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Grant XL question

Who knows...maybe the Washington has been jacked up and I'm seeing the difference between a well tuned radio (the Grant) and one that has simply been peaked (Washington)?

I calculated loss through coax (100 feet of RG-8)...the Grant is down to around 2 watts, while the Washington is still nearly 4 watts...and the Grant has no where near the swing of the Washington.
 
i dont have a answer to you problem other than whats been said already . but just for comparison purposes , my washington swings/modulates about 16-17 watts PEP . i have a variable deadkey and can adjust it from half a watt up to 4 watts . it might could do another few watts i wanted to push it , but id rather have the cleaner signal and let it coast along . i let the 500V do its job when i need or want more power .
 
The Jerk said:
Well I did t again last night just to verify...set the Grant up, tried to talk to a local friend about 8 miles out...nothing. Hooked up the Washington within 30 seconds and was "almost eight S-units" at his end. I have no reason to think he is jerking me around, he could care less which radio I use...he's a good guy. Now, I'm not saying his S-meter isn't generous, but going from not being heard to being heard without problem...

I am using a Dosy TR-1000...the meter's reading is relative I know, but it does provide some reference.

I was also thinking about the antenna vs dummy load thing...the antenna is a constant, not a variable, between the radios. How would an antenna, that is not changing, cause two radios to react differently? While it might not provide the same reading as a dummy load, that load should not change by swapping radios around? I mean, I could see an issue trying to use a mobile, but this is a fixed dipole.
Click to expand...

for him to hear a 5w radio @ 'almost 8 S units' and NOT hear a 4, 3, 2 even 1 watt radio 'not at all', suggests a problem with HIS rcv. not your xmit. the db vs watt has already been adressed here, so 'S8 with 5 watts' would equate to 'S4 with 2.5 watts;. of course, not too many radios read S-units in even numbers, so now i'd be skeptical. anyway, if his rcv is so far out of align & S-meter VR turned UP to account for weak signals.....well MAYBE then he wouldn't hear your XL. rcv-wise, the XL is superior to the washington, & a STOCK xl probably is, too. a WELL modded XL is by far the better radio. i'd look into the XL some more.....and maybe find another radio-check partner.
 
Well; lets see...

If you are using decent 'RG-8' coax - like Belden 8237 (it helps to specify; as ALL RG-8 is NOT the same quality. eg: Radio Shack RG-8 is HORRIBLE and Belden 9913Flex is xlnt - both are RG-8), you will have a 4 watt loss at the antenna with a 100 ft length of coax. The reason I got 4 watts of loss is because I put in the value of power of your PEP - which should be swinging around 18 watts PEP - not your deadkey power. A Grant XL is equivalent to the Cobra 148GTL - in that it has a single-final output with the same output device.

However, all of this doesn't add up to a spit in the river - as this isn't the problem. Clearly, there IS something wrong with the Grant XL. All other things being equal; it should do close to the performance of the other radio - if not the same or better. At 6-8 miles away - he should be hearing you fine with either radio. Is there anyone close by you that can check your radio out? Maybe the final device is having a problem? That would be my guess.

Either that - or your 'friend' is jerking you around. BTW - is your handle 'The Jerk'? Maybe he is playing you. With a handle like that - you should encounter SOME goofing around. OK, OK - let's say he isn't jerking you around (just kidding around - too!). Seriously; there MUST be something wrong with that radio. There is no other explination that I can see. Unless you haven't said anything else that would play in here...
 
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i agree rob, something is wrong with the grant.

The Jerk, (i hate calling you that, but its your screen name so... LOL)

even though your wattmeter says the grant is putting out 3 watts carrier; its not smart enough to know what frequency that 3 watts is actually at.

for example, each CB radio has a low pass filter built into it after the final amplifier stage. its job is to let the 27mhz signal through while attenuating the harmonics at 54mhz, 108mhz, etc...

if there is problems with that low pass filter circuit, it might be attenuating the 27mhz signal while letting the harmonics through.

so, while your wattmeter shows 3 watts, we dont know if that 3 watts is actually at 27mhz or whether its at 54, 108 etc...

