Magnum 1 unusable on 10M

[PA241TwistedCopper]

I have a Magnum 1 radio that I bought from a CB'er friend. He bout it from Les Comm and never opened the radio.

This radio sounds phenomenal on 11M and the SSB stability is as good as any radio out there. Problem is when I went to check in to our local 10 Meter net, all anyone was hearing was a rush of static with my signal on USB 28.495. Everything looked good on my end. Power out, SWR, modulation... All looked on my end that everything was fine.

After some further investigation, AM and FM modes work great on both 10 and 11M. Also, the closer I go to the CB band, the more the audio comes up and the less static is heard. At about 27.900 or so it sounds pretty good. By 28.300 the audio is audible but covered in static. At 28.495, when I turn the modulation and power way down, my audio can barely be heard by a close station, but my voice was not recognizable.

On 11M, I get great audio reports. Any thoughts about what to look at? Like I said, it's a "Les Comm Enhanced" radio, but Lester would not help me once I told him I was not the original owner.

I have a local tech I can take it to, but some insight would be appreciated. Thanks in advance.

 

[sp5it]

It is narrowband chickenbander. Without switched or varactor tuned circuit it is impossible to achieve good performance on 3MHz bandwidth. Period.
Mike

 

[PA241TwistedCopper]

Actually, it's a 12Meter and 10 meter from the factory.

I have a friend that uses his on both 10M and 11M with no issues, not to mention it works fine on AM and FM.

I could really use some help/guidance, not bashing the product itself.

It is narrowband chickenbander. Without switched or varactor tuned circuit it is impossible to achieve good performance on 3MHz bandwidth. Period.
Mike

 

[sp5it]

No, it is not. it is so-called 10-12m radio to fool FCC to be able to sell it in USA. Face the truth, it is just a chickenbander.
Probably yours was peaked and tuned on 27MHZ causing band edges work poor.
If it is 10M TRX, how to set repeater shift and tone to open them?
Mike

 

[PA241TwistedCopper]

Again, it works 100% on both AM and FM modes on 12, 11, and 10M? Again, I have a friend locally that uses him on all 3 bands with no issues.

It does have the ability to shift and has tones for repeaters, but that's completely irrelevant to this thread.

I say this with all due respect, but please... I really don't need your chickenbander rhetoric and preconceived fallacies. I am a general class operator and get a little weary of ham operators that think of responsibly operated CB as the Antichrist. I talk locally on CB, at legal power, because there are no local hams that talk locally, regularly. I also have an RCI 2950DX that is capable of 12 THROUGH 10M and it is flawless doing so.

If anyone has anything useful to add, I would greatly appreciate it.

I sincerely hope this guy's attitude is not representative of this entire forum.

 

[BJ radionut]

maybe see what your buddies name is listed under and see if Lester did a video on that specific radio and find out how he modified or changed it when ordered???

 

[w9cll]

Actually, it's a 12Meter and 10 meter from the factory.

Actuallly Sp5it is correct, that rig was never really intended to operate on 12 or 10 meters. That being said I have no doubt is can be adjusted to operate there decently. Whatever was done to it to make it an 11 meter rig needs to be undone and restored closer to factory performance.

 

[Low_Boy]

My guess is with the others. Less tuned the radio for 11. meters and it needs to be retuned. Probably best to tune it near 27.4050 MHz and it will do 10 and 11 meters.? Just my thoughts.

 

[Robb]

Even Cobra 148's will exhibit this issue if the chassis isn't broad banded by changing out a few disc caps in the appropriate places after hacking the PLL for more channels or even changing the xtal; then re-tuning of the TX coils become necessary. So i wouldn't blame the radio per se - or any radio that had been hacked and then subsequently incorrectly tuned.

 

[PA241TwistedCopper]

It's obviously misaligned, but I am certain it can be corrected. Many of these Magnum 1s work fine on all 3 bands. Mine won't, not because the radio is incapable, but because a hack misaligned it.

I was hoping someone would have an idea what might be out that SSB is the only mode affected.

My guess is with the others. Less tuned the radio for 11. meters and it needs to be retuned. Probably best to tune it near 27.4050 MHz and it will do 10 and 11 meters.? Just my thoughts.

