[Hallicrafters] HT-45 tank coil

[Dave Thompson]

Gang,

The designer of the hT-45 was Lee W0AIW later W0AR of Radio Industries.  In a 1960 CQ he had an article on the Loudenboomer which ran the 4CX1000.  Lee used the B&W 850 tank coil s it was designed for 1 or 2 3-400's and even 4-50a's or 4-400A's.  I had one in a homebrew 4-400 amp we built in 1958. Radio Industries sold the amp under the name Loudenboomer II. Hallicrafters bought the rights to the amp which they sold as HT-45.

The easiest thing to do is find one maybe on one of the sales sites.  They sell for $60 to $100,  There is little reason to change out a 3-400 for a 3-500 but 3-400's are getting rare. The HT-45 is a fine amp and an run 900 watts CW and over 1 KW PEP SSB. Keep the map to about 250 watts out on AM linear. The power supply with the HT-45 was a separate and was somewhat low on plate voltage at 2500V. Eimac recommends 3000V on a single 3-400/3-500.  

73 Dave K4JRB 



-----Original Message-----
>From: Jim Liles <hallicrafterssr2000 at k9axn.com>
>Sent: Sep 30, 2018 11:45 AM
>To: "jeff podengo.com" <jeff at podengo.com>, "hallicrafters at mailman.qth.net" <hallicrafters at mailman.qth.net>
>Subject: Re: [Hallicrafters] HT-45 tank coil
>
>Jeff,
>
>The SR-2000 uses #10 wire not 12.  If you wound it with #12, the coil form will melt.     
>
>The coil in the HT-45 looks like the BW850A which is copper tubing for 10 and 15 and maybe #8 for the lower bands.  The designer must have been thinking about a 4000 watt xmitter when he designed it.
>
>Nice project!  The 3-500 won’t get more power out than the 3-400, power supply won’t do it
>
>Regards Jim
>