Vintage Motorola HT220's

[RFI-EMI-GUY]

Thanks for the memories! I did some cleanup on the HT-220 today and did an internal inspection and was very pleased to find the inside is pristine and from what I can tell untouched. The cover seals were intact and no signs of any water intrusion at all. Clean as a whistle. I did see a broken ground off the main board final amp that can be very easily resoldered. Other than that it's in excellent shape. The plan is to get rebanded down to 2M. It's in the right band split. Whoever had this radio took very good care of it. The channels were labeled PD, PW and FD so maybe a village manager or something. All simplex so possibly a small town perhaps.

The case is perfect. No scratches, scuffs or cracks. Some Simple Green with a toothbrush to remove the grime and some denatured alcohol to remove some old dymo label goo finished off with Armor All and the case looks almost new.

I did get a quote back from Bomar. $40 a crystal and a $100 minimum. I'm going to try Quartzlab as well. I've heard some good things about them and their pricing is half of Bomar. They just have a 30 day lead time.

What I can't find is the crystal specs from Motorola or the frequency formula.

I did send an email to Edison Fong this afternoon asking if he still has any access to any service manuals. I'm coming up dry on that effort so far.

I worked for Motorola in Schaumburg in the late 70's into the early 80's right out of college. Good times. Saw lots of neat stuff being developed there.

Don't quote or blame me on this but I think for a VHF radio TX is Fo /9 and RX is (Fo -11.7)/3.

Check the installed crystals for marking and see if it makes sense to the current simplex operating frequency.

Also those radios had two options for high and low side second IF injection so you might have an 11.xx second oscillator that the manual tells you to shift to another +/- the 2 times the second IF freq. Nobody ever pays attention or changes that. I may have one or the other of those crystals in my small crystal collection. I dont think the selection affects the RX crystal calculation. But I could be wrong. The crystal formula was printed at the bottom of the schematic as I recall.

I would not try to tune one without the manual or at least a schematic and layout. Bob Hicks could probably do it by memory. I used to tune them but now, I have to read a manual to tune a simple MX-300. You probably won't have to tune IF coils. If you do, make sure you use a Sinadder.

To make a correct 50 Ohm RF connection for the antenna required a mystery Z adapter. I had several at one time, but long gone. If you don't have that, make your final tuning into a proper antenna for RX off the air, and TX field strength. If you lash up 50 Ohms, it will be wrong.

What split is it in? I thought 150.8-162 was common.

 

[K9RPL]

Thanks for the tip. The main board has two crystals, 16.345 and 16.800.

Your formula works for TX but I have to substitute 16.8 instead of 11.7 to get the right RX crystal frequency as installed in the radio.

This radio from what I can tell is the 150-162 split. The channel frequencies are in the 154MHz band.

I was able to get a hold of Ed Fong and he said he thinks he might have a manual. Fingers crossed.

Im looking for someone who can still do the rebanding for me. THe hands and eye aren't what they used to be. Besides, I don't have the gear anymore either.

 

[K9RPL]

Decided not to reband it. Too much trouble. Going to leave it as is and look for one already converted. I'm going to enjoy seeing it at my desk everyday...

 

[RFI-EMI-GUY]

Thanks for the tip. The main board has two crystals, 16.345 and 16.800.

Your formula works for TX but I have to substitute 16.8 instead of 11.7 to get the right RX crystal frequency as installed in the radio.

This radio from what I can tell is the 150-162 split. The channel frequencies are in the 154MHz band.

I was able to get a hold of Ed Fong and he said he thinks he might have a manual. Fingers crossed.

Im looking for someone who can still do the rebanding for me. THe hands and eye aren't what they used to be. Besides, I don't have the gear anymore either.

So 16.8 MHz is the first IF frequency? I am more familiar with UHF so probably guess that wrong. Then 16.345 is your second LO frequency to get you a 455 KHz second (final) IF frequency.

