Gates Radio H-5078 Transmitter/Exciter

[W2WDX]

Hi all,

Ok ... I'm sure you all saw the eBay auction. I won the GATES RADIO TRANSMITTER H-5078.

So ... even though it seems like a pretty straight up thing, does anyone have any knowledge or documents for this thing. I haven't gone to pick it up yet so I haven't seen it, but based on the photos it looks like a straight up band-switching HF AM/CW transmitter using what maybe either a pair of 6V6 or 6L6 modulating a single 6146, maybe? My guess is 25-30W output. (I does say 50W input on the back panel.)

It does appear to have an Oscillator, but I wonder how frequency is sourced. Is it a crystal (and what type) or does it use a VFO input (or both).

There seems to be a relay in it, but of course not sure as to the precise function. Also it looks like the audio input has been modded from low impedance to high impedance, so I will have to explore just how that was done.

I'm gonna take the thing and do my usual once over and restore it, so any knowledge out there would be a great help. Documents or a link to some would be great. Google yielded nothing in that respect, and the "BAMA" site had nothing.

Just in case anyone is wondering, this transmitter is for my use and it will not be offered for resale through my business.

Can't wait to check it out, get into the thing and get it on the air.

Some images below.

Thanks in advance,

John W2WDX

Images From eBay Auction

Gates Radio H-5078 Transmitter/Exciter

Click on Images for Larger Views

[ke7trp]

That is really neat.  Sorry I cant be of help but it sounds like a really neat transmitter.

C

[w1vtp]

Congrats!  Looks like a 6146 from the top view.  Variable inductor suggests a PI net out.

Sounds like a fun project for a good restore - take you time with this.  Maybe Pete can help you with the manual

Al

[W2WDX]

It's interesting for sure!

I just don't know what market Gates was marketing this for. I did find a price list for Gates dated 1958 and it shows the price as just over $12,000, so it was hyper-expensive for a low-power Shortwave AM transmitter. Consider that a BC-5P one the same price sheet cost about the same. Very odd.

(Oops ... I just noticed I have the wrong model, this is a M-5078, not 5076. Ignore the above. Looks it sold for about $595 in 1958. Still that would be about $4600 in today's dollars!)

It does look like the relay is used as T/R. There are 2 SO-238's on the back and a coax is coming from near the relay. So maybe it's T/R for a receiver output. I guess I'll find out.

Yeah I thought that looked like a 6146, and judging from the input power, that's the most likely candidate. It could also be one those 8xxx series industrial tubes similar to the 6146. It's is probably a Pi Net out, like you say. It looks like a variable plate tune cap, roller inductor & a vari-cap with a switched fixed cap bank for loading.

It looks like there may be a BNC connector at the rear on the side where the Oscillator is, which may be a VFO input. I know from the price sheet they mention a crystal for sale for this. The key input is already on the front panel. The voltages seem to come in via a Cinch-Jones connector. This thing reminds me of a Clegg Zeus.

Well I guess we will find out for sure soon enough!

John

[W7TFO]

If you haven't tried already, call Harris in Mason/Quincy and ask for the publications person.

I have bought some really obscure paper from them in the past.

They also have a military-contract operation in Florida, if it is still functioning.

73DG

[WA3VJB]

This guy came up in a search by brand and model number, as having a book for $10.

Nationwide Radio & Eq. Co. LLC
Mark Olson "President"
1490 Norfield Rd
Suamico, Wi. 54173
 
Email: ke9pq@new.rr.com
Phone: (920) 434-8097
Before 9:00 PM Central


From the paint scheme and the logo, that looks like it dates to the early-mid 1960s.  I wonder if that is an exciter deck for one of their larger HF rigs, and it got separated from the rest of the transmitter.  I have an old Gates catalog, and this site may reveal it too.  It may never have been sold as a stand-alone item, so that could explain why it's not turning up in broader searches.

http://www.hallikainen.com/down/

[W2WDX]

Follow-up ...

I just found the complete Gates catalog from 1958. I'm downloading now. The first 100 pages did have the schematics for all the radios, so hopefully the part I'm downloading now will have at least a description and maybe a schematic for this radio.

The site is slow, slow, slow (63kb/s) so its taking forever!!! Ack!

Maybe once I get the complete download I'll up it to my website and put the link in the documents section here.

John

[W2WDX]

This guy came up in a search by brand and model number, as having a book for $10.

