Changing frequency range of Galaxy DX959

[epicenter]

Hello I recently bought a Galaxy DX959 CB transceiver and it performs very well on 27MHz. However I would like to modify it to be able to listen to other bands, like 28-30 mhz, 21, 14 or 7 Mhz.

It is my theory that I can swap the crystals in the radio for others at differing frequencies to change the freq range, and add switches to pick a crystal. However, the radio contains 3 crystals. What's each one's purpose? Do AM and SSB have their own? Is tx freq set by a different crystal than rx?

This seems to be the theory on which 'viagra' a/b boards are designed but I would prefer the cheaper and more fun approach of crystal swapping on my own.

Current plan is to change xtals and view the result freq on the onboard counter.

Another idea is to find where the frequency from the xtal in question goes, and replace it with the output of my pulse generator (10hz-124MHz) but I am unsure this will work as it is not a sine wave output.

Thanks for any ideas!

 

[loosecannon]

im sure that a crystal switching arrangement could be breadboarded up to give the radio different bands of 40 channels.
that is the possible part of what you want to do.

the problem lies in all the tuned circuits down the line from the PLL section.
for different reasons, each of these circuits is built with a specific bandwidth of operation in mind.

yes, they can be broadbanded a bit, but the range of this type of radio is about 2-2.5mhz max.

so, if you want to change the radio to work on 7-9 mhz, yes, it could be done, but you would end up having to change most of the parts in each of the tuned circuits to do it, among many other changes that would have to be made.

anyone who has the knowledge to work out all the math to do such a thing could build their own 7-9mhz transceiver with less headaches.

sorry, its just not gonna happen,
you're not alone though, many have had this same idea,
LC

 

[Wire Weasel]

Well spoken Mr. LooseCannon sir.

Now you listen to him epicenter before he goes OFF on you

 

[Robb]

Agreed.
It wouldn't be worth the effort to do it.
A CB is a CB is a CB. What is the point in making it something it is not. Knock yourself out if you must to prove something to yourself.

If you want more frequencies, get a HF rig and be done with it. Unless you want to learn more about radios and electronics, then I can understand that. Let us know how that works out. I have a 959 -actually a Ranger TR-696FD-1(same thing)- and it is stock as far as freq's go. If you want more radio than what you have, get a AR-3500/CPU controlled freq selection and be all over the band. Or a nice 10/11 meter export radio like a OmegaForce or a Galaxy DX99V or something similar. One of the best uses for a low-output radio like the 959 is to use it with a low-drive amp. They modulate OK on AM and SSB is OK too.

 

[n0zna]

you can change xtals,it will be low on recieve.I does work.I use a old 23 ch Cobra 138 in my car for 10 mtrs.It isnt a power house.5 wts USB...but it works.73s de JW

 

[loosecannon]

oh yeah, forgot to mention; if any of you know where the heck to order the crystals that would be needed, please let me know!!!

i dont know of any manufacturer in the US that still takes individual orders anymore.

anyone?
LC

 

[Robb]

Try this site. Lotsa stuff like what you are looking for.
Crystals, oscillators, filters, precision crystals, TCXOs and more from International Crystal

 

[sp5it]

Change x3 crystal. This gonna do the trick.
Mike

 

[V8Vega]

These guys built mine several years ago, but I think they still do custom orders.
Crystals, oscillators, filters, precision crystals, TCXOs and more from International Crystal

 

[ButtFuzz]

Changez-Les (or yet another way to skin said cat)

I'm assuming a few things here:

1. Radio has RCI-8719 PLL and n code of that PLL can be modified. 2n - 1 yields one hundred twenty-seven 10 KHz "channels" or 1.27 MHz bandwidth.

2. existing n codes are most likely 91-135, and the maximun the radio can be taken "down" in freq by simply modifying the PLL is somewhere around 160 KHz, or 26.815 MHz.

So... Maximum range without changing mixing crystals is ~ 26.815 to 28.045 or thereabouts. That doesn't get you up in the 10 meter novice/tech ssb phone band from 28.3-28.5.

If we changed the mixing crystal to yield overall frequencies 450 KHz "higher", we would then cover from approximately 27.265 (ch 26) to 28.495 with the standard 2 switch PLL modification.

I'm not so sure that is worth it.

How 'bout you have a tech install a custom kit, with custom mixing crystals? Instead of the standard 40 below -- FCC 40 -- 40 above scenario, You could have FCC 40 -- 40 above - (28.300-28.750).

That radio should easily be broadbanded enough to to that... maybe a tiny bit of tweaking will be in order.

As far as changing crystals to make it, essentially, a general coverage receiver? Maybe not such a good idea...

Have fun, and if you need me to calculate the additional mixing crystal values for you, I'll be more than happy to do so.

Rob

 

[26TAZZ]

I thought that may be a way like the old cobra 148 and using the crystal 11.325 but I don’t know if will work on a galaxy dx-959

 

[nomadradio]

Simpler on the 959. Just break the connection between the channel selector and the PLL chip on two wires.

https://cbtricks.org/radios/galaxy/dx959/dx959_freq-mod_1.htm

Channel chart is https://cbtricks.org/radios/galaxy/dx959/dx959_ch-chart_after_mod.htm

73