wrote:
On Mar 5, 3:26 am, Mike Coslo wrote:
wrote groups.com:


The simplicity was what attracted me to them. No filters, nonotch,
no pbt, no RIT, no - well you get it.

Note that the
75 meter one stops at 3.8 MHz. Heath figured that by
simplifying the output pi network to the most extreme degree,
they could save a few dollars. Coming up with a 50 ohm
antenna was the ham's problem.
The 75 meter rig I have tunes to 4 MHz. It's also a HW22a, probably a
later mod. But all that simplicity is a good thing for a lad raised
mostly on integrated circuits! 8^)

The 75m transceiver is the HW-12A. It runs 3.8-4.0 MHz. That's all
the phone band there was back when the rig was produced.

Thanks for the correction Dave. I should have looked at the back of the
unit when I was composing my email



There's a
mod in one of the mags--CQ, I think--that puts in a fixed silver mica
cap with a little trimmer cap in parallel for making the thing work on
both 3.8-4.0 and 3.7-3.9 MHz at the flip of a mini-toggle switch.
That'd give you a bit more room to roam.

Now there is serendipity for ya! I was trying to align the thing, and
having some trouble with the top end. And the unit had this extra switch
on the front. Since I couldn't find the schematic for the "a" version, I
wasn't sure if that switch was part of th ea version or not. Preliminary
looks made me think that it might have been something to lower the
frequency down to the CW portion of the band. But it looks as if my rig
has that mod .


In it's era, the TS-830 was somewhat of a DXer's and contester's dream
machine.
That receiver has an extra filter slot for cascading filters. One can
still buy after market filters for it.

I can believe that it was very popular. The hybrid concept is
interesting. I especially like that you can turn the tubes off if you
just want to listen.

- 73 de Mike KB3EIA -

On Mar 5, 3:20 pm, Michael Coslo wrote:
wrote:
On Mar 5, 3:26 am, Mike Coslo wrote:

The 75m transceiver is the HW-12A. It runs 3.8-4.0 MHz. That's all
the phone band there was back when the rig was produced.

Thanks for the correction Dave. I should have looked at the back of the
unit when I was composing my email

Not a problem. I'm fairly familiar with the series since I ran them
mobile for a number of years.

There's a

mod in one of the mags--CQ, I think--that puts in a fixed silver mica
cap with a little trimmer cap in parallel for making the thing work on
both 3.8-4.0 and 3.7-3.9 MHz at the flip of a mini-toggle switch.
That'd give you a bit more room to roam.

Now there is serendipity for ya! I was trying to align the thing, and
having some trouble with the top end. And the unit had this extra switch
on the front. Since I couldn't find the schematic for the "a" version, I
wasn't sure if that switch was part of th ea version or not. Preliminary
looks made me think that it might have been something to lower the
frequency down to the CW portion of the band. But it looks as if my rig
has that mod .

If I run across the mod, I'll forward a scan of the information to
you. There was another easy mod which padded the carrier oscillator
frequency in order to roll off some of the annoying high frequency
hiss on receiver, while adding fullness to the transmitted audio. It
had the added benefit of more carrier output for tune up.
Your HW-12A may have that mod as well.

In it's era, the TS-830 was somewhat of a DXer's and contester's dream
machine.
That receiver has an extra filter slot for cascading filters. One can
still buy after market filters for it.

I can believe that it was very popular. The hybrid concept is
interesting. I especially like that you can turn the tubes off if you
just want to listen.

The '830 doesn't get points for being an early hybrid, but it does get
points for having that cascaded filter availability. The early
Hybrids were rigs like the Yaesu FT-101 and variants along with the
Kenwood TS-520 and TS-820. Drake used a hybrid design in the T4-XC/R4-
C transmitter/receiver pair but there was a mix of tubes/solid state
devices in the receiver. The Drake 2-C receiver might have been the
earliest hybrid design amateur receiver.

Dave K8MN