the wattmeter may not discriminate between freqs, but your antenna sure does. so, you can easily see how trying to push a 54mhz signal through an antenna that is tuned for 27mhz would severely limit how far the signal gets out.

this is all a guess on my part, but its the only thing i can come up with to explain why a 5 watt radio gets an S-8 and a 3 watt radio cant be heard.

so, lets do a little test. not sure where this will lead us, but at least we'll be closer to an answer.

hook the washington up to the SWR/wattmeter and straight out to the antenna. no low pass filters, amps, or anything else in line.
just radio-SWR meter- antenna.

measure the SWR using the meter built into the washington, and post it here.
now measure the SWR on the dosy TR1000 and post that here.

now do the same thing with the grant. radio- SWR meter- antenna.
measure the SWR on the meter built into the grant, then on the TR1000.

now hook up your system like this: radio- low pass filter- Wattmeter-antenna.
yes, i want the low pass filter to be BEFORE the wattmeter.
record the deadkey wattage of each radio and post the readings here.
lets just deal with deadkey readings here until we get this sorted out.
no sense throwing modulation in there just to confuse things more.

post all of those readings here, and lets see if that tells us anything.
who knows, maybe they will all be fine and we'll be back at square one.

again, SOMETHING weird is going on here, and i just want to get closer to figuring out what that is.

im very interested to see what you find here,
LC
 
Rob KI6USW said:
Well; lets see...

If you are using decent 'RG-8' coax - like Belden 8237 (it helps to specify; as ALL RG-8 is NOT the same quality. eg: Radio Shack RG-8 is HORRIBLE and Belden 9913Flex is xlnt - both are RG-8), you will have a 4 watt loss at the antenna with a 100 ft length of coax. The reason I got 4 watts of loss is because I put in the value of power of your PEP - which should be swinging around 18 watts PEP - not your deadkey power. A Grant XL is equivalent to the Cobra 148GTL - in that it has a single-final output with the same output device.
Click to expand...



The RG-8U is .404"D, 95% shield, Made in USA stuff the local shop sells...it has a stranded copper center (looks to be around 16ga) and a copper braid shield...not sure of the brand, but this particular shop seems to sell decent stuff.

If I had to guess, I'd say it was Belden...but it should be imprinted with the name?

I really need to buy that 259B...
 
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loosecannon said:
i agree rob, something is wrong with the grant.

The Jerk, (i hate calling you that, but its your screen name so... LOL)

even though your wattmeter says the grant is putting out 3 watts carrier; its not smart enough to know what frequency that 3 watts is actually at.

for example, each CB radio has a low pass filter built into it after the final amplifier stage. its job is to let the 27mhz signal through while attenuating the harmonics at 54mhz, 108mhz, etc...

if there is problems with that low pass filter circuit, it might be attenuating the 27mhz signal while letting the harmonics through.

so, while your wattmeter shows 3 watts, we dont know if that 3 watts is actually at 27mhz or whether its at 54, 108 etc...

the wattmeter may not discriminate between freqs, but your antenna sure does. so, you can easily see how trying to push a 54mhz signal through an antenna that is tuned for 27mhz would severely limit how far the signal gets out.

this is all a guess on my part, but its the only thing i can come up with to explain why a 5 watt radio gets an S-8 and a 3 watt radio cant be heard.

so, lets do a little test. not sure where this will lead us, but at least we'll be closer to an answer.

hook the washington up to the SWR/wattmeter and straight out to the antenna. no low pass filters, amps, or anything else in line.
just radio-SWR meter- antenna.

measure the SWR using the meter built into the washington, and post it here.
now measure the SWR on the dosy TR1000 and post that here.

now do the same thing with the grant. radio- SWR meter- antenna.
measure the SWR on the meter built into the grant, then on the TR1000.

now hook up your system like this: radio- low pass filter- Wattmeter-antenna.
yes, i want the low pass filter to be BEFORE the wattmeter.
record the deadkey wattage of each radio and post the readings here.
lets just deal with deadkey readings here until we get this sorted out.
no sense throwing modulation in there just to confuse things more.

post all of those readings here, and lets see if that tells us anything.
who knows, maybe they will all be fine and we'll be back at square one.

again, SOMETHING weird is going on here, and i just want to get closer to figuring out what that is.

im very interested to see what you find here,
LC
Click to expand...


