[AMRadio] HB Xmtr, was: Home Brew AM Transmitter Wanted

Brian K Harris brian.k.harris at philips.com
Tue Mar 28 12:56:09 EST 2006

Finding suitable modulation transfomers is hard.  Finding suitable chokes 
is harder, specially those as large as the 158 pound 50H monster in my RCA 
BTA1R1.  Unlike 2 meter handhelds, you won't find many modulation chokes 
or transformers the size you need at hamfests or even on EBAY.  That's why 
I moved quickly when I found a complete set of spare iron for my RCA 
BTA1R1.  The RCA cost $500.  The spare iron cost more.  Was it worth it? 
No doubt.

If you must build your own, I think the best economic deal is to buy a 
broadcast transmitter and rob it of its parts but doing so seems such a 
waste.  Why destroy something that is so well engineered only to replace 
it with something that probably won't be?

Brian WA5UEK

Philips Semiconductors
2140 Lake Park Boulevard, Suite 200
Richardson, Texas 75080 USA

Mobile: 214-763-5977 (preferred)
Office:   972 705-2484
Fax:       972-705-2450
Email:    brian.k.harris at philips.com

Larry Keith <kq4by at rocketmail.com> 
Sent by:
amradio-bounces at mailman.qth.net
2006-03-28 11:19 AM
Please respond to
Discussion of AM Radio <amradio at mailman.qth.net>

Discussion of AM Radio <amradio at mailman.qth.net>

[AMRadio] HB Xmtr, was: Home Brew AM Transmitter Wanted

I have been looking at HB AM Xmtr designs.

One of the more interesting ones can be found on the
amwindow.org web site.  It is a pair of 813's
modulated by a pair of 813's.  That makes it
interesting to me since I already have a stash of

The designs doesn't look too complex.  It requires
about 5 - 10 watts of RF drive and 20 watts of audio. 
Those should be easy enough.

>From looking at the xmtr and power supplies
schematics, it appears that the only "scare" parts are
the modulation transformer and the Heising choke. 
Would anyone care to comment of availiability of such
items?  Specs shown are:

Mod Xfmr -- 300 - 500 Watts, 2:1 step down.

Heising choke:  50 H @ .5 A



Larry Keith 
231 Shenandoah Trail 
Warner Robins, GA 31088-6289 
kq4by at rocketmail.com 

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