[content deleted]


From the paint scheme and the logo, that looks like it dates to the early-mid 1960s.  I wonder if that is an exciter deck for one of their larger HF rigs, and it got separated from the rest of the transmitter.  I have an old Gates catalog, and this site may reveal it too.  It may never have been sold as a stand-alone item, so that could explain why it's not turning up in broader searches.

http://www.hallikainen.com/down/

Ah yes ... very good. And I have dealt with Mark before. $10 seems reasonable. I'm going to keep looking online though, but it's good to know.

It's the hallikainen site I am downloading from right now! ftp://www.hallikainen.org/pub/bh/ It is listed as a separate transmitter in the 1958 Gates price list, so it dates back to right around the time Harris bought them. Probably just before since the Harris name isn't on it.

Thanks.

John

[W2WDX]

One thing I do like about it is the Mod transformer seems to be the largest transformer in the box!

John

[K6IC]

John,

I cannot add anything meaningful.

But,  it looks like a very sporty rig ..  handsome.  Have fun with it.  Vic

[KE6DF]

I found a couple pages of info, but they are too big to upload.

Tubes:

6146 final
6AG7 xtal oscillator
6AQ5
12AU7 x 2 audio amps
6L6 x 2 Modulatiors
5R4 rectifier
OA2 x 3

[W2PFY]

Anyone have any idea what it's intended purpose was?

Maybe an early studio link from a ball game?

[W2WDX]

What's odd about it is its an HF rig (2-32mHz) and low power. So I suspect it's an exciter for one those huge Gates HF amplifiers.

[W2WDX]

Ok ...

According to the Gates catalog (no schematic BTW) it's a standalone continuously variable HF transmitter. It came with a handheld carbon mic, has built in PTT with a relay for switching the receiver antenna line. High Level Class B modulation, 100% duty cycle! Two crystals with selection on the front panel.

The 1958 catalog says its range is 8-32MHz but this one is obviously is set-up for 2-32. (It may be a typo in the catalog.) They claim a frequency accuracy (using the ovens) of .005%, and .02% without the ovens.

Each cabinet measures 14.5"W x 9.5"H x 11.5"D, so it's relatively tiny. Both cabinets together weigh 80lbs.

It seems what we have here is a commercial quality Ranger with 100% duty cycle.

Interestingly, they also made several other PTT HF radios, this one being the smallest, up to a 700w input monster called a CMW-1. Two 100TH's Class B modulating a PP pair of 100TH's in Class C. Audio is comprised of a built in low level mic pre (Class A), 600ohm input and a built in Limiter, Phase inverter and then PP through several additional stages.  All this packed into a single 84" high rack. And it's PTT!!! Hmm ... I need to find one of those too!

I'll go get the thing and shoot images as I go through the restore and post it somewhere, maybe in the Restoration section on the board.

So if anyone finds a schematic let me know.

Thanks again,

John, W2WDX

[N0BST]

There was (maybe still is though likely unused now) a broadcast auxiliary services band (for remote broadcasts) up around 26MHz.  May have been designed for that use.  Still, even by the late 50s VHF Marti units were taking over.

Scott Todd

[The Slab Bacon]

IIRC, Gates (and Harris) made "commercial" HF stuff as well as broadcash stuff.

That thing may have been used for ship to shore or aeronautical applications, especially if it is set up for PTT from the factory.

[KA3EKH]

No way can I ever see something like that being used for a remote or RPU function. There was or still may be a 26 MHz allocation under broadcast auxiliary but only ever seen that used for old first generation wireless microphones and them being FM. Marti appears to have had many old tube transmitters and receivers that date back to the late fifties and sixties so any wireless remotes back then were VHF and you also have to remember that in the old days of radio before the brake up of phone company you would buy dry pairs from the phone company for all your remotes. When I was in high school I worked as an assistant engineer and one of my jobs was setting up the little mixer at the remotes and testing the phone line or patching the phone line into the system back at the station. From what I recall the station paid about $6 per remote for each dry pair we got from the phone company and often that would include sending out a phone company employee to install the drop at the remote location. Places you used a lot like car dealerships and sports stadiums already had drops there but remember doing the setup for the state fair each year and the phone company would run a line to our location regardless of where we were.  Cannot imagine what it would cost today if you tried to get a dedicated dry pair installed. So the heavy use radio RPU stuff did not start until after 1980 today Marti VHF and UHF is all we use in this market for remotes. in the bigger markets where HD radio has been deployed they have had to go to things like Zephyr ISDN systems or other bidirectional junk because of the delay that HD introduces so a lot of the Marti stuff is being dumped now, in a HD world you cannot do real time remotes. Know it has nothing to do with the mysterious Gates box but just wanted to tell another boring radio story, maybe the Gates thing is one of the early examples of the government sales side of the company and an ancient ancestor of Harris Falcon series transceivers?