154.xxx/9 = 17.1xxxx TX crystal, (154.xxx -16.8) / 3 = 45.7xxxx RX crystal. Do you have TX and RX crystals that follow that convention?

I don't know how well a 150-162 range radio will tune to 146 MHz . You could probably drop in a set of MURS crystals and get it working with minimum tweaking.

It is a shame that the 70's did not get put on the internet!

 

[RFI-EMI-GUY]

If you do get it working some Lithium Ion cells will make it work well.

 

[K9RPL]

i checked the existing crystals and your formula matches exactly if you use the 16.8MHz. TX in the 17MHz range and RX in the 45MHz range.

The 150-162 won't tune to 2m directly, it has to be converted. I did find out there are some government units that had frequencies in the 148MHz range and don't need the conversion. I chatted with Ed a little while ago hence my decision not to reband. But the idea of MURS is interesting. The radio already has crystals in that range already. Hm...

 

[K9RPL]

I got a set of MURS crystals ordered from QuartsLab in the UK. Six weeks to delivery and $40 each including shipping. Not cheap but they had all the correct data on he HT-220. If these work I'll probably order anther set. I also found a set of PL reeds for a good price I may have a lead on a radio that's aready on 2M. Fingers crossed...

It's been a *long* time since I've worked with PL reeds. Can someone refresh my memory on the socket config. I don't remember if they should only be plugged in one way. The socket isn't keyed on the PL Deck. Also, anyone got a lead on the schematic for the PL Deck on the HT-220? My service manual is for a Carrier Squelch version.

 

[rja1]

Have some memories about these Motorola bricks. I was part of a large influx of new hams to the local repeater club in the early 90's. There was a group in the club who looked down their noses at the newbies. We soon discovered that these people were not open to any new ideas & there was lots of fighting about club politics. One of the newbies ran for club president & won. The original group was furious & tried to make trouble. They were mad we had speakers come in & talk about ham radio related stuff.

One of the newbies made available HT-220's set up for our repeater, maybe 10 or 15 of 'em. When the bs from the old guard got really bad, all the newbies left the club & formed another club, the "QSY Society." Several of us who had the HT-220's got them set up for simplex operation..........on the original clubs repeater INPUT frequency. shortly after, we were at a nearby hamfest & sold 4 of these to a fellow who has a small cab company........all his employees spoke spanish. Boy, was it fun listening to that repeater for a good while.

 

[K9RPL]

Oh, you're a baaaaaad boy 😂

 

[a417]

Those suckers were built like tanks.

I used one to beat thru a plate glass window during a fire at a store in downtown Cincinnati.
Not even a scratch on it after that abuse.
I still carried it for years after that.

Saw one used as a wheelchock on a brush truck, once.

 

[K9RPL]

Saw one used as a wheelchock on a brush truck, once.

Ouch...

 

[RFI-EMI-GUY]

I got a set of MURS crystals ordered from QuartsLab in the UK. Six weeks to delivery and $40 each including shipping. Not cheap but they had all the correct data on he HT-220. If these work I'll probably order anther set. I also found a set of PL reeds for a good price I may have a lead on a radio that's aready on 2M. Fingers crossed...

It's been a *long* time since I've worked with PL reeds. Can someone refresh my memory on the socket config. I don't remember if they should only be plugged in one way. The socket isn't keyed on the PL Deck. Also, anyone got a lead on the schematic for the PL Deck on the HT-220? My service manual is for a Carrier Squelch version.

As I recall there were Vibrasendors and Vibrasponders. The HT200 uses a Vibrasponder to generate and filter a CTCSS tone. The socket was not keyed. I think you could plug in either way. Think of it as a 1:1 transformer with a tuning fork as the magnetic core.

G & G Communications

 

[K9RPL]

Yeah, It's a Vibrasponder. I don't remember having to worry about which way to plug it in but wasn't 100% sure. Thanks.

