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1-9 of 9 messages
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Just a thought - Convert CB handheld to 10m CW QRP
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by WD4W on April 6, 2007
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I was looking at a stack of CB HT's I have owned for a few decades and thought I would pitch the crystal controlled versions that I probably will never ever use again.
Being interested in recyling and QRP operation I had an idea that maybe I would convert a CB HT to operate on the 10 meter band using CW as the mode of operation.
It would seem to be a do-able task.
What do you think?
- Charles
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RE: Just a thought - Convert CB handheld to 10m CW
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by WD4W on April 6, 2007
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A quick google search turned up this reference:
Convert CB walkie-talkies to 6, 10 or 15 meter operation.
POPULAR ELECTRONICS [1] Apr 1964 (v.20#4) pg. 61
- charles
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RE: Just a thought - Convert CB handheld to 10m CW
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by WB6BYU on April 6, 2007
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Certainly quite a number of CBs were converted to 10m in the past.
You can probably find some inexpensive microprocessor crystals that
will put either transmit or receiver on 10m - the problem is getting the
other crystal so it can transceive. (Unless it is one of the newer crystal
sets that only uses one crystal per channel.)
For CW the first thing you'll want to do is to short out the secondary
of the modulation transformer - they often don't take well to the
abrupt ON/OFF of transmitter current. Then you'll need some sort of
BFO for the receiver and a VFO that controls both transmit and receive,
though the receiver bandwidth is probably wide enough that you only
have to get the receiver close enough to use a variable BFO for fine
tuning.
Or just rip out the insides and build a new transceiver for your favorite
band inside the case. Here are some possibilities:
http://www.phonestack.com/farhan/
http://www.qrp.pops.net/Idaho.htm
http://www.qrp.pops.net/willy.htm
http://www.intio.or.jp/jf10zl/3trssb.htm
http://www.intio.or.jp/jf10zl/3trcw.htm
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RE: Just a thought - Convert CB handheld to 10m CW
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by AA4PB on April 8, 2007
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You can have custom crystals made but the cost for a set is probably so high that you could have purchased a QRP kit with a VFO.
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RE: Just a thought - Convert CB handheld to 10m CW
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by WD4W on April 8, 2007
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Thanks for the input on all of the QRP rigs. I ran across an article that uses the CB finals for a QRP rig, and another were the CB was converted to 10 meter AM only.
I will check out the URL's you included in your post. Thanks again.
- Charles
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RE: Just a thought - Convert CB handheld to 10m CW
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by N3AWS on April 27, 2007
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In the late 70's and through the 80's "73 Magazine" did a number of articles on converting CB's to 10 meters--mostly AM & SSB, but also CW and even FM. Possibly some of your CBs might be these same models, but I would think most of these articles (if you can get your hands on them) would be mostly for ideas only. Parts might be difficult to come by also.
73,
Jim N3AWS
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RE: Just a thought - Convert CB handheld to 10m CW
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by KC8NBD on October 8, 2009
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i have a SBE Sidebander II that quite possibly never saw a day of 11m use. it is converted to 10m. it is a clean conversion...so clean that i am still investigating mods. this is a perfect rig for converting to 10m.
my goal is to convert 3-5 more for matched set. 80, 40, 20, 15, and 6m.
i am looking for a cw kit to add to an am/ssb only radio or the schematics to build it.
also a variable power circuit or kit to control tx power 5w-mw cw 10-mw ssb.
also so many people argue legal/not legal to operate one like this. i think it is a shame to not retrofit a great radio that outlived its original purpose. is this legal for us? 73's kc8nbd QRP! Rocks!
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RE: Just a thought - Convert CB handheld to 10m CW
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by W5FYI on October 8, 2009
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As already pointed out, there were many conversion articles in 73 back in the CB heyday, and I recall at least one that involved moving a handheld rig to 10M AM.
AM is an easy conversion--switch out one crystal and realign the IF cans.
CW was a little more complicated--you had to insert a BFO in the receiver in order to get the CW tone. It also helped to replace the ceramic filter to narrow up the receiver passband, and to be able to adjust the IF in order to tune in the narrow band signals.
There was also the craze of converting CBs to FM, and I believe I read in Bob Heil's book that a handheld CB could be converted to ham FM. (I used Heil's book to convert a $2 used Midland CB to 10M FM and had a hoot, using the rig mobile to talk with stations as far away as Seattle in one direction and Miami in the other from my QTH in Oklahoma). Conversions to FM involved installing an FM discriminator circuit inside the receiver.
If you can find Bob's old book, The 10M FM Handbook, it will really help you with CW, AM and FM conversion ideas, especially if we ever get any sunspots back again.
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RE: Just a thought - Convert CB handheld to 10m CW
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by WB6BYU on October 8, 2009
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It is perfectly legal to operate such equipment on the
ham bands, but modified equipment is not allowed to be
used on CB.
You can send reasonable CW simply by feeding an audio tone
into the mic circuit, as long as you have sufficient
rejection of the carrier and unwanted sideband. In fact,
SBE sold a CW adaptor for the SBE-34 transceiver that
did this. A more difficult mod is to apply keyed DC to
the balanced modulator which will generate CW on the
carrier frequency, but then you need to shift the VFO (or
the carrier oscillator) off frequency to receive on the
same frequency. An SSB receiver will receive a CW signal,
so no modification is required. You can add an audio filter
if you want better selectivity for CW.
While the CB to 10m conversion probably only required a
change of crystal, going to the lower bands will also
require changing the signal frequency tuned circuits
in the receiver and transmitter. You may also find
that some of the RF chokes and/or broadband transformers
don't have enough inductance for the lower bands, and
some bypass capacitors may need to be larger.
You also need to check the frequency conversion scheme:
for example, some rigs use a 10.7 MHz IF, which can be
expected to have problems on 15m (since 21.4 = 2 * 10.7).
On 40 and 80m you'll want to generate LSB rather than USB,
which is actually good because you can simply change
from low side injection to high side injection, but it
means that the tuning will be backwards unless you can
change that, too.
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