It sounds as though the VFO stops oscillating at 300 and up. Find out the actual oscillation range of the VFO and  listen on a general coverage RX or if you have a counter, connect it to the VFO output and see what's going on. Those rigs are easy to work on.

Dale W4OP

You might find my article on updating the RME4350 in the March 2012 issue of Electric Radio of help.
The OA2 does not require a shield.
I have repaired several of the  ball drives and the article addresses this along with a backlash issue.

GL- a very nice receiver,

Dale W4OP

Hi Terry,
Contact John at:  jlandrigan@pol.net

Excellent silk screening  and great pricing.

Dale W4OP

Although the Alps dye sub cartridges are still available, I seem to recall Alps got out of the printer biz in 2007 or so.
I had seen a blurb saying one of the current printer manufacturers had a white ink cartridge, but I was never able to track it down.

Recently, I did the artwork for a KW Electronics KW-1000 front panel (grey with white lettering) and sent it off to a friend. He silks screened the panel and I must say, it is at least as good as the original.

Dale W4OP

The white paper is a background color- the lettering/graphics would  still be in black or color.
I don't think that white decal paper would look very good on a black cabinet.

Dale W4OP

Hi Jeff,
I regularly copy New England, Louisiana  and the west coast from North Carolina on the current 600M band, very easily.
Of course, like 160M, it's a winter band for anything serious.
Here's a good link to get interested amateurs started:
http://www.500kc.com/
Dale W4OP

I don't have any direct knowledge about that rig, but I have seen that sometimes there is a burr on the shaft and rotating  just the knob a bit may get around the burr. Older knobs  commonly had 2 set screws and I recall loosening one and having the other already somewhat loose (yet initially overlooked by me) and having the same issue.
Perhaps working the knob a bit may eventually get it off.

GL,
Dale W4OP

I have been listening to the current 600M band for several years. With ARGO software monitoring the QRSS gang, you can fit a different station every few Hertz. But I also hear  a lot of beacons and 2 way QSO's. No one is going to use half wave dipoles. Even if you got it up 600' or so, it's still a cloud burner. Loaded Inverted L's seem to dominate for TX while active whips, loops, K9AY's and Beverages are used on RX. Even my 550' long Beverages perform very well down there.

You can buy a transverter from Juma, or Elecraft looks to make the K3 work down there. There are other synthesized TX designs out there also.

It's a fun band full of surprises.

Dale W4OP

Have you put the meter on a bench supply with a current limiting pot and run it through out it's range? Simle test.

Dale W4OP

I well recall as a kid being scared to death listening to the Radio Moscow propaganda sessions and then there was the Moscow Mailbag- I think a lot of those letter were made up in order to forward the Communist agenda of the day- but scarey stuff to an 11 year old, never the less.

Dale W4OP

Monitoring Times still publishes a monthly SW Listener's guide.
I too miss Passport and their reviews.

I enjoy  logging the LW NDB's and also the HiFER stations around 13.5MHz.
Radio Havana Cuba still has their DX/SWL program hosted by Arnie Coro- always interesting.
Then there's the pirate stations below 40M amateur.

Radio Canada International used to broadcast some great local flavor programs in the morning. I haven't listened in a while- my fault.

Dale W4OP

Hi Ken,
I am with you. I have owned 2 SDR-IQ's and find them interesting pieces of test gear, but I don't care for a receiver that has to have a separate computer to run it and no knobs.

That's where the Elecraft K3 comes in. It has superb sync detection and the P3 display is as good as the SDR displays- and no computer required. Now that the VGA card is out, I can see the display from across my lab.

Dale W4OP

I was simply interested in Steve's answer as there were 2 issues in your posts I disagreed with:
1. Resonance improves S/N
2. A narrow band antenna would yield a better S/N than a broadband antenna.

Perhaps you could tell me what part of my posts were in error though.

Dale W4OP

Hi Fred,
While you're in contact with Steve run by him your theory that a broadband antenna will yield  a poorer receiver  S/N than a narrow band antenna.

Dale W4OP

Makes perfect sense. Thanks for the link to Tom.
Again, to think that resonance has anything to do with S/N at HF is to assume that the antenna must "know" the difference between a signal and noise on the channel. To think that an antenna's bandwidth limits sensitivity is also wrong as it is the following stages that determine the ultimate S/N. The only exception I can think of is that if the receiver's IP3 is so poor that the wide range of a broad band antenna might overload the front end. Then again, simple wire antennas are a VERY POOR filter even if narrow band, and modern receivers are not prone to overload.

In addition, Fred has commented that resonance implies  a match (which implies maximum power transfer). As we know, even EWE's, Pennants, and Beverages with their very low gain, still are plenty sensitive for HF. I do amplify my Beverages but only to bring their overall level up to that of my TX antennas, making on-air  comparisons easy.

Back to resonance. Resonance simply means the lack of reactance and has zero to do with a good match or VSWR except for a very small class of antennas.
Imagine, if you will,  a resonant end fed half wave antenna. It's end Z is a function  of conductor diameter and height above ground- but for wire antennas at HF will be somewhere in the 2K--> 4K range. This  is a VSWR of 40:1 up to 80:1.
So it is not only true that a resonant antenna has nothing to do with S/N but also does not guarantee a match or low VSWR.

Aside from dipoles at certain heights, Moxons, closed waveguides with a 1/4 wave probe,  and Half Squares, most antennas are not resonant and/or do not present a 50 Ohm match without requiring  require some sort of matching if they will be used for TX. For RX, it's a non-issue.

Finally, measure the input Z of your HF RX. You will find in most cases, it is anything but 50 Ohms resistive over its spectrum
Dale W4OP