| WB0KWJ |
Rating:  |
2023-09-26 | |
| Transmitter Good/Receiver Bad |
Time Owned: more than 12 months. |
The HW-7 was the second Heathkit I built when I was still a teenage novice class operator in Kansas in the 1970s. All was well except for a bad solder joint on pin 10 of the CA3035 audio amplifier IC. I was unable to trace the problem. The guys at the Heathkit store fixed it in a matter of hours.
The HW-7 looked a lot nicer and more professional than the corresponding Ten-Tec offerings of the time. The competing Ten-Tec unit had an exposed, easily damaged slide rule dial. Electrically, the rigs were not much different from each other.
The HW-7 had a nicely designed, easy-to-use transmitter. The VFO was stable and the dial calibration was surprisingly accurate. The crystal socket is a vestige of the days when novice class operators were still restricted to crystal control.
The receiver was sensitive enough for a rig of its type and time, but also hopelessly prone to microphonics, AC hum, and AM-band interference. I was fortunate then not to live near an AM station. Some operators used batteries instead of an AC supply to alleviate the hum. I used a 10,000 microfarad filter capacitor in parallel with the supply, an exotically high value in those days. The selectivity was controlled by passive filtering. Single-signal reception was not possible.
As with any QRP rig, a good antenna was (and is) a must. A 1 microvolt input would give a readable signal if you were wearing good headphones, which had to be high impedance. The receiver heard both sides of the CW signal. HW-7 operators learned to tune down the band from the top so they would be on the correct sideband.
The defects of the HW-7 were obvious then, and it is probably the case that the HW-7 was put on the market before it was fully tested--or, perhaps, despite testing and what had to be internal protests. As originally shipped, the dial markings quickly rubbed off from contact with the inside of the dial window. A pair of spacing washers behind the front panel, which should have been in the original design, fixed the problem. Heathkit knew of the problem, and gave me a new dial from stock. The sidetone oscillator sounded as if it was having trouble getting going, and even then gave a highly distorted tone. Inaccuracies in the schematic made repair a challenge.
I never had much difficulty with the precise receiver preselector adjustments the receiver required because I replaced the tiny stock Heathkit knob with a much larger one. The problem was that Heathkit used one 365pf variable capacitor to cover the entire tuning range, from 7 to 21MHz, rather an a small variable with switched capacitors and inductors. AC hum in the receiver could be reduced by using a battery. A high-pass filter could help reduce AM band interference. An Army surplus audio filter helped me with the audio selectivity problem. There was little to be done with the microphonics unless the user wanted to replace some of the ceramic capacitors which were serving as piezo microphones. It is hard to get rid of microphonics when your audio gain is 10,000 or more.
Most annoying to me was the insufficient transmitter offset--only about 75 Hz on 40 meters. This was a serious design oversight. The offset was created by transmitter loading, and should have been implemented directly with a switched-in capacitor or varactor diode. An ordinary reverse-biased signal diode or transistor junction probably would have had sufficient capacitance to reliably move the transmitted signal to about 800 Hz. HW-7 operators working transceivers without receiver incremental tuning (very common at the time) would walk up the band as each operator re-tuned to hear the other. I had a selection of crystals, and could get around the problem by calling CQ on crystal control and tuning around with the receiver to hear the response.
The HW-7 was pre-WARC and had only 40, 20, and 15 meters. 80 meters could have been added fairly easily because the base frequency of the direct conversion oscillator was already at 3.5 MHz. 80 meters is a difficult band for QRP because of the antenna dimensions involved. 10 meters would not have been too much more difficult to add, and might have been a more credible choice for QRP. Of course, in those days the song "Convoy" was a hit, and we worried about losing all of 10 meters to CB.
Despite all the limitations, I continued to use the rig occasionally even after earning my Extra class license. I still have it and it still works. Some of the carbon resistors have changed value enough to require replacing. I eventually worked almost all the states and a little nearby DX with the HW-7 and just a 14-AVQ vertical. A friend attached the HW-7 to his triband beam on a 50 foot tower and worked a station in Japan on 15 meters on a day of friendly propagation--an impressive feat given the 1.5 watts of output on 15 meters. Perhaps more impressive was hearing Japan in the receiver.
If the ratings were based on sentiment -- reflecting the time that there we still had Heathkit stores and a multi-band transceiver kit was a reasonable one-day project for a teenage ham -- the rig would get a "five." Objectively, the "two" rating reflects the combination of a "four" for the transmitter and a "one" for the quality and implementation of the receiver.