My guess is with the others. Less tuned the radio for 11. meters and it needs to be retuned. Probably best to tune it near 27.4050 MHz and it will do 10 and 11 meters.? Just my thoughts.

 

[BJ radionut]

http://radioaficion.com/cms/magnum-1-tune-up/

http://www.cbtricks.com/radios/rflimited/magnum_one/Magnum 1 - Variables1.pdf

 

[nomadradio]

If someone has "tweaked" it to optimize 11-meter power output, that can screw up the other bands that it's meant to cover.

AM and FM modes are often more forgiving of small alignment boo-boos. SSB signal quality is more easily affected by a marginal circuit fault.

Does make it sound as if some circuit is becoming unstable on those frequencies. Not a common fault, but possible.

Some kind of measurement that narrows down what's malfunctioning could be helpful. More than one way to make a SSB transmit signal sound terrible.

There's a "Tuneup info" page here: http://www.cbtricks.com/radios/rflimited/magnum_one/index.htm

Doesn't look terribly informative. I would at least try "tuning in" the radio's PLL output on a receiver that covers 16 MHz. Set to CB channel 1, it should feed 16.27 MHz into the receiver and transmit mixer sections. A coax jumper with the sleeve backed away from the plug will get you a half-inch long 'sniffer' antenna for the receiver. If you can tune it in using SSB mode on the external receiver, set it for a steady tone pitch. Key the mike and see if that steady tone gets disturbed.

If it does, the PLL could be the root of what you're hearing.

73

 

[PA241TwistedCopper]

Th

If someone has "tweaked" it to optimize 11-meter power output, that can screw up the other bands that it's meant to cover.

AM and FM modes are often more forgiving of small alignment boo-boos. SSB signal quality is more easily affected by a marginal circuit fault.

Does make it sound as if some circuit is becoming unstable on those frequencies. Not a common fault, but possible.

Some kind of measurement that narrows down what's malfunctioning could be helpful. More than one way to make a SSB transmit signal sound terrible.

There's a "Tuneup info" page here: http://www.cbtricks.com/radios/rflimited/magnum_one/index.htm

Doesn't look terribly informative. I would at least try "tuning in" the radio's PLL output on a receiver that covers 16 MHz. Set to CB channel 1, it should feed 16.27 MHz into the receiver and transmit mixer sections. A coax jumper with the sleeve backed away from the plug will get you a half-inch long 'sniffer' antenna for the receiver. If you can tune it in using SSB mode on the external receiver, set it for a steady tone pitch. Key the mike and see if that steady tone gets disturbed.

If it does, the PLL could be the root of what you're hearing.

73

Thank you!

 

[9C1Driver]

Again, it works 100% on both AM and FM modes on 12, 11, and 10M? Again, I have a friend locally that uses him on all 3 bands with no issues.

It does have the ability to shift and has tones for repeaters, but that's completely irrelevant to this thread.

I say this with all due respect, but please... I really don't need your chickenbander rhetoric and preconceived fallacies. I am a general class operator and get a little weary of ham operators that think of responsibly operated CB as the Antichrist. I talk locally on CB, at legal power, because there are no local hams that talk locally, regularly. I also have an RCI 2950DX that is capable of 12 THROUGH 10M and it is flawless doing so.

If anyone has anything useful to add, I would greatly appreciate it.

I sincerely hope this guy's attitude is not representative of this entire forum.

You need to realize that 95% of the market for this radio is 11m, all these Export style radio's are. They are sold as (wink wink) 10m and 12m radio's for the sole purpose of getting past the FCC. Once converted and tuned for 11m use some might work up on 10m and many probably won't depending on what has been done to them. Very few hams actually use a 2950 or Magnum 1 for ham radio talking.

By the way, if you think Mike is being hard on you go to an all ham radio forum and ask them for help with your Magnum radio. You probably won't like what 90% of them tell you.

 

[Captain Kilowatt]

I have yet to see an out of the box 10/12m radio not work on both bands at the same time equally well. They ARE broadbanded enough to cover both bands however they are USUALLY tuned by the seller to optimize 11m and that usually ends up with the radio having poorer performance at the extremities of the coverage 1e. above about 28.300 or below 26.300. That has been my observational with these radios anyway. I have heard many that sound fine on both 10 and 12m right out of the box.