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Title: T-47A/ART-13 on LF, CU-25 replacement? Post by: SM6OID on April 02, 2020, 09:08:10 AM Hi!
So, if I want to use my T-47A/ART-13 on 630 m, how to make that happen? I was thinking of having a "tank cirquit" that matches to a 50 Ω feedline. Or any other cleaver idea? Title: Re: T-47A/ART-13 on LF, CU-25 replacement? Post by: Noddyswl on May 23, 2021, 09:22:10 AM HI...the ART13 was from memory not 50 ohm out but matched to antenna impedance througha 'tuner' . It used a trailing antenna and the winding gear for the antenna was calibrated for frequency.
You will find information on internet about using capaciors at the antenna outlet which are suited to the voltage and frequency. My set actually has a cunning device installed to tune the tank to antenna but there's a lot of info around including a Collins u-tube video covering a lot on the set..also covering repairs. Does that help at all? I can't refind the brilliant ART-13 book which was saved on my computer so I'll have to go trying to find it to post access on the site. My Regards Title: Re: T-47A/ART-13 on LF, CU-25 replacement? Post by: SM6OID on May 23, 2021, 10:20:27 AM Hi!
I do know what needs to be done to make it work well into a 50 Ω load between 2-18 MHz. The question is how to use in the LF range, thinking of the 472 kHz band. Title: Re: T-47A/ART-13 on LF, CU-25 replacement? Post by: KA3EKH on May 24, 2021, 01:50:43 PM Just curious, why do you want a 50 Ohm line and match? Its not like you will be easily able to match an antenna unless you have something that’s around a thousand feet long. Understand that you can build a base tuning network for feeding from the transmission line to the antenna but why not just use a open wire feedline between the transmitter and antenna and go with a higher impedance transmission line like the open wire they did in military use?
Title: Re: T-47A/ART-13 on LF, CU-25 replacement? Post by: SM6OID on June 21, 2021, 04:52:18 AM Hi! AMfone - Dedicated to Amplitude Modulation on the Amateur Radio Bands
The situation is like this, today I do not have a CU-25 or anything like it. I wish to put out a signal on 630 m. Why matching to 50 Ω? With the current physical layout of my shack and antenna arrangements, I feel that this is the most (only?) practical solution? So, the original question is back, any suggestions of how to solve this? |