Grant XL question

[The Jerk]

I have a Grant XL (actually two of them). I am considering using my spare as a base and selling this President Washington I just bought, however; this particular Grant seems to be low on power. I'm seeing around 3 watts swinging to under 7 watts, running at 14.1VDC (regulated 10A supply)...

I know the Grant was "tuned" by the PO for straight AM and was most likely ran hard (knowing the group of people it came from). I had it redone by DTB, full alignment for use on SSB...so its most likely set about as good as it gets.

My question is this: is it possible that the final (stock 1969) is weak from being ran hard on AM? Would having the final replaced gain me anything?

I'm looking for at least similar numbers/performance as the President. The President does 5 watts swinging to almost 15 watts, and there is a definite lack of power when trying to TX with the Grant to another base in the area (compared to the Washington). As far as I can tell, the President is unmodded power-wise (all the slugs still have the factory wax in them)...I would think the Grant should show similar numbers as the Washington??

Both radios were tested sitting side-by-side on the same antenna and watt meter...the only variable is the radio itself. Both have good audio, just one has more power than the other.

I guess I'm trying to determine where to stick my $$ next...do I try to get the Grant, indicated to be the better radio, into similar numbers as the Washington; or do I have the Washington reworked (I know its badly in need of an alignment on SSB) and use it???

 

[loosecannon]

which washington do you have, the one with the 5 pin mic connector or the 4 pin connector?

if its the 5 pin connector, then it is very similar to the grant.
the grant will have a bit better of a receiver in it, but they are basically the same design.

so, either one will be a great base station.

as for the final being weak, i seriously doubt it.

transistors tend to be either open or shorted when they give up the ghost, or start to work intermittently, like it works until the radio gets warm and then it doesnt work.

if you are seeing 3 watts swinging to 7 wattsl that sounds like a stock radio working properly.
sounds like DTB gave the radio an alignment but didnt "peak" the radio for any more wattage, which is fine. a good tech wont do that unless you ask them to.

what kind of difference is the receiving station seeing between the washington and the grant?

just so you know; the way it works is that you have to quadruple your power output to gain 1 S-unit on a receiving station's meter.
given the difference in the power output of the two radios, i would guess that your friend is seeing about 1/2 an S-unit difference, favoring the washington.
i wouldnt worry about that little of a difference.

if you would like to "pump up" the grant a little bit; you can do that yourself pretty easily.
it involves taking the bottom cover off the radio and turning a couple of variable resistors (VR), or "pots".
if you make a mark on the "pot" with a sharpie indicating the position it is currently in, you can just put it right back where it was if you dont like the change.

all you need is a jewelers screwdriver small enough to fit the slot in the VR.
(dont ever use a metal tool on the tuning cans, but on a VR you can get away with it if thats all you have.)

the VR's you are looking for in the grant are VR7 for modulation and VR10 for the deadkey adjustment.

first, adjust VR10 to set the deadkey (carrier) where you want it.
i wouldnt go over 5 or 6 watts, as you will create lots of heat when you get long winded, and you want to leave room for the modulation to increase your power. (if you adjust the carrier too high, your power output will actually go down when you talk. this is called downward modulation)

VR10 is located in the rear right section of the PC board. (radio upsidedown with knobs facing you) its hard to see because of all the wires on top of it.
look just in front of and to the right of that transformer.

VR7 is your modulation adjustment. most people just turn it all the way up and leave it there. then you just use the mic gain control on the front of the radio to set your modulation where you want it.
i remember you being concerned with TVI and bleedover so i must say that this does carry with it the possibility of causing some bleedover. whether or not this is a problem for you is for you to decide.
remember though, that you made a mark so that if there is a problem, you can put VR7 back where it was.
VR7 is located in the middle of the PC board just a bit closer to the right side than the left.

doing these adjustments should give you the ability to set the grant so that the power out is the same as the washington. then you can compare them again and see which one you like better.

if they were mine, i wouldnt sell any of them, as they are some of the best radios ever made IMO and are getting harder to come by.

good luck,
LC

 

[The Jerk]

Well then, I guess I'll have the Washington (5 pin mic) reworked and leave the Grant as-is...

I'm pretty sure the Grant is set up correctly, and I am not going to trying adjusting things since I would probably just undo the work that I paid to have done...

