[ARC5] ARC-5 T-20 Frequency coverage and other questions

[Mike Everette via ARC5]

When I made a 160 meter transmitter from a BC-457, I put 2 mc at the top end of the dial and played with the tracking adjustments until 1.8 mc came in at the middle.  As mentioned before, the VFO and PA coils were completely rewound, except for the small coil inside the form of the VFO coil.

Seems like I recall that even with the rewound coils there was a problem with getting 1.8 mc at the very bottom and 2 mc at the middle, and still getting the PA to track with the VFO; so I settled for 2 mc at the top and it worked fine.  At least over the 160 meter band.  1.8 mc was dead on the halfway point of rotation.  The VFO low end was 1.6 mc but I don't think I ever tried to make the VFO and PA track all the way down.  Didn't need to anyway; I had no interest in running a "Poyrit" broadcast station.

This transmitter actually worked a bit better than getting on 160 with a retuned 2.1-3 transmitter.

As for the tuning caps in the transmitters, I think all of them from the 3-4 mc through the 7-9 mc use the same tuning caps and air padders.  Not quite sure about the 2.1-3 but it may be the same as well.  The ARC-5 transmitters covering 500-800 kc, 800-1300 kc, and 1300-2100 kc are very different, though, with regard to variable caps.

73

Mike
WA4DLF

 
--------------------------------------------
On Thu, 7/31/14, David Stinson <arc5 at ix.netcom.com> wrote:

 Subject: Re: [ARC5] ARC-5 T-20 Frequency coverage and other questions
 To: "AKLDGUY ." <neilb0627 at gmail.com>, "J Mcvey" <ac2eu at yahoo.com>, "ARC-5 List" <arc5 at mailman.qth.net>
 Date: Thursday, July 31, 2014, 8:06 AM
 
 Moving the MO down a full
 MC would not give you 
 KC-for-KC dial
 calibration.   As you go up or down in 
 frequency, the change per degree of rotation
 also changes.
 The T-20 covers 1300 KC for a
 full rotation.
 The T-19 covers only 1000, so
 your dial calibration 
 would not track over
 even a short range.
 
 I have
 moved T-20 and BC-457 down to 80 mtrs before
 but don't remember how much I changed the
 MO cap
 or the PA padder.  I do remember I
 removed the lock screws
 and I could move the
 MO down enough with a small screw
 driver
 through the hole on the side, so it didn't need to go
 
 "full mesh."  Neither did the PA
 padder. 
  I put 4 MC at the "top"
 end of the scale and 
 made a "tuning
 chart."  Worked well.
 
 GL OM ES 73 DE Dave AB5S
 
 ______________________________________________________________
 ARC5 mailing list
 Home: http://mailman.qth.net/mailman/listinfo/arc5
 Help: http://mailman.qth.net/mmfaq.htm
 Post: mailto:ARC5 at mailman.qth.net
 
 This list hosted by: http://www.qsl.net
 Please help support this email list: http://www.qsl.net/donate.html