekend.
Alan
G3NYK
----- Original Message -----
From: "Laurence KL7 L" <[email protected]>
To: <[email protected]>
Sent: Saturday, April 08, 2017 4:11 PM
Subject: Re: LF: QRSS10 477.7 kHz/New TX
Joe - the warmness of the air coil was questioned with the author a few
years ago when I built a few uep's whilst operating in 9V1 - no issues just
a little heat which may be a concern if vfo etc was in the same enclosure.
no sign of your sig down here this time in XE - just too noisy at the moment
73 Laurence KL7L/XE. el60
On Apr 8, 2017, at 10:07 AM, "[email protected]" <[email protected]> wrote:
On Tuesday a new tx (gw3uep design) was built and worked very well.
An IRFP140, sm capacitors and 1mm wire was used although L2 (7uH)
beacme quite warm. The 1 uF caps (type unknown... yellow and stamped BEC
C11C) did their bypassing without complaint.
Roelof had an O copy on yesterday morning (the 7th) during the
first on the air test.
G4JNT Andy's explanation of how the reactances are absorbed by the
L network which brings the drain impedance to 50 ohms is enlightening.
Is there a way to find impedance at the drain or is this just the
R value on Alan's G3NYK Class E spreadsheet?
The new TX will be on again 9 Apr. 0000-0900 utc
Hopefully this design will be merciful on FETs. If not, there's a
3-500 waiting on the shelf.
73's
Joe VO1NA
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