[Collins] low out on 17 meters

[Bob and Sue Jefferis]

Dale,

Just adding to Jerry's insight. In case you are not intimately familiar with the 32S-3, you should be able to get full scale grid drive in "TUNE" mode with the "MIC GAIN" control between 10:00 and 11:00 O'clock if the unit is in good condition and properly tuned (and aligned).   In "Lock Key" mode you should be able to get full scale grid drive with the MIC GAIN set between 12:00 and 1:00 O'clock. Of course, you do not want to leave the unit at full scale grid drive very long unless you have a spare set of PA tubes on hand (hi).

73, Bob. KF6BC

73, Bob, KF6BC
On Jun 23, 2011, at 10:51 AM, Dr. Gerald N. Johnson wrote:

> Getting maximum power out of the PA will require moving the loading 
> control to a lower value that the 50 ohm mark. But the problem may be 
> low drive to the PA also. Check that to see if you can drive PA grid 
> current in the tune or CW position up like it does on 15 meters.
> 
> If you can't get the PA grid current on 17 meters its probably a sign of 
> not quite perfect tuning rack tracking. That tracking is set by the 
> relative slug positions and is less critical on the bands with each 
> having adjustable trimmers. The complete cure is to do a complete rack 
> alignment starting with preset capacitor positions on 80m and peaking 
> the slugs. The trouble with such a complete alignment is that there's a 
> fair chance of some capacitors being stuck and so not readily adjustable 
> without a whole lot of work. I think what I'd try is to work with only 
> the band D trimmers and try to find a setting of the capacitors that 
> allows decent drive on both 17 and 21 MHz adjusting the rack knob for 
> each band. This is compromising the tuning, not fixing the tracking, but 
> fixing the tracking can turn into a excessive amount of work with some 
> stuck trimmer capacitors.
> 
> I suspect the 17 meter tracking can be improved on from that book start 
> on 80 meters with the trimmer capacitors set to 2/3 C, but each tweak of 
> slug means a total realignment. Typically to make tracking circuits 
> track we adjust the slugs at the LF end, and the capacitors at the HF 
> end and they interact. If I was going to do that, my LF would be 17 or 
> 14 MHz on band D and my HF would be 21.4 or 21.6 MHz still on band D. 
> Then with the tracking worked up, for those bands, I'd have to adjust 
> the trimmers on 80m contrary to the book's instructions and on all the 
> other bands.
> 
> 73, Jerry, K0CQ, Technical Adviser to the Collins Radio Association.
> 
> On 6/23/2011 9:33 AM, yash at aol.com wrote:
>> 
>> 
>>  The max I can tune on 17 meters is around 60 watts  75S-3/32S-3,  the 17 meter crystal is in the D-1 position and the receiver is controlling the transmitter. tried moving the crystal to transmitter,no change.Is there a solution for 17 meters or is this the nature of the beast?
>> thanks for any help on this.
>> 73 dale wt4t
>> 
>> 
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