 

[RFI-EMI-GUY]

Yeah, It's a Vibrasponder. I don't remember having to worry about which way to plug it in but wasn't 100% sure. Thanks.

Some of the older radios used a large copper "banana" Vibrasponder that was a tone controlled relay. It was unreliable and Bramco developed the later version Vibrasponder that we are all familiar with.

A historical and technical overview of tone squelch (PL, CG, QC, CTCSS, etc.) systems.

When I worked at Motorola, one of the engineers had a motorcycle and apparently had an ignition noise problem. He made RF chokes from cut off copper Vibrasponder housings and slipped them over his spark plug ignition leads.

 

[K9RPL]

Copper housings? Those are *really* old school!

 

[K9RPL]

Just thought I'd update this. My QuartSLab crystals for MURS came in and they work just fine in my HT-220. I'm ordering another set...

 

[rescue161]

I have a crystal on the way for an old Minitor 1. During my search for Minitor parts, I was reminded how much I loved the HT220 and MT500, so I found a few MT500's and plan to have the recrystaled using QSL. I got 2 MT500's in the mail so far and I had forgotten how big these radios were. I can't wait to start using them on my GMRS and ham repeaters.

 

[Falcon9h]

God, you guys are bringing back memories!! In the 70's I never had the $$$ for an HT-220... I lived in the NY/NJ metro area so at any average hamfest there was the "New York Crowd" as I called them that had legions of 220's, exotic 12 channel jobs from Portable Clinic with multiple PL's, really heady stuff, and if you were rich enough to have one, crowds would gather around you. One guy had *three* on his belt. "Theres the crowd, must be 220's!" And it would be. Jealous is an understatement!
I remember hearing talk that the feds would wander around hamfests looking for hot 220's. Everyone got real cautious for awhile. There were fests all over NJ then. (moved away in 04 so don't know what there is now, plandemic and all that)
10 years after the fact I had my own stable of 220's, all mint and perfectly tuned up, effin' beautiful. Now I wish I'd kept every last one, but synthesized radios were coming around and I got caught up in that. I even scratchbuilt a 12 channel setup out of obtained parts, from the ground up. *Individually* wired each coil on my fabbed circuit board and crystalled it up. Got really good at tuning them, and I was a good "microsurgeon."
Money still dictated Bomar over ICM at the time and I'd go right to the factory in Middlesex to pick them up. Really hot redhead worked there at the time 😍. I understand ICM went out of business?
But then the next seduction came along, MX, Saber and the rest. Still have Sabers lying around but no programming capability anymore.
That's my 220 story. Thanks ever so much for calling up the memories! 👍👍
God, I can't believe that was forty some-odd years ago...

 

[xmo]

After Motorola moved HT220 production from Schaumburg to Ft .Lauderdale, Spectronics ended up with a ton of HT220 boards. They would sell them to licensed hams for $100.

For about another $100 you could order all the parts to make it into a radio - a great deal if you were a ham.

There might have been some - ummm - "abuses" by entrepreneurial hams that taught Motorola to not make that mistake again.

 

[WPXS472]

Well, it seems Motorola didn't learn their lesson after all. I remember several times seeing boxes of GP300 manufacturer reject boards at Dayton. An acquaintance made and sold quite a few "parts" GP300s.
I was told that a HT220 fell of an ocean going ship once, to be recovered months later. They washed the salt water out of it and it worked. Supposedly. I kind of believe that is an HT220 urban legend. I once worked on a UHF 220 convertacom model that had lived its life in a mine of some sort. I spent hours trying to clean what looked to be iron dust out of the thing. Never did get it going. I hope I never see another one. The VHF 1 freq., either slim line or omni were good solid radios. I repaired several, and re crystalled quite a few. My favorite Motorola hand held is the MX300. Easiest to repair were the HT90/HT440. Back when I worked for the government, I used to get them by the box full. The owners would wait until they had a bunch before sending them in for repair. Oh, those were the days.