Electronics > RF, Microwave, Ham Radio

Whatever Happened to Ham Radio?

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I was lucky a year or two ago when I got a pristine TS-520S with manual from an old guy (ha!  I'm older than he!) who had bought it new in 1975.  It works great.  He said the finals had less than 5 hours on them.

I added a homebrew digital display using arduino; all external, no mods needed to the radio.

A thermal shot of the R-1000.

Wahoo!---I just had a contact on the local 2m repeater with VK6ATX mobile, using the old Yaesu FT411 I picked up, (along with a 2m "brick" RF amplifier, & a couple of small power transformers), for $A50, a couple of Hamfests ago.

The FT411's Nicads had, of course, "gone to battery heaven", but I managed to remove them after a bit of butchery, temporarily replacing them with 2 little PP3 9v Alkalines.
Up to now, because of the non-rechargeables, I have been limiting use of the radio to calling in after the weekly "ham news", so this is its first longish contact.

The 2m repeater is usually dead silent, so it was a nice surprise to hear him calling.

I think I've got the ham virus back, so I will really have to get back into "fix it" mode so I can use the stuff that needs my (currently dead) power supply!
Maybe even fix some non-ham stuff!! ;D


--- Quote from: bob91343 on November 28, 2021, 06:07:47 am ---At one point I owned three R-390A receivers.  I did a few modifications and at the time I thought it was the greatest receiver out there.  If you limit your contest to tube radios, it wins on every level.

That being said, it is eclipsed by my TS-940S.  Not as great a selection of bandwidth, but nearly everything else is better on the Kenwood.

--- End quote ---

can you be more specific? I wanted a r390a for a while and I was interested in how it compares to modern radios. I guess the newer radio is more sensitive? I am wondering what the limiting factors are, since with HF it is normally not noise I think (since atmospheric noise dominates when a real antenna is connected to the system).

The R-390A is a fine radio.  It's big and heavy and runs very warm.  Its mechanical construction is complex and needs occasional service.

The speaker impedance is such that one needs an external transformer to drive most speakers.  The S meter is not calibrated in S units, a minor annoyance.  I don't recall the antenna input impedance, whether 50 Ohms is an option or not.

The frequency stability is not up to modern standards; a long warmup is a good idea.  Nor is the frequency resolution, with one dial division each 200 Hz (vs most modern radios with 10 Hz or even 1 Hz steps).  If I remember correctly, switching from USB to LSB requires some juggling of tuning and BFO dials.  CW seems to require yet a different setting.

I changed mine over to solid state rectification to eliminate the hot rectifier tubes.

Those are the main shortcomings.  As for convenience, changing frequency is a major chore, especially large frequency jumps.  If you are on 75 meters and want to QSY to, say, 20m CW, there is no way to do that quickly.  There can be annoying backlash of the dial, causing differing readings depending on tuning direction.  If you are an SWL, going over the hump at each MHz can really be a pain.

The audio CW filter and the wide selection of bandwidths are a definite plus.  Sensitivity is not an issue, as the incoming noise level swamps the internally generated noise and there is plenty of gain.

When I got rid of mine, I felt a pang of regret.  Now, years later, I don't look back.


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