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| WD4LNW |
Rating: |
2015-05-08 | |
| More Fun with Transmit Offset |
Time Owned: more than 12 months. |
This is a follow up to my previous review. Since I have worked with the HW-7 for a while now, I can say that I really enjoy using this rig more since I added a small circuit to achieve a 750hz transmit offset on all the bands. I was able to make a few contacts with the stock radio, but now it is much more fun and I almost always get a reply when I call. Back in the 1970's the bandpass of most receivers were not as narrow as they are today. So, if you work QRP, you better be pretty close to zero beating the other stations you intend to call. My stock HW-7 had almost no transmit offset on 40 meters, nearly 1300Hz on 20 meters and 400 hz on 15 meters. I chose to build a small circuit modeled from an old ARRL article and refined by Rich, KR7W. The other improvements I made were to set a fixed side tone level and to add a receiver muting circuit. Now when I am sending, the side tone is more pleasant and I no longer hear loud thumps when I'm keying. I realize a lot of you will not see any point in going to all that much trouble, but I enjoy a challenge and I wanted to make my HW-7 more that a bookend. All these mods were completed without drilling any holes in the circuit board.
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Earlier 4-star review posted by WD4LNW on 2014-01-21
I have been in amateur radio for 40 years now, and owned all kinds of HF gear, but never tried an HW-7 until recently. I can see how someone's first impression with the receiver is not good, but it takes practice learning how to tune this radio. A DC receiver is prone to feedback and overloading, and without a balanced mixer, will not reject strong AM broadcast stations if not tuned properly. I bought my HW-7 on ebay a couple weeks ago and before I hooked it up, went through the alignment procedure in the manual. One of the two final transistors was bad, and I had one in my parts bin here...no big deal. Output is less than 2 watts on 40 meters and about 1 watt on 20 and 15. Properly setting the preselector is the key to making the receiver work. Plan on spending a while getting the hang of the HW-7 . I found what really helps is to run this rig through a fully shielded antenna tuner as this helps reject signals from other bands. The first time I transmitted I got 599 reports from a station in Texas. Since then, I have worked California, Maine and the Midwest. If you take time to understand how to make the receiver work for you, you will enjoy the little radio. |
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| K9MHZ |
Rating:  |
2013-12-10 | |
| Junk |
Time Owned: more than 12 months. |
| Don't buy this radio....it's not worth it. There's a reason why Heath came out with the HW-8 after a few years.....people were pretty disgruntled with the hum and microphonics. The receiver wasn't particularly good, and the preselector is pretty pathetic. There are many much, much nicer QRP rigs to choose from....just avoid this thing. You'll be glad you did. |
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| N2DTS |
Rating: |
2013-12-09 | |
| good in its day |
Time Owned: 3 to 6 months. |
My first radio, bought new from heathkit over in Philadelphia, built in a day.
I worked many stations on it, got a 15 meter beam and put it in the roof, and worked people out west, many great contacts, then I got an HW101.
I suppose I did not know how bad it was back then... |
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| WB2JNA |
Rating: |
2010-11-26 | |
| Not all that bad |
Time Owned: 0 to 3 months. |
I recently bought a used HW-7 and have been having fun using and modifying it. I have found that the side tone is bad but you can disconnect it at capacitor C45. The unwanted shortwave station reception can often be eliminated by adjusting the preselect. The transmit offset on 40 meters is too small, about 40 Hz I'm told, but if you tune the signal you're calling close to the top side of zero beat (about 200- 250 Hz) it seems to work out OK. I've worked several stateside and European stations on 20 and 40 meters in a few weeks of casual operating, and all with about 2 watts out and a dipole that's half inside my apartment. You may find the T/R relay operates erratically, but it can be bypassed with an external switch. If you buy one, try to get a schematic! I have found this to be a fun little rig for casual operating and modifying.
