[AMRadio] BC-610 terminating impedance

rbethman at comcast.net rbethman at comcast.net
Sun Oct 30 14:09:32 EST 2005


Download a copy of the manual, TM 11-286.

This can be gotten from:


This is WB2FCNs web site.

The area you want to look at in the TM starts around page 43.

In the Military versions of the HT-4, (BC-610s), there are what looks like HV fuse clips on the top of the final loading cap.  Depending which loading coil is used, either C-455 or C-454, dictates whether you use a 55uuf or a 100 uuf vacuum capacitor.

If I had spares, I'd hook up with you and we'd talk.  Unfortunately I do NOT.

There are OTHER changes that MUST be made to the TX - OR - damage can occur.  These are some MINOR rewiring that are COMPLETELY reversible!

If you own and use a BC-939 tuner, it ALSO must have some rewiring done, and use of another one or two vacuum caps are used.  With the BC-939, the "long wire" specified for operations from 1Mc to 2 Mc is 125 ft.

As to the HT-5 speech amplifier, I strongly suspect that a BC-614 speech amp CAN be used in lieu of the HT-5.  Watch that "E" place for them to turn up.  They do from time to time.

The other place to go would be the T-368 BC-610 mail list through QTH.NET.  Join the list and meet some other owners of the BEASTS!

Bob - N0DGN

> With all this interesting discussion about the BC-610 I'm reminded of a 
> question I asked a while ago regarding the padder-cap for 160 operation.
> I do not have a BC-610, nor, other than photos, have I ever seen one.  I do 
> have the Hallicrafters HT4-B, which was made in 1938, and was the basis for 
> the BC-610.
> In the HT4-B, there is a platform in the rear left corner of the RF 
> compartment with four banana jacks.  These jacks are hard-wired in such a 
> fashion that if a capacitor were plugged into two of the jacks it would be 
> in parallel with the variable tune cap.
> I was told, years ago on the air, that this assembly was to be used for a 
> plugin fixed air capacitor for low frequency operation.
> I use a 50pf vacuum cap for 160 operation, but I'd certainly like to know 
> more about the plugin air cap.  And, if any still exist, because I'd 
> certainly be in the market for one.
> Also, I'm still looking for the HT5 speech amp.
> TNX,
> Barrie, W7ALW 
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