Sidebar Sidebar
  • You can now help support WorldwideDX when you shop on Amazon at no additional cost to you! Simply follow this Shop on Amazon link first and a portion of any purchase is sent to WorldwideDX to help with site costs.
  • Click here to find out how to win free radios from Retevis!

Expo 100 expander channel kits info needed

nomadradio said:
Never made a record of the letter codes.

The A kit uses a crystal originally cut for 14.920 MHz to take the radio down 44 channels.

NOT 45 channels like an export radio's band selector. These kits originated in the late 1970s before export radios with multiple bands became popular. The kit's lower band would put channel 1 onto the "40" position of the selector. Same deal for the upper channels, a 15.800 MHz crystal gave you channel 40 with the selector set to channel 1 on the upper band.


When multi-band radios took over the market, they didn't order new crystals, they just added capacitors to the oscillator circuit. One in parallel with the lower crystal to pull it down one whole channel, and a capacitor in series with the upper-channel crystal to move it up one channel.

Just one problem. This reduces the feedback through the crystal, and reduces the output level of the kit. We got in the habit of removing the disc cap in parallel with the lower crystal, and putting a 4.7 uH RF choke in series with the crystal to bring the frequency down one channel. The upper crystal doesn't seem to have this problem in the newer "plus/minus 45 channel" kits.

To go down 45 channels in a radio like the Cobra 29, you want 14.910 MHz, and 15.810 for uppers.

The lower-band crystal in a "C" kit is 11.1758 MHz, the upper is 11.4758 MHz. This kit fits radios that use a 11.325 MHz factory crystal.

The other kit for radios that use a 11.125 MHz crystal like Uniden Washington use 11.2595 MHz for the upper band. Can't seem to find the lower-band frequency. Probably 10.9725 MHz. I think this is the "B" kit.

And the "N" kit is just the "A" with a clarifier circuit and a green wire that connects to the radio's clarifier control.

The A kit is for AM-only radios, the N is for SSB radios.

73
Click to expand...
any idea where I might find an expo kit for a president P300??? cant find any info, thanks
 
the only place I know of that has channel kits now is lesters truck stop in Florida and his sale page is Lescomm I think it is. thought I had a link saved for his site but do not..you can do a google search and it should come up.
here is a link to one he has for sale on ebay. you can message him on ebay and see what he has available for your radio.

https://www.ebay.com/itm/L29-3-LesC...h=item2abca5495f:g:jYkAAOSw-GNb4bKD:rk:2:pf:0
 
Last edited:
hairball-NWPA said:
any idea where I might find an expo kit for a president P300??? cant find any info, thanks
Click to expand...

President P300 is the same board setup as the AX-144, AR144, PC122XL (uPD2824 PLL), so if you wanted an Expo, you'd need an Expo N Kit. But, the sidebands would be off, as there is no provision to add the USB/LSB offsets to the VCO frequency, so you would need to slide the Clarifier one way or the other to get back to center slot.

You could use either a Galaxy Viagra A or B board, both of which have SSB offset capabilities.
The Viagra A has individual coils for each crystal to be offset for each sideband (and AM), and individual varactor diodes for the Clarifier for each crystal.
The Viagra B board uses an MC145106 PLL (SMD) and 2.5kc steps for SSB and AM offsets, and diode programming to change bands, and a single varactor diode to the offset mixer crystal they used in their board for their additional PLL, to tie in to the Clarifier circuit so the B board can be slid with the Clarifier too.
I bought one of each a few years ago when RF Parts still had them, to evaluate them, I put the A board in my PC122XL to test it out, and have since left that project to the side, I never tried the B board.
 
  • Like
Reactions: tecnicoloco and Shadetree Mechanic
snow bird said:
Ok whats the New way? just asking!
Click to expand...
Well to quote a certain CB technician(whom I criticized in the past, not allowed to mention his name by order, don't want to be Killowatted HiHi! But on this issue I agree), according to him those expo boards are crap, and drift. Better off not wasting your time, and get one of those new channel boards that do an end run around the existing PLL, more stable. Even easier buy a Galaxy clone with channels, just saying.
 
