[Heathkit] DX-100 vs DX-100B

[wb8owx at fuse.net]

Thanks all, especially Glen, for the information on the DX-100 vs DX-100B, Ive just started to tear into it today, picked up the Jan QST as well today at local hamfest where the guy did the complete restoration, while that certainly makes it look nice, Im relegated to more of a shoe string budget, got the transmitter for free, so cant complain.  Starting today on the exploration of actual condition...thanks again  Tim K8WBL  (WB8OWX)



> 
> From: Glen Zook <gzook at yahoo.com>
> Date: 2004/07/24 Sat AM 09:24:13 EDT
> To: wb8owx at fuse.net,  heathkit at mailman.qth.net
> Subject: Re: [Heathkit] DX-100 vs DX-100B
> 
> The DX-100B uses the 3-section variable capacitor in
> the antenna loading whereas the DX-100 uses fixed
> capacitors and a 50 pf variable for the antenna
> loading.  Heath did have a field modification kit to
> change the loading capacitor arrangement on the DX-100
> units to a 3-section variable.  Transmitters thus
> modified were called DX-100A.  That is why the 2nd
> model of the DX-100 was called the "B" model and not
> the "A" model.
> 
> The DX-100B has two capacitor values changed in, I
> believe, the driver circuitry, to improve the drive
> especially on 10 meters.  This change is very minor
> and I have seen the details of making the modification
> to the DX-100.
> 
> The DX-100B only has one crystal position instead of
> four as in the original DX-100.  However, the single
> position can be accessed through the door in the top
> of the cabinet whereas in the DX-100 you had to remove
> the transmitter from the cabinet to access the crystal
> sockets.
> 
> The DX-100B uses the "Apache" style cabinet instead of
> the larger version of the DX-100.
> 
> The DX-100B came with the holes for adding the SB-10
> SSB adapter already drilled whereas to use the SB-10
> with the DX-100 you had to drill these holes.
> 
> Now, there is an approved Heath modification to add a
> spotting switch to both the DX-100 and the DX-100B. 
> There was a field modification kit available for this.
>  The kit also has provision for changing the keying of
> the DX-100 and DX-100B to help with chirping. 
> However, if you make this modification the VFO runs
> continuously when the transmit switch in "on".  If you
> happen to use your receiver to monitor your keying
> this can be annoying!  You can download these sheets
> from BAMA at http://bama.sbc.edu and do the
> modification yourself.
> 
> The kit came with four-page instructions including a
> template for drilling the hole for mounting the
> spotting switch.  You can duplicate this modification
> fairly easily.
> 
> There was a modification kit available from Heath to
> add the SB-10 SSB adapter to both units.  This added a
> switch on the front panel and two SO-239 UHF
> connectors on the rear panel.  Basically you diverted
> the driver from connecting directly to the final
> amplifier tubes and added circuitry to change the
> final from Class C to AB-1 when the transmitter was
> switched to SSB.
> 
> Frankly, the DX-100B and the DX-100 are basically the
> same transmitter.  The changes made to the DX-100B
> actually resulted in a slightly lower price to
> manufacture (elimination of two switches - the antenna
> loading and the crystal selection, 3 crystal sockets,
> etc.).  Also, the Apache style cabinet was cheaper
> than the older style cabinet (which I personally
> prefer - but my 2nd primary transmitter back in 1960
> was a DX-100!).
> 
> I have a DX-100 in my AM shack.  If you are
> interested, there are photos on the K9STH website the
> URL of which is listed at the end of this message.
> 
> Glen, K9STH
> 
> 
> --- wb8owx at fuse.net wrote:
> 
> First...what is the difference between the DX-100 and
> the DX-100B 
> 
> =====
> Glen, K9STH
> 
> Web sites
> 
> http://home.comcast.net/~k9sth
> http://home.comcast.net/~zcomco
> 
> 
> 		
> __________________________________
> Do you Yahoo!?
> Yahoo! Mail - 50x more storage than other providers!
> http://promotions.yahoo.com/new_mail
>