Hi Jim
The mod you suggest would be easy enough technically but mechanically it
would be difficult to fit the larger inductor required for 472 Khz into the
cabinet
I would suggest building and external inductor/capacitor and then disable
the internal L/C COMPONENTS and feed the RF from the tubes via a suitable
capacitor to the external MF cct and you should be in business.
With this sort of power output you would need to ensure that the RF
connectors, coax, and Antenna loading inductor can handle the power.
Different ball game when using high levels of RF especially at LF/MF
Why not modify one of your DECCA amplifiers as i have done and it works a
treat. It has been in service now for several years and is as steady as a
rock working into my 1/4 wave inv L antenna.
73 and gl with your project
de MAL/G3KEV/SCARBOROUGH/IO94SH
-----Original Message-----
From: James Cowburn
Sent: Thursday, June 7, 2018 12:19 PM
To: [email protected]
Subject: RE: LF: First MF transmission from Oscar LU1DOW
Great work and as has been said, nice to see a tube amp doing the heavy
lifting !
I wonder if I could press my TL922 into service on MF? It's lying idle
since I got my SPE 1K. Any comments on how I might need to mod it much
appreciated
At the moment, I feed the signal from my Elad SDR Tx from the 0dBm output
into a broadband 1w ebay special and then the 1w goes into a Hafler 9505 and
gives me about 500W up the wire
Cheers
Jim G7NKS
-----Original Message-----
From: [email protected]
[mailto:[email protected]] On Behalf Of Chris Wilson
Sent: 07 June 2018 11:58
To: VIGILANT Luis Fernández <[email protected]>
Subject: Re: LF: First MF transmission from Oscar LU1DOW
Hello Luis,
Please pass congratulations to Oscar and good luck on his next
endeavour. Nice to see a valve (tube) amp in use, I am still hankering after
building one myself for LF. Good to see Argentina on the MF map, I always
thought they were all beef farmers or wealthy polo players ;)
Thursday, June 7, 2018, 9:17:14 AM, you wrote:
Hi MF
While there is only residual activity in north hemisphere, we are
aproaching winter solstice in south hemisphere
Oscar, LU1DOW, confirms his first QRSS transmissions were successfully
received by LU8YD at 1000km. See picture attached
This is the first MF ham transmission in Argentina. A great
achievement
Oscar is using a tube amplifier with a 4CX1500A running about 1400w if
I recall correctly. The antena is a Marcony T
20m long and 20m high. He was using this setup in LF and recently
modified it to MF but the bad weather delayed
the transmissions untill now
Next goal is to modify the exciter to be able to work with WSPR.
Martin YV7MAE and Ruben EB8ARZ looks like ideal
candidates to receive his transmission
Good luck Oscar !
73 de Luis
EA5DOM
--
Best regards,
Chris mailto:[email protected]
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