  • Like
Reactions: NZ8N
The Expo 100 "A" kits are for AM-only radios.

The "N" kit has the same two crystals, but with a clarifier circuit added. This is why the Expo list specifies it for SSB radios.

If you install the A kit in a sideband radio, you will find that the range of the clarifier is now much too small to be useful on the upper and lower bands.

73
 
  • Like
Reactions: tecnicoloco and NZ8N
sonoma said:
I have looked at them numerous times but never could make my self buy one do to the price. Lescomm has a good kit for the channels and a lot cheaper.
the expo kits are just about all gone. I still have some kits for the galaxy radios and cobra 29 and 148 radios. since I have stopped working on customers radios the kits are just setting.
I have a few radios I have thought about putting them in but never got the urge to do them.
Click to expand...
Sonoma, do you still happen to have any expo kits for the 148 and if so would you be willing to part with one. I know this thread is a couple of years old but I stumbled across it and figured it would be worth a shot. Been trying to hunt one down for months. 73s

Tom
 
Dark star if you install the Expo kit for the 148 radio again you will only be able to tune the radio for AM channels as the xtals for the ssb channels will not tune the ssb range I went through all of this and have a post on here about tuning in for the ssb channels. I have the Expo A kits and S kits I sell on Fb and flea bay all the time, many different versions. The A kits are signal injection and the Expo L and B kits are just a switch to control the correct xtal needed for the band you want again AM channels. Even doing the clarifier to track it is still off. The xtals you need are 11.4758 for 40 high and 11.1758 for 40 low.

If anyone needs Expo A and Expo S kits i have 1 band 2 band and 3 band for the Cobra 29s 25s and many other radios that use the same pc board there are about over 100 radios that the A and S kits will work in. One A kit comes with a 4 position rotary knob that will replace the delta tune switch as its useless in an AM radio.

So anyone you can google dss56cb sales and message me on Facebook or message me here

I also have a post in the for sale area. thanks DJ56 Boston Ma.
 
  • Like
Reactions: Shadetree Mechanic
dss56 said:
Dark star if you install the Expo kit for the 148 radio again you will only be able to tune the radio for AM channels as the xtals for the ssb channels will not tune the ssb range I went through all of this and have a post on here about tuning in for the ssb channels. I have the Expo A kits and S kits I sell on Fb and flea bay all the time, many different versions. The A kits are signal injection and the Expo L and B kits are just a switch to control the correct xtal needed for the band you want again AM channels. Even doing the clarifier to track it is still off. The xtals you need are 11.4758 for 40 high and 11.1758 for 40 low.

If anyone needs Expo A and Expo S kits i have 1 band 2 band and 3 band for the Cobra 29s 25s and many other radios that use the same pc board there are about over 100 radios that the A and S kits will work in. One A kit comes with a 4 position rotary knob that will replace the delta tune switch as its useless in an AM radio.

So anyone you can google dss56cb sales and message me on Facebook or message me here

I also have a post in the for sale area. thanks DJ56 Boston Ma.
Click to expand...
Thank you for that info. I've actually bought an A kit from you on ebay for my 29 and it worked great. I've recently bought the 5 position rotary kit from you for my 148 as you said it would be more stable on ssb than the crystal based board kits. You have fantastic customer service on ebay and I highly recommend anybody interested in these kits to not hesitate buying from you. Thanks again.
 
  • Like
Reactions: dss56 and Shadetree Mechanic
sonoma said:
I have looked at them numerous times but never could make my self buy one do to the price. Lescomm has a good kit for the channels and a lot cheaper.
the expo kits are just about all gone. I still have some kits for the galaxy radios and cobra 29 and 148 radios. since I have stopped working on customers radios the kits are just setting.
I have a few radios I have thought about putting them in but never got the urge to do them.
Click to expand...
Sonoma what did the Galaxy kits consist of was it a pll mod or crystal swap? I know this post is old got nothing else to do but read.
 

dxChat
Help Users
  • No one is chatting at the moment.


      Top Bottom
      Back