Not sure where you got that I have a low-pass filter...maybe because I asked about them at one point?

The setup is radio, a Mini-8 jumper, Dosy R-1000, 100 feet of RG-8U, and my dipole. All I do is switch the jumper from radio to radio...

The SWR is the same for either radio...the SWR is approximately 1.4:1 for both radios, on channel 14. There is no SWR meter in the Washington, but there is in the Grant...its showing 1.5:1.

baby005.jpg


As you can see, very basic shack...
 
well, im back to stumped then. LOL

yes, i thought you had bought a low pass filter because i remembered a previous thread where you had asked about them.

your problem does not make any sense.
usually when a problem doesnt make sense, there is something that is found later that seemed to be unrelated at the time, but ended up being a direct cause of the problem.

im afraid there is not much more i can help you with without being there to actually look inside the radio and see the setup with my own eyes.

can you run both radios in your vehicle and get a couple of radio checks from there?

or maybe take the radios to someone else's house and use their setup to get a couple of radio checks.

who knows, im out of ideas for the moment,
good luck,
LC
 
The Jerk said:
The RG-8U is .404"D, 95% shield, Made in USA stuff the local shop sells...it has a stranded copper center (looks to be around 16ga) and a copper braid shield...not sure of the brand, but this particular shop seems to sell decent stuff.

If I had to guess, I'd say it was Belden...but it should be imprinted with the name?

I really need to buy that 259B...
Click to expand...

I like coax that has a foil around the center insulator and full braid. Velocity factor should be as high as your wallet can afford. I use the Belden 9913Flex - which is roughly equivalent to the Times/Microwave LMR-400.

Since both radios showed a 1.4 to 1 match; that pretty much eliminates the antenna/coax system as the problem. So - it points the finger clearly at the Grant XL. Since you have another radio to test in this system, and if that should work OK - it will prove conclusively that the Grant XL has a problem.

LC is right about the meter reading ALL power coming thru it - including harmonics. Which may skew what power it is really putting out. Either the Grant XL needs to be tuned up - or a final transistor is at fault. Using a filter between the radio and your watt meter will determine that the power entering the meter is seeing just the 27 mhz range - and NO harmonics. If you have one or can borrow a decent one - it may help to diagnose the radio's output reading. Personally, - I think it is the final. It is a common problem that can happen to anyone at almost any time. You never know when one will snap until they do...
 
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thanks for the flowers rob.
yes, you understand exactly what i was trying to determine with the low pass filter in front of the wattmeter.

IDK, he's got me perplexed on this one.
something strange going on inside that grant for sure.

TJ,

dont you dare figure out what the problem is without telling us! LOL

i need closure here!
LC
 
Hopefully I can drop both radios at DTB on Friday...if he doesn't hate me now...

The entire reason I started this thread was because I read both radios sort of share a similar chassis...I know the Washington has a 1969 final, and I'm pretty sure the Grant does too. Therefore I expected both to perform similar, and if they had, I would use the Grant...much to my surprise, there is night day difference. I know that I'll never see the wattage from the Grant as I would my Uniden 76 (also DTB tuned, and doing even slightly better than the Washington), but I expected a little better performance than what I'm seeing from the Grant (or am I grasping here?).

I know that meters are only a reference...that's the reason I was wondering if the Washington had a screww driver in it at some point, and it was just cranked up; whereas the Grant was tuned properly and I was seeing real watts (if that makes sense)...I know nothing of the history of this Washington (but it does have extra channels, so someone was in there for sure).

I will pull my other Grant from the car tonight...see what it does on my setup. I know it talks good...I use it almost every day.
 
Well...it doesn't appear to be the radio...at least not from a problem.

Hooked my spare Grant up, keep in mind this is adjusted to drive a 2-pill TS350. Just shy of 2 watts, and swinging less than 5. It drives my amp perfectly.

But I was also still unable to make any contact, even to the main highway less than 0.5 miles..its one step below a major interstate with heavy truck traffic..

So I guess between the loss from the cable and low power, that's my problem.

And obviously this Washington has been modified.
 

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