 

[secret squirrel]

If DTB tuned your Grant. Then I am willing to bet he tuned it for best transmit. I would not retune the output, you more than likely not see any improvement in transmission. How does the Grant XL sound on the air

 

[The Jerk]

If DTB tuned your Grant. Then I am willing to bet he tuned it for best transmit. I would not retune the output, you more than likely not see any improvement in transmission. How does the Grant XL sound on the air

I've been told it sounds very good...

I highly doubt I could add much to this radio, other than screw it up. I believe DTB does very good work. Its just puzzling why two similar chassis are dissimilar (although maybe the Washington will be simialr to the Grant when its finished?).

And to answer the other question...the difference at the receiving station is being heard or not being heard at all, there is that much difference between my Grant and the Washington. Its not a matter of S-units, its a matter of being heard or not being heard...the Washington is putting almost 5 s-units on the station that the Grant can't even reach. And again, same antenna, same coax, same jumper, and same meter. More local contacts that can hear each radio can't tell a difference in audio quality (they bot sound good).

 

[freecell]

"I'm seeing around 3 watts swinging to under 7 watts, running at 14.1VDC (regulated 10A supply)..."

an OEM Grant XL @13.8VDC with the mic gain in the fully clockwise position into a 50 ohm load produces 4W of carrier and anywhere from 12 - 18W PEP out of the box, as do most all fcc certified cb radios.

 

[The Jerk]

"I'm seeing around 3 watts swinging to under 7 watts, running at 14.1VDC (regulated 10A supply)..."

an OEM Grant XL @13.8VDC with the mic gain in the fully clockwise position into a 50 ohm load produces 4W of carrier and anywhere from 12 - 18W PEP out of the box, as do most all fcc certified cb radios.

Which is close to what I'm seeing from the Washington...5 watts and around 15 PEP. What would cause the Grant to not produce similar numbers, since they are very similar?

 

[freecell]

making measurements into a reactive antenna system instead of a purely resistive dummy load for one thing. the XL is certainly capable of the same PO as the Washington.

"What would cause the Grant to not produce similar numbers, since they are very similar?"

transmitter alignment.

 

[Sonwatcher]

The Grant XL has the same chassis as the Cobra 2000gtl and 148gtl and Madison. They are single final, dual conversion chassis

I believe the Washington board is the same as the 142gtl and is single final, single conversion chassis.

If you are going to adjust the Washington do not use the same VR's as the Grant xl . They are different.

You can find the info on the Washington 8719 PLL below

CB Mods

 

[loosecannon]

just for the record, i would never suggest that you go into a radio that DTB has tuned and start messing around with it.

the two adjustments i alluded to are very simple to do and can be put back if not wanted. i understand if you dont want to do it, i just wanted you to know what would be involved so if you wanted to have both radios at the same 5 watt key and 15 watt swing and then note the differences, you could.
up to you.

now, as for one radio deadkeying 5 watts and the other deadkeying 3 watts and there being a 5 S-unit difference between the signals is just not possible if all other things are equal. physics doesnt lie.

i call shenanigans on the guy who says he hears a 5 watt radio with 5 S units and cant even hear a 3 watt radio.
watts are watts, and it doesnt matter what kind of AM radio produces them.

get some signal reports from other sources.
if things are as you describe them, the stations should see about a 1/2 S unit difference, (maybe 1 S unit to account for any discrepancies).
thats how the world works and your radios do not defy the laws of physics; i guarantee it.

sounds to me like there is something else going on here.
i agree with freecell that you need to test both these radios into a purely resistive load. (a dummy load)

what kind of wattmeter are you using?

good luck,
LC

 

[The Jerk]

now, as for one radio deadkeying 5 watts and the other deadkeying 3 watts and there being a 5 S-unit difference between the signals is just not possible if all other things are equal. physics doesnt lie.

what kind of wattmeter are you using?

good luck,
LC

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.

 

[Sonwatcher]

How is the mic gain set on the Grant ?

 

[The Jerk]

How is the mic gain set on the Grant ?

The AMC limiter is intact, and the mic gain is set about 1500. It sounds loud through the talkback, and all contacts <1 miles state the audio is loud and clear.

 

[Sonwatcher]

Are you using the same mic on both radios ? I wouldn't go by how loud the Talkback sounds.

 

[The Jerk]

Are you using the same mic on both radios ? I wouldn't go by how loud the Talkback sounds.

Yes, I have been swapping the same RK56 back and forth between these radios...I only have two 5-pins for three radios. The 56 was bought new less than a month ago.