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| K7SZ |
Rating: |
2010-08-18 | |
| Heath's 1st Gen QRP Rig |
Time Owned: more than 12 months. |
| I built my first HW-7 in 1972, while stationed at Lajes Field, The Azores (1936 Comm SQ). I finished it up on Superbowl Sunday and split my attention between listening to AFRTS' broadcast of the Superbowl Seven on radio (and Mercury Morris break a 1000 yrd rushing record) and listening to 40M CW!! My first QSO was with a VE in Scarsboro Ontario, Canada!! He refused to believe that I was QRP!! I lived on base just below the base MARS station, CWU-20, and every time they went on the air on or near 20 or 40M the HW-7 RX would get wiped out!! Took it to a Field Day in 1973 on Lake Thunderbird outside Oaklahoma City (stationed at the 3rd Mob) and made a couple of Qs, but nothing serious. All in all it was a rather feeble attempt by Heathkit to market a QRP rig, but they made up for the horrendous record of the HW-7 when they trotted out their HW-8 transceiver a couple years later. I had a lot of fun with that HW-7 but it was a lot of work using that really poor receiver. Never had problems with the rig other than that. |
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| KE7WAV |
Rating: |
2009-05-11 | |
| Oldie But Goodie |
Time Owned: 0 to 3 months. |
I inherited an HW-7 and checked out all of the reviews about the radio then fixed it up to use. I have a few pointers to share for those who look at these transceivers.
-Hum If you want to get rid of it good grounding is an absolute must as well moving the power supply as far away from the rig as practical. Do this and bye-bye hum!
-Tuning This rig can hear both sides of the signal start at the top of the band and tune down and use only the side you hit first. If you pass the zero beat you have gone too far!
-Preselector Tune in carefully and take your time, switching out the stock knob for a bigger one can only help. $2 well spent if you ask me. It will really struggle with interference and weak audio without carefully peaking the preselector.
-Answer CQ's or tail-ending a QSO are your best options. You can call CQ but remember to tune up a little to hear the station calling you and then stay put; don't lose your contact by fiddling around. Also if the station is really weak chances are you'll sound even weaker to him; call the stations with a solid signal.
-Have fun, don't get frustrated just relax and have fun.
Finally, I love this rig it is fun to hear your call coming back from a station 1200 miles away and getting an RST of 569, when you are using 3 Watts fed into a homebrew dipole up 11 feet! These rigs are classic and fun, but not the greatest in the world. |
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| WB0FDJ |
Rating: |
2008-12-20 | |
| Simple as can be |
Time Owned: 0 to 3 months. |
| My cousin was planning on getting his ham ticket and built one of these radios. He brought it to me to put on the air to "check it out". It had some problems: receiver sensitivity was pretty lousy on all but 40 mtrs. (Don't think he ever got that problem reversed) So I hooked it up to my 14AVQ (which had all of about 6 radials!) seriously doubting that the thing would be heard next door. I still remember the shock of having two enjoyable QSO's with hams also in the midwest and reasonable RST's. The basic idea of the radio was OK but it's importance now is more historical: it lead to the much better HW8 and 9. For me it lead to me buying my first new-in-the-box rig, a Ten Tec Argonaut 509. |
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| N6KYS |
Rating: |
2007-03-03 | |
| Terrible receiver section |
Time Owned: more than 12 months. |
| This thing is terrible...deaf receiver, microphonics on the cabinet. The transmitter portion isn't bad, but the receiver design makes it miserable to use. Get an HW-8 or 9 instead! |
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| KB3LFC |
Rating: |
2004-07-20 | |
| Great old rig |
Time Owned: more than 12 months. |
While there may be lots of room for modification improvements, I used my old HW-7 "as is" in the late 1980s and early 1990s (when I was KC3YD) to work a lot of DX. I used the gray peth to work a 2XQRP with a JA station several days a week for about two weeks and worked most of Eastern Europe and Russian Oblasts on 40 Meters after the BCB stations would start shutting down.
I bought the old rig from a ham for $10. He was convinced that QRP was "a worthless waste of time." It was the best $10 I ever spent.
Presently, this fine little rig is in a rented storage bin but I plan to dig it out before winter sets in. Right now I'm using an HW-9 and I do have to admit it is a lot easier to usethan the HW-7 and has a little more "soup" power wise. The previous owner added a digital freq display and the WARC band packs, something the HW-7 certainly lacks.
When zero beating a frequency you have to 'tune up" on the signal to go back to the operator. I have had QSO's with the HW-7 by simply calling CQ, by "tail-ending" a QSO, and of course by answering a CQ call. I have even had a few operators tell me that I was "BSing" them about being QRP. They simply couldn't believe my 1.5 watt signal wasn't 50 or 60 watts.
A "final." Don't bother asking me if I'm interested in selling my HW-7 -- I'm not.
Tom Mitchell KB3LFC |
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